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JFern
01-07-2017, 12:33 PM
Anybody have experience with these? They're polyurethane inserts that fill the voids in the factory rear subframe bushings, and allegedly they can extend the life of the factory bushings and help prevent mount failure. I wasn't aware they made these until I read the Grassroots Motorsports journal on their E46 M3 build:

http://grassrootsmotorsports.com/project-cars/2004-bmw-m3/first-stop-our-new-m3-bimmerworld/


We had heard the stories about cracked unibodies and assorted other horrors. From what he could see, the rear subframe connection points looked good. Cracked unibodies are usually accompanied by destroyed bushings and abused cars, he said. Our bushings looked good.


Powerflex also offers inserts for the rear subframe bushings. If the stock bushings aren’t bad, these inserts should maintain the status quo and save the rear subframe mounts. Plus installing the inserts takes much less time than dropping the subframe to replace the bushings. James felt that our car was a good candidate for this fix.

The above advice comes from James Clay @ Bimmerworld. Color me interested!

Johnmadd
01-07-2017, 01:14 PM
Interested.

JFern
01-07-2017, 01:54 PM
Worth noting they come in the yellow durometer, which I think is their softest, likely making them a good match for the stock rubber.

http://i.imgur.com/1MmLKC8.jpg

Johnmadd
01-07-2017, 03:50 PM
Goof idea imo. I've had bad subframe bushings before on a bmw, it feels like you're swinging the back of the car all of the time.

So, just pound them in the open slot?

slater
01-07-2017, 04:12 PM
i've seen them before. it looks like you still need to lower the subframe to install - how else would you get the top inserts in?

JFern
01-07-2017, 04:38 PM
You would still need to drop the subframe, but only a few inches instead of all the way out. If your current bushings are still good, this avoids the difficult process of pressing out the old bushings and pressing new ones in.

Johnmadd
01-07-2017, 04:47 PM
The bottom takes the most abuse.

slater
01-07-2017, 06:52 PM
The bottom takes the most abuse.

i doubt it, they both take abuse, and arguably the top side is more important as it provides a flatter, larger contact surface on the RACP.

WOLFN8TR
01-07-2017, 09:44 PM
I've heard bad things about Powerflex bushings. And if you are going to drop the subframe you might as well reinforce it.

VinceBar Subframe Kit
http://www.zhpmafia.com/forums/showthread.php?18871-VinceBar-Sub-Frame-Reinforcement-Kit!

slater
01-08-2017, 05:28 AM
vince actually runs the yellow powerflex subframe bushings on his car...

and yes, i absolutely agree on reinforcing. i know most folks are scared off by it, and i can certainly appreciate that - but if you are serious about longevity of the car, the VinceBar kit is really the only answer that makes sense to me.

gary, are you getting the VincePlates, too? :)

WOLFN8TR
01-08-2017, 10:17 AM
vince actually runs the yellow powerflex subframe bushings on his car...

and yes, i absolutely agree on reinforcing. i know most folks are scared off by it, and i can certainly appreciate that - but if you are serious about longevity of the car, the VinceBar kit is really the only answer that makes sense to me.

gary, are you getting the VincePlates, too? :)

Interesting.

Yes I'm waiting for Vince to finish the plates in February and he will ship out everything together.