In Reply to: Thanks Michael! Car goes in the shop next week(mor posted by e) -Huzurdd on July 18, 2001 at 22:22:03:
the bolt point on the rear sub-frame
the upper spring perch
the shock mount point.
If you have rear coil-overs there is only one point to pick up for the springs/shocks.
Remember too trianglulate between the mountplate at the shocks and the subframe mount plate (have a hole cut into this one, there is a good weild point at the place the bolt holder is weilded to the pan by bmw. Also, you may need to replace the subframe mount bolt after an off, they do get slamed by curbing).
In my 2002, I put solid steel subframe mounts on. this made for a REAL stiff rear end, it is also REAL uncomfortable on the road (yes, I have Fla. tags on it). I took old mounts, removed the rubber bushing, and took what was left to a machine shop. I brought a good one for them to modle off of, and had the shop weild a 3/16" top and bottom plates on, with a tube weilded between them to hold the bolt. Will you have a dedicated race car? Are you willing to remove the rear interior, or at least make it useless? If your class allows steel subframe mounts, does it allow you to pick up the subframe/diff mounts? this will involve cuting through the floor pan, but makes for a very solid car.
The real question is what class (how much modifacation you will be doing) will you run in. Keep in mind that the more modifacation your class allows, the more expensive the cars you are running against will be. If you run in a basically unlimited class, you will be out there with the likes of Alfred DuPont. He can put a gazillion dollars into his car if he wants. Can you? This is why I run in SCCA ITB. Limited modifacation, restricted tires (DOT certified), limited buidget, but I am competitive! this is what makes it FUN, and that is the idea! I finish (if I do not go flying off the track) in the top five out of 15 or 20 cars. I do not go 150 mph into turn 2, I generate around 1.15 g loading on the tires, I have almost no down force, but it is closr racing, and a lot of fun.