What should I do first to my 325ic for autocross?

Question

I have a 92 325ic (E30, M20 engine). Although my skills are lacking, even for me the car is too slow. It was suggested to me to replace the air filter, get a performance exhaust, performance chip and add a limited slip. I was thinking also of a different steering wheel. It's an automatic. I autocross maybe 5x per year.

Thanks

This is also my daily driver.

Answer 1

Paul sounds like he might have raced before! I gave him a thumbs up.

The rest were posuers!

Tires are first and not just any tires. Get a set of BMW factory rims from a salvage yard and mount up the Latest Kumho or BF Goodrich autocrossing tires. The tirerack.com is the best and the sales staff if ordering by phone will be very helpful(they all race).

Next thing is to get a Schroth 4 point harness that bolts in with your seatbelt mounts. Simple and fairly inexpensive, ie. you can't get that much time shaved off your run for 100 bucks by anything else.

Suspension tuning is for after you get a grip on your driving!

You are the biggest equation in lowering your times. At 5 events a year it will take about 3 years before you need to add anything else and the tires will last that long, barring accident.

ASE Cert Auto tech, SCCA Member since 1978 Solo II, all over the USA, Middle Georgia region, Iowa, Rocky Moutain Region, Dixie Region, Outlaw clubs in SD, Land O Lakes Region- Yeah, I love it!

Answer 2

The biggest element in Autocrossing will be the driver - so first and foremost, pay attention to your driving. Make sure you are using all of the course and that you are consistently hitting your apex and entry and exit points... make sure on exit you are feeding in throttle as you unwind the wheel. Watch the faster drivers and pay close attention to their lines and to the places on course where they decide to compromise speed (in order to gain it someplace else).

But in terms of increasing the car's performance... the one single item that will give you the biggest improvement are tires. This will improve every aspect of performance!

Next up would be to make sure that the car, as is, is optimized: get an alignment, and one that is not to factory specs, but one that is appropriate for autocross and track (ie, more negitive camber, less toe-in, etc); have the car corner balanced.

After that, looking at dampers will be the next spot. Then moving to bigger (ideally adjustable) anti-roll bars. And springs would follow here.

A chip that is more aggressive on the spark or a more open exhaust are nice... but everything you mention combined will not come close to getting you the improvement better tires will offer (or what adjustable ARBs would bring for that matter). While such changes are good, these are relatively minor in terms of actual performance. The limited slip is a very nice addition, but again, not something that will offer the improvements you will get elsewhere.

A good sports steering wheel is a nice change (generally a little smaller diameter), sports or racing seats can be a great upgrade to help hold you in place... and along the same lines, a good set of driving gloves and shoes are good investments as well.

Answer 3

Your best bet is ditch the pile of crap. Convertables are heavy. Next check the latest rules to see what you can get away with. Depends what class you run/want to run. An air filter won't produce HP, but they sound good eh? A full exhaust system (including headers) would probably be the best thing. A chip also does wonders. If you go with a limited slip, I would recommend a Turner Motorsports diff. They are available up to 4.11. A 4.11 would make that car scoot! A steering wheel won't make you faster. Other things to look at...a cam....even a modest cam would really up your useable torque, and go well with a chip and exhaust. The suspention is probably the second best thing you could do. Fit a nice set of Intraxx coilovers, or a stage 2 Dinan kit. Either of those setups will greatly help corner speed, and keep the car flat with the throttle on. But again...get rid of that convertable automatic and buy a coupe/sedan and get it with a manual. Much more performance just from that alone. (probably cheaper than all the mods too!)

Answer 4

Absolutely the first thing to do to your car for autocross is get stainless steel brake lines. This will increase braking performance and safety. You may want to get an upgraded brake package as well but at this age in your car, it may not be worth it.

Next is suspension then engine performance. CAI or short ram + exhaust + chip will get you at most +15hp. Manufacturers will usually quote you a higher value but its generally +5hp per each of these parts. You might want to consider a turbo or a supercharger... depending on what your budget is.

If you get a perfectly tuned suspension, you'll lose less speed in the turns.

Answer 5

For autoX the suspension will be the best bang for the buck mod you could do. Then performance intake, chip, limited slip diff, exhaust. Also think about where you can save weight. Pulling seats out for the event, sound deadening, etc.

Answer 6

Great car for autoxing (cept the auto , lol) . I have to second the stainless brake lines , its a small security . The suspension makes a huge difference . The stock suspension has to be shot by now .

Answer 7

if its an automatic, you might as well get a newer 325 with a stick, sticks are much more competitive in autocross

Answer 8

1. Driver
2. Helmet
3. Tires

After that, look at the classifications, and see what's allowed.

Answer 9

when did u changed your spark plugs.
just get a qualified mechanic to check the plugs and if found bad,just change to good recommended injections spark plugs for best performance.u will save on your fuel too.
Try it out.

Answer 10

Cram it up your ***?