A little Aero test

[Highlandor]

So decided to kill 2 birds with one stone and do a little aero test whilst taking my newly complete Group C collection out for a spin (been waiting 3 months for the 787 and C9).

Used Le Mans for 2 reasons, mainly because of the long straight and high speed corners and well, to be honest, it's Group Cs at Le Mans.

Not a major or that comprehensive test, just curious about aero as it seems to be alot 'stronger' within the setup than before. Starting with higher amount of downforce cars, then will (hopefully) go to middle and lower downforces classes/carat some point. Just looking to see how much of a difference between various levels.

So test specs:

PS4 - disc version
Pad
Steering sensitivity 5
Controller set to directional buttons
Manual gears
All driving aids off apart from ABS 1

Le Mans - no chicane
Time Trial
6:30
Sunny 21c
Surface 31c

Mazda 787
Everything stock
Racing HARD tyres

Didn't realize that online lobbies have different times of the day than offline time trials, so chose the early morning one. I couldn't see track temp in online lobby (?) but noticed wind was different, which reminded me of interesting video made by WombleLeader (attached at bottom).

I started with 787 in time trial, then recreated this in online lobby, the figures for online lobby are in italics. Quite surprised as Rotational G figures were identical (I was expecting them to be a bit different, but everyone of them was identical (interesting))

After finishing initial test with 787, decided to do a quick test with Jag and Merc, so did max aero and min aero runs for them. At this point, noticed wind direct was perfectly parallel with Mulsanne straight, so did an on the spot experiment of turning around at the bottom of the Mulsanne straight and driving straight back up it (i.e. into / against the wind). These figures are shown as highlighted.

The wind speed figures of 4.4-4.6 are approx as I initially wasn't going to include these, so the only info I had was 2 runs that were saved in leaderboard of time trial, one was 4.4 and the other was 4.6, so have to admit, the wind figures might not be 100% accurate for each run..

I think that's about it for now, plan is to go down a class and repeat, but we'll see how things go. This is just meant to give a rough idea of the kind of difference aero makes, this is NOT a test to find out what the 'best' aero setting is.

In terms of handling it was quite surprising that all 3 cars struggled badly when max aero was applied at both the front and rear, especially in first turn going into chicane with cold tyres. All 3 spun off uncontrollably with snap oversteer. This is why I did 2 laps for each run, to compare how the cars felt with tyres warmed up.

As expected, lowest downforce meant all 3 cars had noticeable understeer, none of the 3 settings where aero was even front to rear felt well balanced, the 2 settings where the balanced was changed to med / max made the car feel better balanced, but nowhere near perfect.

Overall, the biggest difference in speed was nearly 40mph, 203 to 241 (38mph to be precise), which seemed like alot, but the biggest surprise was how bad the cars felt when max fr and rr aero was applied.

If you don't have much experience or knowledge with tuning high aero and you're looking for a starting point then go with medium front and max rear, it's not perfect, but it's not a bad starting point. Then tune little by little from there.

 

[Highlandor]

Seeing as it looks like pre V1.71 SaRG data is currently moot, I looked back at what stuff I had to see if there was anything else that could be compared post V1.71 to previously.

One of the things that I felt had some validity was the aero test, as this could be re-created and some of the results would be a valid comparison.

Also, technically, changing the toe does mean that those results should be invalid, but I did the first 3 runs on the new stock toe setting, then changed the toe setting and did another run, which resulted in the exact same top speed(s). So, for the last 3 runs, I just went ahead with the modified toe figure, but accept this is not technically correct.

Another aspect of this test that potentially impacts the validity is that I didn't compare the new min / max aero figures with the old min / max aero figures. I did a numerical comparison rather than a % comparison, so again, accept this impacts validity. At some point I'm hoping to go back to this and compare new maximum values against old aero. These results do show that the more aero a car has, the more it's top speed is reduced, and this was something that was linear, each stage of reducing aero got a higher top speed

Aero differences detailed here:

• #1

Results of top speed comparison to pre V1.71:



One thing that was noticeable pretty much straight away was how the PP points were reduced along with the top speed. So I looked to try and find some other types of cars that I had data for that could be compared to see if the PP point reduction was linked to visible aero changes.

After (a lot) of searching, I found 4 cars that I felt were a valid comparison, 2 which had aero and 2 which had no aero at all and all 4 were the same pre and post V1.71.



All 4 cars showed a reduction in PP points even though their aero figures were unchanged from V1.71 update. Unfortunately, didn't have any top speed data for these cars as obviously had no idea the date was going to do this.

Interesting.

Going to have a little play around with the PP / aero settings for the couple of WTC800 test / grind cars. With everything that has gone on, I can't remember how the fr aero impacted the PP points, I know that the rr aero wold impact the PP points and the more rear aero you had the more it reduced your PP points.

But that doesn't explain why the 4 cars with no aero changes had their PP points affected, so this indicates that aero might not be the only variable at work here.

Except.....

Spoiler: y'see.....