[cvc 22349a]

Originally Posted by tibra1

The OEM springs/dampers..w such a low spring rate they will be working overtime to compensate for the stiffer subframe bushings..the biggest benefit hands down will be upgrading to coilovers..modding other points in the car w/o addressing this would be counter-intuitive

Whoever told you that probably sold you or installed your coilover kit
I'm using the zsp springs with Koni sports, M3 front control arms and rear subframe bushings and a few other parts, and I can tell you the added stability of the M3 bushings provides a better platform for the springs and dampers to do their job and reduces bind. My car handles very well and I'm sure the springs and dampers aren't 'working overtime' due to stiffer M3 bushings; the opposite may be true..

[tibra1]

Originally Posted by cvc 22349a

Whoever told you that probably sold you or installed your coilover kit
I'm using the zsp springs with Koni sports, M3 front control arms and rear subframe bushings and a few other parts, and I can tell you the added stability of the M3 bushings provides a better platform for the springs and dampers to do their job and reduces bind. My car handles very well and I'm sure the springs and dampers aren't 'working overtime' due to stiffer M3 bushings; the opposite may be true..

Originally Posted by luckyu

I think whoever told you that was pulling your leg, tibra

Thats good that you like the way your suspension handles.. Im saying if u want max peformance out of your suspension you need to do coilovers and you did Konis now why you chose to keep the OEM springs is confusing, dampers and springs should be matched for best results and the OEM springs even ZSP have a very low spring rate so yes your dampers are going to wear much quicker than if you had gone with a stiffer spring..

Springs and shocks are the most important upgrade hands down.. I have not heard of anyone who has upgraded to M3 bits w/o changing the OEM springs and dampers..I did my own research on this car for 2 yrs..so no I didnt just "listen" to the vendor selling me parts

[tibra1]

Originally Posted by hdrewh

They're listed as separate parts and prices an realoem.com. Where are they sold as a kit?
Thanks.

They are sold as a kit at HP Autowerks and Tischer.

[cvc 22349a]

Originally Posted by tibra1

Thats good that you like the way your suspension handles.. Im saying if u want max peformance out of your suspension you need to do coilovers and you did Konis now why you chose to keep the OEM springs is confusing, dampers and springs should be matched for best results and the OEM springs even ZSP have a very low spring rate so yes your dampers are going to wear much quicker than if you had gone with a stiffer spring..

Springs and shocks are the most important upgrade hands down.. I have not heard of anyone who has upgraded to M3 bits w/o changing the OEM springs and dampers..I did my own research on this car for 2 yrs..so no I didnt just "listen" to the vendor selling me parts

Which spring do you think Koni used when calibrating dampening for the E9X? I don't know; just asking. My guess is the oe sport spring; I know they work with stiffer springs.
I don't want to lower my car as I already scrape the bottom of the front bumper a bit driving into my garage, plus my car is a DD so I don't want to further degrade ride quality.
The M3 subrame bushings were a must for me as I've increased grip and torque so the rear subframe was sloshing around way too much.
I'm sure a quality c/o kit reduces dive, squat and roll and allows for quicker transitions but at the cost of ride quality and clearance.
With a slightly larger rear sway bar and the M3 front control arms, my car handles well.
I just disagreed with your statement that stiffer springs are required with M3 subframe bushings installed based on my experience...

[e90pilot]

One thing I noticed on the track: once I installed the M3 tension rods and control arms, my car understeered more. I had to be very patient with the wheel on turn-in and gas pedal on exit. Looks like the front and rear need to be done together. I currently use Dinan's Stage 3 suspension. ZSP ride quality was pretty bad but had a lot of body roll. Dinan's is slightly busier but much less body roll. If you're going from a non-sport car, you'd probably find it too uncomfortable. I think BMW has since changed the ZSP setup and it's more compliant.

OP, you said that you won't track the car. If you don't track it, I don't really recommend the M3 bits. Just the front components I replaced cause the front to crash over bumps harshly and have caused more road noise. I had no idea how much the stock bushings isolated the car from vibrations of all frequencies. I'm going to assume the same for the rear. The strange thing is the fact that the M3 doesn't have that harsh of a ride and is not noisy. Maybe the Michelin tires are better at absorbing bumps and vibrations than my Direzzas.

[tibra1]

Originally Posted by cvc 22349a

Which spring do you think Koni used when calibrating dampening for the E9X? I don't know; just asking. My guess is the oe sport spring; I know they work with stiffer springs.
I don't want to lower my car as I already scrape the bottom of the front bumper a bit driving into my garage, plus my car is a DD so I don't want to further degrade ride quality.
The M3 subrame bushings were a must for me as I've increased grip and torque so the rear subframe was sloshing around way too much.
I'm sure a quality c/o kit reduces dive, squat and roll and allows for quicker transitions but at the cost of ride quality and clearance.
With a slightly larger rear sway bar and the M3 front control arms, my car handles well.
I just disagreed with your statement that stiffer springs are required with M3 subframe bushings installed based on my experience...

Thats fine..there is definitly no "right or wrong" here..its all about what results you want to get...I wouldnt say upgrading springs is "required" but it is "optimal" when using m3 subframe bushings. For maximum suspension performance and grip..you need to address the OEM springs as they are too soft..if you are happy with your setup..

[bmw888]

Just curious what size of the 328i front sway bar

[hdrewh]

renewing this thread with a basic question - does the BMW Performance Suspension install require dropping the rear subframe?

If so I would take the opportunity to go with the M3 subframe bushings. If not, I'll skip those for now.

Thanks,

[ciomas]

Gentlemen, would any one here be able to tell me the part number for that headlight regulating rod? I dont seam to be able to find it on RealOem. I would be very grateful