Autox alignment suggestions

[sab0276]

Looking for alignment and ride height suggestions for a 2001 M Roadster. Mods inlcude:
TC Kline SA Coilovers 450# front 500# rear springs
Front OEM strut hats swapped for more camber
IE Subframe Bushings
KMAC Eccentric RTABs
Strong-Strut and Butt-Strut
235/45R17 and 275/40R17 Azenis on stock Roadstars

Car hasn't been aligned since suspension was installed. Looking for good autocross alignment settings.


Pics from this last autox event this weekend:







-Scott

[JByrd]

I would suggest you start out a zero toe, then move it out as much as a tenth inch if you need to.

[Markl006]

I spent all my money on wine and women - the rest I wasted.

[SunzOut]

I spent all my money on wine and women - the rest I wasted.

[z3papa]

While alignment helps, nothing helps a BMW more than lots of front negative camber. I'd say crash bolts before getting the alignment would be in order.

[sab0276]

So any suggestions on actual aligment specs (numbers)?

-Scott

[z3papa]

JBryd's response is probably as detailed as it may get as negative camber is not something you can dial in. It's what your setup allows. Caster likewise. Personally, I have 6 caster and 3.8 negative camber with an 1/16th toe but the only variable is really toe.

[PbFut]

You spent how much on suspension parts and then did not bother to align it?????

Replies are correct but they are not giving the reason why you can't get to number you need. Since the OP does not have camber plates, he can not adjust camber or caster. Swapping OEM hats helps and crash bolts or shims will get a bit more but you will still be less than -3 camber. Depending on autox track, you will want -3.25 to as much as -3.8 camber. zero to as much as an 1/8 out toe and as much caster as you can find. Plates are needed to get to alignment settings this aggressive and it will not be good on the street.

[z3papa]

You spent how much on suspension parts and then did not bother to align it?????

Replies are correct but they are not giving the reason why you can't get to number you need. Since the OP does not have camber plates, he can not adjust camber or caster. Swapping OEM hats helps and crash bolts or shims will get a bit more but you will still be less than -3 camber. Depending on autox track, you will want -3.25 to as much as -3.8 camber. zero to as much as an 1/8 out toe and as much caster as you can find. Plates are needed to get to alignment settings this aggressive and it will not be good on the street.

Not sure if you were responding to me but to answer your question -- yes I did get an alignment with all specs outlined. My point was my alignment won't do him much good as they are premised on my car's adjustment level. By the way, 3.8* negative camber with 6 caster actually can be street driven but is pretty reactive for the typical street driver. When dialed back to 2.5* negative camber, the car is a bit slower but less twitchy.

[Car54]

look at all those curbs!!!

[Z3racer701]

If you wanted adjustable on the back, get rid of the K-Mac's, which don't stay where they're set, and install the Ireland camber and toe adjustors. To do it right you have to take the sub-frame in and out a couple of times, first to mount the tabs in place then align and tack, take out weld, and align again. It's the only way to have equal adjustment on both sides. Second, strut tower adjustors are the only way to get any alignment on the front. I myself haven't bothered with any of this on my street car, I bolted in Koni singles with the stock springs and have even tire wear all around. But the primary thing you should do is read the rule book for the class you want to run in and understand if it's really close and you have a shady part on the car, like the K-mac's or the swapped stock strut tops, you will get protested and disqualified. In Improved Touring, there's a saying... IIDSYCYC (if it doesn't say you can, you can't) and the flip side is IISYCTYBWC (if it says you can, then you bloody well can). That is if it's not legal to run strut adjustors and you swap the strut tops, you've already lost the race. The flip side is if it is legal to run the adjustors and you only swap the strut tops, you've also lost the race. Choose wisely young padawan, and the force will go with you

James

[phrider]

If you wanted adjustable on the back, get rid of the K-Mac's, which don't stay where they're set, and install the Ireland camber and toe adjustors.

KMAC changed their design a bit, and if cranked down, they stay put (Jeff the Alignment Guy at Stokes Tire in Santa Monica knows how). Mine have stayed for years.

There is a new adjustable bushing by AKGmotorsports that some are exploring. See the thread http://forums.bimmerforums.com/forum...&highlight=AKG , especially post #22 on relative install cost. Erik Link at Edge told me that the adjustment ease is better with the AKG bushings than the IE weld-ins.

[The ZED]

I occasionally autocross, but mostly street drive. Dinan set it up with -1.6 camber front with about 3.7 caster and .15 toe. Rear was -2.0 camber and .19 toe. I liked it and it doesn't eat through the tires as fast. BTW I have the Dinan camber kit.

[SunzOut]

Being new to Autocross as well, I'd love to get more knowledge on the best way to setup the car but from what I have seen so far there is no "set it to this" method. You will have to work your way to the best setup by running the car and working on its handling problems and your driving skill/style.

These two sites list some of the basic changes and how they affect the handling (although they have opposite views of Tire pressure changes!!)

http://www.m5board.com/vbulletin/showthread.php?t=114743
http://www.rallylights.com/other/stuning.htm

You can’t adjust your caster or camber on the front, so you’re stuck with that. You can adjust toe (Toe Out = reduced understeer)

On the rear you can adjust Camber and Toe so you may be better trying to make the handling suit your style by adjusting that end.

Your shock adjustment and tire pressures are going to have the most effect at an event.

You need to get an alignment done - set the back end to a reasonable neg camber (-2) and the toe within stock specs. Then work with tires and shocks to set up the handling.

Also removal of Rear sway bar has been suggested as improving handling.

After our first Autocross School I have to much understeer and to much oversteer but I suspect both of these are related to a heavy right foot.

I plan to crank on more front neg Camber and work on the tire pressure as well as training the right foot!!

[Car54]

Being new to Autocross as well, I'd love to get more knowledge on the best way to setup the car but from what I have seen so far there is no "set it to this" method. You will have to work your way to the best setup by running the car and working on its handling problems and your driving skill/style.

These two sites list some of the basic changes and how they affect the handling (although they have opposite views of Tire pressure changes!!)

http://www.m5board.com/vbulletin/showthread.php?t=114743
http://www.rallylights.com/other/stuning.htm

You can’t adjust your caster or camber on the front, so you’re stuck with that. You can adjust toe (Toe Out = reduced understeer)

On the rear you can adjust Camber and Toe so you may be better trying to make the handling suit your style by adjusting that end.

Your shock adjustment and tire pressures are going to have the most effect at an event.

You need to get an alignment done - set the back end to a reasonable neg camber (-2) and the toe within stock specs. Then work with tires and shocks to set up the handling.

Also removal of Rear sway bar has been suggested as improving handling.

After our first Autocross School I have to much understeer and to much oversteer but I suspect both of these are related to a heavy right foot.

I plan to crank on more front neg Camber and work on the tire pressure as well as training the right foot!!

Please elaborate on your rear suspension tuning techniques. Do you have adjustable trailing arm suspension geometry or are you advising the OP to get them.

[SunzOut]

Please elaborate on your rear suspension tuning techniques. Do you have adjustable trailing arm suspension geometry or are you advising the OP to get them.

the OP as KMAC rear adjusters....I have the IE weld in adjusters.

[yokoseiki]

If you wanted adjustable on the back, get rid of the K-Mac's, which don't stay where they're set, and install the Ireland camber and toe adjustors. To do it right you have to take the sub-frame in and out a couple of times, first to mount the tabs in place then align and tack, take out weld, and align again. It's the only way to have equal adjustment on both sides.

I know a lot of folks like the Ireland kit but after spending all weekend removing mine after 1 year of use, I would only reccomend it to people that are not serious into autocross or track driving. Firstly as far as autocross it throws you into a prepared class but minus that I was never happy with the performance of the kit. I found the kit was not compliant with aggresive rear trailing arm bushings like poly or delrin as it skews the axial alignment of the bolts. This created a ton of static friction. In addition to that the metal channels you weld onto your subframe actually bend, and in my case were broken by the lobes on the eccentric bolts. You should put a VERY thick bead to gusset and reinforce it. Finally on a more technical note although it fixes the toe and camber problems on lowered vehicles it does change the roll center noticeably.

[sab0276]

What are your thoughts on the KMACs?

-Scott

[yokoseiki]

What are your thoughts on the KMACs?

-Scott

Scott, I also used the "newer" KMAC bushings prior to the IE kit and they actually work pretty well. Use Gastave's charts to figure out how the toe and camber couple. But even the newer kit does loosen, and you need to check them all the time. The problem that I had was the KMAC bushings were actually bending the trailing arm mounts inward. Imagine concave shaped bending around the holes that the bolts will go through. The "stiction" wasn't that bad because the total range of adjustment is somewhat smaller than the IE kit.

As far as what I am doing now is similar to Groupe N E30 touring cars. I am using a 5/8 rod end in replacement of one of the control arms and keeping the inner intact. This gives me toe adjustment without changing the sweep angle. The rod end actually has to slide left to right. Not sure why but that's how BMW did it. In order to fix camber I decided that I am going to finalize my rear ride height, actually cut the control arm at the inner arm and reweld to correct the excessive camber. If the rules for my class were different I would actually make a moveable mount but I'm not allowed to change my pickup points. I can only repair or reinforce them. Yes I know this removes any adjustability but to be honest I've run anywhere between -1 and -4 degrees in the back and found very little difference in performance. I only found that launching is much better with -3 degrees or less of camber. I'm going to set it for -3 degrees at my lowest ride height and just leave it there from now on.