E30 Roll Centers

[Ronan]

I have my subframe raised 12mm and just got an alignment the other day. Rear camber was -1.7 and .25 degrees of toe in. I do not have any adjustability on my trailing arms. And I have had very even tread wear and I autox once a month.

Ronan

[Digitalwave]

Thanks Chris. I appreciate your input. I may just start PM'ing you my questions. ;)

[nando]

raising the subframe 12mm in the rear is going to be about a 1/2 degree change. no way you're getting 4.5 out of that.

[Digitalwave]

I figured as much. I've tried getting measurements between the tie rod end and the barrel of the wheel since my struts are off the car, but without knowing the angles the tie rod is going to be at, it's really hard to say. I may just need to buy both the 13mm and 19mm spacers and test fit once they are back in the car.

[kronus]

16" wheels can have somewhat different barrels, so you won't know if it clears until you try.

raised subframe mounts are worth it IMO, the closer the camber/toe alignments are to their original positions, the less likely to slip or bind.

[Digitalwave]

I'm not opposed to adding in the trailing arm adjusters, but I should have mentioned that I think that correcting the roll center is as important or more important than the camber change for me.

[e30_302]

Why not just weld in trailing arm adjusters? Then you can set the camber and toe to pretty much whatever you want.

Can't really say on the roll center spacers, I've got a 1" spacer on a regular E30 strut. It worked, barely, with a 15" wheel. Had to get the grinder out.

[Digitalwave]

I am running E30 M3 suspension on my non-M so I have the opportunity to add roll center spacers to the front, and of course raise the subframe in the rear. The car is a dedicated track car (HPDE), but not being built to any rule book. I am running H&R Race springs. It is easy to tell I could benefit from the spacers in the front just looking at the control arms. My questions are:

1) I am running 16" wheels. Measuring the clearance in the front, it looks like I MIGHT be able to run a 19mm roll center spacer, but it would be very tight. Should I just stick with the 13mm to give breathing room in case I change wheels down the road?

2) Is it worth raising the rear subframe 12mm when running H&R Race on a track car?

I don't remember my last alignment specs, but I remember the rear had more camber than the front. I can only get so much out of the front before the spring hats impact the strut tower, due to the stock diameter spring. I don't plan to go to coilovers yet. It seems like raising the rear subframe would help balance out the camber, as I'd rather have more in the front. I'd like at LEAST 2.5* in the front, and 1.5-2* in the rear. My concern is the conflicting information I've read about how much the 12mm risers affect the camber. I've read as little at 0.5*, and as much as 4.5*.