'90 325is in the SPSC Karussel

[getfast]

which group is this? I was going to do COM this year but will be moving from Mass to DC so need to find a good group in DC area.

http://www.nasaracing.net

There are lots of good groups in this area, but NASA's my favorite. :D

Jon

[rwh11385]

Nice pictures. I think you diff is too short though....... ;)

The car felt good in there with the wacky spring setup. The section coming into the bowl is pretty hairy though. There's a wide right hand sweeper onto the front straight (counterclockwise) where you're floored in 3rd and sliding. You put it in 4th just before you go under the bridge, then go over this blind crest (we called it the "ski jump") and literally catch air. The further to the right you go, the worse it is... and the more loose you'll be when you land the car! Keep your foot in it and get the car to the middle of the track and hit the rev limiter in 4th, then heel-toe down to 3rd and get into the ABS and cram the car left into that bowl. The car was loose on entry as it went from flat to banking, but you just just feed in throttle and hold the wheel to the left and look up and it sticks... until you exit the bowl about 6000rpm in 3rd.

Now THAT sounds very exciting, with a mix of too much fun and a little scary. 8)

[getfast]

http://www.s14.net/forums/showthread...&threadid=9128

Just from watching this vid, it looks like a ton of fun, but yea, definetly more than a few pucker-inducing moments.

Just had a chance to watch this from work (dial-up from home = booooo.) This guy skips an entire five-turn section of the track... a section that we ran on Saturday. So consider the S14 video to be missing 1/4 of the fun... :twisted:

Jon

[Jared K]

I am interested in learning more about your spring setup, H&R Sport front, Race rear. How is the ride? Is body roll still an issue?

I've read in Fred Puhn's "How To Make Your Car Handle," that the front suspension should have a lower frequency than the rear to minimize pitching motions over bumps. Most E30 spring setups seem to violate this "rule". However, yours actually conforms to the rule. So, I wonder if the ride is actually improved over a regular H&R sport setup with a benefit of improved handling?

BTW, I'm trying to determine spring rates for a ground control coilover kit. Based on the theory, I think most people are using rear spring rates that are too low compared to the front. However, I know that in practice things may be different.

[getfast]

I am interested in learning more about your spring setup, H&R Sport front, Race rear. How is the ride? Is body roll still an issue?

I've read in Fred Puhn's "How To Make Your Car Handle," that the front suspension should have a lower frequency than the rear to minimize pitching motions over bumps. Most E30 spring setups seem to violate this "rule". However, yours actually conforms to the rule. So, I wonder if the ride is actually improved over a regular H&R sport setup with a benefit of improved handling?

BTW, I'm trying to determine spring rates for a ground control coilover kit. Based on the theory, I think most people are using rear spring rates that are too low compared to the front. However, I know that in practice things may be different.

This is all a matter of opinion (based on my silly little experiment), but here goes:

The ride is firm but definitely not jarring. Around town or on the highway it isn't much stiffer than, say, a stock E36 M3 with some decent shock/struts. The rear end feels more solid (read: twitchier) than the front, which is always exciting over various road irregularities. Compared to just having the Sports back there, the change is not really noticeable until you push the car (or hit a good-sized hole in the road.)

On-track, the car still feels soft on corner entry but at least it doesn't understeer much (except in the slowest and/or most horribly worthless off-camber and/or decreasing radius turns of course.) For the most part it finally rotates into corners the way it should, and many times it steps out nicely... which suits my driving style and desired corner exit speeds just fine. It will also get totally ass-out "dorifto" sideways if you want it to. :twisted:

Body roll is still an issue (but not for long... ST swaybars incoming this month woo hoo!) Proof of the still-softness of the ride can be seen in pictures and on the tires... all four outside edges get punished, particularly the fronts (although to be fair, I still have stock amounts of negative camber all around... for now.)

Honestly I didn't do this experiment out of some finely-reasoned measure of suspension frequencies. (It's been years since I read that Fred Puhn book, or any other related book.) The only reason I installed the Race springs on the rear was because the car understeered horribly on road courses with just the Sports installed, and it pissed me off. The slower the turn, the worse it pushed... which made autocrossing an exercise in futility as well.

Basically once the H&R Race springs came off back-order and arrived, it really killed me to see them on my dining room table until the ST bars (back-ordered) and GC camber/caster plates (ordered but still waiting) showed up. I was facing three autocrosses and a track day in the last six weeks of '04, so I said screw it and put the Race springs on the back. I didn't know what to expect but I've actually been very pleased so far. (Pleased enough that I won't change a thing until I install the front Race springs, camber plates, and both swaybars simultaneously.) In terms of balance, the car feels pretty damn good right now IMHO. The grip level could definitely improve, and the softness/sloppiness on corner entry could go away, but the dynamics are exactly how I like them.

Also, I'm the wrong one to ask about spring rates. It's my first E30 and half the battle is learning to get fast in a new car as I constantly make changes. BUT I wll say that finding a setup that suits your driving style is the most important thing. When my E30 is a spec racecar I want it to handle just like it does now, but with more overall grip and greater precision. Lap times be damned, it will always be a blast to drive, because that is the point of the whole experience. The confidence I'll gain from that, paired with increasing familiarity and greater skill, will hopefully make us competitive eventually. That's the goal anyway!

Jon