[Noize]

Hello,

I have a manual transmission sport package car and would really like to start autocrossing it when I can. I've autocrossed about 3-4 times in my life previously and had a day at the Little Talladega Grand Prix track in my WRX, but would like some pointers for the BMW.

I cut my teeth first on track with FWD Hondas. Then I went to the WRX, then to the Evos.

This car is a lot different. First off, its rear wheel drive. Second, its a freaking whale! The last Evo I had just had power mods and no handling mods. That car was very surgical in its handling precision. This one isn't. I don't care what class I get bumped into, because I'm a n00b and won't be competitive. I basically just want to go out there and get better and better each time.

I feel that the runflats are a big weak point. I believe that running Azenis or Hankook RS2 would be a huge performance increase. They aren't available in stock size, but they are in 235 front and 265 rear, everything else being the same. Tires, alignment, and maybe swaybars? What are those of you who are faster doing? I don't want to lower the car at all; its a lease and I don't want to get too crazy with it. I'm just looking for some basic things that will give me a better chance for success.

Also, how do you guys run traction control on track? Do you run the system completely defeated or do you leave the stability control/brake assist on?

Thanks for any info and sorry for the newbie RWD racer questions!

Seth

[longodj]

Hey, I ran my 335xi in an autocross and I completely agree with the RFT concerns. Get some standard stick tires and you'll be fine, I was sliding like hell in an AWD on my Conti RFT :-P Also, I noticed that running without DSC (completely defeated), I ran much better than with. Granted that's on an xi not an i, but if you are confident with your driving, you should be able to out handle a computer (not saying I can...but at least I'm optimistic). If you want a big suspension upgrade on a leased car, go for swaybars. I'm actually trying to get a local auto shop to install some within the next couple weeks. The UUC SwayBarbarians are supposed to be fantastic and take away a lot of that whale roll. Good luck!

[shimshimhada]

Pick up a set of non-staggered Azenis RT-615s, awesome grip for the price and you shouldn't have to worry about overheating them in an autox.

I agree with going with at least some rear sways to dial out some of that understeer that you're definitely going to get.

Turn DSC completely off, it gets in a way too much.

[Noize]

Thanks guys! I appreciate it.

Hey shim- When you say not staggered, would you suggest 265/35 all the way around?

[shimshimhada]

Originally Posted by Noize

Thanks guys! I appreciate it.

Hey shim- When you say not staggered, would you suggest 265/35 all the way around?

That would be loads of grip, but pricey! Non-staggered just means same size all around. Last few times I autoxed, I got a crapload of push, my driving style doesn't help either.

245s all around should be good too. What are your wheel widths?

Since you've autoxed before, you prolly know this, but jack up the tire pressure in the front and lower it in the rear.

[Mattscott]

Hey, you should go to california speedway on october 6th and 7th, track day

[ScheerSpeed]

Originally Posted by Mattscott

Hey, you should go to california speedway on october 6th and 7th, track day

ive driven that track and won a race in the formula Renault, if u need any pointers pm me.

[rsjames]

Which group are you running with? Be sure you know their rules before you start modifying your car. You could find yourself bumped into a class with much more heavily modified cars.

If it's SCCA, the Stock class allows changing the front swaybar, but not the rear. You can also change shocks, and exhaust past the cat. Wheel sizes must remain as stock, but you can run different wheels (within 0.25 inch offset). You can run pretty much any tire you can safely fit on the stock wheels.

And, yes, turn off the electronic aids. Be prepared for some massive wheelspin on the right rear thanks to the lack of a limited slip.

Richard

[AGIO_330i]

I like the Falken RT-615. Great tire for a great price.

[S4to335]

stock tires?

[gloster]

How much should decent swaybars run installed? Will they impact ride quality for day to day driving?

[S4to335]

The rear sway in the e90 is apparently not an easy install. I would think in the $150-200 range to install..plus the price of the bar itself. If you get fronts..probably double it. ride quality will be slightly affected...this is based on me installing bars on other cars in the past..not my E90 335i.

[Richardo]

I just ran this weekend and did well (won the FS stock class ). I don't have any modifications on the car; it's completely stock. You'll love how it drives on the autocross, even without the modifications.

I'd have to agree with all of the posted comments. Though I felt the run flat tires did better than I expected, I'm sure I could have shaved another 2-3 seconds by having good non-RFTs. Be aware that the choice of tire might move you to a different class.

The course we ran was very twisty (even for autocross); it was pretty much sharp turns 100% of the time. The three things that helped me the most were:
1. traction control completely off. I tried it with DCS (full on), DTC (partially off), and completely off. I got the best times with it completely off (by a full one second margin).
2. power oversteering. I used to autocross a Porsche 914, and wow does this car drive differently. Although heavier, the 335i was just as predictable and sure footed in the turns. I did a lot of late apexing and tried to apply power at just the right time to avoid burnouts (due to lack of LSD. Still it seemed like most of the steering during the race was via throttle rather than the wheel.
3. equal tire pressure back and front. I got best results with 40 psi & 40 psi. However, I didn't try anything higher than that. After the race I saw tire rub down to about the treadwear and traction rating marks on the sidewall, so I probably could have run with even a little higher pressure.

Good luck!

[leftcoastman]

Originally Posted by S4to335

The rear sway in the e90 is apparently not an easy install. I would think in the $150-200 range to install..plus the price of the bar itself. If you get fronts..probably double it. ride quality will be slightly affected...this is based on me installing bars on other cars in the past..not my E90 335i.

Rear will cost a bunch to install. More like $250-350. I did the rear only - dials out a lot of the understeer so you carry higher apex speeds, but you can't accelerate worth crap going out of turns b/c you're just lighting up the inside tire.

It's becoming a real issue. I might get a front one just to even things out a bit.

[S4to335]

LSD...leftcoastman...LSD...(not the drug)

[gloster]

Originally Posted by S4to335

LSD...leftcoastman...LSD...(not the drug)

Now *that's* a good but frickin expensive solution.

leftcoastman -- how did your ride quality (daily driving) change with the rear sway bar install?