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Das Fun-DLC wurde mit folgenden Inhalten angekündigt:

Fun Pack DLC Contents

CARS

  • Audi Sport Quattro S1
  • Citroën DS3 RX Supercar
  • Renault R5 Maxi Turbo
  • Ford RS 200 Evolution
  • Audi EKS RX Quattro WRX
  • 1969 Ford Bronco 'Brocky'
  • Mustang RTR Spec - 5D
  • Mustang '66 RTR.

TRACKS

  • Circuit De Barcelona-Catalunya Rallycross
  • Brand Hatch Rallycross Historic.

Sehr geil, freue mich. Das Rallycross Zeugs macht unglaublich Spass

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Physics of the Japanese Car Pack DLC

Datsun 280ZX Turbo AAGT: You guys are gonna like this one; it’s a total hot rod. There’s not a ton of historical data for it as reliability issues kinda hindered its racing career, but we can look past that and just let it run strong as it did at its best.

AAGT was IMSA's take on Group 5-style regulations to get some new, interesting cars entered in the series. It allowed any engine to be installed in any chassis so long as they were from the same manufacturer. So here we have a 4.2L V8 from the Nissan President Limo, tweaked and tuned with the biggest turbo they could find. The lazy, 200hp road car engine ends up here with something in the range of 940hp@7500rpm when using full qualifying boost pressure of 36psi. It was good for 208mph at Daytona, fastest in a straight line in a field which included a number of Porsche 935 K3s.

Other than that, it wasn't the greatest car to be honest (hence the short racing career). Suspension is basic struts at the front and simple wishbones at the rear; nothing fancy but it makes for predictable handling. Power runs to the rear through a 5-speed Hewland and ZF-type clutch & plate differential; I expect they at least experimented with a spool to help put down the huge power in a predictable manner, like in the 935s. Aero additions with that massive bodywork on the rear end are mainly to help with high speed stability. I’m sure it was good for modest net downforce on the rear, but overall this thing was dominated by aero drag. Weight was 200kg heavier than a Porsche 935, so it didn't corner particularly well and it burns through tires quickly. But, man, is it a hoot to drive and it can hang pretty well on tracks that favor top speed.


Honda Civic Type-R: Nothing too fancy here other than being a well-polished FWD hot hatch design. It's a lot like the Megane RS275 with 30hp more and independent rear suspension, or like the A1 quattro with 50hp more and FWD only. Fun, fast little car. 310hp doesn’t sound like a lot these days, but it arrives in a useful manner and the 6-speed manual is geared so each ratio is properly spread for track use; no extra-long highway gear on this one. It is prone to the usual FWD behavior when driven hard and pushing the 235 rubber - a bit of torque steer, a bit more lift-off oversteer. Personal best here so far is a 7:53 at the Ring on sticky semi-slick tires, so that real world target of 7:43 is surely in reach for the faster drivers amongst you all.


Nissan Skyline GT-R BNR32 Group A: Godzilla, right? The fundamentals of this car are actually quite similar to the R34 we have in game. FIA’s historic database of old homologation forms was a valuable source of information in putting this one together.

Suspension uses a neat multi-link setup in the front where the steering axis is separate from the links which control bump/rebound motion. Sorta halfway between a strut, Ford's Revoknuckle concept, and a traditional double wishbone. Gives really compact packaging, 100% camber recovery, and a nice steering axis. Cool stuff. Rear is nothing unusual; just a fairly ordinary multi-link design with a lower A-arm. Again, same basic geometry shared with the R34 car.

Engine also has a lot in common with the R34’s RB26 2.6L-turbo straight-6 and is the real killer feature for the car. Early in its racing life, this thing was putting out over 600hp @ 3bar and just destroying the competition. That performance was pegged back somewhat with extra weight and intake restrictors, which is a method we’ve copied here. Two 33mm intake restrictors hold power to ‘just’ 490hp and is near max power in a range all the way from 6000rpm right up to the 8700rpm rev limiter.

Was generous in the aero model and gave it a bit of downforce (very small amount) with modest drag levels. Research showed most comments on the Group A version were that the front makes some lift and the rear wing gives good downforce to the rear, so expect a moderate amount of aero-induced understeer...on top of some mechanical understeer thanks to the strong front bias to weight distribution of 60%. The suspension setup compensates somewhat by being stiff at the rear to encourage low speed oversteer. Interesting combination which is apparently also used by few modern GT3 cars.

Cool thing about these Skylines is that they were, at the heart, RWD and the AWD system was computer controlled to engage a clutch in the center and lock the two axles together only when the rear axle started to lose grip and spin. Our model is set up the same way, just with simple friction and viscous clutch action mimicking all the electronic control in the middle. Funny thing is that Nissan tested the Ferguson system (as in the Lotus 56) early in development of the Skylines as it does mostly what they were after - no lock until axle speed difference is above some threshold - and the system they ended up making basically does the same thing, just with massively more dynamic control where the Ferguson system was fully passive.


Honda 2&4 Concept: Neat to see a concept car that truly works as designed! The reference material Honda provided had great detail of the suspension geometry - including spring and anti-roll bar rates - so that very little guesswork was needed in taking this from experimental concept to something that actually works on track.

Didn't pull any tricks in the suspension design from the CAD reference and it works quite well with the BAC Mono dampers. The simple chassis structure, known mass and known components made it easy to approximate weight distribution at roughly 53% rear and center of gravity height at a mere 30cm above ground without the driver on board. With driver, these number shift to around 53% rear and 28.5cm high thanks to sitting so low and far back in the car. Another neat finding is that the offset chassis and driver position combine to just about cancel each other out for any lateral weight bias. More signs of this as a radical yet functional concept. Nice one, Honda.

The RC213V is a pure MotoGP race engine, which usually brings about some uncertainty as to claims of power level and such, but this one was fairly simple to put together due to the customer versions of the same thing on the market. All research signs point to it being a very strong unit matching the claimed 220hp at 13,500rpm and a fat power band keeping it above 190hp for everything north of 10,500rpm. A VFR1200F DCT does the job of putting that power to the ground through too-skinny rear tires. I say ‘too-skinny’ because 220hp is a lot to manage(!) and, despite 56% rear weight, the rear rubber only has a 51.7% bias in width. It’s still a lot of grip and it is stupid fast - almost on pace with GT3 at Long Beach where top speed isn't vital - while rewarding smooth driving. Don't overcompensate in slides; it'll probably correct itself if you don't add more energy with big inputs. Really fun drive so long as you keep it smooth and let the car do most of the work. 

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Physics of the Fun Pack DLC

Ford Bronco RTR 'Brocky': Drivetrain for this guy is a classic off-road racer setup. Engine is a Ford Performance Z427 cranking out 600hp@6500rpm and 560lb-ft@5000rpm. Power goes through a stock TH400 three-speed automatic and transfer box to give either RWD or 4WD -- You can use the center ‘diff’ Spool to toggle this in setup. Spool=Yes for 4WD and Spool=No for RWD. The final drive ratio has a setting for the transfer box low range gear, but really this is only useful for rock crawling. There are also some optional TH400 gear ratio sets you can run, but the real thing is stock as is default setups with the 2.48, 1.48, 1.00 gear ratios. Typical differential setup Vaughn uses is a spool at the rear and ratcheting locker in the front.

We had the real Brocky scanned for art production and this proved ideal for drawing up the long-travel suspension geometry, even the 4-link solid rear axle works great over its 18" range of travel. The complete truck weighs in around 4500lb with about a 50:50 weight distribution. Motion ratios of the suspension mean it balance well with a 650lb/in front main spring and 200lb/in at the rear. Dampers are matched to some similar King units, but there is a big adjustment range in these things depending on the type of terrain being driven. We’ve gone fairly stiff and digressive for the rallycross tracks present in game, and that seems to work pretty well.

Thing is maximum fun at the RX tracks. It's about 4-5s slower than the RX cars, but being so big and changing direction so much more slowly makes it all feel like a real event as you slide around. It becomes a beast in RWD mode; not fast at all, but great at doing donuts and it drifts like a champ. It's neat how responsive it is to setup changes. You get something completely different with AWD, max ride height of 40cm and balanced anti-roll bars versus lowering it some, changing to RWD, and setting up the ARBs like a circuit racer. Very big toy truck.


Audi S1 EKS RX: This one was fun to assemble as Audi sent over some wonderful reference details. The suspension geometry - struts all around as usual - has some interesting anti-dive/lift/squat properties which combine with springs which are a bit stiffer than some other RX teams use. Set up with 400lb/in springs on all corners and big front anti-roll bar makes it handle almost like a soft, tarmac road course setup. That matches up pretty well with how we can see the chassis move in recent race videos. No complaints here; it drives great with all that information applied.


Audi Sport quattro S1: Great fun researching this car; it's famous enough and cloned enough that there is quite a lot of information for it on the web. The more you read about it, the more amazing it is that it worked at all! They basically started with an Audi 80 and kept cutting bits out of the middle until the wheelbase was only 2.2m to try and make the handling more nimble. That works in theory, but being an Audi you still have the engine slung way out beyond the front axle, so early homologation versions had horrible weight distribution like 62% front. Moving the cooling system to the rear and various other tweaks eventually helped get it to a 51:49, but all articles I've found still say that the chassis really works best if you are aggressive with it to get turn-in rotation.

Engine for the S1 version is generally described as peaky with quite a bit of lag, and that comes through here - and it makes sense when the dashboard gauge reads all the way up to 2.5bar (36psi) boost! It is a smooth 450hp, but you'll find yourself waiting a bit for the power unless you row gears and help hold it high in the rpm range. They even ran it a few times with Porsche's early PDK gearbox - also used in some Porsche 962C factory cars - to stay on boost better. It's neat, in some old videos you can clearly hear the difference in the PDK car shifting and how smooth that unit flows through geares. Impressive to think that our Audi 90 IMSA GTO is an evolution of this same basic engine 4 years down the line and it was then doing 700+hp with 10psi less boost. Turbo tech came on very strong in the '80s.

The early quattro system as in the race cars used a kind of planetary/Torsen/viscous combination center differential. It let them adjust fore:aft power balance, do some torque biasing on slip and still lock up if one end loses grip completely. Works really well when copied into our systems. Feels a lot more typical of AWD road cars than something like the modern RX designs and reminds me a lot of our time in the Subarus at DirtFish. Front diff defaults to a viscous LSD and rear to a typical ZF-type Salisbury LSD, which appears to be how it ran most of the time.

Suspension is simple MacPherson strut all around. Aero is nothing special but does help stabilize the car nicely. Gearbox is the 6-speed manual it ran most of the time with ratio set pulled from the old FIA homologation forms. Have let it use the same tire set as the modern RX cars. Probably a good bit better than period rubber (Or maybe not! Group B was pretty wild and using F1 rubber compounds in period wouldn't surprise me) but it's a good drive on them out of the box and good fun to slide.

So...it's a chassis that understeers until you push it hard enough, aero that works mostly to keeping things pointed in the right direction once a slide does start, plenty of power but only above 6000rpm and with some lag, and a great AWD system to put that power on the ground and pull out of corners. Racing this thing is fantastic once you get the hang of keeping it on power and how it likes using pendulum turns for initiating turn-in.


Renault 5 Maxi Turbo: Ceci n'est pas un rallye. The Maxi was Renault hanging on to an aging format in a time with AWD was clearly the way forward in rallying. Mid-engine, RWD, double wishbone suspension, 60% rear weight bias, and 2.5kg/hp may as well be specs from the Renault R.S.01 GT3 car, and this comes through in how it drives. This car was a tarmac specialist in 1985 and it really is one terrific circuit racer. On the whole, it matches up quite well with the Audi quattro, with the per track favorite being all down to how much gravel there is. Daytona is 85% tarmac and gives the Renault a 0.5s advantage per lap; Loheac flips that and the Audi is a 1s favorite; circuits like Hell or DirtFish are more balanced and the match-up is nearly even.

Like the Audi quattro, there is a great deal of information available about it in the form of old homologation papers and people who have restored and maintained the cars since their heyday. The chassis is a very simple design as far as suspension geometry, with the measured kingpin and caster values of 15° and 11.5°, respectively, giving good steering feel especially during opposite lock situations and powering out of corners. Drive comes from the C7K 1,527cc turbo 4-cylinder for 360hp at around 3bar boost absolute, through a 5-speed manual and 40% lock clutch & plate differential on the rear axle. The turbo had a very early anti-lag type of system which recirculated boost airflow to keep it spooled up so long as you don't spend too long off throttle; once boost does drop, it takes a good few seconds for it to come back on.

The restoration folk were a big help in having already measured typical wheel rate of the rear springs and torsion bar front suspension. It runs significantly stiffer than the Audi - again, showing its focus on tarmac events - and with a chassis balance that is far more typical of GT cars than pitching it sideways into gravel hairpins. What's especially telling of differences in the two cars is the chassis moments of inertia that fall out from our models. While both are similar overall dimensions and the Renault is 18% lighter than the Audi (900kg vs 1090kg), the moments of inertia are upwards of 60% lower for the Renault! That's the value of having most of the mass concentrated within the wheelbase; the car is much more eager to turn and respond to steering inputs. Nimble chassis via basic design rather than through modifying a car to make up for deficiencies.

So it's a much nicer handling car, but where the challenge arises is putting power down on the gravel. Power per kg is similar with the Audi, but going to only two tires means you have to be doubly careful about its application. This car doesn't like being tossed around and backed into corners for you to then plant the throttle and power out; that's far more likely to just end in a spin or the engine bogging down. How it gets speed is by using the brakes to rotate the car into a tight, late apex, use just enough power to keep the rotation from stalling, and then feed it back in through the exit with opposite lock to control direction if necessary. It's a lot more difficult than the Audi where anything goes to help fight the natural understeer of its chassis-drivetrain design; that car is all about being rough to make it do what you want while this one is about being smooth to take what it will give you. That's the trade-off of being a tarmac specialist. Loose stuff is pretty tricky, but you can more than make it up by treating it like a flyweight GT on any pavement sections; brake super late, smooth fast apex, power down hard through the exit. Sweet little car.


Ford RS200: Like the other Group B cars, this one proved great for research as 1.) there is a ton of interest in the car and 2.) people who have restored them share tons of old documents and information. Scanning through the original owner's manual is particularly cool, with a whole section on starting and driving the car written by Jackie Stewart.

This car is a classic example of huge potential which didn't have a chance to develop. Ford had spent a ton of time developing the front-engine, rear wheel drive Escort RS1700T for Group B only to throw it all away before entering a race as they saw AWD was the future. And so work started on the RS200 in mid-1983, well behind the rest of the competition and using a lot of parts which were left over from existing projects.

The engine is a Cosworth BDT 1.8L turbo 4-cylinder developed for the RS1700T and is a fine engine, producing upward of 440hp@7500rpm with a wide powerband that runs from 5500rpm right up to the rev limiter at 8500rpm. The parts-bin special nature of the early RS200 cars meant it was fairly heavy, though, at 1050kg and this put the engine at the small end of the displacement scale for its weight class. Evolution versions of the BDT-E, had they competed, were enlarged to 2,137cc and people who have since tweaked and tuned them can see upwards of 800hp!

Clever positioning of the 5-speed gearbox meant an even weight distribution of 50:50 (ideal, in theory) and a simple double wishbone suspension controls the chassis well. The AWD system is comprised of three Ferguson viscous limited slip differentials left over from Escort and Sierra projects. No exact rating for these RS200 diffs online or in old books, but we know from the Sierra Group A car that they tended to run in the 100-500Nm range. Standard setup is for 63% power to the rear with the viscous center controlling differential slip between the axles. It's a good configuration for stability, viscous diffs all around, but does generate a fair amount of understeer. Steve Millen once said "It's quickest to drive the car into a turn very hard, pitch it in with oversteer and maintain that attitude through the corner with the throttle." and that definitely works; it's a car that takes well to the Scandinavian flick technique and chassis rotation follows the steering quite directly. Still, it tends to drive a little tight unless you are rough with it; not slow by any means, but less exciting than the other two above.

This 1986 version of the car sorta feels like it lands squarely in between the Audi and Renault. It has the mid-engine and tarmac handling of the Renault combined with the AWD traction (and inherent understeer balance) of the Audi. Further development probably would have made the car significantly lighter or more powerful and solved any handling issues to produce a truly strong competitor. But Group B was cancelled in 1987 and the RS200 project ended after only a 1-year run.


Ford Mustang RTR Spec 5-FD: Star of the show in this pack, I suppose. smile.png Fundamentally, this thing is pretty simple and works almost like a dirt track racer. Take a basic Mustang shell, strip it down to basics, add a Roush-Yates V8 making stupid power levels, drive it through a 4-speed Andrews dog box to a ratcheting locker rear end, and change up the suspension geometry/setup to make the handling dominated by those rear tires.

Neat aspect of the Formula D rules is that the chassis-side suspension pickup points must remain stock but wheel-side is free. Up front that means a custom control arm for the strut to push the wheels out for wider track and a significant increase caster angle. The rear gets more interesting. Standard Mustang rear end uses a funky multi-link suspension which is surely great for road car use, but probably a little finicky to deal with when tuning a race car. So to get around this, they’ve used the stock pick up points mixed and matched with a custom upright and control arms to make a pure double wishbone configuration with the right kind of anti-squat and roll center properties to help with drifting. There are some good pictures on the interwebs showing what they did.

The trick in drifting it really is mostly about finding a setup that suits your style. We’ve included a few baseline options to get you started. The competition setup runs super low tire pressures and softer rear end to lift the inside front tire like you’ll see Vaughn’s car do in FD events. It’s a good way to get huge drift angle at high speed, but takes massive commitment to hold that edge without over-rotating or straightening and spearing off in the other direction. The ‘drift’ setup takes more of a demo day approach with higher pressures and more rear end stiffness to balance with the front. It is easier to get into a drift but generally slower through turns as a result; which is fine, we’re doing this for fun and not to impress the judges during a tandem run. I’d recommend playing with both setups to see which feels better as a starting point for your personal style then mainly tweak tire pressures and anti-roll bars from there. Small changes to handbrake strength can have a good effect in tuning the car, as well, for those of us without full analog handbrake hardware.

Being late in getting these notes written up, I’ve already seen some of your videos drifting the car and it’s great stuff to see. Love the tandem runs and seeing others get on with such a different driving style. Try it in VR if you have a chance!!


Ford Mustang RTR 1966: There's a lot in common between this one and its main competition, the 1969 Trans-Am Camaro: 5L V8, control arm front with Hotchkiss rear axle, ~2800lb total weight, and decent aero for the time.

For the engine, we took the GT350 302ci V8 as a reference point. There were claims of race-prepped engines cranking out 480hp@8000rpm for Trans-Am, but this is a fairly big number considering the homologation street car (not all that different) was generally agreed to produce 350hp and the Camaros it raced against were dyno-tested to show something in the low-400 range...and those won most of the races. Our model uses dyno data from similar cars and balances it in the 415hp range at 7800rpm to fit well with the rest of the class. FIA's historic database came through again with lots of good information, including a wide range of the gearbox options used in 302ci Mustangs from that era and all are present here.

This car benefits from an improved model of the Hotchkis rear suspension design. Many thanks to you guys for isolating the issues our old version of this geometry had on the Camaro. The investigation into why that one would fall apart resulted in a much more accurate model within the chassis solver limitations (no flexible links) with a roll center that moves more correctly with chassis motion. The Ford Escort models have been revised for this new approach as well.

All of these racers from the Trans-Am era went through some intense modification to cut weight and become race ready; coolest of these processes being an acid dip to thin out sheet metal. They commonly got the cars so far below the 2800lb minimum weight that large amounts of ballast could be placed around the car to get an ideal weight distribution, taking the car from maybe 55% front to balanced at 50:50 or even a little extra on the rear if it suited the track. Suspension setup leans heavy on vintage GT350 data and it works out very well here. It drives like an old muscle race car. Good power but nothing compared to modern cars, loose bias-ply tires so the chassis moves around a lot but never really snaps away suddenly, aero that is fairly neutral, very average brakes and good cornering from wide tires in an era where rubber was just starting to get really sticky.

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Mehr Details zum SETA Reifenmodell von pCARS2

 

SETA TYRE MODEL DESCRIBED

Seta tyre Model (STM) is a full dynamic tyre simulation. Actually, it is three coupled simulations, one for the tyre carcass, one for the tyre tread and contact patch, and one for heat transfer simulation. It is also modular, where different carcass and tread simulation techniques can be used interchangeably. For example, off road racing may use a different tread simulation.


CARCASS SIMULATION

The carcass simulation used in Project Cars is a finite element simulation with specific computational optimizations specific to real time tyre simulation. The carcass is discretized into small connected “elements”, each one flexing and deforming due to forces.

Features:
 

  • Elastic behavior changes with speed, temperature, and pressure
  • Rolling resistance changes with speed, temperature and pressure
  • Sidewall buckling at low pressure
  • Bias Ply, Radial, or Hybrid construction
  • Gyroscopic Effects
  • Dynamic response such as vibration, telescoping, and twisting




TREAD SIMULATION

The tread simulation used in Project Cars is a finite difference simulation of the contact patch, with the tyre tread “flowing” through the contact patch. The whole tread itself is discretized into elements much like the carcass, but the contact patch itself is a finite difference grid.

Features:
 

  • Flash Heating, which is the change of temperature in the outermost rubber layer through the contact patch.
  • Componentized grip model. Each component is affected differently by road surface conditions, wetness, and temperature.
  • Deformation – the rubber deforming in and around asperities, resisting sliding motion.
  • Adhesion – the rubber bonding to surface rubber and material.
  • Tack – the sticky tacky grip you can feel on your shoes when walking a rubbered in track, related to adhesion.
  • Tearing – the ripping of rubber from the tyre
  • Cut – grip from the geometry, edges, grooves, and siping of the tread, with particular effect in dirt and gravel
  • Tread channel depth and water handling.
  • Discretized and temperature sensitive wear
  • Curing
  • Temperature sensitive elastic properties



The carcass and tread simulations are coupled such that there is no roughness or “stepping”, while still preserving the detail of both simulations. The contact patch size, shape, and pressure distribution is determined by the carcass simulation and is used by the tread simulation. The forces on the tyre from the road surface are simulated in the tread simulation and transferred as external forces to the carcass simulation.



HEAT TRANSFER SIMULATION

The heat transfer simulation handles heat flow between brakes, wheel well, rim, carcass, and tread layers. The heat transfer amongst tread elements, from tread elements to the road surface, and from the tread elements to the air are handled directly by the tread simulation (including advection and evaporation). The pressure of the tyre is maintained by the carcass simulation via the ideal gas law.



Emergent Effects

Most effects just “fall out” of STM without explicit coding for effect:
 

  • Fy, Fx, and Mz vs slip angle curves, complete with realistic nuances, such as Mz inversion
  • Inclination effects such as camber thrust
  • Complex and sometimes subtle changes in behavior due to load, heat, pressure, and speed.
  • Proper behavior at a standstill and very slow speeds, although due to limitations of consumer force feedback devices, oscillations may still occur. Many tyre models break down at a standstill.
  • Flatspots
  • Hydroplaning
  • Changes in behavior due to surface differences, such as surface roughness, track rubbering in, wetness, and dirt.

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Slightly Mad Studios and BANDAI NAMCO Entertainment Europe are excited to announce the ‘Porsche Legends Pack’, the second expansion pack for Project CARS 2, will be available across all platforms in early March.

Seventy years on from the launch of the very first Porsche road car in 1948―the Porsche 356―comes the Project CARS 2 ‘Porsche Legends Pack’, a visceral and unmissable celebration of Porsche’s 70th anniversary.

The ‘Porsche Legends Pack’ will come with: nine legendary cars hand-picked from the storied history of Porsche: one FIA-certified track intimately associated with Porsche―a first in any simulated racing game: 20 liveries: nine community events: and five new career events, all carefully crafted to integrate into the Porsche experience.

The nine iconic Porsche cars include their current GT-runner, the 2017 Porsche 911 RSR that will add this elite brand into Project CARS 2’s already essential line-up of GT racers.

The 911 RSR will join eight more historically significant Porsches hand-picked from the last 70 years, such as the 1972 Porsche 917/10―the car dubbed the “Can-Am Killer”―an analogue monster whose 5-litre flat-12 boxer was mated to two massive big-box turbos to create what many consider the most brutal car (1,200bhp!) in sportscar history.

Ahead of the ‘Porsche Legends Pack’, Slightly Mad Studios has released a new Update 4 for Project CARS 2 for PC (Steam), which will be available imminently for the Xbox One, and PS4.

Update 4 includes numerous performance and stability improvements, gameplay balance tweaking, UI and render enhancements, and extensive AI improvements across many locations and vehicle classes.
For full details, follow this link.

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Physics of the Porsche Legends DLC

Better grab snacks and a beverage, because this is a long one. From the production side, I'm not sure we've ever had a more interesting or well-documented group of DLC cars to work on. Each one of them was an absolute joy for us to build up and it's great to see so many people enjoying the drives.

Porsche Carrera GT: Just a great car; all the bits of it are in a great balance. Research for this one proved particularly productive as there is a strong and open community of owners at Rennlist who love to talk about their cars and share experiences.

The engine is that famous V10 which began life with intention to race in the 3.5L era of Formula 1. It was shelved for a bit before being brought back for the aborted LMP900 project, and eventually grew to the 5.7L variant used here. The owner's manual includes a nice dyno plot of the engine's full range which matches up well with independent dyno data and served as our main reference point. It makes a smooth 600hp with plenty of torque from 5500rpm right up to the limiter at 8400rpm. Feedback from owners is that it's just a perfect example of a naturally aspirated engine to drive once you get the hang of starting off with the aggressive clutch and virtually no flywheel. (2005 model year updates added some software anti-stall auto-throttle to help get the car rolling) Power goes through a 6-speed manual and clutch-pack LSD to the rear wheels. Ratios spaced in nice progressive steps that increase speed by about 30mph in each gear; combined with the fat torque curve, it feels like you always have a good gear to use and the whole thing is working with you.

Aero claims for the car are modest with CdA=0.72 and a useful downforce of 400kgf @ 330kmh, with both values being backed up well by Sport Auto wind tunnel tests. Aero balance is actually slightly forward of where you would expect on a road car, but still in a nice position given the car's weight distribution and heritage of being set up by Porsche factory race drivers of the era.

Suspension is a very simple double wishbone design with coilovers on inboard rockers. Very similar setup to the Enzo from that same supercar era. Rocker-pushrod design appears to work out to a motion ratio of 1:1 (Suspension tuning being one of the few things not discussed at length on rennlist, aside from how to lift the car for daily use on rough roads) and good photos of one car being worked on show 90N/mm springs at both ends. Those wheel rates, the 1455kg DIN weight & 60% rear weight, and a typical Arnao-Porsche damper setup work out to a very nice chassis balance.

The car did originally have a strong reputation for oversteer as it rolled out from the factory - both in general cornering and lift-off oversteer. It has an adjustable rear anti-roll bar, and their test drivers liked it in the firmest position. Randy Pobst had a good article about it during his time as a Porsche factory driver and pins it on their test drivers all having strong karting background. A bunch of kids who grew up winning races by adopting a ‘pitch sideways and catch’ driving style; heavy emphasis on oversteer in the baseline setup. Porsche eventually changed to shipping cars with the rear bar in the middle of three settings, and pretty much every owner has moved to the softest setting for 'very slight' understeer and increased confidence in the car. Our setups default there too.

It is very quick. In testing on Trofeo R tires, I'm lapping the Ring in around 7:15 (Jussi turned a 7:07, the speed demon). Given that we're modeling newer, better tires, and the official lap done back in 2004 was a 7:28, we appear to be right on target for performance.


Porsche 935/78 'Moby Dick': While the real thing was an awesomely big job of hacking the rulebook to make the car lower, longer, and more powerful, for us it works out to a fairly mild mod of our existing 935/77. That chopping of the chassis to lower the entire car plus new bodywork front and rear made the car significantly more efficient. Wind tunnel data from the time shows 10% less drag and 50% more downforce compared to the 935/77, though 97% of that downforce is applied to the rear axle; not exactly great for cornering speed, but does wonders for high speed stability and that was the whole purpose of this car. The real secret weapon here was the new four-valve, 3.2L engine with water-cooled heads (code 935/71). While not a huge power advantage on paper over the 3.2L 2-valve 930/80 unit we have in the 935/77 and 935/80 models - 750hp@8200rpm vs 740hp@7800rpm, both at 1.4bar boost - it can pull right up to 9000rpm and maximum boost of 1.7bar puts it well over 800hp for qualifying. The broader power band plus the improved aero mean it will gets up over 365km/h on the Mulsanne straight while feeling perfectly stable going flat through the kink. It may burn through fuel in a flash, but it's happy cruising around those old tracks at high speed all day long.


Porsche 911 Carrera RSR 2.8: Huge credit to the old Paul Frère books which just go into ridiculous on every racing model from the 1970s and were an invaluable resource putting this together..

The 2.8L flat-6 is good for 308hp@8000rpm and drives the rear through a type 915 5-speed. There's a big set of alternate race ratios, but the engine is smooth enough that you won't often feel the need to adjust things per track. The standard ZF limited slip differential could be set for 40% or 80% lock; 40% feels good on ours as a baseline (6 clutches, 50° ramps).

RSR race models were stripped down to 900kg for a neat 40/60 weight distribution. This was the time when wind tunnels were just starting to see use in developing race cars, and the 911 proved particularly terrible at the beginning with upwards of 300lb lift happening at the rear axle in the initial tests. The duck tail addition helped balance that and cut about 75% of the rear lift, but still left significant lift overall. Numerous other tweaks just didn't work very well, resulting in a car with downforce on the front end and lift at the rear, until the 'Mary Stuart' setup which actually made useful downforce at both ends of the car for only a small drag penalty. We've gone with that kind of configuration for our aero model as it just drives the best of the bunch.

Suggested suspension setup for the RSR was effectively identical to the street RS models, with zero camber at the front, -1° at the rear, a touch of rear toe, torsion bars of 18.8mm diameter at the front and 23mm at the rear with 18mm anti-roll bars at both ends. Stiffness numbers make this look soft, but the car is so light that it all works out in the end. It does get faster if you make it lower and stiffer, but the relationship between stiffness and difficulty is quite direct on this car. Dampers are very similar to Bilstein valving spec for the real thing - 100/220 on the front and 160/210 on the rear. Brakes for the RSR came straight off of the 917 prototypes; more than adequate for the job!

I'm loving driving this thing. It's easy to see why they are so popular for vintage racing; the balance of power and grip is great, and the steering feel works perfectly with the chassis balance to glide through corners with the rear end hung out. Top speed isn't especially high at around 250km/h, but the lightness and handling make it a good match for the old Camaro and Ferrari 365. Multi-class at Le Mans with this will be great fun; 911 giving all it's got for 250km/h on the Mulsanne while the 917 and 512M blast by doing closer to 390km/h!


Porsche 917K: I've never seen so much detailed documentation on a 45 year-old car before; made putting this together very easy. Nice dyno plots, full gearbox/differential specs for various circuits, multiple wind tunnel and track aero tests in various configurations and an array of ride heights, complete chassis blueprints for suspension geometry, corner weights, fuel usage, etc. etc. etc. Amazing stuff in these old Frère books.

Engine for these 1971 cars was the 4.9L version of Porsche's flat-12 making an even 600hp@8400rpm and 415lb-ft@6500rpm. Unusual engine as it was essentially two regular 911 boxer 6-cylinders joined together in the middle; the length of such an arrangement meaning that power had to be taken from the middle of the crankshaft to help control vibrations and the gears used to achieve this essentially making for a 32:31 overdrive. Also note that while these are traditional 'air-cooled' Porsches, there is a radiator at the front you can damage which will cause some trouble. They ran an 80cm-wide oil cooler up there, and the 917K variants even going so far as to carry a 55L (no, that's no a typo) oil tank to help regulate engine temperature over the endurance races.

That engine drives the rear through the same type-917 gearbox we have later in the 936/77 (minus the power take-off overdrive) and was run as either a 4- or 5-speed unit depending on the track and model type (K models usually going 4-speed, LH 5-speed). Same internals, but they would just block off 5th gear and select ratios to suit a given track with only four gears; an easy thing to do as the power band is quite wide and the engine doesn't need to be up at the top of its range for best performance. Standard differential was a ZF with 75% locking (8 clutches, 40° ramps) and preload. Track tests were done with 25% locking and steady state handling improved slightly, but sudden throttle lifting would then cause the car to instantly spin out.

K models tended to be lighter, even needing ballast to get up to the 800kg minimum, and roughly a 63.5% rear weight bias.

Suspension design is nothing too special and typical of the time: double wishbones up front, radius rods plus inverted lower wishbone at the rear. This is another area with great documentation for camber and toe changes w.r.t. suspension motion, which where is a fair amount of both. Matching that in our model and using real setup values from the period all works out to make good sense; they often ran zero, or even positive, camber at the rear and quite a lot of toe-in at both ends. The camber helps agility at low speed while the toe-in stabilizes, and it all cancels out at high speed under aero load such that the rear tires stand perfectly upright when you are over 200mph, which is good for endurance of the tire carcass. Progressive springs/geometry were used in the design, complicating matters, but some track aero tests provide spring compression for a known aero load so working out typical average rates for the suspension stiffness was easy and drove well from the start on those numbers. The blueprints plus old setup sheets also helped to work out wheel rate for typical anti-roll bar sizes used. Easy stuff and all just works when we put it on the car.

Like the 911 Carrera 2.8 RSR, this was the very beginning of the wind tunnel era and it helped them make one slippery car. Downforce levels are nothing astounding, but useful and well-balanced for high speed stability. Drag levels are astonishingly low at around 400lb for the 917K, making it good for over 350km/h while feeling perfectly comfortable through the Mulsanne kink flat out. Overall a very easy drive at just about any track with great stability and tons of grip from the giant, 14.5" wide rear tires. Feels like they would be good for cruising around at race pace all day long, which is what they were designed to do.


Porsche 908/03: It's like the 917's flyweight sibling and was a surprise highlight of the group for me. Same chassis frame design, same suspension geometry, same width tires, same basic layout of flat engine mounted in the middle driving through a 5-speed gearbox to ZF differential at the rear. Differences largely boiled down to the engine, aero concept, and materials selection.

The engine was an evolution of Porsche's flat-8 design, going from 2.2L and 270hp in the 1966 910 models to the 3.0L unit here good for a quoted 350hp@8500rpm though the best examples were making upward of 370hp. Not nearly the power levels of F1-derived units it competed against in the Group 6 P3.0 class (you will have moments begging the car for a little more top speed) but it was reliable, had a strong power band from 6600-8700rpm and, most importantly, was very lightweight. The 5-speed gearbox and differential bore a lot of similarity to the 906, 907, and 910 before it (and even the Carrera RSR) with the ZF 80% lock differential being commonly used; default setup on ours uses the 40% lock configuration as it's a bit easier to approach for a starting point.

Rules of the day very clearly put an advantage to the S5.0 class cars at long races on fast tracks like Daytona, Sebring, Le Mans, and Spa. As the 917 was already doing well there, this allowed Porsche to give clear focus on making the 908/03 a tool specifically for winning at the twistier tracks where the absence of a minimum weight could be put to good use - particularly the Nordschleife and Targa Florio. Aerodynamically, this meant cutting off the roof to save weight with spyder bodywork and a short tail design. Lots of iteration and wind tunnel testing from the 908/02 to 908/03 models resulted in a car that made a nice amount of useful downforce (around 450lb @ 150mph) with a useful balance (around 60% rear) without too much sensitivity to ride height changes, and all for only 10-15% more drag than the 917K design (40-50% more than the 917LH).

Then there was extensive use of magnesium, aluminum, and titanium through the chassis to cut weight as expense of reliability, knowing that the car would be used more for 1000km races rather than 24hr endurance fests. All-aluminum chassis frame weighed in at only 35kg, titanium usage throughout the suspension, magnesium in the gearbox and brakes trimmed weight further. A clever use of epoxy around foam core even resulted in an entire bodyshell for a mass of only 12kg. They even experimented with chome-plated beryllium brake rotors for a further 30lb weight savings, but the wear characteristics of these were sub-optimal. In the end, they had a car which tipped the scales at only 545kg - on average between 100-140kg lighter than any other 3.0L prototype - with a near-ideal weight balance of 55% rear.

So you've got a prototype sport racer as light as an F1 car of the era with just as much rubber and more usable downforce. A bit down on power, comparatively, but it more than compensates for it with the aero grip and nimble handling. One of these broke the 1969 F1 Nordschleife record in 1971 on the way to a 1-2-3 finish in the 1000km race. (granted, F1 retook the record later that year by over 20s) On our modern Nordschleife track, I'm comfortably lapping near 7-minutes flat in this. The 917K feels fat and lumbering by contrast (at all of 800kg!) and is about 10s per lap slower. The situation reverses, of course, going to Le Mans where the 917 can use its power advantage and pull a 15s lead per lap. There are a bunch of tracks in between those two where they come out just about equal - like Oulton Park - and they should make for some great multiplayer competition.


2017 Porsche 991 RSR: What started as a variant of the 991 GT3 R has ended up with quite a different feel thanks to the increased front weight distribution and completely different suspension concept.

The engine begins with the same 4.0L base as the GT3 car, but they must work some serious magic on it for the LM GTE spec RSR. Same layout and capacity with smaller restrictors - 2x31.5mm vs. 2x40mm - and it makes more power than the GT3 car at 520hp. Best guess is the thing would be close to 700hp if run unrestricted...which, IMHO, the FIA/ACO should allow since these are all more like prototypes than GT cars anyway. Still revs to 9400rpm like the GT3, but the smaller restrictor mean power drops off earlier and it is best between 8000rpm and the shift point of 8500rpm. Steering light LEDs reflect this.

Gearbox is your typical 6-speed sequential with a nice array of ratios to select from. Differential is clutch & plate type with the usual Porsche locking values of 45% power / 65% coast. An option for the RSR is to use a viscous pack instead of clutch preload; personally I prefer the steadiness of clutch preload so that is how it's set up by default.

Suspension on the RSR deviates totally from the GT3 R, which must stay close to the original road car. The RSR goes double wishbone front and rear, and our reference material gave good enough data to draw up a new model to reflect what they've done here plus some baseline suspension setup info. Steering feel from the new design is nice but it's definitely a big step away from your ordinary 911. Where the GT3 is more forgiving and does a great job at planting the rear end, this one is more tuned for prototype-like sharpness and carving into high speed corners. It's a bit more 'pro' to drive and quite a bit faster over a lap as the reward.

Then there's the big feature of this car: moving the engine ahead of the rear axle to a mid-engine layout. Nobody will share hard numbers on such a sensitive topic, but our best estimations show this moves the weight distribution forward 4% to about 55.5% rear and reduces the moment of inertia by about 10% in yaw. Makes the car more nimble and does good things for cornering performance with the tire sizes used on these cars.

First tests have it running 15 lap stints at Le Mans with a best time of 3:57 and Long Beach in the mid-1:16s. Pretty close to the real world targets as those will come down with setup work and a better driver. A nice addition to our LM GTE class.


Porsche 917/10: Can-Am was so badass. Minimal rules, maximum speed and creativity. Minimum weight? Nah, we don't need that. Maximum engine size? Nah, don't need that either, and use turbos too, if you like. Just have two seats, enclosed bodywork, and 'reasonable' safety to the design.

Porsche sorta got into Can-Am by accident. They had entered a 908 because of convenience (there happened to be a shared weekend with the 6-hour Watkins Glen race) and did well, but were too far down on power to compete for a win. Further experiments with a spyder version of the 917K (near double the power of 908) were also insufficient on power. The car looked like a good base and the series a good challenge, plus they could use the additional North American exposure. Solution: Turbocharging it out the wazoo.

The engine in our model starts as the 917K base but with compression ratio lowered significantly to 6.4:1 and two giant turbos from a diesel truck strapped on, producing in the neighborhood of 1.3-1.5bar boost. At the 1.3bar race boost level, this makes for a 5.0L flat-12 outputting over 1000hp@7800rpm and 1000Nm torque in a range from 5000-7000rpm. Tighten some screws in the wastegate (this was early turbocharging, everything was mechanical) for some extra boost and you get north of 1250hp. The cooling system struggles to keep up with this for anything more than short bursts, so it was common for drivers to back off on the boost during races to save the engine.

Gearbox was an evolution of the 917 unit, strengthened to handle all the extra torque and reduced to 4 speeds. The differential was also a casualty of the design change. Tests using a spool on the 917K were positive for high speed stability and it removes another part which can break under the massive stress, so all the Can-Am 917s used a locked, spool differential.

Aero development in the wind tunnel continued, and with all that extra power, drag could be afforded for the sake of downforce production. Late versions of the 917/10 tested at around 1100lbf@150mph for downforce with a 75% rear balance and roughly 1.7:1 lift:drag efficiency. The car would make its own weight in downforce at around 180mph. Impressive numbers for the time! All of the downforce led to some suspension design changes so to reduce camber change with the travel which was inevitable under load at high speeds, plus adding back some anti-dive and anti-squat to the geometry to handle the braking and acceleration loads. Minor differences from the 917K or even 908/03, though. Old testing/race notes give some suspension stiffness targets they used; it ran very stiff at the rear to hold up almost a ton of downforce on the rear axle.

The chassis went through various lightening and strengthening phases, some even using a magnesium chassis frame that brought total weight below 800kg (1200hp to move only 800kg!) while the most successful/reliable cars from Penske weighed in at 820 and 837kg with 65% on the rear axle. To last through 200-mile races without refuelling, the cars could hold 325L of fuel in tanks either side of the cockpit. With driver weight and full fuel load, weight distribution moves forward to 59.5% rear.

Tires were big...really big. Rears are a full 17" wide tread. Think of it this way: the car is about 217cm wide and the rear tires combine for 110cm of that. The driving dynamics are very much dominated by the rear end and getting that power down. All that rubber plus a spool on the axle makes it push at low speed unless you run a very aggressive suspension setup with soft front and stiff rear. Downforce adds with speed and it is balanced enough to the rear that it also adds some understeer for the sake of planting the rear tires when the boost is on (with low rear wing settings and qualifying boost, it will spin the tires up through 150mph). Despite the tendency to understeeer, it is easy to rotate because there is always so much power on tap to help. Be ready to use the brakes a lot. It accelerates so fast that you are approaching most turns 40-50mph faster than any other car of the era. It has good enough cornering grip, but the key to performance is getting into and out of the corners like the rocket it is. Use that power and it is faster than an F1 car of the time.

Also, it does little wheelies on a hard launch. Raise the revs to build boost, dump the clutch, and this happens. This one is huge fun.

Jussi: Initial test at Nords put me at 6:32 and classic Le Mans at 2:55. That first value is as fast or faster than modern GT3s can handle Nords and almost half a minute quicker than I managed in the 917K, and the second is 20 seconds quicker than the 917 managed in 1971. Which was already 10 seconds quicker than the Ford Mk IV managed in 1967. Ludicrous machine.


Porsche 959 S: The supercar way ahead of its time.

Engine for this one was a detuned, 2.85L version of the 962 Group C race engine and one of the great cases of underrating power output. Quoted spec is only 450hp@6500rpm and 500Nm@5500rpm, all arriving thanks to boost pressures in the range of 1.9-2.1bar absolute. A fairly modest output for the top speed which was independently tested many times in the 197-200mph range. The owner’s manual includes a ‘dyno plot’ and our first tests with an engine matching that plus the right amount of aero drag (a very slippery claim of Cd=0.31) resulted in a top speed of only 175mph. It wasn't until adding ~70hp with a much fatter power band that the straight line performance numbers begin to make sense. I'd guess the real 959s were all producing more like 600Nm and 520hp, with over 500hp in a range from 6000rpm right up to the 7600rpm rev limit. Beefy.

Gearbox is a 6-speed manual, though it is is technically only labeled a 5-speed in the car with an additional gear for off-road. '1st' is quite short and is labeled 'G' for 'terrain' use. For most circuit driving, it does work best to think of 2nd as the lowest gear in slow corners and 1st/G only for rolling out of the pits or off the starting line.

Suspension differs from your typical 911 in that it uses a basic double-wishbone configuration. Each corner had a pair of coilovers and these could be actively adjusted for both damping rate and ride height in the Komfort model. The 959S Sport model bypassed that for stiffer springs and fixed damping to save weight.

The AWD system in this car was remarkable for the time. Rather than a center differential, it has a set of electronically-controlled clutches connecting the driveshaft to the front differential. The computers take into account static and dynamic weight distribution, wheel slip and surface grip, plus a number of other factors and send between 20-40% of the torque to the front axle. (alternatively, the driver can fully lock those clutches for off-road/low-grip use. Center spool option in game does this.) To make this work, the front tires are sized 1% bigger than the rears so that there is always some degree of slip at the central clutch to enable the variable torque transfer. We mimic this in game with a set of centrifugal clutches with the right range of torque holding capacity in the middle of the car. Altogether great for acceleration and high-speed stability, but the drawback of this is that there was always 20-40% of the engine torque being used to drive the front wheels forward; meaning some of the front tires' lateral grip capacity was compromised and the car generally understeers on power. Road tests from when the car was new point out this tendency to power understeer and that the rear end only really steps out via aggressive trail braking, after which is can easily be brought back in line by using power to pull the car straight. The fastest approach to most corners on a paved circuit is to be tidy on the entry and position the car to get back on power rapidly just past the apex.

The car's aerodynamics were focused heavily on drag reduction to get those high top speeds. Porsche marketed the design as being "zero lift". That's a great accomplishment considering the 911's reputation for lift-induced handling issues, but zero lift also means zero downforce. Combined with the car's hefty mass (Sport model over 1530kg in independent tests) and narrow tires (only 235-wide front and 255 at the rear), the 'supercar' performance on this one mostly comes via the fantastic engine and its ability to pull so strongly out of corners to a big top speed.

The cornering speed deficit hold it back from being truly supercar-fast on a dry circuit. Comparison tests of a 959 Komfort against the Ferrari F40 at Fiorano put the F40 at somewhere between a 6-10s per lap advantage...and that’s a short lap. In game, our 959S is roughly a 7:40 car at the Nordschleife. Not slow, for sure, but a ways off other iconic supercars which had more focus put on speed through curvy sections of track. Still, the car was a remarkable technical achievement, has wonderful handling manner on track, and is great fun to turn laps in even if it's not going to be setting any world records. Take it to the RX tracks too; it is a great match for that type of driving.


Jussi: Side note: The same basic system was later used for cars like the Nissan Skyline GT-R (and the current GT-R), Lamborghini Huracan and a ton of other cars, and the modern Haldex system is essentially a reversed version of this system (front-wheel drive with an electronic clutch to transmit power to the rear when necessary). Definitely ahead of its time.

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Patch 5 ist da

Neu ist der Ferrari 488 Challenge von der 2017er Ferrari Challenge dabei.

Patch Notes:

  • Addition of the Ferrari 488 Challenge car, and liveries from the 2017 Ferrari Challenge series. This is the latest Ferrari to feature in Maranello’s single-marque championship, and the most powerful car in the series’ 25-year history.  
  • Addition of two new layouts to the Porsche Leipzig on-road circuit.
  • Corrected a small number of turbo and suspension issues on various cars.
  • Resolved an issue where some drivers would appear stuck on track during qualification or race session.
  • Resolved an issue where the end of race results would display incorrectly.
  • Resolved multiple ghost loading issues in time trial.
  • Polished the Online Reputation calculations, including tweaks for when players retire due to excess damage.
  • Corrected an occasional issue of players being taken to the wrong lobby if the host set up a new lobby whilst the old one was populated.
  • Mechanical failures no longer include aerodynamic damage.
  • Various improvements to the AI at a number of tracks and conditions.
  • Solved an issue in career when, under certain circumstances, the standings would not display correctly.
  • Multiple other miscellaneous fixes and optimisations.
     

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Patch 6 und Spirit of Le Mans DLC sind da:

Project CARS 2 - PC Update 1.6.0.0

Various improvements, fixes and optimisations.

Fixed occasional stability issues.
Improved usability of in-game tools.
Improved AI ability at various tracks.
Improved the penalty system.
Optimised tyre wear in wet conditions.
Optimisations to LiveTrack at various tracks.
Improved track-limit zones.
Other miscellaneous fixes.

 

Spirit of Le Mans DLC

Fahren Sie in Le Mans von damals und von heute um den Sieg, mit dem Project CARS 2 “Spirit of Le Mans” Paket. Bestreiten Sie das Duell der Titanen im Ferrari und Porsche auf dem haarklein und realitätsnah gestalteten Rundkurs von Le Sarthe, der auch im Film Le Mans zu sehen ist. Fahren Sie den V12 Ferrari 512 S und 512 M sowie den Porsche 917 LH mit luftgekühltem Zwölfzylinder-Mittelmotor und erleben Sie die große Ära der Rennautos. Dann folgt ein Sprung zu den High-Tech-Helden von heute - dem Toyota TS050 Hybrid, dem Porsche 919 Hybrid und zwei von Audis überlegenen Modellen, dem Audi R18 (Fuji 2016) mit hohem Grip und dem schnellen Audi R18 (Le Mans 2016). Helden von früher und heute auf dem legendären Rundkurs Le Sarthe: das ist der “Spirit of Le Mans”.

 

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Physics of Spirit of Le Mans DLC

It's June. Time for endurance racing. smile.png

Audi R18 e-tron quattro (2016): Being that the car was retired after 2016, Audi went the extra mile and provided some impressive reference material for this one; something of a rarity for top-level, high-tech cars. It was possible to fill in the few remaining gaps with data from the 2014 car and make a model which I feel is a very good representation of the real thing in our systems.

Engine is the same 4.0L turbo diesel they have been using for 6 years with constant, little updates for the regulations. By 2016, being in the 6MJ hybrid that meant reduced fuel flow so it would only make about 520hp peak and it holds that from 3500-4250rpm, which is the entire rev range you use. The ICE drives the rear wheels through a 6-speed sequential (down from 7 in previous years) with ratios that, best I can tell, didn't change through the entire season. We have added in a couple alternate final drive ratios in ours to cater to the wider variety of tracks.

Up front, the hybrid system had a huge upgrade since 2014. Flywheel is gone and replaced with batteries, with the motor upgraded for 350kW peak power (limited by rule to 300kW at Le Mans). Analyzing on-board telemetry shows the energy store works out to a nice, round 1kWh and the system software does some fancy tricks to send an average of 260-270kW to the wheels during each energy burn. The hybrid system normally cuts off around 260km/h even if there is plenty of energy left in storage; getting up to that speed is what makes lap time, not excessive burn for higher top speed. Our hybrid system can't do all the same tricks as the real thing (steering sensors, GPS, etc.) but it was possible to calibrate for a similar result to the real thing while using the full 6MJ over each lap at Le Mans.

Aero model is similar to our 2014 car data with more efficiency and less drag to hit the right top speed reference points: ~320km/h at Le Mans, 295 @ CotA. There were some rules changes meant to cut LMP1H downforce in 2016, but the teams surely clawed it all back and cornering performance looks close to the mark on the 2014+ downforce levels. We do have the R18 artwork split to Le Mans and high-downforce variants for liveries. Jussi had a great idea to split our aero model between the two, so the low-drag LM version gets steps 0-5 and high-downforce model has steps 4-10. Choose your variant wisely to suit a track and your own driving style.

Neatest thing about this one was the detail sent over by Audi in the CAD model. First LMP1 car where we could do an exact model of the suspension geometry to see how they handle sending so much power to the front wheels without harming steering feel. There is an almost absurd amount of caster angle built in, and the front would be better described as multi-link than double wishbone. The front and rear bars of what look like wishbones aren't actually connected at all at the upright, and allow the wheel to move fore-aft slightly when steered. It looks like it shouldn't work at all, but it actually drives great and gives better FFB than approximating a pure double wishbone setup from the same links.


Porsche 919 Hybrid: This and the Toyota were still active during dev time, so information was a bit more secretive on them. It uses a chunk of its base from the 2016 Audi R18 and the differences are largely due to the power unit.

Engine here is a 2.0L turbo V4 which Porsche claim generates 'just under' 500hp with the 8MJ fuel flow limits. Mapping out fuel flow, estimated thermal efficiency, boost pressure curves, and all that, we can be pretty certain that it holds at that 500hp (or slightly above) from 5,500rpm right up to the shift point we see in on-board telemetry at 7,800rpm. Augmenting this are electric motors on the front axle for an additional 300kW where the typical strategy is to burn hybrid power up to around 280kph and then let the internal combustion take it from there to top speed in the 313-320kph range depending on traffic/drafting effect. Used like this at the beginning of Le Mans' six long straights, it eats up almost exactly the 8MJ energy allowance per lap while shaving upwards of 10s from the average lap time. Impressive stuff considering that top speed on each of those sections doesn't really change whether using hybrid power or not; just that with hybrid power you are at top speed for almost the entire time. Charging happens with a regenerative braking system like the Audi and also adds a generator on the turbocharger which takes extra energy which would normally dump out the wastegate and directs it into the battery at a rate of up to about 40kW. You will see the battery charge increase during full throttle driving thanks to this.


Toyota TS050 Hybrid: As is usually the case, three years of rules stability saw the main competitors converge on similar approaches in how to get best performance from the energy they were allowed to use. Where 2014 saw a Toyota take pole position with a lap where its top speed was nearly 40km/h slower than that of Audi's on their fastest lap (336 vs 298), by 2016 the three big teams had all honed in on similar aero and hybrid strategies which saw performance over all segments of a track become quite similar.

Engine is a 2.4L V6 twin turbo compared to Porsche's 2.0L V4, and both make around the same 500hp in a wide band from 5,000-8,000rpm due to fuel flow restrictions of the 8MJ energy class. Main point where they differ is the hybrid system. Porsche run regenerative braking on the front axle plus an MGH unit taking excess exhaust energy from the turbo to charge a battery which powers a motor on the front axle alone. Toyota don't do turbo-compounding, but do take regenerative braking from both axles and then deploy hybrid energy to both axles as well; the only one of the three 2016 cars to send extra power to the rears via the hybrid system. I like very much what this does to the car’s handling. In the Audi or Porsche, you can sometimes catch yourself out using the hybrid too early when exiting a turn, spin the front wheels a bit and waste time+energy+cornering power. The Toyota, on the other hand, is only pushing 150kW to the front tires instead of 300kW, so it is a little easier to get on the hybrid boost early without upsetting balance of the car. Does a better job at equalizing tire temperatures and wear (at least for my driving) even if there might be instances where it gives up a little performance when the rears can't handle the full 700hp and it kicks into the traction control. Takes a slightly different driving style than the point & shoot Porsche or Audi, but all three are super close in performance over a lap by the end.


LM P1H 2016 Hybrid use and strategy: One big difference for these 2016 cars is that we've changed the hybrid system to activate on button press rather than throttle input. Rules for the real car don't allow it to be on a button like this, but the real systems are becoming so complex that we can't really copy their action from throttle input alone; it worked fine for the simpler cars of 2014, but not now that everyone is in the high energy categories and working out better energy deployment strategies. Manually controlling the hybrid to match closer what we see done in the real thing has a significant effect on lap times. Avoiding any wasted energy on unimportant parts of the track and saving it for big burns made me about 4s per lap faster in the Porsche and 2s in the Audi; plus it gives a fun push-to-pass feature if you manage to save a little energy while racing closely with anyone.

The most effective hybrid strategy in these three cars tends to center around finding the slowest corners of a track and burn energy on the exit up to about 260-275km/h. Using more of the battery than that yields diminishing returns and is better saved for a slow spot elsewhere on the track. Run some practice laps at each track to see how the car recharges over a lap and where you might want to save hybrid energy to have a full boost out of the slowest corners.

Qualifying can change your strategy a bit too; consider Fuji as an example. In a race at Fuji, you would typically save up charge from the second half of a lap and boost out of the final corner to reach a 290km/h top speed early on the long, Start:Finish straight, doing this consistently lap after lap. In qualifying, however, you don’t care about the lap before or after and can use this to your advantage. Exit that last corner and accelerate to about 240km/h, only then using the hybrid for extra top speed of 310+ from the start-finish line into braking for the first corner. Then finish the lap with a long boost right out of the final corner for the best lap time. It doesn’t work for multiple laps in a row, but stringing together a fast second half of the straight to start a lap plus fast first half of the straight to end it shaved over 1s from my typical race pace lap time.

A similar quirk comes into play at Spa-Francorchamps. Rather than burn all of your energy our of La Source before Eau Rouge, save 50% charge or so for the Kemmel straight afterwards. It is a long, uphill run, and boosting to top speed immediately after Eau Rouge can be a huge win for your lap time. Every track will have unique strategy plays like this, so experiment and keep an eye out for what works best in both qualifying and race situations.


Porsche 924 Carrera GTP: This one is a funny little piece of history thanks to those three letters at the end of the name - GTP. Porsche had introduced a 924 Turbo model but there was not enough time to meet homologation requirements for it to run in the production GT category as intended. Simple solution: Just run it in the GTP class against other full-on prototypes where the rules were effectively 'have a roof and a minimum weight for your engine size'...300hp disadvantage and road car aerodynamics be damned, the 924 Turbo would be racing!

There is a fantastic documentary video of the car's restoration over HERE where the drivers all talk about how great 924 GTP was; having some of the best handling they ever experienced...high praise when the group includes five-time Le Mans winner Derek Bell. And that great handling paid off as the race was *very* wet. Despite being a good 50mph down in top speed and lapping 30s slower in qualifying, the 924 GTPs used their strengths to pull off a fantastic result of 6th overall (3rd in class) with the other two cars in 12th and 13th.

Design-wise, the car is both very similar and very different to the 911 Carrera RSR 2.8 we have in game from the Porsche Legends DLC. The differences, obviously, are that this one is front-engine with a 2.0L turbo 4-cylinder sourced from Audi. Doubling boost pressure from the street 924 Turbo to 2.5bar, it cranks out 320hp with a smooth torque curve and power is fed through a 5-speed manual Getrag G31 much like the road car but with a wide range of ratios to choose from for race use. A clutch-type limited-slip differential with symmetrical 40% lock is standard issue, much like in the 911 Carrera RSR and even 908/03.

Engine position, roll cage addition, and general lightening of the chassis make for a total car weight of 945kg with 52% rear balance. Suspension uses struts at the front and trailing arms at the rear, like the 911 Carrera RSR; spring and damper settings for that car also work here to great effect. It even used brakes from the 917 parts catalog, another 911 Carrera RSR similarity. For tires, they fit the widest things possible. This car is around 100kg lighter than the BMW M1 Procar and with 160hp less, but it has more rubber at both ends; thing has a surplus of grip in the dry and wet. While it can struggle on top speed tracks, it is so easy to chuck around that time can be made up quickly in twisty sections of tracks and it has come out ahead in testing here at the shorter tracks.


Porsche 961: A real unicorn here; they only made the one. While Group B and the 959 are largely remembered for rally racing, circuit racing was always part of the plan and the 961 was to be Porsche's customer car in that regard. The end of the Group B era and cost of a 961 compared to competitive Group C machinery cut those plans short and left us with only one example of what was, for nearly 30 years, the only AWD car to race at Le Mans.

Chassis construction was not all that different than the road-going 959S model from our Porsche Legends DLC. The usual strengthening and lightening measures were undertaken; the highly-computerized AWD system was simplified to a fixed 20:80 power balance front to rear; the 'zero-lift' aerodynamics were bolstered to produce some downforce for the necessary cornering grip at expense of a higher drag coefficient; and the 959 engine, which was in turn a de-tuned 956/962C race engine, was swapped back out for a Group C racing version of the 2.85L twin-turbo flat-6.

The race-spec engine brings power up to 680hp @ 7,800rpm and drives through a 6-speed gearbox just like from the 959S but with a range of ratios as setup options. For Le Mans, they ran the rear end with a spool axle as a reliability measure (fewer moving parts to break) but you can be sure it would have run a clutch-type LSD at the rear had it raced in a full WSC season; ours does that with a typical 40/60%-lock differential at the rear.

Wider fenders, mild diffusers on the flat floor, and an aggressive rear spoiler cost about 20% in drag increase over the 959S for a gain of roughly 500lb downforce at 150mph. Not a huge amount, but very welcome to help stabilize the 1150kg car in cornering and under braking. The extra drag limits top speed to 205mph on the Mulsanne straight; about the same as the 959S road car despite the extra power and some way off the top Group C cars it raced against, but still a respectable number.

Tuning the suspension proved to be not a difficult job at all. The 959S had already forgone the fancy, adaptive, computerized suspension of the 959 Komfort model in favor of fixed-rate dampers and ride height. Turns out that, being some 400kg lighter, the 961 races extremely well on the same springs and dampers of the 959S. Drop the ride height, stiffen the anti-roll bars to account for increased cornering grip from the racing slicks and it is ready to go. Probably my favorite handling car in its class. Maybe not as exciting as the F40LM's turbo lag or Mustang's pure torque, but it inspires huge confidence on corner exits where you can plant the throttle to the floor and let the AWD system pull the car out with just the right amount of slip angle. The Audi 90 IMSA GTO finally has something that can compete with it in the rain.


Porsche 917LH: The 917LH models are very similar to the 917K at fundamental levels. The main evolution here is in the aerodynamics with a heavy focus on top speed for Le Mans. Early iterations of the LH bodywork were great for drag reduction, but also generated significant aero lift at the rear. That deficit had largely been removed by the 1971 model we’ve simulated here; wind tunnel tests showed about 300lb downforce @ 150mph with a stable balance of 20-25% front. That’s enough to hit a solid 390km/h and feel perfectly comfortable taking the Mulsanne kink flat out.

The longer bodywork plus other detail changes of the LH model pushed them up above 820kg and closer to 66% rear weight.

See our Physics of Porsche Legends DLC thread for more notes about the common engine and gearbox used by these cars.

http://forum.projectcarsgame.com/sho...he-Legends-DLC


Ferrari 512M & 512S Coda Lunga: In researching this one, the word most often used for it by drivers, owners, and Ferrari's engineering team was 'under-developed'. I suppose that is a fair criticism considering it only took a single race win to the Porsche 917's 17 in the 1970 and 1971 seasons, but you also have to consider that the 917 began life a year earlier in 1969 and benefits from an extra year's worth of development at a time all aspects of car design, aerodynamics chiefly, were moving at a extraordinary pace. That Ferrari were able to win Sebring 1970 in a 512S variant right at the start of its life shows how strong a platform they had.

The technical directive for 512 was essentially to use as much existing material Ferrari had to build a 917 beater. For this, the engine took castings and design cues from the recent 6.9L 712 Can-Am engine with bore and stroke reduced for a capacity of 4,994cc. It had a slight power advantage over the Porsche flat-12 (610 vs 600hp) and, being a known and tested architecture, was generally reliable and less sensitive to over-revving than the Porsche. Peak power comes between 8,700-9,000rpm and it is happy spinning up to 9,600 if you get favorable winds or a nice draft down the Mulsanne. Drive goes to the rear through a simple, 5-speed gearbox designed in-house and a ramp & plate clutch differential; the similar layout and weight balance means a 75% locking factor works well here as it does in the 917 (some drivers in period preferred using a spool axle). Gear ratio setup was distilled to four crown wheel & pinion options to adjust final drive for top speed of the circuit; the longest, 11/35 (3.182:1), being the choice for Le Mans and getting the Coda Lunga variant up to 230mph.

Tube-frame chassis for the 512 was essentially carryover from the 612 P Can-Am car. The basic concept and design was standard Ferrari construction of the time (much like how the 908 and 917 variants evolved from the same base) and it all works well. Suspension geometry produces benign handling with nice steering feel, letting you focus on placing the car and putting power to the road. Reading old race reports, it seems the main issue they had was one of quality control and inconsistency where not all 512 chassis were build exactly to the same standard. Teams which had the most success, namely Penske, put a lot of work into extra prep of their cars to make sure the design worked as intended.

The chassis did have a significant weight disadvantage to the Porsche; tube steel fabrication making for a frame maybe 100kg more than the 917's aluminum chassis. Later 512M examples have a claimed weight of 815kg, but this appears to be a dry weight while true, Le Mans scrutineering weights from 1971 put the cars more in the range of 880kg with fluids included. The 512 S Coda Lunga models weighed in at an average of 940kg.

Aerodynamics is a big area where the 512 suffered from lack of development. It never saw a wind tunnel (early versions of the 512S even had little road testing because of an unfavorable winter in Sicily) and was drawn largely from past experience about aero ideas which should work in theory. Huge difference to the extensive wind tunnel program of the 917 models, and it showed at Le Mans where the Ferraris typically had between a 6-10mph deficit on similar, long-tail bodywork. Short-tail 512M models will top out around 217mph where the 917LH reaches 240. The 512 S Coda Lunga is good for another 10-15mph, but setting up for that comes with a handling penalty of losing maybe 50% of rear downforce compared to the 512M, which itself is some way behind the 917 for downforce numbers. The Coda Lunga gets very light going over the Mulsanne hump at speed, so be careful with your steering inputs when taking that crest at 230mph.

That all sounds like it adds up to a car which will just be smoked by the Porsche at every track in game, but truth is they proved quite well balanced in testing during our development. For one thing, the Ferrari ran wider tires at both ends, especially the front (285mm wide vs. 235mm), and that extra grip helps counter the aero deficiencies. Then there is that engine. The air-cooled Porsche flat-12 was a tremendous machine, but it was also a complex design and Porsche's own data shows that it was quite peaky in power production. Its peak of 600hp is only held for a few hundred rpm; go outside of that range and it drops significantly, change up a gear and it might dip below 500hp for an instant. That Ferrari V12, though, was a known design with which they had lots of experience. It's torque curve is much smoother and holds it over 550hp (90% of the peak 610hp) all the way from 7,500 to the limit at 9,600rpm, letting it pull much harder after each gear change. There may be a lower top speed, but it gets there more quickly and that is where you can find a lot of performance.

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