[Theconnman2]

I recently posted that I put a M3 diff in my 335i and got a pretty decent amount of PMs as to how I did it. So I thought I would start a thread so there is answers for everyone and I don't have to keep answering the same questions. There is already a thread like this that is extremely long, and difficult to find solid yes or no answers to how it is done. That being said, if you have any questions about the swap post em up.

Below is the general info PM I have been sending to people.


If you have a 6Mt the m3 differential you get should be 3.15 ratio as it is closest to stock, you can find them on ebay from $400 to $1000 plus. Obviously try to find the lowest price one you can with the least amount of miles. Mine had 20k on it and was 400. The next part is getting m3 axles. These fit the oe hubs on the 335i. The hardest part is the driveshaft. You have to have the front flange on your current driveshaft that attaches to your transmission and have it welded onto a m3 shaft. You also have to have the m3 shaft shortened. I also installed solid mounts into the sub frame as it is my weekend track car, but this isn't nessasary. Though I would recommend replacing them with m3/poly/oe while you have it apart.

Also,
Don't forget new fasteners for axles to diff, driveshaft to diff, axle nuts, support bearing for driveshaft (335i one not m3), and diff fluid (which is really expensive as it HAS to be bmw fluid)




Edit: looked up what I paid for the diff and edited the price on here as I had it wrong.

Edit: added information on center support bearing.

[titium]

any vibrations? few of the guys in Australia that have had this done have run into balancing issues resulting in vibrations.

[Theconnman2]

Originally Posted by titium

any vibrations? few of the guys in Australia that have had this done have run into balancing issues resulting in vibrations.

I personally don't have any unexpected vibrations. I get more clunking and noise from having soild mounts back there, that's about it.

There are two reasons I would think you would get vibrations from installing an m3 diff (or any diff for that matter)

1. You didn't get your driveshaft properly Balanced.
2. The differentials are balanced out of the factory but some use different weights of fasteners to achieve the full balance. The link below explains that.

http://www.m3post.com/forums/showthread.php?p=19483010

[Chris@VargasTurboTech]

This is similar to what we've done on the shop car and we love it. The M3 diff is strong, lots of ratios available, and reasonably priced. Plus the input shaft is MUCH stronger, which is a big deal if you launch at the track. Good post!

[Theconnman2]

Originally Posted by Chris@VargasTurboTech

This is similar to what we've done on the shop car and we love it. The M3 diff is strong, lots of ratios available, and reasonably priced. Plus the input shaft is MUCH stronger, which is a big deal if you launch at the track. Good post!

Thanks! It's awesome to hear that some of the bigger guys also are using this method.

[peterparker]

I wonder if the driveshaft shop can create a custom drive shaft. Have you ever looked into that?

[Theconnman2]

Originally Posted by peterparker

I wonder if the driveshaft shop can create a custom drive shaft. Have you ever looked into that?

Are you referring to a carbon fiber one? It has been done by people, but costs quite a bit. You also have to make sure it will fit in the tunnel, (right diameter) I know that some people were having problems with that. My shaft only cost a fraction of that to have modified, but no doubt a carbon one would be ideal.

[feuer]

Originally Posted by Theconnman2

Are you referring to a carbon fiber one? It has been done by people, but costs quite a bit. You also have to make sure it will fit in the tunnel, (right diameter) I know that some people were having problems with that. My shaft only cost a fraction of that to have modified, but no doubt a carbon one would be ideal.

What is the total $ spent on this? Used m3 diff, m3 half shafts, m3 prop shafts and customization (cutting, welding & balance ) I assume at least $1500. Corrrect?

[Theconnman2]

Originally Posted by feuer

What is the total $ spent on this? Used m3 diff, m3 half shafts, m3 prop shafts and customization (cutting, welding & balance ) I assume at least $1500. Corrrect?

I got my diff for 400
Shafts and driveshaft for 400,
Balencing was a little under 200
Hardware was under 50
Fluid was around 100 because I had a hook up

[feuer]

Originally Posted by Theconnman2

I got my diff for 400
Shafts and driveshaft for 400,
Balencing was a little under 200
Hardware was under 50
Fluid was around 100 because I had a hook up

I hope you don't mid disclosing the drive shaft shop that did the welding and balancing for you?

[Theconnman2]

I had a local shop do it

http://www.machineservice.com

[DR-JEKL]

This is the expenditure for my M3 driveline retrofit:

Bear in mind I bought my driveline (everything sways all control arms subframe brakes hubs etc etc) 3.5 years ago back then M3's were worth more and it was a low mileage driveline with 24k miles.

Also the workshop overcharged me, they had quoted $2.5-3k AUD on the retrofits they'd performed in the past...

[Theconnman2]

Originally Posted by DR-JEKL

This is the expenditure for my M3 driveline retrofit:

Bear in mind I bought my driveline (everything sways all control arms subframe brakes hubs etc etc) 3.5 years ago back then M3's were worth more and it was a low mileage driveline with 24k miles.

Also the workshop overcharged me, they had quoted $2.5-3k AUD on the retrofits they'd performed in the past...

Wow, that is quite the list. I have a majority of those parts also, but like to spread it out over time so it doesn't feel like as much haha

[roadkillrob]

Originally Posted by DR-JEKL

This is the expenditure for my M3 driveline retrofit:

Bear in mind I bought my driveline (everything sways all control arms subframe brakes hubs etc etc) 3.5 years ago back then M3's were worth more and it was a low mileage driveline with 24k miles.

Also the workshop overcharged me, they had quoted $2.5-3k AUD on the retrofits they'd performed in the past...

For 10k usd, I could trade my 335i + 10k and get an equivalent mileage M3 with the diff already installed!

[DR-JEKL]

Originally Posted by roadkillrob

For 10k usd, I could trade my 335i + 10k and get an equivalent mileage M3 with the diff already installed!

I'm in Australia it's a whole another ball game here as our car prices are a lot higher then the US.

My 335i in 2013 was worth $50k AUD an M3 was worth $90-100K AUD.

Back then it made some financial sense...

Also to do a quaife LSD upgrade and m3 components such as sways subframe bushes arms etc was about $7k AUD back then.

[07tundra]

SO i've located a 2008 m3 diff with 50k miles and all i'll need is the axels and the drive shaft thats it ? Just making sure it would suck to start this and run into road blocks

[Theconnman2]

Originally Posted by 07tundra

SO i've located a 2008 m3 diff with 50k miles and all i'll need is the axels and the drive shaft thats it ? Just making sure it would suck to start this and run into road blocks

The first post has all the different componentstyles you'll need, also donot forget to make sure the ratio is the one that you want in the diff.

[07tundra]

Originally Posted by Theconnman2

The first post has all the different componentstyles you'll need, also donot forget to make sure the ratio is the one that you want in the diff.

3.15 is what the m3 diff has theat shld be a good compromise between 3.08 and 3.46

[Theconnman2]

Originally Posted by 07tundra

3.15 is what the m3 diff has theat shld be a good compromise between 3.08 and 3.46

Yup, that is the one you want

[Anytyme]

I was excited for this thread up to the part where it says I need m axles I already invested in my dss Axles so I guess sadly this isn't an option for me then right?

[Theconnman2]

Originally Posted by Anytyme

I was excited for this thread up to the part where it says I need m axles I already invested in my dss Axles so I guess sadly this isn't an option for me then right?

Not with those axles, correct. Different size flange on the diff I believe

[dreyo27]

for the 6 speed 335i with the m3 diff do you remember the length of the driveshaft? in MM?