Quote:
Originally Posted by subieworx
I get the same thing in my e91 xi with just H&R springs. To me it definitely feels like a shifting subframe. Same exact feeling that is felt in older Mustangs with a small panhard bar.
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You have to wonder what is going on here. So far some people have mentioned this happening only after putting sport springs and shocks, springs alone. Some have done these things and not experienced it (like my car). Other folks say the rear is loose only on high TQ cars under hard launches.
One guy replaced all the rear subframe bushings with M3 ones and still says it is happening. Others (mainly with high TQ cars) say it helps but many go to a diff lockdown kit and delrin or solid bushings.
Going to guess that higher mileage cars that have been beat on a lot will have more of a problem, as will same with high TQ and many hard launches.
PROBABLY (caveat) it is a function of the weakest link phenomenon. It is a 5 link rear (with a bushing at each end each link) with subframe bushings, diff bushings etc etc. You stiffen up something in that whole complicated system (like shocks or springs), then the next thing starts to flex.
edit: in my case the Eibachs are at the softer end of lowering springs (vs H&R sport or race), plus the shocks are set near full soft (for a reason). I plan to mess with that setting for summer, maybe then some of this rear wiggling will start.