Setting up an E36 M3 (or 325 et al) for stock autocross

[John V]

Well after two seasons of tinkering and lots and lots of input from the guys who used to compete with these cars a lot, I think I finally have a setup I can be happy with and thought I would share it. This is a compiliation of personal experience, input from BobT and Mark Sipe (several of his thoughts are paraphrased from this article ). Next year I will probably split my time between this car and an RX-8, but I hope to attend at least a couple Tours and the Finale with this car.

1) Tires. I've tried the V700 Ecstas in 235/40/17, the Victoracer in 245/45/17 and in 255/40/17 and the Hoosier A3S03 in 245/40/17. Of these, the Victo 255/40 and the Hoosier are the fastest. The Hoosiers on common asphalt lots aren't a whole lot faster (guess a couple tenths) but the feel is amazing. The 255/40 Victo is sloppy, at best, but it works - I had even tire temps in the mid 180s on a 85 degree day with the tire rolling over to the sidewall edge. Pressures for the victo are 40 front and rear assuming a proper alignment (see 6). Pressures for the '03 are moot since you can't get 'em anymore - I ran 38F/36R. '04s will have to be a lot higher, and you'll have to pay attention to keep the front temps under 140.

2) Wheels. On a '95, the 17 x 7.5" setup all around is fastest. Don't bother with the factory option 8.5" wheels in the back. Any of the aforementioned tires will fit under stock fenders assuming a 5mm spacer up front and no spacer in the rear.

3) Shocks. These are an absolute must, especially since the stockers are pretty much toast by 40k miles. The Koni SAs I've been running work very well and have plenty of adjustment range for the stock springs - rear DAs would be nice, but you don't need them. Settings I run are 3/4 from full stiff (FFS) front and 1 turn FFS rear. The stiff fronts help keep the front tires in contact with the pavement coming out of corners, helping corner exit speed, which is everything in autocross. The stiff rears help the car from nosediving so much on braking. Too much rear rebound damping will hurt transfer of weight to the front tires trail-braking into a corner, too little will make the car squirrely when going from full throttle to full braking situations.

4) Sway bar. I'm running the Racing Dynamics 27mm front bar set to full soft. This bar in full soft has the same geometry for the endlinks as stock, but the bar is much larger in diameter. Actually, I think a slightly smaller front bar (26mm Eibach?) would work a bit better - once the inside front wheel is off the ground the bar has done all it can. The theory here is twofold. One, the front bar limits body roll, which helps make up for the car's lack of front camber and poor camber curve. Two, the car is much faster through transitions with the front bar. Anyone who thinks a fat front bar will make the car understeer needs to come drive mine.

5) Exhaust. Not much to be gained here, but the Borla is about the lightest aftermarket exhaust around, on par with the Bimmerhaus, it's the cheapest, and it's streetable. You save around 25lb with this exhaust.

6) Alignment. Big tinkering area here. I tried a few different things before bucking the trends and going with what Mark Sipe suggested. First, get over the fact that you can't get any camber up front. Stock M3s vary widely from -.7 up front to -1.3 up front, which is around where mine is. I personally run zero toe up front. The last change I'm going to make is to run 1/8" total toe-out up front. This only helps turn in, not absolute grip, but it can make the car more lively in slaloms, which is where the M3 really shines.

The rear end is where you need to play with things to get good results. A stock M3 will push like a pig coming out of corners on-power. Autocrossing is all about getting on the power early and often. Get over the fact that the car is not going to go around tight constant-radius corners quickly and focus on coming out of them quickly. The key to doing this is minimizing the rear grip by dialing out all the camber. You'll wind up with between -.5* and -.7*. It's easy to see on the adjusters when you're at minimum camber, but a bubble gauge helps. Next, set the rear toe. I previously ran 1/8" total toe-in. That only exacerbates the car's tendency for on-power understeer. At the very least, dial out all the toe. If you're bold, dial in 1/8" total toe-out. I personally am very happy with zero toe, and it's nice and streetable. I probably would not go to the track like this, but for autocrossing it is a must. The rear end will literally steer you around the corner on-power with these settings.

Side benefit is the car is a monster trail-braker and will rotate in high speed corners with only a slight throttle lift. If the car is a little loose at high speeds, dial in more rear rebound damping or bump up the rear tire pressure a psi.

7) Brake pads - I've tried the stockers and Axxis Ultimates. The Ultimates, IMO, have a little better initial bite but are easy to modulate. You don't want a too-grabby pad when autocrossing. Smoothness is key.

8) Driving style. Took me a long time to accept this, but you won't be able to corner steady-state with an RX-8 or an S2000 because of the lack of front camber / wheel width. The solution is to be patient and get on the gas as early as you can. With this setup the car is very fast transitionally. Slaloms and high speed offsets are your friend. I take increasing slaloms WOT whenever possible. If they're decreasing (tightening) slaloms, a slight lift before each turn-in event will make the back end dance nicely. Still, the car is benign enough that I'll let anyone drive it.

Thanks to Mark Sipe and BobT. Sorry for the length. I hope the autocrossers who read this find it helpful.

John V

[ComBIRDable]

Originally Posted by SoloII///M

Sorry for the length. I hope the autocrossers who read this find it helpful.

I'm thinking you just saved me a couple of seasons of experimenting!

Thanks for the article.

Scott

[TeamSlowdotOrg]

Nice info. I wonder, has anyone ever REALLY tried with an E36 328? I don't think it'd be horrible in DS except for the lack of a limited slip. Sport package wheels, springs, and rear swaybar, a front swaybar and some konis on a lightly-optioned car and you're 100 lbs or so lighter than the 330's and still able to fit 245's, albeit with a whole lot of sidewall (talking about 245/45-16's here). Oh well. Race tires are in my past now, and besides I'm too cheap and lazy to develop a stock class car.

[hellrotvic]

Great write up. Lots of great tips. I'm still trying to dial in the correct tire pressures...

Thanks!

[jmott]

Originally Posted by TeamSlowdotOrg

Nice info. I wonder, has anyone ever REALLY tried with an E36 328? I don't think it'd be horrible in DS except for the lack of a limited slip. Sport package wheels, springs, and rear swaybar, a front swaybar and some konis on a lightly-optioned car and you're 100 lbs or so lighter than the 330's and still able to fit 245's, albeit with a whole lot of sidewall (talking about 245/45-16's here). Oh well. Race tires are in my past now, and besides I'm too cheap and lazy to develop a stock class car.

ITRs are sooo much lighter : /

[///MD]

Good Stuff!!
Thanks alot, man! It's great to pass on the experience...

[MWhip]

Great insight...thanks...

[TeamSlowdotOrg]

Originally Posted by jmott

ITRs are sooo much lighter : /

Yeah, I know. I beat a bunch of them at Nationals in a heavy IS300, and autocrossed one this year (6th at the Toledo national tour in Matt Grainger's car). 2nd place wasn't an ITR. 1st place last year wasn't an ITR. They're awesome cars but they're still FWD and that means there are certain things they cannot do, even if the disadvantages are somewhat muted in Stock where just about every car is fighting understeer.

[paypiper01]

If I plan on running 235/40/17 all around would I still need the 5mm spacers?

[PJ325i]

Great write-up!!!

Time to start experimenting

[jmott]

Originally Posted by PJ325i

Great write-up!!!

Time to start experimenting

note, since he wrote that, the Kumho 710 has arisen as the dominant tire.
Though the new hoosier is close

[drivesfast]

this was a good read and i have an e30 325i. it is some good insite for me as i have not autox'd this car yet, or a FR set up ever. again, good write up.

[John V]

Yikes! It seems like a lot more than just a year ago that I wrote this.

[simracer]

Great write up, John and good to see you again from the old SHOtimes (Taurus SHO) list. I sent you a PM, but you might not have come across it yet.

Later!

[GroovinPickle]

Great thread, I'm glad it was bumped back up. I've got a few questions for John or anybody else who might have experience running in a stock class.

I've got a '99 M3. The only modification is a set of Koni single adjustables. Since I've got a '99, I'm stuck running 7.5" wide wheels in the front and 8.5" in the back. With that in mind, what are the options for tires these days? A fella in the classifieds section is selling a pair of unused Ecsta V700 235/40-17, but of course then I'd have to find another pair, and Tire Rack says they're looking at 3+ weeks until they get some, maybe much more. And I'd have to get them shaved, right?

Are there any other options on tires? I think Hoosiers are too expensive and will wear too fast for me. Can I run V710 245/45-17 all around, or will it be too tall/wide in the front?

[MdMcoupe]

I feel very lucky to have people like John V, Doby, Bren, etc. in my local area. They are BMW freaks..(even though John V kills in Clyde's Rx8), and ALWAYS willing to help the new guyz figure things out.

Thanks for the good write up

[scoobywrx]

Added to my watched topics.. Why not leda's though?

[John V]

Originally Posted by GroovinPickle

Great thread, I'm glad it was bumped back up. I've got a few questions for John or anybody else who might have experience running in a stock class.

I've got a '99 M3. The only modification is a set of Koni single adjustables. Since I've got a '99, I'm stuck running 7.5" wide wheels in the front and 8.5" in the back. With that in mind, what are the options for tires these days? A fella in the classifieds section is selling a pair of unused Ecsta V700 235/40-17, but of course then I'd have to find another pair, and Tire Rack says they're looking at 3+ weeks until they get some, maybe much more. And I'd have to get them shaved, right?

Are there any other options on tires? I think Hoosiers are too expensive and will wear too fast for me. Can I run V710 245/45-17 all around, or will it be too tall/wide in the front?

I ran 245/45/17 Victoracers when I first started playing with the M3, and they worked well enough. We run some pretty big courses around here (though nothing compared to some of the Texas stuff) and the extra MPH didn't hurt at all. I tried the 235/40 V700 Ecstas and really hated them. They have no sidewall stiffness and they heat cycle very quickly. The V710 in 245/45 is a good option if it fits. Run it front and rear.

JV

[PedalFaster]

The 245 V710 fits -- the Simanyi / Tanquary M3 from California was running it.

[nick325xit 5spd]

Originally Posted by scoobywrx

Added to my watched topics.. Why not leda's though?

Find a set of ledas that a) fits BMWs, and b) is on sale for ~$600. That answer your question?

Mind you, a good set of Ohlins would probably be pretty fucking awesome.

[John V]

Yeah. For most applications, for 99% of drivers, off the shelf single adjustable Konis work pretty damn well especially for how cheap they are.

[paypiper01]

John, I have a stock 99 M3 and I just got back from Active Autowerke in Miami. I asked them to try to duplicate as best they could your alignment settings. Specifically, I asked for -1.3 front -0.7 rear camber and 1/8 toe out front and zero toe rear.

I took the car to AA because I figured if anybody could do an alignment on a BMW to customer specs it would be them. The car has never been in an accident or collision of any sort and is totally stock. While at AA, I also had them do the RTABs. Here is what they said was the best they could do:

Camber:
Left FR -0.5 Right FR -1.0
Left RR -1.4 Right RR -1.4

Toe:
LF .13 RF .14 (he convinced me to go with this toe)
LR .01 RR .04

The AA guy (Craig) said that it just was not possible to get more camber up front without camber plates or getting slots (??). As for the rear, he could get one side to go to -0.7 but the other side would only go down to -1.4 so he left both at -1.4. It was obviously disappointing that AA could not even come close to your settings. Is this a year specific issue or is this a lazy alignment guy making excuses?

I have been autocrossing and tracking cars for about 2.5 years now but mostly fully prepped street prepared cars with adjustable suspensions. I know each stock car is different but the discrepancy here is pretty big. What do you think?

thanks
JJ

[Kerry]

Seems a bit suspicious.

He's right that he can't adjust the front camber, but that reading is way off. A good alignment mechanic is gold - took me a while to find one. If that reading is correct, your car should be pulling to the left.

The rear should be easy to adjust. I had -2.0 in the rear and got my guy to turn it out to -1.0. This was after another mechanic told me he couldn't adjust anything and left the rear toe way out of whack - it actually ended up stressing the shock so much the seal blew on me.

[Mhyrr]

If that's .13 and .14 without a -, its toe IN. Positive toe = toe in, negative toe = toe out. While nice on the street, that sucks for autocross, try -.05 or more? I've given up on the conversion and just look at degrees now.

[nick325xit 5spd]

That's a useless alignment. I'd believe him on the camber, but the toe is crap front AND rear.