Aero Base data

[PPiDrive]

@uber_understeer

If the car has a 53% if should be able to work, if you fdf is 75 then just 75*1.0095 and have that as your rear wing. So set your rear wing to 75.7 and your all good. If you rear wing has too much downforce for that just set at at max or min (as close as your can to get that number) and tune it or fine tune it with springs and such. Its a base guide just set at as close as you can.

Rereading this, I think I may have attempted the math backwards and done %RW /% FW for the ratio which checks out with the numbers I posted. Oops.

If I have the lowest downforce setting of 50 (in the front) and the math tells me to put the rear aero at 56 (same Mazda RX-3 example) you’re saying I should just set it as close to this as possible, so I would set the rear aero at 75 (it’s lowest setting)?

I don’t think I would ever use the aero that low, I typically leave it where the game has it or put it higher up for cornering with few exceptions. I just wanted to clarify for my own understanding, and it seems I goofed on the maths a tad.

[uber_understeer]

what about having the front at 75? that means that the rear wing can be 76.

[FEUERDOG]

Your findings are interesting.

Using similar test methods many of us early calculator tuners came to similar ratio relationships in the FM1, 2, and 3 days for weight distribution and spring values.

In my personal testing for ForzaTune4 and 5, I concentrated on leaving the aero tuning relationships up to the tuner/driver, only using personal guides for ratios that I used.

Where you have found an almost direct inverse weight distribution relationship, my findings were also tied to a relationship involving drivetype.

Whats cool, now that I look at some of my tunes, is that your 53% transition point fits our assessment too. We’ve trialed and tested values ranging from 60~50% in our suspension testing, finally settling on or about 52.5%.
In FM2, 3 and 4 the centerpoint for spring biases was 47.5%.
We don’t know why the change for FM5,…but testing proves it out.

In FM5 I use predetermined inverse ratios to determine rough aero settings, with the final values being determined based on speeds/accelerations needed.

For an example:
FF (60/40) cars use roughly 2:3 aero ratio
FR (50/50) cars use close to a 1:1
However, for RR(40/60) cars and some AWD builds, my ratios reverse back to a 2:3
(FWIW I almost never use aero ratios that exceed 1:2/2:1)

The reason for this reversal is simple, the suspension biases/balances are already based calculated, therefore instead of reversing the spring bias(unrealistic) it made more sense to adjust the aero as needed. The aero being an optional fine tuning value to begin with.

Your post leads me to think that finding a non-aero’d chassis tuning bias may be found,…and possibly explain the 47.5% to 52.5% chassis center switch in FM5.

Good stuff.

[uber_understeer]

also adding that the formula is assuming that you are having no rake and no anti rake on the car (even ride heights) because I have notised that rake and anti rake affect the aero balance a lot. Having a higher rear ride height compared to front (rake) adds downforce to the rear wing and anti-rake add down force to the front wing, I don’t know how much but its worth noting as I am using this aero formula and experimenting with cars with no wings or cars with ride heights I cannot even up.

[GRD_4_3L]

@uber, I am curious about how you have determined the effects of rake/anti-rake on the changes to downforce. Is that just the subjective “feel” of the car?

In FM, downforce is adjusted by assigning the amount of LOAD generated by the wings (supposedly) but the effect of rake ON the downforce is best done in angle/degrees. For eg. if the static rear wing is at 10 degrees (wrt the car) and the rake is set at 2 degrees, the rear wing will be 12 degrees wrt the road. It would be unrealistic for T10 to evaluate the front/rear ride heights then adjust the rear wing downforce load based on the height difference; it can be done, but it will be artificial/arbitrary.

What I feel with the rake is that the downforce on the rear “may” be accentuated at high speeds (+100mph) but in midspeed corners I feel the rear being more “wobbly”. Perhaps I should have increased the springs to offset this but I did not.

[uber_understeer]

I haven’t worked out a system or formula but there is defently and strong link between the two, Could be vital for no aero builders.

I think the rake effect of balance is more of + and - rear downforce and not a % or Multiplation. I think this because you can really easy (too easily) adjust you ride height to balance your aero with no wings/aero. (eg 1960’s F1 cars (wingless))