steering and suspension Lowering question. Need help!

[Senna27]

So here's my dilemma. When I added camber plates it raised the front by 1/2" or so. To balance out the rake, a shim was added to the rear. The problem is, it's changed the handling for whatever reason. It's not as comfortable to drive at speed, especially turn in. I would like to lower the car back to where it was. 

 

I'm looking for options, the simpler the better.

 

Here's my current setup:

 

Eibach springs (no other info available, installed in '86)

Koni shocks (fronts are adjustable)

Turbo front bar

Dinan adjustable rear bar (mid of 3 settings)

Ireland front camber plates

Ireland front strut bar

E21 5 speed and LSD

Bridgestone S03 195/50/15

Panasport 15x6 ET29

 

Like I said, car was much better before camber plates were installed which raised the ride height a noticeable amount. A slight amount of camber was added to the fronts, but the plates were added mainly to be able to equalize camber left and right. 

 

I have a track day coming up at Mosport on August 1st. where I'll be driving people around at speed all day so I really want to get this sorted before then. At the moment it's going to be a real handful.

 

Would lower springs be a easy/viable option?

 

First pic is after camber plates, third is before...

 

 

 

 

 

Edited June 28, 2016 by Senna27

[2002Scoob]

It's very likely not the ride height that's contributing to your handling characteristics, but the setup of your new camber plates and if you had a follow up alignment after installing. Post up your camber settings and if, or if not you had an alignment done after and what your settings were.

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[2002Scoob]

Ps, I think your ride high looks pretty good to me!

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[jrkoupe]

I wouldn't think the car should feel like this.......not just from what u mention. Your current  ht looks fine.

 

 

check front (and rear) align.....

 

are they fixed plates?..i ran those as well....edit, actually I see those are adjustable plates.

 

 

on turn in, is the car loose?.....or is it darty?

Edited June 28, 2016 by jrkoupe

['76mintgrün'02]

forgive me for asking this question again, but did you have the weight of the car on the wheels (plus the recommended added weight), when you tightened up the suspension components?  I ask because tightening them with everything hanging can lead to a slightly higher ride height (and short lived rubber bits).  Perhaps the half inch is merely the thickness of the camber plates.

 

 

[eurotrash]

1. Glad you are not expecting to adjust camber significantly with out small springs.

2. if you have regular eibach springs, up front you can cut half a turn at a time to get it where you want.  I did on mine (before going full retard). Billy Sport shocks with 15x7 et25 wheels with 195/50/15s. looks about the same as your car. I think I had 2 dot pads in the back.

 

 

 

This suspension is now on this car.. 

 

Edited June 28, 2016 by eurotrash

[Senna27]

10 hours ago, 2002Scoob said:

It's very likely not the ride height that's contributing to your handling characteristics, but the setup of your new camber plates and if you had a follow up alignment after installing. Post up your camber settings and if, or if not you had an alignment done after and what your settings were.

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The car had a complete alignment after installation and camber was set equally left and right. It was a couple years ago so I no longer have numbers. 

[Senna27]

3 hours ago, jrkoupe said:

I wouldn't think the car should feel like this.......not just from what u mention. Your current  ht looks fine.

 

 

check front (and rear) align.....

 

are they fixed plates?..i ran those as well....edit, actually I see those are adjustable plates.

 

 

on turn in, is the car loose?.....or is it darty?

Front camber plates were installed to both add a little more camber and to make the amount of camber the same on either side (as it wasn't before). A shim or pad was added to the rear springs to compensate for the extra height of the camber plates. Car was then aligned.

 

I know this sounds strange but the car feels like it has a little more body roll on turn in, then you get this snap oversteer thing happening if you're not really smooth (and I'm pretty smooth). Never did that before. 

[Senna27]

3 hours ago, '76Mintgrun'02 said:

forgive me for asking this question again, but did you have the weight of the car on the wheels (plus the recommended added weight), when you tightened up the suspension components?  I ask because tightening them with everything hanging can lead to a slightly higher ride height (and short lived rubber bits).  Perhaps the half inch is merely the thickness of the camber plates.

 

 

All suspension was done (tightened) properly by Marcus Glarner. 

[AceAndrew]

1)  How long have the plates been on the car?  2002 adjustable camber plates are typically used on race cars and it is understood that the spherical (and radial) bearings are wear items.  Depending how you drive on the street, it is reasonable to have to replace them every 5k-10k.  In addition, if the clearance washers were not correctly installed then it can be jumpy with the springs binding.  Look for rub marks on the tops of your spring perches.  Look for marks on your inner fender at the same time, the stock springs can only go so far inward before hitting the inner fender.

 

2)  The adjustable camber plate is meant to be used with 2.5" springs.  It can be used with stock 5" springs (and stock spring perch), but as you note the sacrifice is that the stack height is taller.  However, given that your original struts were bent that must have been the only option for you at the time.  If your car has some down time you can actually have your struts bent back to mach (and gussets welded to the base), negating the need for adjustable camber plates altogether.

 

3)  Your increased body roll feel sounds like A) alignment is no longer bueno  and/or  B) What Mr.MintGrun mentioned, that Mr. Glarner may have tightened the suspension while the wheels were hanging off the ground. 

 

[Senna27]

38 minutes ago, AceAndrew said:

1)  How long have the plates been on the car?  2002 adjustable camber plates are typically used on race cars and it is understood that the spherical (and radial) bearings are wear items.  Depending how you drive on the street, it is reasonable to have to replace them every 5k-10k.  In addition, if the clearance washers were not correctly installed then it can be jumpy with the springs binding.  Look for rub marks on the tops of your spring perches.  Look for marks on your inner fender at the same time, the stock springs can only go so far inward before hitting the inner fender.

 

2)  The adjustable camber plate is meant to be used with 2.5" springs.  It can be used with stock 5" springs (and stock spring perch), but as you note the sacrifice is that the stack height is taller.  However, given that your original struts were bent that must have been the only option for you at the time.  If your car has some down time you can actually have your struts bent back to mach (and gussets welded to the base), negating the need for adjustable camber plates altogether.

 

3)  Your increased body roll feel sounds like A) alignment is no longer bueno  and/or What Mr.MintGrun mentioned, that Mr. Glarner may have tightened the suspension while the wheels were hanging off the ground. 

 

1) Plates have been on the car for a couple years and were installed with new bearings. Car has less than 2,000 miles since. There are no rub/wear marks on spring perches or inner fender.

 

2) If there's no easier fix, I may try removing the camber plates and have the strut/struts straightened and welded. 

 

3) I guess it couldn't hurt to have an alignment done. Mr. Glarner has been building and racing BMWs (including this M5 I used to race) for longer than I can remember. There's not a chance he would tighten the suspension with the wheels hanging off the ground. 

 

 

[FB73tii]

2 hours ago, Senna27 said:

the car feels like it has a little more body roll on turn in, then you get this snap oversteer thing happening if you're not really smooth (and I'm pretty smooth)

 

I would not think that raising both the front and rear by 1/2" would cause that big of change. If I understand correctly, you've driven this configuration about 2,000 miles, and it has had this behavior the whole time?

 

I would consider looking at other causes--sometimes multiple things happen at once and you can chase your tail thinking it is one thing when actually it is something unrelated. Not saying that is the case, but worth considering. One thing you could do to isolate the issue is to go back to the original configuration and see if the issue goes away (of course re-setting the front toe). If not, it could be something as simple as tire pressure (did you get new tires in the past 2 years?), or the rear subframe bushings wearing out, or the bolts holding them becoming loose (yes, that has happened to me). Or a leaking shock, or something else. I'd get under the car and do a nut-and-bolt check of the entire front and rear suspension and the subframes as well.

 

The IE adjustable plates do give you more caster, but that should not cause the issue you are having. You could try dropping the rear tire pressure a bit to see if that helps the oversteer. What is the diameter of your anti-roll bars? I run equivalent to 25mm on front, 22mm in the rear, but my set-up is likely quite different than yours (stiff springs, coilovers, bilstein sport, adjustable rear toe and camber).

 

Best of luck sorting this out--Fred

 

[Senna27]

12 minutes ago, FB73tii said:

 

I would not think that raising both the front and rear by 1/2" would cause that big of change. If I understand correctly, you've driven this configuration about 2,000 miles, and it has had this behavior the whole time?

 

I would consider looking at other causes--sometimes multiple things happen at once and you can chase your tail thinking it is one thing when actually it is something unrelated. Not saying that is the case, but worth considering. One thing you could do to isolate the issue is to go back to the original configuration and see if the issue goes away (of course re-setting the front toe). If not, it could be something as simple as tire pressure (did you get new tires in the past 2 years?), or the rear subframe bushings wearing out, or the bolts holding them becoming loose (yes, that has happened to me). Or a leaking shock, or something else. I'd get under the car and do a nut-and-bolt check of the entire front and rear suspension and the subframes as well.

 

The IE adjustable plates do give you more caster, but that should not cause the issue you are having. You could try dropping the rear tire pressure a bit to see if that helps the oversteer. What is the diameter of your anti-roll bars? I run equivalent to 25mm on front, 22mm in the rear, but my set-up is likely quite different than yours (stiff springs, coilovers, bilstein sport, adjustable rear toe and camber).

 

Best of luck sorting this out--Fred

 

Yes Fred, this behavior has been there the whole time since adding the camber plates and raising the rear. The change in handling was subtle but I can definitely tell it's different. 

 

Tires are getting on (still lots of tread) but they're getting on in age. I will be replacing them before my track day on Aug. 1st. Tire pressures are always set to 34 psi all around. New urethane bushings were installed a few years ago. Car will be getting a going over including a complete nut-and-bolt before I hit the track.

 

I'm not sure of the anti-roll bar diameters off the top of my head. 

[jireland2002]

Some general observations --  Over steer means the front has more traction than the rear. Increased front camber (generally good for handling) should increase front traction.  Your soft springs do allow for a fair amount of  body roll and raising the center of gravity does not help.  The springs may be allowing car to fall over on it's nose which will unload the rear wheels.  A full tank of fuel might help.  Bad rear subframe mounts will make the rear act funny as the forces change during corning.  I would recheck the camber and toe both front and rear.

I'd suggest cutting a 1/2 coil off the front springs, lowering the back to where you had it, using bigger sway bars.  Ultimately you should go the adjustable height front with 2.5" IDsprings
 

[M3M3M3]

-just getting it "aligned" is not enough.   Aligned TO WHAT SPECS?  That is critical. 

-crap tires make a huge difference in car balance.   Just because tires have tread does mean they are usable.  Old tires with lots of heat cycles are unpredictable.

-always 34psi is not the right approach to tie pressures.   They should be set HOT, as in, immediately coming off the track hot. 

-small amounts of high change in rear has big effect on rear camber and toe.

 

Get it aligned correctly to track specs (search!)

Get new tires. 

Read a good book like bonduant's "going faster"

 

Then go back on track.