Hi all, looking for some input and if I'm missing something obvious. I'll try to keep it short.

I have about 10 HPDE days on my completely stock MY02 with street alignment and AP1 size RS3's. So I have decent feel for how that car drives.

I recently bought a MY00 to gradually turn into a dedicated HPDE car. Took it to WSIR and Buttonwillow recently and it understeers BAD in comparison. Turn in is not solid, and I can't hold maintenance throttle in sweepers or the car pushes out. Alignment is -1.3 F camber, -2.2 rear, 0 F toe, slight R toe (previous car was OEM alignment). Same RS3's on AP1 wheels. It has Swift swaybars, but from what I've read these are about the same as MY02 stiffness front, and stiffer rear, so should cause oversteer if anything. Suspension is OEM, but likely not original to the car (could be AP2?). I can't think of anything else significantly different about this car. Would any of the above cause understeer? Something else major I'm missing?

 

Im no guru but the oem shock changes every other year.

Diference between ap1 and ap2 is considerable. Ad to that the suspension geometry changes and sway bars they were made to go with.

My first guess would be the shocks.

Lets see what others have to say about it


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If it indeed is an AP2 suspension of some sort, it will have springs biased more for understeer.

 

Assuming the surface and conditions were arguably the same and the front tires are not shot, same pressures, etc ... Either the numbers are not accurate or something is worn on the suspension. Is the caster the same?

 

That's a big camber differential, with too much relative rear to front...first guess. Second, how much rear toe in?

 

That camber is not helping your situation either. Need way more in the front

 

Bushings may not be holding your alignment

 

Run wider rims up front and fatter tires.

 

Front lcas?

I went with a solid front whiteline day bar and disconnected the rear this stabilized the car drastically. But my experience is autocross not hpde

 

Thanks everyone, appreciate the input! You gave me some stuff to check...

I found the alignment printout. The rear toe is 1/8" per side, 1/4" total. They told me -1.3 was the max even front camber they could get. (Seems low?) Perhaps I should take out some rear camber to balance it out. Caster is 5.6 degrees.