Posted by: drracing | August 8, 2018

24 Hour of Le Mans 2018 – Race Analysis – LMP1

Hi everybody,

although with embarrassing delay, this post will focus on the numbers relative to this year Big Race.
It is the first time i analyzed a 24 Hours Race, but i will basically use the same approach i used for other analysis, crunching the numbers provided by FIA/ACO about the race and trying to understand how each of the main actors performed.

This year race was full of promise, with a lot of hot topics on the table, like Fernando Alonso racing (and winning) with Toyota and with a lot of drivers with previous Formula 1 experience taking part to the competition.
Beside this, the LMP1 class has been interested by a revolution, with Toyota remaining the only work team attending the WEC Superseason and being joined by several private teams, running cars without any hybrid system.
The deal had to be that these teams, running with significantly smaller budgets than any manufacturer, would be helped by the rule to get close to Toyota’s performance, mainly through a series of breakthrough mainly regarding aerodynamics, weight and the amount of usable energy for each lap.
All good, if it would not be that the ACO/FIA introduced a further series of “strange” rules with the aim to ensure to Toyota a safe advantage on the competition, although the first race of the Superseason in Spa had already showed how much quicker the Japanese cars were compared to privateers.
Among others, some of the actions consisted in a reduction of the fuel flow that the privateer could use, of the amount of energy per lap and a fixed stint length, that had to be one lap shorter than Toyota’s one, in green flag race conditions.
I would not dig too much into the details of these decisions, but i can say i was extremely disappointed to see similar actions coming so late before Le Mans, with the clear intention to ensure Toyota’s victory. Something that Toyota didn’t need at all.
Beside the reduction in the fuel flow, that most probably put the privateers in an extremely uncomfortable position of having less power than they expected, with this affecting also their ability to deal with traffic (the best qualified private car didn’t have any speed advantage compared to LMP2 cars, for example), the fixed stint length, in particular, is something that goes completely against the spirit of LMP1 technical rules, that from the beginning always focused on efficiency; this also took out a very interesting strategical element during the race, with every team having to pit after a mandated amount of laps.  No more reward for drivers being able to save fuel or teams deciding for a different approach, as the same Toyota did in 2016.

In the LMP1 class the race itself has been poorer of emotions compared to previous editions, with each car more or less doing its own race and the class itself being practically divided in two subclasses: Toyota and all the others.
On the other hand, anyway, it must be said that Toyota was very fast, also compared to previous editions, both in terms of pure speed and general pace and that Toyota’s two cars pushed against each others more or less for the whole race.
Alonso did indeed an amazing job, being not only incredibly fast but also dealing with traffic like a Le Mans veteran.

Enough words. Let’s get to the numbers now!

 

We will take a look to the LMP1 class first (i will deal with LMP2 in a separeted entry), focusing our attention on the two Toyota (car n.7 and the winning car n.8), the two Rebellion-Oreca cars (car n.1 and car n.3) and the fastest (before its retirement) SMP Dallara (car n.17).
By simply looking at the following table, showing each car best lap times, the average of the best 20, 50 and 100 laps and the “all clean laps” average, we immediately see that Toyota were simply in another class, with the fastest car of the Japanese team (car n.8) being consistently about 2.4 seconds quicker than the best Rebellion (car n.3), no matter which metrics we consider.

LMP1 best laps table

 

It is interesting to notice how car n.8 seemed to have consistently a better pace than the sister car, with the gap getting bigger as we consider more and more laps and staying between 0.2 and 0.6 seconds.
Focusin on the privateers, the best lap overall was actually obtained by the n.1 Rebellion, about 2.4 seconds slower than the best Toyota and 0.3 seconds faster than the sister car n.3 and the SMP Dallara.
Anyway, if we move on and consider the average of the best 20, 50, 100 and all clean laps, we see how car n.3 was constantly faster than car n.1 and, indeed, the fastest private LMP1 overall.
It is interesting to notice how, although car n.3 and car n.17 had more or less the same best lap, the SMP Dallara was actually slower than both Rebellions, although it fought for a long time with car n.3 before it retired, with the Rebellion apparently not being able to overtake the Russian crew, despite having a better pace. We will see in a few moments what could be the reason for this.

The following plots show the best 20, 50 and 100 lap times obtained by each car. In the last one i took out the SMP car, because their retirement during the night made useless to look at the best 100 laps, as shown also by the very high lap time they had in the table we just considered for the average of the best 100 laps.

 

LMP1 best 20 laps

 

LMP1 best 50 laps

 

LMP1 best 100 laps

 

These plots seem to confirm what we could conclude already by looking to the previous table.
Toyota was much faster than any private team. If we add this to the longer stints they could do (the winning car n.8 did two pit stop less than the third classified car n.3) and to the shorter refueling times, it is easy to understand why most fans thought the EoT didn’t work too well.
Car n.8 was sensibly faster than car n.7, while car n.3, the fastest privateer squad, was constantly faster than car n.1.
The SMP Dallara was not completely off pace, but still consistently slower than the Rebellions.

Let’s now break down our analysis and consider the sector times of each car.

As usual, the track has been divided into three sectors, the first one being the shortest (about 32 seconds for an LMP1 car) and the following two being much longer, as shown in the following track map.

 

track map

 

The first sector is the slowest one, being composed by part of the box straight, the dunlop chicane and the Esses, up to the entry of Tetre Rouge.
The second one is all about acceleration and top speed, being mainly composed by the Mulsanne straight (with its two chicanes) up to entry of Mulsanne’s Corner.
The third one is a mix of straight line parts and very high speed corners, like Indianapolis and the Porsche Curves, but it also includes the two slowest corners of the track: Mulsannes corner and Arnage, both normally driven in first gear.
The performance in the Porsche Curves is a real indicator of how much downforce the car has.

We will start with the first sector.
Here we have the first interesting surprise. The two Toyota were not the fastest cars here, with the honors being taken by the two Rebellion, as shown in the following table.

 

LMP1 best sec1 table

 

Car n.3 was not only the fastest Rebellion, but also the fastest car overall in sector 1. Both Rebellion were faster than the two Toyota, if we exclude the “all clean” laps metrics where car n.8 was slightly quicker than car n.1.
Car n.17 is relatively close to the two Toyota.

The following plots, relative to the best 20, 50 and 100 laps help us to get a visual feeling about the relative performance of each car compared to the others.

 

LMP1 best 20 sec1

 

LMP1 best 50 sec1

 

LMP1 best 100 sec1

 

The first two plots show an interesting point: car n.17 was faster than the two Toyota as well, if we only consider the 6-7 sector 1 times, but falls significantly behind after the 7 mark.
We could speculate about the reasons behind Toyota not being the fastest car in the first sector.
One reason could be that they could opted not to use the hybrid power so much in the first part of the track, as there were no long accelerations were they could deploy it effectively.
Beside this, Sector 1 is a pretty twisty section of the track, where handling and downforce surely play a role.
The privateers are lighter than the two Toyota and could have a very efficient aerodynamic, if the teams did a good job fully exploring the rules. As we will see, most probably this means a very high downforce for the two Rebellion-Oreca.
We have to keep in mind that the gap between car n.3 and car n.8 was anyway pretty small, in absolute terms: we are talking about 0.1 and 0.25 seconds, depending on the metrics we consider. As we said, the first sector is a very short one, so the differences between different cars cannot be too big, in absolute terms.
The magnitude of the gap in sector 1 must be kept in mind, as we move to consider sector 2.

The situation in sector 2 was in fact the opposite, with the two Oreca-Rebellion being slower not only than the two Toyota, but also than the SMP Dallara.

 

LMP1 best sec2 table

 

Sector 2 is where the Toyota builds the most of their gap on the non-hybrid cars, despite this sector being slightly shorter than the last one.
This is where the hybrid deployment can be used more effectively with the cars having to accelerate out of two pretty slow chicanes.
The gap between Toyota car n.8 and Rebellion car n.3 is between 1.5 and 2 seconds.
On the pure performance, the two Orecas are also sensibly slower than the SMP Dallara, with car n.17 being 0.6 seconds faster than car n.3 if we consider the best sector 2 time and about 0.3 seconds if we consider the average of the best 20 sector 2 times.
This is easier to visualize by looking at the following plots, relative to the best 20, 50 and 100 sector 2 times.

 

LMP1 best 20 sec2

 

LMP1 best 50 sec2

 

LMP1 best 100 sec2

 

The first plot shows very well how the SMP Dallara seats pretty much between Rebellion and Toyota, in terms of performance, although closer to the Swiss team. On the long run, anyway, the Russian car loses its advantage and its line even goes above the one of the two french cars.
It is also interesting to notice how both Toyota and Rebellion cars are extremely closer to each other in this sector. The reasons for this are probably connected to both cars of each team using similar aerodynamic settings and on sector 2 being not a track section where the driver can make too much difference.

The performance of each car in sector 2 seems to indicate that the Dallara run with less drag than the two Orecas.
This seems to be confirmed if we look at the speed trap data, with the speed trap being located before the first chicane on the Mulsanne straight.

 

LMP1 best speed

 

The SMP Dallara tops pretty much every metrics of our table, as long as the car is on the track. Its top speeds are consistently higher than the Rebellion, with both non hybrid teams being faster than Toyota.
A lower drag (or higher engine power) of the car n.17 with respect to car n.1 and car n.3 would justify its higher top speeds and its good performances in sector 2.
On the other hand it is still extremely revealing to think that, in a part of the track where (with traditional racecars, without any hybrid system) the top speed would normally make a difference, the car obtaining the best times is the one (Toyota n.8) having among the lowest top speed. This is the magic of accelerating like a rocket ship every time the boost of the hybrid kicks in.

The plots relative to the best 20, 50 and 100 top speeds achieved by each car help to identify some further points, beside giving, as usual, a clearer feeling of the difference between each car and the others.

 

LMP1 best 20 TS

 

LMP1 best 50 TS

 

LMP1 best 100 TS

 

The first thing catching our attention is, again, the higher top speed of the SMP Dallara.
Anyway, another interesting point related to the difference between a hybrid and a traditional internal combustion engined car can be clearly seen in the last plot.
Here we notice how the two Toyota have a much bigger scatter in their top speeds compared to the two Rebellion cars, whose top speed remains more constant even when analyzing more laps.
The reason why this happens lies most probably in the higher flexibility that an hybrid system offers to the drivers to cope with race situations. When needed, the two Toyotas could probably deploy more energy through the hybrid system to help, for example, in overtaking maneuvers, thus also achieving higher top speeds.
In normal situations, on the other hand, they would probably achieve much lower top speeds.
In a traditional car, on the other hand, if there is no special needs to coast before the brakings to save fuel, the driver simply keep the throttle completely open every time, thus having a smaller variation on the recorded top speeds.

Combining the data relative to sector 2 and top speed, we could spot the reason why car n.3 could not overtake car n.17 for a long time during the race, although being faster in terms of pure pace. The SMP crew had simply a better top speed, this making very hard for Rebellion drivers to try any attack.

What about sector 3?
Since sector 3 is composed of pretty different sections, including long straights and both fast and very slow corners, we will use not only the sector times for our analysis, but also some data relative to “best specific sectors” times provided by the FIA/ACO.
If we look at the following table, showing the best sector 3 time and the average of the best 20, 50, 100 and all clean sector 3 times, we can only recognize how big Toyota’s advantage on non hybrid cars was.

 

LMP1 best sec3 table

 

This table shows again Toyota’s superiority compared to any competitor, but also how the gap was now “only” about 1 second in a 91 seconds long sector, which is a smaller relative difference compared to sector 2, which was only about 77 seconds long and where Toyota was about 1.5-2 seconds faster than the best Rebellion car (n.3).
This rings a bell. For some reason, although being much faster than the privateers anyway, the gap that Toyota had on other cars here was not as big as would expect, interpolating what we have seen in sector 2.
We keep this in mind and we will come back on this in a moment.
We take a look to the plots showing the best 20, 50 and 100 sector 3 times of each car first.

 

LMP1 best 20 sec3

 

LMP1 best 50 sec3

 

LMP1 best 100 sec3

 

What these plots show, beside the gap between Toyota and the non-hybrid cars, is that the two Rebellions are constantly quicker than the SMP Dallara, despite the russian car having better top speeds, as we have seen.
This indicates that the two Rebellion were particularly effective in the more twisty part of this sector, which includes both very slow and very fast corners.
Some of them are the famous Porsche Curves, which are a sequence of tremendously fast corners, pretty much at the end of the lap.
Incidentally, although they are not a track sector per se, the FIA/ACO provides the best times each car obtained in the Porsche Curves section.

Porsche Curves

 

Key to the performance in these corners are downforce and aerodynamic balance, as the cars negotiate them at very high speed. The two Rebellion cars are not only on top in the list here above, but also have a substantial advantage on every other LMP1, with the best time of a Toyota being only fifth, with a gap of more than 0.4 seconds to the best Rebellion. Keeping in mind that this section is only about 14 seconds long, we can immediately recognize how much quicker the two Oreca were than the two Toyota.
Part of the difference in this sector could also come from the hybrid power not being deployed by the Toyota, leaving the two Japanese crews with less power than a privateer LMP1.
These seems the final prof of the Oreca running a very high downforce package, compared to other cars and typical Le Mans standards.
And this seems to explain why Toyota didn’t have such a big margin on Rebellion cars in sector 3, compared to what they had in sector 2.

Although i have always appreciated the fantastic technological battle that made for extremely exciting championships and races in the LMP1 class in the past few years (with Audi, Porsche and Toyota battling on track often wheel to wheel), i have immediately felt a strong interest and simpathy for the many privateers who built and raced cars in Le Mans this year.
Anyway, i have to admit that i think this last Le Mans was a pretty boring race and what disappointed me the most is that this came most of all as a consequence of the regulations and to the adjustments that FIA/ACO did without any apparent technical reason.
Balancing the performances of so different cars and teams, using different technologies and having completely different resources is surely extremely difficult.
Anyway, we all know how WEC was saved by private teams jumping in with nearly no advice, when Porsche stepped out, so it is pretty disappointing seeing how the rules pegged them down just a few days before the big race.
Nonetheless, these analysis should show how some of them have managed to do a great job in designing and building really competitive cars.

 

 

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