Rear Subframe Bushings Questions

[yokomo963]

Hey everyone,

I want to get the rear subframe bushings and diff bushings swapped out and was wondering what everyone was running on their track cars. I'm not looking to go solid (i don't think), but was wondering if anyone has tried the condor speed shop UHMW bushings? Or stick with Polyflex (i have the street bushings throughout my e46 m3)?

Also, what's the usual quote for a shop to drop the subframe and get these installed? I just got quoted $1k just for labor from my local shop... Seems high to me, so deciding if I should shop around or not. This shop has been working on my e46 for awhile, but out of all the maintenance he's done, I've never had anything come close to $1k for labor minus rod bearings...

Thanks,
Eric

[Mark Aubele]

I put solid aluminum in the diff and subframe in my wife's 135i. With poly I could've had it done in a few hours. The aluminum was extremely difficult to press in the subframe in 2 locations. Not bad other than that. It's a lot of work, 1000 seems about what it would cost at a good shop.

[amg6975]

Just go straight to solid subframe mounts, don't mess around and waste money going through the various solutions. You won't regret it.

[135]

Go solid for RSB and solid for diff bushes if you want.
See my summary here: https://www.1addicts.com/forums/showpost.php?p=26144719

[yokomo963]

Originally Posted by Mark Aubele

I put solid aluminum in the diff and subframe in my wife's 135i. With poly I could've had it done in a few hours. The aluminum was extremely difficult to press in the subframe in 2 locations. Not bad other than that. It's a lot of work, 1000 seems about what it would cost at a good shop.

Did you do it yourself? Is it reasonably do-able for someone fairly mechanically inclined? I really want subframe bushings but for 1k for labor to drop the subframe, I'm debating if I wanna wait till I've saved enough for a LSD and do it all at once...

Originally Posted by amg6975

Just go straight to solid subframe mounts, don't mess around and waste money going through the various solutions. You won't regret it.

Originally Posted by 135

Go solid for RSB and solid for diff bushes if you want.
See my summary here: https://www.1addicts.com/forums/showpost.php?p=26144719

I'm on the fence about solid bushings... Some clubs/classes won't allow solid bushings. I know solid would be best for performance though.

[135]

Originally Posted by yokomo963

I'm on the fence about solid bushings... Some clubs/classes won't allow solid bushings. I know solid would be best for performance though.

Turner Motorsport sell RSBs and Diff bushes that are a combination of Delrin and solid aluminium to comply with some regulations and classes (e.g. Grand-Am, BMW CCA and others), where a solid metal mount (contact point) can't be used. The Delrin is used as the non-metallic contact point and aluminium sleeves are pressed into the Delrin.
They are more expensive that full solid aluminium.
Check the regs for the classes you'll be competing in to see if it's allowed.
You're next best option might be BMW Motorsport Group N bushes but they are a lot more expensive than TMS solid/delrin. Otherwise, just get M3 RSBs.

[Mark Aubele]

Originally Posted by yokomo963

Did you do it yourself? Is it reasonably do-able for someone fairly mechanically inclined? I really want subframe bushings but for 1k for labor to drop the subframe, I'm debating if I wanna wait till I've saved enough for a LSD and do it all at once...

Yes I did do it myself. It isn't all that difficult, although 2 bushings were extremely hard to press in. I think it is something anyone mechanically inclined could handle, especially if you went with Poly.

[AndyW]

I did the whiteline 2-piece poly for my 135i tracktoy. Whatever you do, rent or buy the bushing install/removal tool. I tried it first with several homebrew methods that only ended in frustration. Using the proper toolset made it straghtforward.

[yokomo963]

Originally Posted by 135

Turner Motorsport sell RSBs and Diff bushes that are a combination of Delrin and solid aluminium to comply with some regulations and classes (e.g. Grand-Am, BMW CCA and others), where a solid metal mount (contact point) can't be used. The Delrin is used as the non-metallic contact point and aluminium sleeves are pressed into the Delrin.
They are more expensive that full solid aluminium.
Check the regs for the classes you'll be competing in to see if it's allowed.
You're next best option might be BMW Motorsport Group N bushes but they are a lot more expensive than TMS solid/delrin. Otherwise, just get M3 RSBs.

Thank you! The solid/delrin is what I ended up ordering to use! Should be in Monday!

Originally Posted by Mark Aubele

Yes I did do it myself. It isn't all that difficult, although 2 bushings were extremely hard to press in. I think it is something anyone mechanically inclined could handle, especially if you went with Poly.

Originally Posted by AndyW

I did the whiteline 2-piece poly for my 135i tracktoy. Whatever you do, rent or buy the bushing install/removal tool. I tried it first with several homebrew methods that only ended in frustration. Using the proper toolset made it straghtforward.

Thanks for the suggestion guys! I think I'll be tackling this project next weekend once I finish installing the ER comp oil coolers! Should be in for a fun weekend

[tsk94]

Good choice with solid, zero NVH increase but huge performance benefits.

[Bimmer-Bob]

I think the Whiteline poly inserts are a good stop-gap that are pretty easy to DIY. I started with them because they were like $45 and an evening in my garage after work. I waited until LSD install for the full polys and had a shop do the work. It's hard for me to imagine a need for anything stiffer, at least not for the street. And I haven't noticed any increase in NVH or squeaking or anything.

It's difficult to overstate how improved the car feels with upgraded rear subframe bushings and an LSD. Like a proper sports car. I can't believe the garbage bushings the car shipped with. No matter which option you choose, it will be a great improvement over stock.

[yokomo963]

Got the car back from the shop this morning with the new rear subframe and diff bushings. I should’ve done this before coilovers!!! Felt so much better... although the stock diff wines and lash sounds are so much louder than I originally imagined especially having an open diff.

But my car is misfiring now so... ��