Posted by: drracing | February 9, 2018

2018 non-hybrid LMP1 – What’s the story?

In 2017, sportscar world was thrilled by the unknowns related to the introduction of all new LMP2 cars, which proved to have amazing performance, both compared to their predecessors and to LMP1 cars.
In 2018, we will live a very similar situation, although this time the revolution will happen at the very top of sportscars ladder.
With the shock followed by Porsche retirement announcement last summer and, initially, also with the uncertainty related to Toyota’s plans, sportcars world had to react trying to attract as many private teams as possible, in order to have a proper grid for 2018. To do this, the regulations ensured some incentives to allow teams and manufacturers with a small budget, compared to the one of an OEM backed team, to achieve performance that are close to that of an Hybrid LMP1 car, although using a standard powertrain.
With Toyota remaining the only LMP1 hybrid team to compete in the top class, the focus is all on the privateers and to what their level of performance could be.
The rules will ensure to non-hybrid LMP1 cars a series of breakthroughs in several key areas compared to what thy hybrids are allowed, to try to compensate for the absence of an hybrid system and the performance disadvantage that follows.
Private entered vehicles will have more freedom in terms of aerodynamics, with different rules regarding for example the design of front splitter and rear diffuser; moreover, LMP1 non-hybrid cars will have a minimum weight of 833 kg (3 kg of which reserved for the on board camera system), while hybrid cars will stay at 878 (again, 3 kg of which reserved for the on board camera). The difference of 45 kg between the two has a pretty deep impact on performance.
Finally, according to the latest agreements between FIA/ACO, Manufacturers and Teams, privateers will be allowed to use internal combustion engines only, but with a fuel flow of 110kg/h, which is nearly 10% more of what they were allowed in 2017. In terms of powertrains, the question remains of course how much power and what level of performance each of the available LMP1 engines will achieve. With the rules stating how much fuel can be used, the focus is all on efficiency, as improving this parameter means either having a higher performance or being able to drive longer with a full tank, both cases bringing their advantages in an endurance race.

At the moment of writing, five private teams have announced their intention to take part to WEC Superseason using four different engines, three of them being supercharged (Cowsorth/Nissan, AER and Mecachrome) and one being a normal aspirated (Gibson). The three turbo engines are all six cylinders; one employs a single Turbo (Mecachrome) and two a twin turbo layout; they are often referred as the favourites, both because supercharging should allow an higher efficiency (although i honestly don’t know if this is true) and because it should help producing a more favorable torque curve. In an attempt to optimize even further how each drop of fuel will be used, Mecachrome also opted for a direct injection approach, moving slightly away from the solutions used in the engine they used as a base for their LMP1 product, namely FIA Formula 2 2018 power unit.
Normal aspirated engines, on the other side, could probably struggle in getting the same energy efficiency as supercharged ones (again, not sure about this) and it is not a case that Gibson opted to increase its engine capacity, probably also aiming to have a more favorable torque curve and keeping the rotational speed lower to limit friction losses. Anyway, reliability could be a key word, above all in Le Mans, where the pure pace is really only one of the necessary ingredients to succeed. Beside this, a normal aspirated engine should be easier to “package” into the car, because of the less demanding requirements in terms of cooling and ancillaries (although Gibson V8 will probably be bigger than the two V6 competitors).
The question that keeps a lot of fans busy, at the moment, is really how much power 2018 LMP1 engines will have.
The easiest way to get to a power figure basing on the allowed fuel flow is to use Brake Specific Fuel Consumption (BSFC), a parameter that indicates basically how efficiently each gram of fuel is used to produce power. This parameter depends on a lot of others, but it is somehow a measure of how good an engine is in converting energy, which surely depends directly on the goodness of the combustion process and on the level of technology that has been developed.
According to the rumours circulating about 2018 engines and to the information that could be collected, it looks very much likely that more than one engine will be able to produce a maximum power in excess of 700hp, with some sources saying that one engine could even get close to 720hp. These values are pretty impressive, not only in absolute terms, but also if we consider the BSFC numbers they would correspond to. Assuming an engine would produce about 700hp with a fuel flow of 110kg/h, it would have a BSFC close to 210 g/kWh, which is an extremely interesting value.

With all of this in mind, one questions still remains to be answered. Which level of performance could we expect for 2018 privateer LMP1 cars?

To try to answer, I started a small project, building a “LMP1-like” vehicle model, using a validated WEC-Spec 2017 LMP2 one as a base and running some Driver-in-the-Loop simulator sessions on some of WEC Superseason tracks, including Le Mans. A driver supported this project, taking over all driving duties.
Starting from a WEC 2017 LMP2, I changed all the parameters that differentiate an LMP1 and an LMP2 vehicle and about which I could find trustable data.
First of all, car overall weight was reduced by about 100 kg (LMP2 cars have a minimum weight of 930kg) and also the inertial properties (mainly moments of inertia) were scaled down accordingly.
The vehicle model was also fitted with four LMP2 rear tyres, because LMP1 cars are allowed to use the same wheel size on both axles (i had to slighlty adjust suspension hardpoints, mainly because of the bigger tyre diameter, but nothing having a dramatic influence on final performance).
I then assumed an engine torque curve based on data relative to an engine similar to one of the four we mentioned, scaling the power up to about 700hp. Interestingly, this engine has a different torque curve than the LMP2 one, but produce its maximum power at a similar rotational speed.
As the engine has much more power than an LMP2 one and the car is much lighter, gear ratios also had to be changed, making them longer to fit the new model. LMP1 cars will most probably have seven gears in 2018, anyway for this study I still assumed a six gears box.
The aerodynamics stayed untouched, and this should be a conservative assumption. LMP1 rules should allow to achieve better aerodynamic performance than what LMP2 rules concede. The only difference we need to mention in this area has more to do with car setup, as with the LMP1 car the best performances has always been achieved with a slightly higher downforce (and more rear biased) setup than what suited better the LMP2 on the same circuit.
Basing on this premise about aerodynamic, if LMP1 engines will really have the power figures we used for our model, LMP1 cars could be even quicker than what has been derived with this study.
Beside these generic data about the car, anything more specific can be shared because all the information are confidential.
The tracks we run the simulations at are Spa, Silverstone and Le Mans. In the following analysis, I will use the performance we achieved with the LMP2 model at each track as a reference and compare it to what the driver could do with the LMP1 one, trying to derive a trend that could help to predict what are the lap times that we could expect for 2018.

Let’s start with Spa, as the Belgian circuit will host the first race of 2018/2019 WEC Superseason.
After running some sessions with the LMP2 car model on this circuit, the best laps the driver could run were in the region of 2’02”7.
As soon as we switched to the LMP1 model the difference was evident, not only in terms of pure speed, but also in terms of handling. The much lower weight allow an higher minimum speed more or less in every corner and makes the car extremely agile and very reactive. Moreover, the four equal sized tyres helps significantly also during brakings and further improve car overall grip also in slow corners.
The best lap time out of a few runs was a 1’56”5, that means 6.2 seconds quicker than with the LMP2 car.
Looking at the logged data, focusing on the speed trace first, the reader can immediately recognize how the car flies through the Eau Rouge – Radillion section and achieve a top speed close to 313 km/h at the end of the Kemmel straight. Also the minimum speed at Pouhon, a long and fast left double corner, is impressive, with the driver being able to negotiate the turn at about 241 km/h. The car had a very predictable behavior in slower corners too, with minimum speeds also slightly above the values achieved with the lmp2. Of course, the amount of power available made necessary some work on the throttle pedal, to avoid excessive wheel spin, above all exiting first and second gear corners, like La Source or the last chicane. This seems to suggest that working on the traction control could be very important, above all when the tyres start to degrade.

 

Spa speed

 

All of this is well reflected in the following plot, showing lateral and longitudinal acceleration traces. Focusing our attention on the lateral acceleration first, we immediately notice how the car reaches peak values well above 3g at Pouhon, but also has substantial grip in slower corners.
Brakings are also showing higher decelerations than the LMP2 car, thanks to higher speeds and lower weight.

 

Spa acc

 

Also in Silverstone, the difference between LMP1 and LMP2 was pretty substantial, with the driver being able to lap in 1’38”67 in the LMP1 and 1’44”1 with the LMP2, which means a gap of about 5.4 seconds between the two. With the track offering shorter straights than Spa and requiring a higher downforce setup, the top speed (at the end of the Hangar straight) is now slightly above 300 km/h. What impress more, anyway, is the speed the driver can carry in some iconic, fast corners like Abbey and Stowe. In the first one, he only slightly reduces throttle opening to help the car turning in and has a minimum speed above 275km/h. At Stowe, a corner with a smaller radius, the minimum speed is anyway above 245 km/h.

 

Silv speed.PNG

 

This is, again, well reflected by the lateral acceleration trace, that tells us the car could achieve peak values above 3.5 g at Abbey and above 3 g at Stowe.
Maximum decelerations are again above 3 g, as in Spa.

 

Silv Acc.PNG

 

Last, but probably most interesting, are the results obtained in Le Mans.
The driver tested once again the LMP2 model first and, after some sessions, he lapped in 3’26”89. We then switched to the LMP1 vehicle model and, again after some training time, he was able to lap in 3’17”21, which is an impressive 9.7 seconds quicker than with the LMP2. This is probably the most interesting result, as we will have a chance to explain later on.
Analysing the most important metrics, focusing on the following speed plot first, we immediately notice the top speed of 349 km/h that the car achieves before the Playstation Chicane.
Beside this, we identify a minimum speed at Tetre rouge of about 215km/h and of more than 265 km/h at the first of Porsche curves.

 

LM speed.PNG

 

Accelerations are good indicators of car overall grip potential and it is interesting to see how car’s lateral acceleration exceeds several time the 3 g mark, as for example at the Porsche curves.

 

LM acc.PNG

 

Once again, top longitudinal accelerations are close to 3 g.

We can summarize the results of this study, in terms of lap times, with the following table:

 

LMP1 vs LMP2 sim

 

Before digging into the analysis of our simulation results, trying to predict what 2018 LMP1 performance could be, we should summarize once again under which assumptions the above mentioned results have been obtained.
I basically up-tuned an LMP2 car, using 2018 LMP1 minimum weight, four LMP2 rear tires, maintaining nearly all chassis related parameters unchanged (see aerodynamics, suspensions main metrics, mass distribution and only adapting the setup according to needs) but changing gear ratios to match new powertrain performance. Among all assumptions, engine power (and power curve) is probably the most open question: I assumed an engine producing a maximum power of about 700hp, which is what many sources seemed to suggest being realistic for these cars. But of course, there is no certainty this will really be the case.
Another very sensible assumption, in terms of performance, is the aerodynamics. I could imagine, assuming carry over LMP2 performance, I should have underestimated what LMP1 cars will be able to achieve. According to the information I have, LMP1 should be able to perform significantly better on this side, compared to LMP2; since two of the four current LMP2 chassis manufacturers will also produce LMP1 cars, I think we can expect they could achieve much better results with their cars, compared to their LMP2 products. Anyway, much will depend on the focus that each constructor will have on Le Mans, as it could come as no surprise that some of them could give to creating a package suiting the Circuit of La Sarthe more importance, even sacrificing some performance on sprint circuits.
The first point we can conclude is that the new privateers LMP1 should be significantly quicker than LMP2 cars, both in terms of lap times and top speeds. This is maybe no surprise, but could indeed play an important role in race and traffic management, as LMP1 cars should be able to overtake LMP2 cars with relative ease.
Anyway, what is probably more interesting, is the comparison between Toyota 2017 performance and what we could expect for 2018 LMP1 private cars.

 

LMP1 vs LMP2 2018 pred

 

The table above shows again our simulation results, including deltas between LMP2 and LMP1 vehicle models, but expands this a bit, assuming we could apply the same deltas to 2017 LMP2 best qualifying lap times, to come to a realistic prediction for LMP1.
As the reader can see, the gap between 2017 Toyota and a 2018 LMP1 privateer, with a car reflecting my assumptions, should be about 0.8 seconds in Silverstone and 0.9 in Spa. Anyway, what is probably more shocking (or interesting) is what comes out analyzing Le Mans performances: if we compare 2017 stunning pole position time (done by Kobayashi) and a prediction based on the delta we obtained with our simulation, we have a tight 0.88 seconds gap (on a 13.6 km long track). I also reported the second best lap done by any Toyota driver (actually again by Kobayashi) to show that Kobayashi’s pole position was something really extraordinary. The second best lap is already above the 3.17 mark and comes very close to our results. Kobayashi’s time was also the results of a track in perfect conditions, as the streets representing the non-permanent part of the circuit had not be reopened to traffic before Thursday in 2017.  As far as i know, Toyota’s team itself didn’t expect to see such a performance, which was also achieved in a lap where they found nearly no traffic.
Moreover, we have to keep in mind two important points:

  • Toyota uses in qualifying the whole energy stored in the batteries or, in other terms, they discharge them completely, not caring about how much energy can be harvested with regenerative braking, because in qualifying only a few laps must be completed. This is probably true in all circuits, but we don’t know exactly if we should expect the same influence on lap times everywhere. Anyway, this means the drop in performance between qualifying and race is pretty big for the Japanese cars, which has not only to manage fuel and tyres, but also face a lower powertrain performance. The non-hybrid cars don’t have this issue, at least if they will not use any special engine setting for qualifying; in any case, the drop in performance should be lower than an hybrid car.
  • LMP1 non-hybrid cars top speed will be much higher than Toyota’s ones. This is particularly true in Le Mans, but will be also the same in some other circuits. In Le Mans, anyway, the difference will not only be bigger in absolute terms, but it will probably also count more because the cars will also spend much more time traveling on straights; this should allow the privateers to take advantage not only on lap times, but also in close fights.

 

We could expect Toyota still having an advantage coming from their hybrid system in tracks where there are more accelerations starting at a lower speed. In general, in sprint circuits they should still have an edge on the privateers and, depending on their effort, could achieve interesting performances on that side.
Anyway, what is extremely interesting, is really the small gap it seems we should expect in Le Mans. Now, surely Toyota will come with an improved car in 2018: even if staying on the same base of 2017, we can expect they will try to improve their package.
Anyway, as we mentioned already, we should not forget that LMP1 regulations should allow to achieve better aerodynamic performances than what we assumed. It looks like engines performance remain the most challenging open question, both in our analysis and in determining 2018 LMP1 privateers final lap times.
It also looks like Toyota probably came to similar conclusions, because in the last few days media have reported about the privateer being a serious challenge for the Japanese team. It is interesting to see these comments, also because Toyota took part at the discussions to define LMP1 non-hybrid rules and agreed with them, as far as we know. It would be sad if they would somehow not show their cards before Le Mans, with the aim to let the FIA/ACO recheck privateers rulebook.
In any case, we could have a very interesting season indeed!

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Responses

  1. Fantastic article thank you for posting. The LMP1 class is going to be far more interesting than people give it credit for. Do you have a estimate about which car and drivetrain package is going to be the fastest and most reliable.

    • Hi Tyler,

      thanks for your kind words and for your comment.

      I think i am not in a position to answer your questions, but for sure reliability will be a very important point, with such young cars.

      I could imagine Rebellion being very fast: they have a stellar drivers roaster and, knowing the quality of Oreca´s cars, they could have a very fast vehicle too!

      On the other hand, i think that also Ginetta and Dallara have most probably done a very fine work. It will be interesting, also to understand which engine will perform better.

  2. Always a very good reading, thank very much for the article! Its a very good introductuon to what we can expected from 2018 lmp1’s. I guess that some times bad things(porsche exit) can create better ones. Cheers and good luck with your projects for 2018 🙂

    • Thank you very much for your comment and your wishes! I really hope our expectations will be fulfilled! If not even overcome!

  3. Just found this brilliant site and as a car and racing enthusiast I am pretty much delighted, that there are some professionals willing to share their broad knowledge. Thank you for that!

    As for Toyota I may be wrong but as I remember still big part of their team is indeed old Peugeot Sport team that was dealing with 908 HDI FAP back in 2010 – the year of Peugeot’s disaster at Le Mans. What I mean is that I think Peugeot Sport team had always had wrong approach to endurance racing. In terms of strategy, car design etc. Looks like part of it is still with Toyota. Of course they were trying to beat rivals while having just a small part of their budget. But now they have rivals with part of their budget and it looks like they are trying to grab victory at Le Mans with lower costs possible, now counting on regulations to help them. I wouldn’t be surprised if Toyota underestimetes their rivals. Again.


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