[DLag30]

Hi,

I was thinking of upgrading the rear subframe and diff bushings using M3 bushings. I have read they provide a better feeling rear end. My question is; can I swap in a M3 subframe into a 335i? I have done sub frame bushings before and found them to be a PITA. My goal is to purchase a M3 subframe with bushings pre-pressed and swapping it into a 335i, skipping pressing out the old bushings and pressing in the new ones.

thanks

[weehe126]

If removing subframe bushings is too big a pain for you, you are in for a world of hurt swapping the whole subframe.

[marconi118]

if you can find a coplete M3 rear axle then go for it

you will get as a bonus alu links, big M3 brakes and stronger exles and M3 LSD etc

[Kevin_The_Clean1]

I wish I could source one that was compete dressed & ready for installation too.

[DLag30]

So it appears someone in the other forums have installed a m3 subframe onto 135i e82 using all the other non-m parts. I guess i found an answer to my question.

[weehe126]

Good luck with the diff, drive shaft and axles.

[Cloud9blue]

Originally Posted by DLag30

So it appears someone in the other forums have installed a m3 subframe onto 135i e82 using all the other non-m parts. I guess i found an answer to my question.

but, why... the whole point of m3 subframe is because of those aluminum control arms and stiffer bushings. the actual difference between the subframe is negligible...

[feuer]

Originally Posted by Cloud9blue

but, why... the whole point of m3 subframe is because of those aluminum control arms and stiffer bushings. the actual difference between the subframe is negligible...

Actually, from modding perspective the non M subrame is better. I'm talking about the bare subframe itself.

[mweisdorfer]

Originally Posted by DLag30

Hi,

I was thinking of upgrading the rear subframe and diff bushings using M3 bushings. I have read they provide a better feeling rear end. My question is; can I swap in a M3 subframe into a 335i? I have done sub frame bushings before and found them to be a PITA. My goal is to purchase a M3 subframe with bushings pre-pressed and swapping it into a 335i, skipping pressing out the old bushings and pressing in the new ones.

thanks

Honestly, the best way to do this would be to keep the 335 subframe and rent/ buy the tools necessary to remove the existing subframe/ control arm bushings. The easiest way to really do this the right way is to take the subframe out of the car, mark with whiteout where specific notches of the existing bushings "are" etc., of the current bushings, and then begin by taking the bushings out one by one.

Subframe bushing tool rental -

http://www.hpashop.com/Bushing-Tool-...g-tool-kit.htm

Rear control arm bushing tool on the subframe -

https://m.ebay.com/itm/BMW-3-E90-to-...cAAOSwyQtVqju0

I have this tool and can personally attest that it works and is of good/ great quality.

You'll need some silicone grease to lube up the subframe & bushings so the new ones go in easier. Plus, silicone won't deteriorate the rubber of the new bushings. Grease will.

You are basically pressing out and pressing in new bushings. A really good torque gun is helpful. Torch & kroil oil will be a lifesaver.

Pelican parts has a good diy on how to best put in the control arm bushings. You can use some of the same concepts on the m3 subframe bushings.

Quite honestly, this is a two person job for most people. It can be done by one person, but its just harder to do is all. You'll need to know all the torque specs etc. a Bentley Repair manual is a great thing.

Make sure you re-torque all the bushings and control arms etc., after about a month. THIS IS SUPER IMPORTANT.

There are a few DIY's out there on YouTube and this forum.

I have done this job and can attest that it's very time consuming but soooo worth it, if you do M3 subframe bushings, & M3 Differential bushings coupled with new bushings through out the entire subframe.

If you live in a rust belt state, I'd encourage you to clean off the rust of the subframe & paint it with 3-4 coats of black, rustoleum 2-1.

I had a few postings on this forum about my experiences. Feel free to look them up.

[marconi118]

go for the complete dressed M3 subframe it is beefier, all tubular made
the 335i one is steel sheet, it bends more

it is bolt-on, only the M3 drive-shaft at gearbox side has to be adapted

[feuer]

Originally Posted by marconi118

go for the complete dressed M3 subframe it is beefier, all tubular made
the 335i one is steel sheet, it bends more

it is bolt-on, only the M3 drive-shaft at gearbox side has to be adapted

Only the rear section of the non M suframe is non tubular. The rest is the same. You say M is better? Try to reinforce the diff and let me know how easy it would be and how much it will cost you. There are benefits of having M subframe but none that you have listed. Well, is only one actually...

[tetsuo111]

Originally Posted by Cloud9blue

but, why... the whole point of m3 subframe is because of those aluminum control arms and stiffer bushings. the actual difference between the subframe is negligible...

No.

M3 subframe has the option for the M3 LSD. Non-M frames don't. The M3 control arm / bushing upgrade is incremental. The M3 LSD is quantum.

[AlexN]

I have done this swap following research on this forum and to me it was very worth it.
I had to piece my rear subframe and M3 diff together (Wasn't too difficult) but now there are several complete low mileage rear M3 subframes for sale on Ebay.
While I was at it, I installed solid subframe bushings and purple Powerflex diff bushings along with beefier sway bars and coilovers and the car is really transformed.

Overall, for the subframe etc, I don't think I spent a lot more than I would have for an M Factory LSD or wavetrac

Here is an example, you can probably over much less. The other's I've seen were in the 1700-1900 range

https://www.ebay.com/itm/2012-BMW-M3...dalC~H&vxp=mtr

[Cloud9blue]

Originally Posted by tetsuo111

No.

M3 subframe has the option for the M3 LSD. Non-M frames don't. The M3 control arm / bushing upgrade is incremental. The M3 LSD is quantum.

To each of their own

M3 lsd are not very well received by those who track their car seriously. If you dig around the M3 forums. Plus, it is difficult to reinforce the diff housing with the M3 subframe. S65 produces much less tq than a stock N54 FYI.

IMO you are better of with aN aftermarket torsen unit for a street car and a real 1.5 or 2 way clutch lsd for a race car.

[feuer]

Originally Posted by tetsuo111

No.
M3 subframe has the option for the M3 LSD. Non-M frames don't. The M3 control arm / bushing upgrade is incremental. The M3 LSD is quantum.

Wow, that is ridiculous. It was maybe the opinion of people 10y ago when platform was new and aftermarket support wasn't all there. Only the lower control arms are an improvement because they allow better suspension articulation (the bottom of the shock mount will yield better angles). Everything else, simply it not.

Originally Posted by AlexN

I have done this swap following research on this forum and to me it was very worth it.
I had to piece my rear subframe and M3 diff together (Wasn't too difficult) but now there are several complete low mileage rear M3 subframes for sale on Ebay.
While I was at it, I installed solid subframe bushings and purple Powerflex diff bushings along with beefier sway bars and coilovers and the car is really transformed.
Overall, for the subframe etc, I don't think I spent a lot more than I would have for an M Factory LSD or wavetrac
Here is an example, you can probably over much less. The other's I've seen were in the 1700-1900 range
https://www.ebay.com/itm/2012-BMW-M3...dalC~H&vxp=mtr

The m3 LSD is wearable part. Must be dirt cheap with low miles to make it wort it. For the money you are taking about, $1700-1900 I will make any none M rear subrame superior to M3 subrame because I will use better and new instead of use parts.

Originally Posted by Cloud9blue

To each of their own
M3 lsd are not very well received by those who track their car seriously. If you dig around the M3 forums. Plus, it is difficult to reinforce the diff housing with the M3 subframe. S65 produces much less tq than a stock N54 FYI.
IMO you are better of with aN aftermarket torsen unit for a street car and a real 1.5 or 2 way clutch lsd for a race car.

Exactly! M3 LSD won't last very long paired up to high torque N54, this is especially true if you install used LSD with 100k. Regarding reinforcements as someone who deals with that I can say is also correct. Is massive and expensive piece that doesn't do a better job compared to compact, light and cheap non M diff reinforcement. Take a look:

[tetsuo111]

Originally Posted by feuer

Wow, that is ridiculous. It was maybe the opinion of people 10y ago when platform was new and aftermarket support wasn't all there. Only the lower control arms are an improvement because they allow better suspension articulation (the bottom of the shock mount will yield better angles). Everything else, simply it not.

Sorry, not clear interpreting your post feuer

In my experience, the rear M3 control arms are no more than a mild improvement to the car's handling. On the other hand, both solid Al subframe bushings and a real LSD are major improvements to the drivetrain. So much so that IME both are mandatory. The rear M3 control arms, not really...

If uprated 335's are too torquey for the M3 diff, than it would be better to use an alternative diff, naturally. I had a Performance Gearing multi-clutch LSD on the last car, but plan to install an M3 LSD on this build.

[bbnks2]

I have an M3 rear-end I will be putting in this weekend. Cost was $1700 for rear-end and $100 to weld the drive shaft. That is less than the cost of a cheap aftermarket LSD (welded diff). Bonus: I get beefier axels, all M3 control arms, M3 bushings, M3 rear sway, and M3 brakes.

You can't reinforce the diff is your argument? You don't brace the diff with a reinforcement plate... you install solid aluminum mounts. A diff brace is a hack way of limited diff movement. Any sane rational person would replace the diff bushings if they could over installing a diff brace. The M3 is much better suited to an aftermarket LSD upgrade if you so desire in the future... People are paying a couple hundred dollars just to put a better back plate on the 135i diff for cooling...

As for the subframe, RealOEM has them listed as follows:
135i: 33316783713 (20.360 kg)
M3: 33312283340 (23.000 kg)

I'd say the M3 rear subframe has a bit more reinforcement to it based on the slightly higher weight. Again, more suited to performance driving. The added weight is easily offset by the all aluminum components.

[feuer]

For $1800 you still end up with used parts. Even with solid aluminum bushings the diff will exhibit movements as there are only 3 mounts. M3 rear brakes might be too big for some people. You have 135i that doesn't play well with low offset wheels that might be required in order to clear 350mm rotor using a 17" wheels.

[Cloud9blue]

Originally Posted by tetsuo111

Sorry, not clear interpreting your post feuer

In my experience, the rear M3 control arms are no more than a mild improvement to the car's handling. On the other hand, both solid Al subframe bushings and a real LSD are major improvements to the drivetrain. So much so that IME both are mandatory. The rear M3 control arms, not really...

If uprated 335's are too torquey for the M3 diff, than it would be better to use an alternative diff, naturally. I had a Performance Gearing multi-clutch LSD on the last car, but plan to install an M3 LSD on this build.

Maybe not so much for your n52 powered car. But stiffer bushings on the m3 and preferably upgraded toe arms, they help a ton to keep things in check with n54.

[AWDBooSTIn90]

Originally Posted by feuer

Actually, from modding perspective the non M subrame is better. I'm talking about the bare subframe itself.

Can you explain why? Im generally interested bc i have a complete M3 rear subframe already, not in the car yet, need a few more small parts.

But now coming from you I would like to know why...

I already have M3 front suspension/Brakes/Hubs.. So I was going to order E90 M3 Bilstein PSS10 coilovers for my car when the subframe goes in.
But i could still have my mind changed by someone that knows a lot more about the E90s then me.

[GnomeChild]

Originally Posted by feuer

For $1800 you still end up with used parts. Even with solid aluminum bushings the diff will exhibit movements as there are only 3 mounts. M3 rear brakes might be too big for some people. You have 135i that doesn't play well with low offset wheels that might be required in order to clear 350mm rotor using a 17" wheels.

Now Feuer; this is being a little disingenuous, no? With the M3 complete K-frame assembly you get upgraded rear axles which are a $1k+ aftermarket investment if you stay 335i. Let’s not forget the M3 LSD includes better cooling and people put supercharger kits on the S65s all day with stock driveline

I’m happy with $1500 spent on a complete rear end swap used than dish out nearly double that and only have LSD/Axles. At least that will get me running; plus the option to rebuild the M3 LSD before placing it in the car

I can understand for a dedicated track car; 600+tq, you’d probably want something more substantial. However, I think for most member’s application; the complete M3 assembly is adequate, if not ideal

[feuer]

Originally Posted by AWDBooSTIn90

Can you explain why? Im generally interested bc i have a complete M3 rear subframe already, not in the car yet, need a few more small parts.

But now coming from you I would like to know why...

Do you know how much it cost to reinforce M diff/subframe compare to non M? https://www.m3post.com/forums/showthread.php?t=839960 Is $1000 vs $150 and a lot more in labor to install.

Originally Posted by GnomeChild

I’m happy with $1500 spent on a complete rear end swap used than dish out nearly double that and only have LSD/Axles. At least that will get me running; plus the option to rebuild the M3 LSD before placing it in the car
l

I explained it well. The issue is that you are doing this primarily for the LSD diff. The $1500 sound sweet however the diff you will get will be worn out already. Why would I spend $1500 on used part when I can have BNIB designed for the car. Also not everyone will DIY this swap and shop will charge way more in labor compared to just diff swap. Is only assumption that M axle are stronger. No test have been done to determine with accuracy. Assessment have been given solely based on axles been wider.