E36 M3 stock hp is over the limit for ITR. Or right at the limit basically. It was deemed to be beyond the performance envelope of the class.
Ron
The M3 engine has no good place to play in the SCCA.After poking around a while 2 BMWs out there look really good, but they are built to NASA specs. Since I plan to continue with our club, I'm trying to figure out where they fit. One is an E36 M3 the other is an E36 325i with M3 drive train. They are both (claimed to be) legal in BMW CCA classes and NASA classes. The best I can tell they only fit in SCCA ITE (ITO in the SEDiv).
The only reason it came up is that one owner has offered to trade me for my DSR and that got me looking at BMWs.
Any opinions?
Thanks.
James, you need to come up here and drive my car. All Z3s are not pathological like yours. Mine is not loose, it's got tons of grip, and it's super easy to drive fast.The some of the problems with the trailing arms are that they're not adjustable, which leads to more problems if they are made so, and there's not any good options for replacing the stock rubber arm bushings. The adjustment problem is inherate to all trailing arm cars, what I've learned is that by putting an adjustment kit on the rear, I now also change the roll center, because I'm moving the axis of the arms piviot points. Now if the objetive is to have a car that turns better in one direction than the other in a nearly unpredictable manner, then this is fine, but we need to turn both direction equally well and to have this be affected by the alignment in a new and different way is not a good thing. As for the busing issue, you'd think that we could just replace them with the common urethan, or even delrin, but because the axis of the arms aren't lined up, the bushings have to be complient enough to multi-axial movement. The urethan bushings that I had installed, are made with two sleves in each bushing, so that when the piviot bolt is tightened down the tab that's welded on the subfame bends in causing binding aginst the bushing. As for the handeling, Jeff I don't think you guys had enough rake in the car, because mine's always been loose under braking, power off, or when the wrong bump unloads the rear and causes the toe to dynamically go out. This is easy enough to control in low and mid speed corners, but around triple digit speed corners, it's begging for a spin. I suspect that because of the speed dependant nature of my problem, there's some aerodynamic issues too. I'm still working on this though, both top and bottom.
James
James, you need to come up here and drive my car. All Z3s are not pathological like yours. Mine is not loose, it's got tons of grip, and it's super easy to drive fast.
I don't know why you say that someone else's Z3 doesn't have enough rake, because theirs is stable and yours is too loose to drive fast. Maybe that means the one with the rake set wrong is yours?
Josh,
I'll admit that maybe my rake might be too much, but I suspect it's not the rake but toe-out in the rear that's caused my problem. As you know mine isn't the only pathologial roadster out there.
Tom Bell told me that he had static toe-out on the rear. Unfortunetly, toe and camber are fixed unless one installs adjustors. Also the Z3 isn't a true power car, it's sort of in the middle of momentum and power. So, one area to conserve power to the rear wheels is not having too much toe in, like maybe 1/16". However, when the rear is unloaded, like after an upshift, the toe dynamically goes positive.
Tom also has the JP allowed rear wing to help keep the rear planted. This kills any lifting going on at the rear and keeps the the toe in, as lift at the rear causes toe out. Thus, the rake is an aerodynamic band-aid for down-force, that's there to keep the toe-in and not out. Note, I'm not asking for an allowance for rear wings, I plan on addressing this within the current rules.
I didn't say anything about the low and mid speed corners. This is strictly a high speed problem, which leads me to think it's probably aero in nature.
James
ps. Tom did warn me, same as I warn any other potential Z racers, before I pulled the trigger and sent TC the money. Oh, and in spite of my experiences, bad things happen when sliding sideways a 100+mph and I've done this sliding several times, I still enjoy racing the Z roady as it's not a cookie cutter race car. So thank you again for letting me know about it.