u/Inewitt

PRE SUBMISSION EDIT: Unfortunately there is no good way for me to get the histograms into this post visually. I apologize that this will be a wall of text but I’m happy to provide the data to back it up if you need it later. Don’t data analyze on your phone kids.

Happy Le Mans practice day everyone! Although I had originally thought this would not be possible as I conveyed on u/Sad_Cow_7425 ‘s post, circumstances on my vacation have afforded me more free time than I expected and I’ve toughed it out with my workbooks from last year on the abysmal sheets for ios app on my phone. I do want to be clear that this will almost certainly be my only post this week, besides maybe a final predictions quick update after practice. If you saw my post last year much of this will be familiar as I’ve copied over much of the descriptions, such is the nature of limited time. With that out of the way, let's get into the meat of this analysis.

The beauty of Le Mans is that not only do we get sector level timing data but we get micro-sector level timing data of each of the sessions. This allows us to really dig into the strengths and weaknesses of the various cars, and see where teams might have room to improve over the course of the week.

Let's get the usual caveats out of the way first. This is a test day. Teams are running different programs, setups, fuel loads, tires, etc. The tires are especially important, and I am once again begging WEC to include tire data in their post session data exports. I won’t be able to tell you who is going to win Le Mans, and that's not my goal. I will provide my opinion on how things are standing heading into practice, and try to provide you with the relevant data to draw your own conclusions.

To understand the value of this data I want to do a quick postmortem on last year’s analysis. How much were we actually able to glean from the test day? Well first I have to start with an admission. It was clear from the test day last year that Ferrari were ahead. Whether I am overly optimistic or just wanted to be conservative with my analysis since it was the first time I’d done it on that level, I really shouldn’t have put anyone in tier 1 with Ferrari after the test day. Between the test day and my final rankings from free practice, which I was quite happy with after the race, we saw Porsche rise to the top tier, and Toyota and Alpine both fall off. Whether there was sandbagging going on or the extreme temperature swing between the test and practice caught people out last year I’m not sure. I think it’s safe to expect a couple of teams to move up a tier this year and a couple to move down. But I wouldn’t expect Peugeot to jump to the top and I wouldn’t expect Cadillac or Toyota to be totally uncompetitive. 

The other thing to note about this year compared to last year is that the times are much closer than the test day last year. The entire field (sans Peugeot) is covered by the same spread that Ferrari to the third best team was last year. That means we might see more relative shifting and changing of the order this year in practice but the field in general should be tighter.

To start

TLDR summary of car strengths and weaknesses.

Tier 1
Cadillac
It’s clear what the point of Cadillac’s offseason upgrades were. They are strong everywhere they were weak last year, and where they were strong last year they are average.

Strengths: Very well rounded, probably the strongest overall. Very strong on the Mulsanne and mid-high speed acceleration.

Weakness: Few real weaknesses, most average in the first chicane, Porsche curves.

Toyota
Toyota were in my top tier after the test day last year but fell off in the free practices. I think their pace is more real this year, but there is also the chance that, like Cadillac last year, they are good in the wrong spots.

Strengths: From slowest in the Porsche curves last year to the standout best. Still extremely good low-mid mostly mechanical grip corners. Think first chicane.

Weaknesses: Low/mid speed straightline acceleration.

Aston Martin
Yes, that’s right, Aston Martin is a legit tier 1 team. However they are much more hot and cold than the Cadillac or Toyota which could lead to issues it carries through into the race.

Strengths: As with last year, Aston is the standout best in low speed traction. They add to that with strength in particularly mid speed cornering but also the Porsche curves.

Weaknesses: The Aston struggles pretty heavily in heavy breaking and top end acceleration. Slow in fast out?

Tier 1a (for Alpine)
Alpine
Alpine were my tier 1A last year after test day as well but fell off heavily by race day. This year they don’t really stand out massively anywhere good or bad. They are considerably closer this year than last but can they maintain it? 

Strengths: High speed corners, Top-end acceleration.

Weaknesses: Mid-speed corners

Tier 2
Ferrari
Look, you don’t think Ferrari will be here come race day, and I don’t either but maybe they finally got hit with the BoP hammer? The irony of course is that Ferrari here is closer to the front runners than most were to them last year.

Strengths: Pretty middle of the pack everywhere. Best sector is the Porsche curves.

Weaknesses: Low speed acceleration

BMW
BMW just seem a little bit off of the front somewhat consistently. They have 1 clear best sector and two clear worst sectors but otherwise are middling.

Strengths: Mulsanne Corner

Weaknesses: The first chicane, the exit of the Porsche curves.

Genesis
While Genesis doesn’t lead any mini sectors outright, they do well enough in enough for their optimals to line up very evenly with Ferrari and BMW

Strengths: Medium speed corners, Porsche curves

Weaknesses: All speeds straightline acceleration 

Tier P (for pain…I mean Peugeot)
Peugeot
Just a quick statistic to highlight where Peugeot is. They have two mini sectors total where they are in the top HALF of teams, and they are the two shortest mini sectors on the track.

Strengths: Breaking my heart, suffering, livery

Weaknesses: France

With that out of the way let’s dive into the nitty gritty.

/Le Mans Timing Loop Map

The data that I have from what the WEC publishes publicly splits the lap into 14 micro-sectors of timing data. They vary from about 2 seconds on the short end to about 32 seconds on the long end, but they all have a story to tell. For each micro-sector I looked at  not only the fastest time but, for two car manufacturers the 5th fastest time, for Cadillac and Ferrari the 10th fastest time. This was done to filter out positive outliers (big tows, extreme fresh tire laps, etc.). I also looked at the full set of times to get a broad sense of consistency.

Sector SCL2
This sector starts at the S/F line and ends past pit exit. On a normal lap this sector is 100% full throttle, and is more exemplary of the capability of cars exiting the Ford chicane on traction since it’s too low speed to see major aero impacts.

Aston Martin and Cadillac stand clear of the field here. Aston’s low speed traction was strong last year but Cadillac struggled here, which will be a theme. Ferrari and Genesis struggle here as does Toyota, one of their few weaknesses.

/Sector SCL2 histogram

Sector Z4
This sector encompasses the first chicane. It is a medium braking zone, and the chicane has a min speed around 100 kph.

Last year Toyota was dominant here, this year they have new company in Genesis. Alpine and Aston are also both closer this year than they were last year. BMW stands alone on the bad side, a decent margin off the rest.

/Sector Z4 histogram and map

Sector IP1
Covering the corners from the dunlop bridge to the apex of Tetre Rouge, this is an interesting combination of corners with min speeds of around 160, 200, and 190 kph. Full throttle time is about 40%.

Aston goes from last last year to first this year, joined at the top by Toyota who continue their mid speed corner strength. Cadillac is a bit behind with the rest all together further back. Not much separating those outside the top 3.

/Sector IP1 histogram

Sector Z12
This sector runs from the apex of Tetre Rouge to the exit of the first Mulsanne Chicane. While the various sectors along the Mulsanne look similar at a glance, each is impacted by both the corner at its start and the corner at its end. As Tetre Rouge has a relatively high midcorner speed, this sector favors cars that would otherwise struggle with the mid-low speed Mulsanne chicanes or the low speed Mulsanne corner.

This is another sector lead by the top 3, with Alpine interloping not too far behind. When looking deeper down the times for consistency, Genesis jumps to the fore, not setting the glory sector but with consistent pace. Ferrari and Peugeot are separated from the group on the bottom.

/Sector Z12 histogram

Sector SCLC
This sector is a short run in the acceleration zone out of the first Mulsanne chicane. It highlights cars able to carry speed exiting the chicane as well as those with strong mid speed acceleration.

If it’s a low speed straightline section it’s Aston and Cadillac at the front, period. This is essentially Peugeot’s only bright spot, leading the trailing pack. Not much separates Toyota, BMW, and Alpine, with Ferrari and Genesis out the back.

/Sector SCLC histogram

Sector A7-1
This sector runs from the exit of the first Mulsanne chicane to the exit of the second Mulsanne chicane. We begin to see in this sector who was quick in Z12 because of their exit of Tetre Rouge, and who was quick because of their run through the first chicane.

Cadillac is well clear at the front here, again showing their strength in an area of the track they struggled mightily at last year. Toyota and Alpine follow with the rest together well behind.

/Sector A7-1 histogram

Sector IP2
The run into and out of Mulsanne corner. Who is strong in heavy braking and low speed acceleration?

Cadillac continues its dominance of the Mulsanne straight handily leading this sector as well. Alpine, Toyota, and BMW are decent, and Aston Martin and Genesis are way off.

/Sector IP2 histogram

Sector A8-1
Another short acceleration sector, full throttle out of Mulsanne corner.

BMW’s time to shine, though Cadillac, Alpine, and Aston are not far off. The rest are pretty inseparable on the back half.

/Sector A8-1 histogram

Sector SCLB
One of the most interesting sectors of the track, running from the exit of Mulsanne corner to the exit of Arnage. It has a long straight, a high speed corner (~250 kph), a mid speed corner (~125 kph), and a low speed corner (~80 kph), so it should be a microcosm of the lap as a whole.

The fastest times here go to Aston and Toyota, but they are somewhat positive outliers where Cadillac is metronomically consistent and quick. As established in the sector description, this sector lines up very well with the overall pace and the tiers at the top

/Sector SCLB histogram

Sector PORIN
This sector is the run from Arnage to the Porsche curves. It is full throttle and mostly traction limited, only starting to get into the aero limits towards the end

If it’s straightline traction it’s Cadillac and Aston, though this being a higher speed section Caddy shines a bit more. BMW and Alpine are not far off Aston, with Toyota a step off them and the other three a step off Toyota.

/Sector PORIN histogram

Sector POROUT
My favorite part of the track, the Porsche curves. With min speeds around 260, 210, and 210 kph this section is pure high speed cornering, one of the best isolated tests for these cars.

Where Caddy was well clear of the field last year, this time it’s extremely even between almost everyone. Toyota has a slight edge. Genesis, Aston, Alpine, and Ferrari are all a quarter step off that, BMW and Cadillac another quarter step off, and the less said about Peugeot the better.

/Sector POROUT histogram

Sector SCL1
From the exit of the Porsche curves to pit in, a functionally straight sector and another full throttle acceleration zone. The difference here is that the cars are exiting a high speed cornering rather than a low/mid speed one. Fortunately the ACO got rid of PITREF so this now also includes the braking for the Ford chicanes.

Aston and Toyota are clearly ahead here with the rest sand BMW not too far behind. BMW struggles here.

/Sector SCL1 histogram.

Sector FORDOUT
This sector covers all of the Ford chicanes and are actually pretty even across the board. My hunch is that the chicanes are limited more by commitment than mechanical grip.

This year it’s very even across the board though Toyota does have one standout sector time.

/Sector FORDOUT histogram

Sector FL
The run to the finish. Another traction/corner exit speed test.

Say it with me: straightline traction, Aston and Cadillac. Slow speed means its Aston favored, and Toyota is not too far off Cadillac. The rest are basically even behind, with Genesis and Peugeot maybe a bit off on the worse end.

/Sector FL histogram

Conclusions
A much closer test day overall than last year. If I had to make a guess, though that’s not something that should be done at this point, it would be a Cadillac and Toyota fight for the win, and I do think it would be a fight. The reality is the picture will change (and already is because I’m so late with this). I hope I can do a quick update after practice is done but this may be the last you here from me this week, in which case I hope this was insightful.