Basic auto-cross setup info needed

JPuehl · 03-26-2015, 03:36 PM

Hello,

I'm new to BMW, just bought a '12 135i with m-sport last weekend, and plan to auto-cross the car but am looking for a basic suspension setup. I've been auto-cross racing for the past 9 year so I have an idea what I want to do but am not familiar with the parts available for the 1 that works. I raced a Scion FR-S the past couple of years, first in C stock then STX. I'm also not new to car/race related forums but am used to threads stickied that have basic/known setups to help newbies get started. I'll probably race in STU but initially want to concentrate on alignment and am interested in a setup that would work for a car that is first a DD and second a weekend warrior.

I've read many posts mentioning "M3 bits", like lower front control arms but don't really mention the range of years that work on these cars and haven't found a thread, yet, that examples why they are used on our car other than they help with camber. I've also read many posts of people using dinan's camber plates but it seems they would raise the front of the car since they fit between the stock top-hat and the strut tower, is that the case?

Any input, including links to existing posts, on parts for a good initial setup would be much appreciated.

Thanks, Jim

Kgolf31 · 03-26-2015, 03:42 PM

How much of a "full" prep do you want to do within STU?

I drive a 128i for STX and I'm about 95% of full prep. So feel free to ask any questions.

IMO, if you're going to do it right forget about the M3 bits.

Dual Adjustable w/camber plates, new subframe bushings, diff...etc. As you know the list can get complex quick.

For example, go camber plates over lower control arms, since per ST* rules it's either one or the other

JPuehl · 03-26-2015, 03:56 PM

That's a good question because I usually take a minimalist approach and only mod my car as needed. A few years ago I did buy and race a '92 MR2 from an SCCA nationals driver that was built to 100% prep for Stock and the car was awesome and wasn't bad to drive DD, I know STU > Street. I could see over time going over 80% but for now I'm just interested in a basic setup get the alignment in check to not abuse the tires too much. As I learn the car I'll upgrade to the "better" parts.

I had Koni yellows and a set of springs and chamber plates on the FR-S and was beating up on guys with less seat time but "high end" coil over set ups, so I was thinking of a similar setup to start with.

The Nebulizer · 03-30-2015, 04:28 PM

I've also just purchased a 135i. I'm only taking mine to FStreet prep.
This weekend I put on an Eibach 20100.310 (for e9x M3, fits e82 well) adjustable front swaybar (soft) and drove it at its first TnT yesterday. I was still on the tires I bought it with (BFG KDW) as it was 30 degrees. The car felt really good. Grip was good, except when turned too far when it gave up and pushed. Out of a hard hairpin (strange course), the electric diff seems to have held back power as it was sluggish with full throttle. But, overall felt good. I have a set of lightweight stock sized wheels (Breyton GTS-R) and tires (245/245 or maybe 245/275 BFG Rivals). I don't feel the car really needs much of anything else to be competitive in FS.

_Ryan_ · 03-30-2015, 04:57 PM

Quote:

Originally Posted by Kgolf31

How much of a "full" prep do you want to do within STU?

I drive a 128i for STX and I'm about 95% of full prep. So feel free to ask any questions.

IMO, if you're going to do it right forget about the M3 bits.

Dual Adjustable w/camber plates, new subframe bushings, diff...etc. As you know the list can get complex quick.

For example, go camber plates over lower control arms, since per ST* rules it's either one or the other

This man speaks the truth. Camber, diff, rear subframe bushing and quality dampers.
Do your regulations allow you to change the drivers seat?

Kgolf31 · 03-30-2015, 05:10 PM

Quote:

Originally Posted by _Ryan_

Quote:

Originally Posted by Kgolf31

How much of a "full" prep do you want to do within STU?

I drive a 128i for STX and I'm about 95% of full prep. So feel free to ask any questions.

IMO, if you're going to do it right forget about the M3 bits.

Dual Adjustable w/camber plates, new subframe bushings, diff...etc. As you know the list can get complex quick.

For example, go camber plates over lower control arms, since per ST* rules it's either one or the other

This man speaks the truth. Camber, diff, rear subframe bushing and quality dampers.
Do your regulations allow you to change the drivers seat?

Must be at least 25 lbs that includes seat + mounting hardware.

I run a Recaro SPG with VAC hardware and I'm 27.2 lbs per seat

boarderofsnow86 · 03-30-2015, 08:32 PM

I'm running in STU this year as well. I probably won't be fully or 90% prepped until the end of the season but I started with rear subframe bushings, diff bushings, and m bits in the rear. Mbits and sway bar in the front. And tires. Coilovers and camber plates are next and stock front lowers since that what the rules allow.

My main problem is front tire camber and size. I am addressing the camber first. I've done the first two events of the season and my front tire wear is very outside heavy.

STU is a rough class for the 135i. Mostly because of the limited front tire section width. It does allow for the modification that I wanted to do for track days as well though.

Kgolf31 · 03-31-2015, 06:49 AM

Quote:

Originally Posted by boarderofsnow86

I'm running in STU this year as well. I probably won't be fully or 90% prepped until the end of the season but I started with rear subframe bushings, diff bushings, and m bits in the rear. Mbits and sway bar in the front. And tires. Coilovers and camber plates are next and stock front lowers since that what the rules allow.

My main problem is front tire camber and size. I am addressing the camber first. I've done the first two events of the season and my front tire wear is very outside heavy.

STU is a rough class for the 135i. Mostly because of the limited front tire section width. It does allow for the modification that I wanted to do for track days as well though.

What are the M Bits in the front?

If you have lower control arms, then going camber plates will be illegal

boarderofsnow86 · 03-31-2015, 01:21 PM

Quote:

Originally Posted by Kgolf31

What are the M Bits in the front?

If you have lower control arms, then going camber plates will be illegal

Correct. When I get coilovers and camber plates I will have to go back to the stock lower control arms. But then I'll be able to get the camber that I want anyway.

JPuehl · 04-01-2015, 03:46 PM

Thanks for the feedback. I ordered some wheels and camber plates with get me started. In doing a bunch of reading, it seems to be 50/50 on where the m-bits are worth the money, plus with the camber plates the camber can be matched side-to-side.

Freon · 04-06-2015, 01:19 PM

Quote:

Originally Posted by The Nebulizer

I've also just purchased a 135i. .

Why hello there, Nebulizer!

YarkoDrives · 06-03-2015, 10:46 PM

Quote:

Originally Posted by boarderofsnow86

Correct. When I get coilovers and camber plates I will have to go back to the stock lower control arms. But then I'll be able to get the camber that I want anyway.

I'm not certain, but the ball joint in the 1M/M3 control arm may not be legal for ST.

the m3 balljoint exhibits the same range of motion as the oem 1-piece rubber bush with two-concentric cylinders. but likely changes the relative amount of metal, also it is multi-axis, and the ball joints are different internal parts.

Quote:

SCCA 2015 ST rules 14.8.H Camber Kits
...
2. On arm-and-strut (MacPherson/Chapman) suspensions, the lower
arms may be modified/replaced OR other methods of camber adjustment
as allowed by Sections 14.8.B, C, or G may be used, but not
both.
...
5. The replacement arms or mounts must attach to the original standard
mounting points. All bushings must meet the requirements of
Section 14.8.B.

here's 14.8.B:
B. Suspension bushings may be replaced with bushings of any materials
(except metal) as long as they fit in the original location. Offset bushings
may be used. In a replacement bushing, the amount of metal relative
to the amount of non-metallic material may not be increased. This
does not authorize a change in type of bushing (e.g., ball and socket
replacing a cylindrical bushing) or use of a bushing with an angled hole
whose direction differs from that of the original bushing. If the standard
bushing accommodated multi-axis motion via compliance of the
component material(s), the replacement bushing may not be changed
to accommodate such motion via a change in bushing type, for example
to a spherical bearing or similar component involving internal moving
parts. Pins or keys may be used to prevent the rotation of alternate
bushings but may serve no other purpose than that of retaining the
bushing in the desired position.

03-26-2015, 03:36 PM	#1
JPuehl Lieutenant 101 Rep 414 Posts Drives: 2011 135i N55 DCT Join Date: Mar 2015 Location: Greater Seattle area iTrader: (0)	Basic auto-cross setup info needed Hello, I'm new to BMW, just bought a '12 135i with m-sport last weekend, and plan to auto-cross the car but am looking for a basic suspension setup. I've been auto-cross racing for the past 9 year so I have an idea what I want to do but am not familiar with the parts available for the 1 that works. I raced a Scion FR-S the past couple of years, first in C stock then STX. I'm also not new to car/race related forums but am used to threads stickied that have basic/known setups to help newbies get started. I'll probably race in STU but initially want to concentrate on alignment and am interested in a setup that would work for a car that is first a DD and second a weekend warrior. I've read many posts mentioning "M3 bits", like lower front control arms but don't really mention the range of years that work on these cars and haven't found a thread, yet, that examples why they are used on our car other than they help with camber. I've also read many posts of people using dinan's camber plates but it seems they would raise the front of the car since they fit between the stock top-hat and the strut tower, is that the case? Any input, including links to existing posts, on parts for a good initial setup would be much appreciated. Thanks, Jim Last edited by JPuehl; 03-27-2015 at 11:30 AM..
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03-26-2015, 03:42 PM	#2
Kgolf31 Brigadier General 460 Rep 4,531 Posts Drives: 2007 Z4MC, 2012 128i Join Date: Sep 2008 Location: Ohio iTrader: (4)	How much of a "full" prep do you want to do within STU? I drive a 128i for STX and I'm about 95% of full prep. So feel free to ask any questions. IMO, if you're going to do it right forget about the M3 bits. Dual Adjustable w/camber plates, new subframe bushings, diff...etc. As you know the list can get complex quick. For example, go camber plates over lower control arms, since per ST* rules it's either one or the other
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03-26-2015, 03:56 PM	#3
JPuehl Lieutenant 101 Rep 414 Posts Drives: 2011 135i N55 DCT Join Date: Mar 2015 Location: Greater Seattle area iTrader: (0)	That's a good question because I usually take a minimalist approach and only mod my car as needed. A few years ago I did buy and race a '92 MR2 from an SCCA nationals driver that was built to 100% prep for Stock and the car was awesome and wasn't bad to drive DD, I know STU > Street. I could see over time going over 80% but for now I'm just interested in a basic setup get the alignment in check to not abuse the tires too much. As I learn the car I'll upgrade to the "better" parts. I had Koni yellows and a set of springs and chamber plates on the FR-S and was beating up on guys with less seat time but "high end" coil over set ups, so I was thinking of a similar setup to start with.
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03-30-2015, 04:28 PM	#4
The Nebulizer Private First Class 23 Rep 109 Posts Drives: e90ZCP M3 & e46 M3 (slicktops) Join Date: Jan 2015 Location: St. Louis iTrader: (0)	I've also just purchased a 135i. I'm only taking mine to FStreet prep. This weekend I put on an Eibach 20100.310 (for e9x M3, fits e82 well) adjustable front swaybar (soft) and drove it at its first TnT yesterday. I was still on the tires I bought it with (BFG KDW) as it was 30 degrees. The car felt really good. Grip was good, except when turned too far when it gave up and pushed. Out of a hard hairpin (strange course), the electric diff seems to have held back power as it was sluggish with full throttle. But, overall felt good. I have a set of lightweight stock sized wheels (Breyton GTS-R) and tires (245/245 or maybe 245/275 BFG Rivals). I don't feel the car really needs much of anything else to be competitive in FS.
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03-30-2015, 08:32 PM	#7
boarderofsnow86 Enlisted Member 6 Rep 46 Posts Drives: 2012 135i Join Date: May 2013 Location: Wilmington, NC iTrader: (1)	I'm running in STU this year as well. I probably won't be fully or 90% prepped until the end of the season but I started with rear subframe bushings, diff bushings, and m bits in the rear. Mbits and sway bar in the front. And tires. Coilovers and camber plates are next and stock front lowers since that what the rules allow. My main problem is front tire camber and size. I am addressing the camber first. I've done the first two events of the season and my front tire wear is very outside heavy. STU is a rough class for the 135i. Mostly because of the limited front tire section width. It does allow for the modification that I wanted to do for track days as well though.
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04-01-2015, 03:46 PM	#10
JPuehl Lieutenant 101 Rep 414 Posts Drives: 2011 135i N55 DCT Join Date: Mar 2015 Location: Greater Seattle area iTrader: (0)	Thanks for the feedback. I ordered some wheels and camber plates with get me started. In doing a bunch of reading, it seems to be 50/50 on where the m-bits are worth the money, plus with the camber plates the camber can be matched side-to-side.
	Appreciate 0 Quote