1M - Rear toe link

[RimasRS]

sorry little off topic but which settings would increase traction zero toe a little toe in?

[MDORPHN]

Originally Posted by RimasRS

sorry little off topic but which settings would increase traction zero toe a little toe in?

For straight line acceleration, zero toe (or very slight toe-in). During heavy braking or cornering, slight toe-in.

Neil

[MDORPHN]

FWIW, found a post by a well-known and very accomplished racer about the changes he made to his GTS4 E92 M3 (also with the advice of James Clay). Mind you this a non-street legal race car. Here's an excerpt:

"The pics show the stock toe adjustment arm still in there, but that's just installed for now until I get the adjustable ones. (http://store.bimmerworld.com/rogue-e...set-p1269.aspx) Also in there are adjustable rear camber links. (http://store.bimmerworld.com/hotchki...set-p1180.aspx) Also all bushings that were rubber have been replaced with spherical bearings.
Stock rear sway bar has been replaced with one from Racing Dynamics. (http://store.bimmerworld.com/rd-sport-swaybar-kits---e9x-m3--e8x-1m-p1875.aspx)"

Neil

[Pete_vB]

Originally Posted by MDORPHN

FWIW, found a post by a well-known and very accomplished racer about the changes he made to his GTS4 E92 M3 (also with the advice of James Clay). Mind you this a non-street legal race car. Here's an excerpt:

"The pics show the stock toe adjustment arm still in there, but that's just installed for now until I get the adjustable ones. (http://store.bimmerworld.com/rogue-e...set-p1269.aspx) Also in there are adjustable rear camber links. (http://store.bimmerworld.com/hotchki...set-p1180.aspx) Also all bushings that were rubber have been replaced with spherical bearings.
Stock rear sway bar has been replaced with one from Racing Dynamics. (http://store.bimmerworld.com/rd-sport-swaybar-kits---e9x-m3--e8x-1m-p1875.aspx)"

Neil

Locking everything down and attempting to take all compliance steer out is a valid way to go in some situations if you know what you're doing. It avoids the issue of taking only some of the compliance out and potentially reversing the direction of the compliance steer, etc though one must take care that you leave in enough compliance to avoid binding and hence loads going through the roof.

The Porsche factory went this route with their race cars. The GT3 Cup car gets revised pickup points but keeps rubber and compliance in 3 of the 5 links to keep (reduced) compliance steer. The RSR however gets monoballs everywhere, with the geometry and pickups revised again. However realize that the tire package has changed radically from the street cars- both race cars use slicks, with the RSRs being massively tall leading to lots of compliance in the sidewall. Also realize the RSRs are pulling over 2.25 Gs of cornering in places, so that suspension would be moving around way too much if it wasn't "locked down".

This does illustrate the arc nicely though: as you move away from what the factory intended by either lowing the car or adding more stick you can likely benefit from careful, strategic upgrades, if you can find someone who can guide you well. First are subframe bushings, as they are only there from NVH- Porsche swapped these for aluminum in the GT3s. Next would be the correct suspension arm, the LCA in GT3 and Cup being a good example, and then finally, when your package gets wild and the loads get extreme, you probably need to do everything. But trying to eliminate movement on a street tire and spring package is only going to slow you down- all that imperceptible steering going on as you're going over bumps is really helping you, and when it works correctly it's actually making micro-corrections the driver would otherwise need to make.

[MDORPHN]

FYI, I've decided to get the Bimmerworld rear camber arm kit that is linked in one of my earlier posts in this thread.

I won't be on track until mid-March and will share my findings at that point.

Neil

[HP Autosport]

Originally Posted by MDORPHN

FYI, I've decided to get the Bimmerworld rear camber arm kit that is linked in one of my earlier posts in this thread.

I won't be on track until mid-March and will share my findings at that point.

Neil

If those are the RE version, we have sold and installed a few with very good customer feed backs. Have fun!

[MDORPHN]

Originally Posted by HP Autosport

If those are the RE version, we have sold and installed a few with very good customer feed backs. Have fun!

Harold -

No, there are not replacement arms, but a replacement inner bushing for the stock arm.

Link: http://store.bimmerworld.com/bimmerw...kit-p1921.aspx


Neil

[scotth944]

I think they may be referring to this:
Rogue Engineering Rear Wishbone Bushings for E82 1M

[Pete_vB]

I got some data from a BMW M3 off of a K&C machine. They definitely toe in under compression at the rear, just like everything else, and I believe the 1M is identical. So the high speed instability must come from somewhere else. I'll ponder...

Looking forward to impressions, Niel.

[MDORPHN]

Originally Posted by Pete_vB

I got some data from a BMW M3 off of a K&C machine. They definitely toe in under compression at the rear, just like everything else, and I believe the 1M is identical. So the high speed instability must come from somewhere else. I'll ponder...

Looking forward to impressions, Niel.

Pete -

They'll be installed -- along with some other goodies -- next week and I'll be on track on the 15th - 16th.

I'll report back.

Neil

[MDORPHN]

OK, some impressions from my past weekend at Summit Point.

As a preliminary matter, I should first note that, in addition to the Bimmerworld rear camber arm bearing kit, I also installed some new front dampers -- replacing the JRZ RS1 shocks with JRZ RS Pro (double adjustables with a remote reservoir).

This, together with a new alignment from RRT Racing, makes it difficult to isolate how much of the improvement is due to the rear camber arm bearing kit.

Having said that, my car has never handled better. Turn-in is excellent and the rear-end easily controlled. It would, of course, step out mid-turn under heavy throttle, but it wasn't abrupt and was easy to catch. In addition, the car was less unsettled by bumps (although I suspect that that was primarily due to the different dampers in front).

I'm still dialing-in the revised set-up, but really couldn't be happier. Heading down to VIR this Thursday evening and will be on track Fri-Sat. Pretty excited about the new track season!

Neil

[Splinterz88]

Neil what are your alignment settings?

[MDORPHN]

Originally Posted by Splinterz88

Neil what are your alignment settings?

Don't have sheet in front of me, but approx. 3 degrees camber in front with zero toe (or just a smidgen of toe-in) and 2.1 degrees in back with .15 degrees total toe-in.

Neil

[Splinterz88]

Thanks Neil. Why did you decide to run replace the rs1 with the rs pros? You are the second person that I know that did that. was at VIR this past weekend first time, but had a blast. Was told by those who had been there before that it's a faster track now. Still hoping that our paths will cross at DE and I can request you as an instructor.

Cheers,
Art

[MDORPHN]

Originally Posted by Splinterz88

Thanks Neil. Why did you decide to run replace the rs1 with the rs pros? You are the second person that I know that did that. was at VIR this past weekend first time, but had a blast. Was told by those who had been there before that it's a faster track now. Still hoping that our paths will cross at DE and I can request you as an instructor.

Cheers,
Art

Art -

I had an opportunity to upgrade to the RS Pro dampers and grabbed it.

I'll be down to VIR again April 25-27 for the Tarheel Chapter school. Sign up!

Neil

[Splinterz88]

I wish, probably won't get back down there until Oct or Nov. I have to do a 3 day event on full course for it to be worth the drive. Maybe some other track.

[bdaddylo]

Neil,

When are you going to replace your rear subframe bushings with these?

http://www.turnermotorsport.com/p-14...m-e82-e9x.aspx

There are a few M3 guys who have done this mod and swear by it.

[MDORPHN]

Originally Posted by bdaddylo

Neil,

When are you going to replace your rear subframe bushings with these?

http://www.turnermotorsport.com/p-14...m-e82-e9x.aspx

There are a few M3 guys who have done this mod and swear by it.

Not going to happen unless/until my 1M becomes a dedicated track car.

Too much NVH for regular street use.

Neil

[M3 Adjuster]

Originally Posted by bdaddylo

Neil,

When are you going to replace your rear subframe bushings with these?

http://www.turnermotorsport.com/p-14...m-e82-e9x.aspx

There are a few M3 guys who have done this mod and swear by it.

I agree with Neil. Solid bushings on a street car ? No thanks. Wanna go former sure that's fine but save solid bushings for your track car. Too much NVH and invariably you will create a weak point someplace else without upgrading lots of other bushings all at the same time.