Subframe Reinforcement Next Week - OE vs. Poly bushings?

[RoyalFlushness]

Hello all,

I know this was debated allot back on M3Forum so I thought I would ask here to get your input and build some content.

I am getting my subframe reinforced next week with Turner plates. Car has 92K Miles on it and while the subframe is down from the car, I know allot of people like to do the subframe bushings as well. My car is a street/track car with mostly spirited street driving and the odd track day.

Do you guys suggest I replace the bushings with OE Bushings or go Poly for the subframe.

Thanks!
Frankie

[oceansize]

I asked this question last week. See this thread.

Bottom line is solid subframe bushings with oe diff.

[RoyalFlushness]

I asked this question last week. See this thread.

Bottom line. Solid subframe bushings with oe diff.

I tried searching and didn't see it. Thank you! Sorry for the double post.

I am not sure if I want to go 100% full solid as the car may return back to stock at some point. Not sure if that matters.

[CrisSilberGrau]

It doesn't matter, solid is best for these cars. If someone is buying this car later on they'd want that if they knew about it at all.

Side question, I'm in Toronto too, and need this done, where are you getting yours done?

[Dash1]

Just upgraded my subframe bushings to solid and differential to poly 95A. I think for weekend/track car that’s the way to go. If you’re worried about nvh oe diff bushings is you’re route but it’s barely noticeable for me. Ymmv. But absolutely do solids in the subframe.

[Andrew 06M3Cab]

Just curious, who is doing the work for you? Always interested to know about good shops. I just did my reinforcement a couple months ago at Argus Automotive in Oakville. I was very impressed with the work and attention to detail. I had a couple of hairline cracks and used the Redish plates. I replaced anything made of rubber/or having rubber in the rear end at the same time, and installed an Ohlins R/T coilover system. I used OE subframe and diff bushings. I did not want the whine with poly diff bushings, and I was a bit nervous how harsh the ride would be with aluminum subframe bushings. Mostly I use the car for street use with the occasional autocross.

[RoyalFlushness]

Just curious, who is doing the work for you? Always interested to know about good shops. I just did my reinforcement a couple months ago at Argus Automotive in Oakville. I was very impressed with the work and attention to detail. I had a couple of hairline cracks and used the Redish plates. I replaced anything made of rubber/or having rubber in the rear end at the same time, and installed an Ohlins R/T coilover system. I used OE subframe and diff bushings. I did not want the whine with poly diff bushings, and I was a bit nervous how harsh the ride would be with aluminum subframe bushings. Mostly I use the car for street use with the occasional autocross.

Never heard of them. RMP Motors is doing it for me. They specialize in track prep / stuff like this. He recommended Powerflex Black Bushings (pretty close to solid) and he stocks them. So I think I am going that route.

[RoyalFlushness]

It doesn't matter, solid is best for these cars. If someone is buying this car later on they'd want that if they knew about it at all.

Side question, I'm in Toronto too, and need this done, where are you getting yours done?

Thanks man. RMP Motors is doing it for me. He recommended Powerflex Black. Since he is doing the work and builds track BMWs all the time, I am going to go with his recommendation.

[heinzboehmer]

Thanks man. RMP Motors is doing it for me. He recommended Powerflex Black. Since he is doing the work and builds track BMWs all the time, I am going to go with his recommendation.

If you're leaning towards doing poly, might as well go solid. I understand wanting to stick with OE parts, but if you're going to install aftermarket parts solid is superior to poly. No wear and minimal to no nvh increase (which seems to not be a concern seeing how you're okay with the Powerflex Black Bushings being pretty close to solid).

Here's some great info on solid subframe bushings: https://cmpautoengineering.com/pages...-the-pros-cons. Check out the chassis rigidity note, it explains quite well why you should go with solid bushings instead of other alternatives.

Btw, you should seriously consider a topside reinforcement solution alongside the plates. Plates address the issue of the mounts cracking, but move stresses to other parts of the RACP. More info here: https://cmpautoengineering.com/pages/technical.

[Syfon]

I asked this question last week. See this thread.

Bottom line is solid subframe bushings with oe diff.

YES! Solid aluminium raised subframe bushings with OEM diff mounts.

I used theses subframe bushings;

https://cmpautoengineering.com/produ...raising-bushes

Amazing quality and with the exchange rate aids for us aussies at the moment, means they're cheap af for you lol

[r4dr]

Same price as Turner solid aluminum mounts after shipping to the US though

So I guess it's a matter of standard vs. raised.

[bassel_sy]

YES! Solid aluminium raised subframe bushings with OEM diff mounts.

I used theses subframe bushings;

https://cmpautoengineering.com/produ...raising-bushes

Amazing quality and with the exchange rate aids for us aussies at the moment, means they're cheap af for you lol

lolllll

[jojo]

Ques- any way to replace the rear diff bushings with OE rubber without having to buy a whole new cover?

[Albino09]

Same price as Turner solid aluminum mounts after shipping to the US though

So I guess it's a matter of standard vs. raised.

If you're doing the subframe bushings, you're gonna want to go ahead and plate your floor. When you plate your floor, you're gonna want to go ahead and get the raised bushings. I would consider that mandatory "while you're in there".

[Dash1]

Ques- any way to replace the rear diff bushings with OE rubber without having to buy a whole new cover?

No, you can buy the softer e36 bushings or get a new diff cover if you want oem