Lead Vehicle Artist Casey Ringley goes through the CADs and gives you the inside scoop on the three LMPs that gave us the best Le Mans finish in history in 2016. They’re all yours to race in Project CARS 2 with the “Spirit of Le Mans” Pack
Le Mans Royalty―the Audi R18
Being that the R18 was retired after 2016, some impressive reference material was provided to us for this car, which is something of a rarity for top-level, high-tech race cars. This data was really great to have as it filled in the few knowledge-gaps we had from the 2014 car and allowed us to build a model which I feel is a really special representation of the real car within our system.
The really cool part of this was the sheer detail sent over by Audi in the CAD model for the R18. This is the 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. The answer? Build in a serious amount of caster angle, with the front better described as multi-link than the double wishbone it would appear to be on “paper”.
The front and rear bars of what look like wishbones aren’t actually connected at all at the upright, thereby allowing the wheels to move slightly fore-and-aft 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.
The engine is the same V6 turbo diesel Audi had been using for six years in 2016, though it was now 4.0L, not the 3.7L that Audi had used until 2014 as they transitioned to future-oriented regulations with energy efficiency, albeit with constant, (though incrementally small) updates to abide by the regulations. By 2016, Audi was in the 6MJ hybrid spec’, and that meant reduced fuel-flow which resulted in the lump making around 520hp peak which it holds from around 3,500 through to 4,250RPM. And that is the entire rev range that you want to be using for optimum performance.
That part of the power unit 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 in-game.
Up front, the hybrid system had a huge upgrade from 2014. The flywheel is gone and has been replaced by a high voltage lithium ion battery, with the motor upgraded for 350kW peak power (limited by rules to 300kW at Le Mans).
Analyzing on-board telemetry shows the energy store works out to a nice, round 1kWh while boosting, 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 260kmh even if there is plenty of energy left in storage―getting up to that speed in a few quick seconds 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 carried over from our 2014 car data with slightly less drag to hit the right top speed reference points: ~320kmh at Le Mans, 295kmh at COTA.
There were some rules changes meant to cut LMP1H downforce in 2016, but the teams surely clawed it all back by season’s start, and cornering performance looks close enough to the mark on the 2014 downforce levels.
We do have the R18 artwork split to Le Mans and high-downforce variants for liveries. Handling QA Lead Jussi Karjalainen 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 Fuji-model has steps 4-ten. Choose your variant wisely to suit both track and your own driving style. (And if you know the weather, you might want to consider that too.)
The 3-time Le Mans-winning Porsche 919 Hybrid―the true heir to the 917 Crown
The Porsche 919 was still actively winning championships during development time for Project CARS 2, so information was a bit more secretive than our development on the Audi R18 that had already stopped racing by that point.
Having said that, the 919 uses a chunk of its base from the 2016 Audi R18 in-game, and the differences are largely from the power unit.
The engine here is a 2.0L turbo V4 which Porsche claim makes “just under” 500hp with the 8MJ fuel-flow limits. Mapping out fuel-flow, along with estimated thermal efficiency, boost pressure curves, etc., means we can be pretty certain that it holds 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 the electric motors on the front axle that tops an additional 300kW (limited by rule for Le Mans). Typical strategy here is to burn hybrid power up to around 280kph, and then let the internal combustion take it from there to a 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―except that with hybrid you are at top speed for almost the entire time as it gets there in a serious hurry.
Charging happens with a regenerative braking system as well as a generator on the turbocharger which takes the 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 ingenious system.
Toyota TS050 Hybrid―180 seconds away from glory in 2016, and the fastest car to ever lap the Circuit de la Sarthe
As is usually the case, three years of rules stability saw the main competitors in the hybrid era 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 (336kmh vs 298kmh), 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.
The Toyota 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.
Where the two part ways is in their respective hybrid systems. Porsche run regenerative braking on the front axle plus an MGH unit taking excess exhaust energy from the turbo to charge a battery which then powers a motor on the front axle alone.
Toyota don’t do turbo-compounding but do take regenerative braking from both axles which then deploys 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 tyres instead of 300kW, so it is a little easier to get on the hybrid boost early without upsetting balance of the car.
It also does a better job at equalizing tyre 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. This takes a slightly different driving style than the point and shoot nature of the Porsche or Audi, but all three are super-close in performance over a lap by the end.
LMP1 H 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 what we see drivers doing in the real cars 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!
The most effective hybrid strategy in these three cars tends to center around finding the slowest corners of a track and burning energy on the exit up to about 260km/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.
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, using the hybrid for extra top speed of 310kmh-plus from the start-finish line all the way into braking zone 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 percent 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.