E90Post
 


TNT Racewerks
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Tracking, Autocrossing, Dragstrip, Driving Techniques > I want to autocross my E90, please help me with some info. :)



Reply
 
Thread Tools Search this Thread
      09-17-2007, 12:40 PM   #1
Noize
Under the radar
Noize's Avatar
United_States
31
Rep
840
Posts

Drives: FWD in reverse
Join Date: Jan 2007
Location: In traffic at idle

iTrader: (1)

I want to autocross my E90, please help me with some info. :)

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
Appreciate 0
      09-17-2007, 05:46 PM   #2
longodj
Major
longodj's Avatar
United_States
54
Rep
1,288
Posts

Drives: 135i
Join Date: Jun 2007
Location: Rochester, NY

iTrader: (3)

Garage List
2007 335xi  [0.00]
1974 VW Beetle  [0.00]
Send a message via AIM to 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!
Appreciate 0
      09-17-2007, 05:59 PM   #3
shimshimhada
Brigadier General
shimshimhada's Avatar
United_States
284
Rep
4,838
Posts

Drives: Portal
Join Date: Jul 2005
Location: Portal

iTrader: (2)

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.
Appreciate 0
      09-17-2007, 06:30 PM   #4
Noize
Under the radar
Noize's Avatar
United_States
31
Rep
840
Posts

Drives: FWD in reverse
Join Date: Jan 2007
Location: In traffic at idle

iTrader: (1)

Thanks guys! I appreciate it.

Hey shim- When you say not staggered, would you suggest 265/35 all the way around?
Appreciate 0
      09-17-2007, 07:09 PM   #5
shimshimhada
Brigadier General
shimshimhada's Avatar
United_States
284
Rep
4,838
Posts

Drives: Portal
Join Date: Jul 2005
Location: Portal

iTrader: (2)

Quote:
Originally Posted by Noize View Post
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.
Appreciate 0
      09-17-2007, 07:27 PM   #6
Mattscott
Major General
Mattscott's Avatar
United_States
106
Rep
8,327
Posts

Drives: 2007 335i E90
Join Date: Aug 2007
Location: Beaumont, CA

iTrader: (2)

Send a message via AIM to Mattscott
Hey, you should go to california speedway on october 6th and 7th, track day
__________________
Legal Disclaimer: Anything I or anyone else says about my vehicle on this website(e90post.com or any affiliated or nonaffiliated sites), pertaining to modifications, is only to gain acceptance from my/our peers, and does not actually represent anything actually existing on my car, and thus, cannot be held against me in any issues, i.e. warranty claims, that may arise.
Appreciate 0
      09-25-2007, 10:14 PM   #7
ScheerSpeed
Major General
ScheerSpeed's Avatar
United_States
289
Rep
5,768
Posts

Drives: '13 F30 Estoril M-Sport 335i
Join Date: Sep 2006
Location: Miami, FL

iTrader: (14)

Send a message via AIM to ScheerSpeed Send a message via MSN to ScheerSpeed
Quote:
Originally Posted by Mattscott View Post
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.
Appreciate 0
      09-26-2007, 12:22 PM   #8
rsjames
Private First Class
2
Rep
122
Posts

Drives: 07 335i Montego Blue
Join Date: Mar 2007
Location: Orange County, Calif.

iTrader: (0)

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
Appreciate 0
      09-26-2007, 12:46 PM   #9
AGIO_330i
Private
AGIO_330i's Avatar
4
Rep
96
Posts

Drives: '06 330i Jet Black
Join Date: Apr 2007
Location: Orange County, SoCal

iTrader: (1)

I like the Falken RT-615. Great tire for a great price.
__________________
Stop complaining!

Once you go Bimmer, you never go back!
Appreciate 0
      10-16-2007, 06:38 PM   #10
S4to335
Brigadier General
United_States
266
Rep
4,380
Posts

Drives: 2014 Audi A4 / 91 Track Miata
Join Date: Jan 2007
Location: San Jose, CA

iTrader: (5)

Garage List
stock tires?
__________________

Car is now gone .... :-(
Appreciate 0
      10-16-2007, 07:02 PM   #11
gloster
Captain
11
Rep
649
Posts

Drives: 335i MT, sport
Join Date: Aug 2007
Location: Cleveland, OH

iTrader: (0)

How much should decent swaybars run installed? Will they impact ride quality for day to day driving?
Appreciate 0
      10-16-2007, 07:04 PM   #12
S4to335
Brigadier General
United_States
266
Rep
4,380
Posts

Drives: 2014 Audi A4 / 91 Track Miata
Join Date: Jan 2007
Location: San Jose, CA

iTrader: (5)

Garage List
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.
__________________

Car is now gone .... :-(
Appreciate 0
      10-16-2007, 08:54 PM   #13
Richardo
Private First Class
Richardo's Avatar
United_States
10
Rep
153
Posts

Drives: 335i AT sport
Join Date: Aug 2007
Location: Texas

iTrader: (0)

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!
Appreciate 0
      10-17-2007, 12:47 AM   #14
leftcoastman
Lieutenant Colonel
38
Rep
1,714
Posts

Drives: 335i
Join Date: Jan 2007
Location: Near some canyons

iTrader: (1)

Quote:
Originally Posted by S4to335 View Post
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.
Appreciate 0
      10-17-2007, 09:46 AM   #15
S4to335
Brigadier General
United_States
266
Rep
4,380
Posts

Drives: 2014 Audi A4 / 91 Track Miata
Join Date: Jan 2007
Location: San Jose, CA

iTrader: (5)

Garage List
LSD...leftcoastman...LSD...(not the drug)
__________________

Car is now gone .... :-(
Appreciate 0
      10-17-2007, 12:47 PM   #16
gloster
Captain
11
Rep
649
Posts

Drives: 335i MT, sport
Join Date: Aug 2007
Location: Cleveland, OH

iTrader: (0)

Quote:
Originally Posted by S4to335 View Post
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?
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 03:23 PM.




e90post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST