Eibach Spring Install-More Frequent DTC Activation?

Incompatible · 11-13-2010, 11:58 AM

Recently installed a set of Eibach springs on my 07 sport suspension Coupe. Drop front was 0.5 inch and rear was 0.25 inch. I have not yet had the car aligned. Everything is properly torqued and no unusual noises. I was careful to not to damage the front ride height sensor during the install. My problem: I have noticed that when accelerating/turning onto my usual freeway onramps the DTC seems to be activating more frequently then before the spring install. I was wondering if:
1. The change in ride height front to rear is being interpreted by the leveling sensors as suspension change by the DTC programming? (Any way to adjust sensors?)
2. If somehow I damaged the front or rear leveling sensors? (How to diagnose?)
3. Is this simply a prealignment condition?
4. An aspect of the spring rate? (Any help by larger swaybars?)
5. Am I pushing the car harder and not realizing it? (It really is fun to drive!)
TIA

pokeybritches · 11-13-2010, 12:43 PM

It was my understanding that the DSC is based on wheel speed and accelerometers. The higher-rate springs may be causing the car to have less traction as it passes over bumps in the road.

aerobod · 11-13-2010, 02:17 PM

Quote:

Originally Posted by pokeybritches

It was my understanding that the DSC is based on wheel speed and accelerometers. The higher-rate springs may be causing the car to have less traction as it passes over bumps in the road.

This is most likely the case. This is a noticeable trait of the Z4M when accelerating hard across an intersection when crossing the ruts left by heavy trucks - lots of momentary flashing of traction control light.

3002 tii · 11-13-2010, 02:20 PM

Quote:

Originally Posted by aerobod

This is most likely the case. This is a noticeable trait of the Z4M when accelerating hard across an intersection when crossing the ruts left by heavy trucks - lots of momentary flashing of traction control light.

WHS ^^

You should find out the eibach spring rates. OEM are progressive so no set number but it's probably near the 300 mark, time to get the LSD man! Haha

vachss · 11-13-2010, 02:22 PM

If you didn't change/adjust dampers when you installed stiffer springs I would think that there could be excessive rebound causing the loss of traction seen. (Time for the Koni Yellows?)

PS. Since most of us are following the same thread on multiple forums, should we just consolidate our replies either here or to the longer/older thread on Bimmerforums?

Incompatible · 11-15-2010, 04:00 PM

Quote:

Originally Posted by vachss

Since most of us are following the same thread on multiple forums, should we just consolidate our replies either here or to the longer/older thread on Bimmerforums?

After some careful experimentation and consideration, I think it's primarily me inducing the wheel slippage and the DTC light activation. The increase in camber has inspired more confidence which has lead to harder acceleration/higher speeds. Looks like I will need to reacclimate to the new handling characteristics.
Thanks to all who posted.

11-13-2010, 11:58 AM	#1
Incompatible Major 55 Rep 1,224 Posts Drives: 07 AW Z4C 3.0Si Join Date: Aug 2007 Location: San Diego iTrader: (1)	Eibach Spring Install-More Frequent DTC Activation? Recently installed a set of Eibach springs on my 07 sport suspension Coupe. Drop front was 0.5 inch and rear was 0.25 inch. I have not yet had the car aligned. Everything is properly torqued and no unusual noises. I was careful to not to damage the front ride height sensor during the install. My problem: I have noticed that when accelerating/turning onto my usual freeway onramps the DTC seems to be activating more frequently then before the spring install. I was wondering if: 1. The change in ride height front to rear is being interpreted by the leveling sensors as suspension change by the DTC programming? (Any way to adjust sensors?) 2. If somehow I damaged the front or rear leveling sensors? (How to diagnose?) 3. Is this simply a prealignment condition? 4. An aspect of the spring rate? (Any help by larger swaybars?) 5. Am I pushing the car harder and not realizing it? (It really is fun to drive!) TIA __________________ If you can't take the time to teach a kid something good, someone will take the time to teach them something bad.
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11-13-2010, 12:43 PM	#2
pokeybritches Colonel 479 Rep 2,782 Posts Drives: ESS/G-Power Z4M, VF Z4, 996tt Join Date: Sep 2009 Location: Los Angeles iTrader: (12) Garage List 2006 BMW Z4M [10.00] 2006 BMW Z4M [8.50] 2003 BMW Z4 3.0i [9.00]	It was my understanding that the DSC is based on wheel speed and accelerometers. The higher-rate springs may be causing the car to have less traction as it passes over bumps in the road.
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11-13-2010, 02:22 PM	#5
vachss Captain 55 Rep 815 Posts Drives: Z4 Coupe Join Date: Jan 2008 Location: Ventura County, CA iTrader: (1)	If you didn't change/adjust dampers when you installed stiffer springs I would think that there could be excessive rebound causing the loss of traction seen. (Time for the Koni Yellows?) PS. Since most of us are following the same thread on multiple forums, should we just consolidate our replies either here or to the longer/older thread on Bimmerforums?
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