Quote:
Originally Posted by wspohn
Must be someone that has setup a car for the street for aggressive driving and has some info on what alignment work best and minimizes understeer. Anyone? Help.....  |
There's nothing that I can say here that hasn't been already said.
Since you mentioned you're an old racer, you MUST know that all alignment settings are compromises between a bunch of parameters (comfort, wear, performance). Camber and toe are the only two adjustable parameters on this chassis, and without camber plates up front and camber arms in the rear you're beholden to the limited amount of adjustment that's available to this car. Meaning about 1º up front and rear in camber, and while toe settings are more adjustable, anything that veers from more than 1/16" either way is going to royally eff up your tire's usability.
As for what alignment "minimizes" understeer...Where is the understeer coming from? Corner entry? Corner exit? This chassis, in capable hands, is actually shockingly neutral. I once handed my keys to a semi-pro racer and after half a dozen laps, his comment was "wow this is the most neutral BMW I have ever driven." Granted I had 3.5º of negative camber up front, with 275 width tire all around.
I hesitate to give you any advice simply due to the vague way you presented your question. For a car that is not likely to see track? But plan to be driven "aggressively?" I'd minimize the rear camber (dial it to ZERO, or less than -1º depending on how "low" you get with your coil-overs) with slight toe-in (1/32-1/16" would do) and maximize front camber with same amount of slight toe-in (1/32-1/16"). Now, how much camber do you REALLY want or need is another question. With little to no camber in the rear, and a ton of camber up front, you may potentially see mid corner to corner exit oversteer, which, IMO, is the preferred set-up for "aggressive" street driving. Granted, not knowing how low you'll end up, that front camber can be as little as -1.5 to -1.7º, to as much as -2 to 2.5º. To get to desired effect, you'd "ideally" want 2x the camber up front compared to the rear on this chassis if you continue to run staggered sizes, or 1.5x up front to the rear ratio if you managed to square it up.
Otherwise, you can go MY route. -3.5º up front and -2º rear. Combined with some "aggressive" driving you'll likely be paying for a new set of tires every 6 months or 5,000 miles, whichever comes first, on THAT setting.