X2. I had bad OE RTAB's and noticed this when my car was all stock. I upgraded to RE Poly RTAB's and they made a big difference. Fast forward to headers and full exhaust, intake, engine tune etc. I can feel the rear end flex under power, it feels loose, normal city driving they are fine. I've been looking at the SDW or the new Turner RTAB's, expensive but I feel they are totally worth it.
RTAB's
http://www.m3forum.net/m3forum/showthread.php?t=584111
SDW RTAB's
Turner RTAB's
BAV Stage 1 - BlueBus - UltraGauge - V1 - Orion V4's - ARC-8's - Brembo 996
TTFS Engine/SMG Tune/CSL 255 - SGT Headers/Sect 1/SCZA - Evolve Eventuri
VIS XTS CF Hood - CF Lip/Console/Diffuser - OE CSL Trunk - BWS 500S 9k/11k
I got the bimmerworld RTABs and I don't notice anything too harsh going on in the back. The problem is I've had a bunch of staff changed recently, so I'm not sure what contributes how. It does see a bit more noisy overall, though I think the main contributors are the poly differential mount and subframe bushings. Vibrations seem to be an insignificant difference. In some cases it seems that there is less vibration than before.
I went over railroad tracks and it was surprisingly smooth.
I can echo both of these statements with my Moog bearings. Dips in the road, train tracks, etc are all super smoothed out with the bearings, but anything with a leading edge that puts a horizontal load on the rear trailing arm (where the rubber bushing would compress to allow the trailing arm to flex out of toe and absorb the impact) rattles through the frame. It's loud.
I'm wondering if the holes drilled in the body of the TMS unit would help dampen some of that impact if you filled them with rubber (or even better, fluid):
Probably a fool's errand, though. I'd try it if they weren't so damn expensive.
Z4m with limiters is what I have installed.
I know most would not agree though.
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Thanks for this. I spent the past two hours researching oe+limiters vs poly vs delrin vs spherical bearing and learned a ton. Just put in an order for the latest revision of the oe rtabs (z4m):
https://www.fcpeuro.com/products/bmw...46-33326770817
And, from what I've gathered, the best option for limiters:
https://vorshlag-store.com/collectio...iters-full-set
I really like the UHMW material that vorshlag uses for their limiters and would put it well ahead of any poly, delrin, or aluminum options. I have used a lot of these materials in industrial settings and was thinking that UHMW would be perfect for this application, so it's worth the price (to me) over the poly limiters that FCP packages with the bushings.
Last edited by ZHPizza; 11-08-2018 at 07:34 AM.
I should also mention that the spherical rtabs are AWESOME on the track and increased rear grip so much that I don't feel like I need an LSD anymore. It's actually quite a bit more difficult to get the car sideways and a bit of a buzzkill when you're tryna hoon.
I just think they transfer too much impact for street use.