Originally Posted by TC Kline Racing
Ok, a lot of information here so I will try and address everything.
First, let's determine where we are taking ride height measurements from. We measure from the rocker panel to the ground, not from the fender. So, at the very front of the rocker panel just where the front wheel well meets the rocker is where we take the front measurement. Then, we take the rear measurement where the rear wheel well and the rocker meet. This may add to the confusion, as we all may be picturing ride heights based on where we measure.
OP, your question seemed more like a 'performance' or 'technical' question as opposed to aesthetics. DSC_OFF is correct (thanks for the backing, btw) that we have done extensive testing on the street and on the track, and this is how we recommend you set your ride height if you want your car to perform. We set our cars up for function, not form. If you are looking for a 'stance' look, I have nothing more to offer, but if you want the car to function and perform well, then set the front ride height where you want, and then raise the rear 3/4" higher than the front. That is your base setting, and then you can corner balance from there.
You mentioned you don't want your car to 'nose dive' under braking......how hard are you braking on the street? That question just seemed more like a track related question
Just so you are aware, the car will actually understeer more as you lower the rear end
, until you hit the bump stops. Once you hit the bump stops in the rear the car will oversteer again. So as you raise the rear end, the car will want to oversteer more and understeer less.
This set-up will be the same between an xi and non-xi, it does not change.
If you want your car to 'perform' on the street and track, this is the race/street proven set-up (assuming your are running the proper suspension and spring rates) based on the hours and hours of testing that we have done with our E90 both on the track and off.
The simple answer was 3/4" rake, but hopefully this explanation helps.
If you have any more questions, please let me know
Thanks for the detailed explanation. Try to learn more about the geometry of quality handling. Just baffled at the amount of conflicting information online.
Also, the weight differential is about 215lbs more upfront on the xi so about 53/47 weight distribution.