A Test on Aerodynamic Setups and Values

Basically what I'm up to here is putting GT5's aerodynamics to the test, as far as downforce adjustments are concerned and the amount of top end mph that they may or may not inhibit. I tested 4 cars of different types and recorded the results. I thought I would share them here, along with my conclusion based on the information I gathered.




Car #1 - Subaru Impreza WRX Race Mod

Aero at Max = 15F/35R
top speed achieved = 181mph

Aero at Default = 12F/20R
top speed achieved = 181mph

Aero at Minimum = 5F/5R
top speed achieved = 181mph




Car #2 - Le Mans C60 Hybride

Aero at Max = 60F/85R
top speed achieved = 246mph

Aero at Default = 55F/80R
top speed achieved = 247mph

Aero at Minimum = 30F/50R
top speed achieved = 252mph




Car #3 - Audi A4 Touring Car

Aero at Max = 35F/60R
top speed achieved = 193mph

Aero at Default = 20F/45R
top speed achieved = 195mph

Aero at Minimum = 15F/30R
top speed achieved = 196mph




Car #4 = Lotus Evora (only rear aero wing available to install)

Aero at Max = 0F/20R
top speed achieved = 194mph

Aero at Default = 0F/15R
top speed achieved = 194mph

Aero at Minimum = 0F/5R
top speed achieved = 195mph




Based on these results I have come to the conclusion that choosing downforce values based on possible top speeds is a null approach to tuning this facet of the car unless the aerodynamics involved can reach very high values. But even with the 5 mph difference experienced between the highest and lowest aerodynamics used with the C60 hybrid, I would argue that whatever time gained on straightaway top speeds would be lost in technical parts of the track. The most prominent thing that I have found these settings to affect is the amount of oversteer and understeer. Next came actual downforce experienced over rough parts of the track. Car handling itself appeared to stay the same, unless the values were quite high, such as with the Le Mans car used in this experiment.



Thought someone would benefit from this. I know it cleared up a couple of questions for myself.

Thanks for the data. I did only a quick test with my Peugeot 908 so far. I found a difference of 13 km/h between max and min aero on La Sarthe without chicanes, which is in line with your data.

There is one more thing I'm wondering: How much does the GT-Auto aero really help? I noticed my McLaren F1 can take corners in Indy with exactly the same speed, no matter if GT-Auto aero is installed or not. GT-Auto aero can for sure alter the aerodynamic balance, but does it really add downforce to increase corner speeds? I tend to believe it does not. What do others think about that?

From what I can tell it does very little if anything at all to increase downforce in a way that is noticeable on the track outside of being able to create more oversteer.

I was toying with the S2000 GT1 Turbo the other day, and all 3 tunes tested had a different rear Downforce setting. This didn't really seem to come into play on any of the smaller tracks, but when I took the car to the High Speed Ring, There was a drastic different in the rear of the cars "grip". The lowest setting of the 3 was 30, middle was 42 and highest was maxed at 50. In the 3 major high speed long sweeping corners of this track, the difference between the 3 was tremendous. The setting of 30, literally sent the car sideways upon entry to the corner, as the rear of the car, simply lacked the grip/downforce to stay in place. With the setting of 42, the rear end did a "Swaying" motion back and forth, but never spun. And the final setting of 50, showed a slight 'swing' only on initial turn in, but then remained planted for the duration of the corner.

With the exception of Daytona, I've yet to see a single track that didn't benefit from more downforce. This includes feel, overall stability and lap times.

After all of my ZR1 testing on Indy, I quickly came to the conclusion that the gains far outweighed the sacrifices. Which made it rather clear to me, that this would apply at every other track, with the exception of daytona, where you can remain full throttle at all times regardless of downforce.

My concern would be the balance front to rear, not so much that you might as well max the downforce since it has no negative speed effect.
What ratio for front to rear downforce has the best handling...
I would expect raising the front to increase cornering traction..
I would expect raising the rear to increase rear traction, and maybe reduce the chance of tire spin..
?

So, for very technical tracks should I max the front aero and zero out the rear?

MowTin

So, for very technical tracks should I max the front aero and zero out the rear?

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I'm no tuner, but my process...

Max HP front and back. Run some laps
Then slowly start lowering the rear aero 3 at a time until you feel the car starts to become unstable. Go back up 1-2 until you find a good balance.

There are a few occasions, where I actually have to do the reverse. Max out the rear, and lower the front, to 'balance' the car.
I had an incident where one car the nose was so planted, but the rear couldn't maintain grip on higher speed entries, even when at max value, and would just swing me around on high speed corners. Lowering the front aero helped the 'balance' and proved to be better.

Adrenaline

stuff

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This is a good method.

Aero main dependancies are antiroll bars, sr/rh, compression dampers, camber/toe and LSD.

At first it was the first thing I tuned, now I'm shifting to finish sr/rh then have a general idea of my suspension and LSD before I tune that.

Unless you want to compensate that by another tuning effect, something equilibrated to have in mind is some values around "rear aero = 1.2*front aero +15" <- formula made by experience only, it's not to be taken as The Truth, only a linear indication of what I founded with two cars, The Thruth should be with squares.

I've gotta say that I agree with Adrenaline's method here.

I also must say I think some of the tests in the OP are a bit flawed, particularly the Impreza... If gearing is too short for the car to be at peak power at maximum speed, you WILL NOT see much top speed gain from lowering downforce... This only applies to those vehicles that have a sharp drop-off in power before redline (Impreza is definitely one of them) but you get my point. I found with my non-RM Impreza that even with only 400hp gearing can just barely be made long enough in 6th gear for optimum top speed... This means maximum length gears (261mph). The RM would be the same. Without doing this, when the car "tops out" it's likely using 50-100hp LESS than peak power; more RPM means less power at this point, meaning that lower drag cannot be taken advantage of.

Interestingly, my Impreza with 396hp actually hits 183mph... I'd assume the car tested had the maximum 500+hp. To see the full gains you HAVE to adjust gearing accordingly.

SS_1182

testing results

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Thanks for sharing. I found similar results in GT4, the effect that adding adding downforce has on top speed was minimal (compared to the difference in cornering speeds).

I also found that the best 0-400m times weren't achieved with minimum downforce, indicating that downforce does increase traction. Haven't tested it specifically with drag times in GT5, but I do notice that rear downforce improves traction out of slow corners.

Glitch yourself 12.5M and pick up the Ferrari F2007 while you can, the maximum front aero is 150; the maximum rear aero is 200. If I remember correctly, the default setup was 108F/120R. Good car to have fun with extreme aero testing, but likewise, I generally find best results near maximum on regular aerodynamic available cars (ie. 40/65)... it's only when you get above that to the more extreme race cars where running it below maximum may show some benefits on certain tracks.