Robbing the E92 M3 and E46 of suspension components

[netto]

If I wanted to get camber and caster adjustment plates for would I need to use e92m or non m ones?

[jts1981]

Hi Bill,
Just writing to see how things are holding up. Any updates?

Thanks,
Jake

[wmandra]

Originally Posted by jts1981

Hi Bill,
Just writing to see how things are holding up. Any updates?

Thanks,
Jake

Been meaning to update this thread for a while.... Everything is holding up great. Worked with Rouge Engineering on a solution for the front M3 wishbones which will be going in soon along with the RE monoball M3 front tension strut bearings. When I bring the car over to them also going to discuss some options for stiffening up the upper rear shock mounts and rear support braces.

I'll post some updated pictures once the car comes back from Rouge.

Bill

[jts1981]

Never fail to impress my friend.

Looking fwd to the pics. Any chance of vids on the track? I track my car a few times a year, but the understeer is a buzz killer, especially coming from a supercharged e46 with full suspension setup.

I am currently leasing my car but not afraid for some bolt ons. I am thinking H&R springs along with the sway bars to start off. I saw Jannisa mentioned a great improvement for understeer, "close to zero." Would you agree?

[wmandra]

Originally Posted by jts1981

Never fail to impress my friend.

Looking fwd to the pics. Any chance of vids on the track? I track my car a few times a year, but the understeer is a buzz killer, especially coming from a supercharged e46 with full suspension setup.

I am currently leasing my car but not afraid for some bolt ons. I am thinking H&R springs along with the sway bars to start off. I saw Jannisa mentioned a great improvement for understeer, "close to zero." Would you agree?

Here's a vid from Watkins Glen last year:

I have no direct experience with the H&R springs on the E89, had the Eibach's on for only about a week and hated them. In terms of reducing understeer it really depends on where you are seeing understeer occur (corner entry, mid corner or corner exit).

Very generally speaking lowering the ride height will help with understeer during corner entry. Stiffer front sway bar will help mid corner if you have excessive body roll. Reducing understeer at corner exit requires changing the front rebound rate on the shocks though which means coilovers.

You can try the springs and sway bars and if it still feels like there is a lot of understeer you can attempt to counter by reducing rear camber (the E89 has quite a bit of camber in the rear from the factory). Reducing rear camber slightly will cause the rear tires to loose grip sooner and increase the potential for oversteer.

Of course always go back to basics and make sure that you're not doing something that's contributing to the oversteer condition (ie. applying power to quick in the corner, trail braking or entering the corner too fast to start with).

[nicknaz]

My car is stock and I went from -2.1degrees rear camber to -1.6 and, as expected, it makes the rear more prone to oversteer / reduces understeer.

I am not 100% sure I like it, because I feel like I can't get on the throttle as early as I used to.

In hindsight, a better solution might have been to max out the front negative camber and leave the rears as is.

[jts1981]

Crr

Originally Posted by nicknaz

My car is stock and I went from -2.1degrees rear camber to -1.6 and, as expected, it makes the rear more prone to oversteer / reduces understeer.

I am not 100% sure I like it, because I feel like I can't get on the throttle as early as I used to.

In hindsight, a better solution might have been to max out the front negative camber and leave the rears as is.

Interesting. How is the tire wear with that camber? I forgot to also mention I have a summer tire "looks" set up, nut seriously thinking of a 18 x 9, 18 x10 inch track set up. Would I have to worry about inner rubbing with the increased camber?

[jts1981]

Btw, I def think my driving style contributes in turn in understeer. I come in a bit hot and try to adjust with throttle. My e46 rear would whip around easier.

[wmandra]

Originally Posted by nicknaz

My car is stock and I went from -2.1degrees rear camber to -1.6 and, as expected, it makes the rear more prone to oversteer / reduces understeer.

I am not 100% sure I like it, because I feel like I can't get on the throttle as early as I used to.

In hindsight, a better solution might have been to max out the front negative camber and leave the rears as is.

I agree with increasing front negative camber as much as possible especially if you're tracking the car. I'm at -1.9 in the rear now and don't think I'll take it much lower, but I'm good on corner entry and exit. Still have a bit too much body roll mid corner which the stiffer sway bar should sort out.

[wmandra]

Originally Posted by jts1981

Btw, I def think my driving style contributes in turn in understeer. I come in a bit hot and try to adjust with throttle. My e46 rear would whip around easier.

Slow in, fast out! Going into the corner fast doesn't help reduce lap times if you're coming out of the corner slow because you can't get on the throttle fast enough.

[jts1981]

Originally Posted by wmandra

Slow in, fast out! Going into the corner fast doesn't help reduce lap times if you're coming out of the corner slow because you can't get on the throttle fast enough.

Yep!! I was still getting to know the car, only racked 1200 miles before my first track day. Can't wait for M school!

[nicknaz]

Originally Posted by jts1981

Crr

Interesting. How is the tire wear with that camber? I forgot to also mention I have a summer tire "looks" set up, nut seriously thinking of a 18 x 9, 18 x10 inch track set up. Would I have to worry about inner rubbing with the increased camber?

I think it would depend on your wheel offsets. I am not sure. If I had to guess you would need stock 255 width or maybe 265 width in the rear to keep from rubbing when the suspension is fully compressed.

My car came from the factory with -2.1 rear camber and no rub with stock tires.

For what it is worth, in my stock car I haven't seen much benefit using a trailing brake or throttle. I think straight line braking and early roll on the throttle has worked better.

[jts1981]

Originally Posted by nicknaz

I think it would depend on your wheel offsets. I am not sure. If I had to guess you would need stock 255 width or maybe 265 width in the rear to keep from rubbing when the suspension is fully compressed.

My car came from the factory with -2.1 rear camber and no rub with stock tires.

For what it is worth, in my stock car I haven't seen much benefit using a trailing brake or throttle. I think straight line braking and early roll on the throttle has worked better.

Thanks for the advice. I'll have to take it more easy on entry.

[wmandra]

Installed the Rogue Engineering monoball M3 front tension arm bushings today along with the M3 front lower wishbones. The OEM bushings need to be pressed out and the new ones pressed in. The quality on the Rogue parts is exceptional and the monoball design will not allow for any deflection at all.

For the M3 wishbones, the guys at Rogue had to make up a mount for the headlight adjuster which is on the opposite side vs the M3. The headlight leveling regulator rod also had to be slightly modified to get everything to mount up correctly.

An alignment was absolutely necessary after the install as toe was completely off. Wishbones added -0.5 degrees of camber up front.

Won't have a chance to try it out on the track for another few months, but initial impressions are good from the drive home.

Here's my current alignment specs:

Front Camber: -1.4 (left), -1.4 (right)
Front Toe-in: 0.12 (left), 0.13 (right), 0.25 (total)
Front Caster: 7.5 (left), 7.3 (right)

Rear Camber: -2.0 (left), -2.0 (right)
Rear Toe-in: 0.21 (left), 0.12 (right), 0.32 (total) - rear toe is an absolute bitch to adjust.

[jts1981]

Hi Bill,
Is the new mount welded to the wishbone? The pic looks only clamped on. I would worry about hard hits and it becoming dislodged. This happened to me a few weeks ago with a stock set up.

Also can you please clarify what mod was done to the regulator rod? Would it be easy to replicate?

Thanks again!

Jake

[wmandra]

Originally Posted by jts1981

Hi Bill,
Is the new mount welded to the wishbone? The pic looks only clamped on. I would worry about hard hits and it becoming dislodged. This happened to me a few weeks ago with a stock set up.

Also can you please clarify what mod was done to the regulator rod? Would it be easy to replicate?

Thanks again!

Jake

The mount is just clamped on, though it's pretty tight. The OEM regulating rod just clamps on as well so I don't think this is much of a problem.

The M3 regulating rod had to be cut and re-welded with a different offset on one side. We just used the stock one as a guide to modify the M3 one.

[wmandra]

Just wanted to post a quick update of where the current suspension setup is and some changes that are coming....

Finally went ahead and replaced the front upper strut mounts with Vorshlag camber plates and decided to try out some new alignment settings:

Front Camber: -2.5
Front Caster: +8
Front Toe: 0.00

Rear Camber: -2
Rear Toe: 0.32 (toe-in)

I ran this setup this past weekend at the track for testing and we're moving in the right direction. Initial turn-in in sharp and the car feels like its rotating right underneath the drivers seat going through the turns. I feel fairly confident these specs are the ones I'll be running for the rest of the season.

That said, there's still some room for improvement. I'm currently looking at replacing the AST dampers with MCS units and converting the rear to a true coilover. The current issue is that the OEM design in the rear definitely has some issues. With the spring mounted in the OEM location the effective Wheel Rate is only 55% of the actual spring rate and since the bottom of the spring sits on the wishbone which is then attached to the subframe, every time the spring needs to compress its pulling the subframe away from the body. This significantly limits the maximum amount of rear spring that can be used as too high a spring rate will end up damaging the subframe.

Moving the rear spring to a coilover setup will increate the Wheel Rate to about 83% of the spring rate and remove the stress from the subframe. This also brings the rear closer in line with the front Wheel Rate of 96%. Using the same 672# springs will increase the effective rear spring rate from 396# to 558# and bring the rear spring frequency more in line with the front. Right now wheel rates are 2.306Hz front and 1.626Hz rear, after the coilover conversion the rear rate will increase to 2.454Hz.

In addition to the coilover swap, I'm also considering replacing the M3 front control arms with a set of spherical front race arms from Bimmerworld (http://store.bimmerworld.com/bimmerw...ion-p2100.aspx) but still undecided on that.

[Asbjorn]

Great information, thanks for the update!

[jts1981]

Originally Posted by Asbjorn

Great information, thanks for the update!

+1

[jannisa]

A delayed thanks for your update.

How different does the rear feel since you switched from 0 toe?

[Furkanyahsi]

Amazing thread, thank you for that useful informations!

[wmandra]

Another small update on this project... Replaced both front and rear swaybars with H&R units with rear bar set on the middle setting. Had the car out at the new track at Thompson Speedway Motorsport Park this weekend and everything felt great. Body roll is much more controlled with the new bars. With the current setup the car was very balanced in the turns, no real understeer or oversteer at all. For most turns I would just trail brake a little on entry to help get the car rotated, then control mid corner and exit with the throttle.

I've decided to run the AST's for the rest of the season, but I'm still researching replacement dampers for next season. Current choices are either the MCS dampers or Penske Racing dampers. Either way, I'll be using Swift springs with the new setup.

Here's some in-car video from Thompson: