[Nigelo]

Wonder what happened? A few folks have managed it so far.

[skyguy]

I guess I'm just wondering whats driving you to want the 335 hubs if you have everything from the m3 subframe? Otherwise, you haven't bolted the subframe up yet? I've got the driveshaft on the way but I'm also wondering why you've decided to join the shaft at the gearbox end, just looking for insight and figuring out what people will need pictures of...

Thanks,
Sky

[Nigelo]

Hi!

Reason for the 335i hubs is to keep the 335i brakes. Otherwise you will have larger brakes on the rear than the front as well as them being designed for the M3 brake cylinder which is bigger. You could keep the M3 rear hubs but you'd need either M3 front brakes+hubs or a balanced front bbk.

As for the main driveshaft / propshaft, you do have a choice. Either 335i shaft from box to after the centre bearing, joined to an M3 diff end, OR an 335i box end joined to M3 shaft before the centre bearing. It's really just to ensure the length from box or diff is correct to the centre bearing mounting point, and that only one cut and join is needed.

[skyguy]

ok, I see. My front bbk is already on the way. I had just figured the easiest way to keep the center bearing in the same place was to keep the 335 front half. Guess I'll be able to tell which half would make more sense once its all bolted up and I have both shafts there. Now I just have to figure out if my offsets will still work for fitment...

[skyguy]

Definitely see it now, back half of the M3 is correct length for dct diff and lines up with the bolt holes in the frame. M3 shaft needs about 2cm cut off and 105/12mm guibo instead of 110mm. Finding somebody in Florida to balance it is also turning out to be tricky. Have an extra M3 shaft if anybody needs one...

[RimasRS]

Originally Posted by skyguy

Definitely see it now, back half of the M3 is correct length for dct diff and lines up with the bolt holes in the frame. M3 shaft needs about 2cm cut off and 105/12mm guibo instead of 110mm. Finding somebody in Florida to balance it is also turning out to be tricky. Have an extra M3 shaft if anybody needs one...

So are you saying that rear part of M3 DCT drive shaft fits perfectly from diff to center bearing? And just front part of the drive shaft should be shortened welded and balanced?

Did any of you who did this... By how much and which part you had to shorten driveshaft? (Was it from DCT drive shaft?)

[skyguy]

The spacing from the m3 diff to the center bearing frame mounting holes is correct for the appropriate m3 shaft. The spacing from trans to center bearing is correct for the 335 shaft. You could do it either way, put the m3 diff end on the 335 shaft or put the 335 trans end on the m3 shaft. Either way it needs to be shorter. For the M3 dct shaft its about 2 cm shorter. Once you see the 2 shafts side by side you'll probably choose to use the beefier m3 shaft.

-Sky

[Nigelo]

Great info there skyguy!

How close is it to 2cm shorter - if you can get it down a little more accurate thatd be amazing - means driveshafts could be made up without having to measure up with everything preinstalled and then wait for the driveshaft company.

[skyguy]

We're still trying to decide the best way to measure it, measure twice cut once I guess? Wish Georgesmooth or Idnan would just post their driveshaft lengths, not like I'm going to blame or hold anyone liable if it doesn't fit correctly on the first attempt.

[N111CUK]

Hi Guys,

Well I'm planning the same thing although I haven't started ripping things apart yet I am just getting my facts straight before I start

So one of the questions some people may have is WHY? and WHAT ABOUT A QUAIFE?

Well in short this route is cheaper for below reasons (asuming your getting a used M3 subframe)

If you install a Quaife you will have a great LSD but everything else is 335i. If you are running stock power then IMHO this works great

BUT most of us are trying to break the sound barrier RIGHT!

M3 complete subframe gives you

1, Amazing LSD
2, M3 bushing all over the rear
3, Bigger Stronger Drive Axles for the bigger power
4, Bigger Stronger Prop Shaft for the bigger power
5, Better sway bar or ARB as we call them over here
6, Rear breaks get upgraded by default if you keep them on

Add this up and for the same price or less the Quaife isn't such a great deal

So HOW do we do this and remove all the smoke from this subject.

Well if I could I would create a KIT and sell it to the 335i fraternity who want to mate a complete M3 Subframe transplant. HE WHO DARES WINS

What would the kit have (Oh! and pleae add to this idea)
Part 1, Prop conversion kit which contains the front prop shaft which mates to the M3 rear prop shaft and MISC parts etc..
Part 2, Optional Front BBK to compliment the M3 bigger rear brakes (the 3rd part is no longer required if you go with this option)
Part 3, Adjustable camber arm? so we can use our 335i hubs, disks and calipers

Some Facts that I have picked up so far (Thanks to Idnan, what a gentleman!)
DIFF RATIOS
M3 7DCT Diff FD 3.15
M3 6MT Diff FD 3.85
335i 6MT Diff FD 3.08
335i 6AT Diff FD 3.46

(FD) means Final Drive for those googlers

So when looking at this data, 335i guys with 6AT trans have there pick of both M3 diffs as they are 0.30 between the two ratio's. BUT IMHO 6MT guys should use the 7DCT M3 diff or else the final drive will be way to short and 1st gear will be unusable

I've opted for the 7DCT Diff as I feel with my power mods, 1st gear is too torqued and I end up starting with 2nd. With this in mind the drop from 3.46 to 3.15 will give 1st gear slightly longer gearing but not as long as the current 2nd gear. Once the 6AT is rolling it makes no odds as the Torque converter will sort things out.
Maybe it might improve MPG on highway cruises

So another important factor is the Prop Shaft modification which is playing on everyones mind.

Which M3 prop to use and how to measure and cut weild it

I have noted that the M3 has two sized props. I believe 7DCT diffs carry the longest prop so maybe for the sake of a cm here and there get the longer one

How to measue it? Well I'm no expert but my theory is to offer it up to the car decide which end to cut (I'm siding with the Trans end) and cut as close to the end as possible. You will then need to use your 335 prop as a donnor to mate this to the 335 tranny

I would measure with some form of solid wire which has zero stretch and clamp it to the diff and then pull it over to the tranny. I would also cut less which may mean more cutting but also means you have options if you cock it up.

Weilding it? well obviously get a professional prop shaft company to weild and balance the prop but until meanwhile I would tack the cuts together like a prototype so you can install it to the car and turn the wheels and see if your prop is fitting in all the right places.

Well good luck to all attempting this and once my project is underway I will detail my steps and offer up real measurements for those of you interested with pictures and all

Thanks

[N111CUK]

Update

I have sourced two prop shafts and after my install may have a complete M3 prop for sale.

Please express your interests

[AWDBooSTIn90]

Anyone have any definitive answers, on the shortening needed, on the front section (Trans side of Center Carrier Bearing) of the m3 driveshaft. When doing a 335i > M3 Rear Subframe/Suspension Conversion.
I would like to know the measurements if someone has possibly already figured this out and has ran their set up. That way i can have the Welding done in the meantime, to cut the M3 DS at the very front and join it to the 335i driveshaft properly.

That way your using 3/4 of the M3 DS, especially from the Rear Diff, to the Center Bearing, and out. Bigger U-Joint at the center bearing, making it a 2-piece DS , so its stronger than the stock 335i DS and fits like normal in the center and the rear diff flange.

Then when the M3 DS comes out of the Center Bearing, it will go to the welded area, joining the two shafts, but also at the correct shorter length. This way you also make sure it fits perfectly to the 335i transmission output flange/guibo.


My setup will be:
M3 DCT Diff
M3 DCT D/S
M3 complete Subframe/Suspension/Hubs/Brakes.

The front suspension already has:
M3 Hubs
M3 Control Arms - Top & Bottom
M3 struts non-EDC w/oem M3 Strut Mounts
M3 Brakes/Rotors
E92 M3 FSB w/ Turner Adj End Links

M3 Brake Master Clyinder will come before I get it all aligned.

[marconi118]

you have to use a M3 DCT DS because it is linger than the 6MT (6MT is too short to mate the 335 gearbox, it has to be lengthened a bit)

cut the flange at the gearbox side where is the factory weld (very thin line)

cut the flange of the 335i DS at the same point

weld the 335i flange to the m3 DS

the M3 DCT DS has to b shortened a bit before welding the 335i flange, I don't remember the exact length

best for you is to measure on your own car from the screw holding the center bearing on the car to the gearbox flange

remember to remove the center bearing of the 335i shaft and put it on the M3 DS
the original M3 bearing will not align correctly with the 335i gearbox


did all this 4 ears ago, works really good

[Koolsilver]

Originally Posted by AWDBooSTIn90

Anyone have any definitive answers, on the shortening needed, on the front section (Trans side of Center Carrier Bearing) of the m3 driveshaft. When doing a 335i > M3 Rear Subframe/Suspension Conversion.
I would like to know the measurements if someone has possibly already figured this out and has ran their set up. That way i can have the Welding done in the meantime, to cut the M3 DS at the very front and join it to the 335i driveshaft properly.

That way your using 3/4 of the M3 DS, especially from the Rear Diff, to the Center Bearing, and out. Bigger U-Joint at the center bearing, making it a 2-piece DS , so its stronger than the stock 335i DS and fits like normal in the center and the rear diff flange.

Then when the M3 DS comes out of the Center Bearing, it will go to the welded area, joining the two shafts, but also at the correct shorter length. This way you also make sure it fits perfectly to the 335i transmission output flange/guibo.


My setup will be:
M3 DCT Diff
M3 DCT D/S
M3 complete Subframe/Suspension/Hubs/Brakes.

The front suspension already has:
M3 Hubs
M3 Control Arms - Top & Bottom
M3 struts non-EDC w/oem M3 Strut Mounts
M3 Brakes/Rotors
E92 M3 FSB w/ Turner Adj End Links

M3 Brake Master Clyinder will come before I get it all aligned.

Sounds like you are doing much of what I did except I added coilovers while I was at it, it turned out to be a great setup for me. The above post is correct in how you should modify the driveshaft, you don't need to shorten it by much sorry I don't remember exact number but I think it was less than an inch for me.

[YO335vert]

Originally Posted by marconi118

you have to use a M3 DCT DS because it is linger than the 6MT (6MT is too short to mate the 335 gearbox, it has to be lengthened a bit)

cut the flange at the gearbox side where is the factory weld (very thin line)

cut the flange of the 335i DS at the same point

weld the 335i flange to the m3 DS

the M3 DCT DS has to b shortened a bit before welding the 335i flange, I don't remember the exact length

best for you is to measure on your own car from the screw holding the center bearing on the car to the gearbox flange

remember to remove the center bearing of the 335i shaft and put it on the M3 DS
the original M3 bearing will not align correctly with the 335i gearbox


did all this 4 ears ago, works really good

is there any company that makes driveshaft that can work on the 335 to m3 diff?
I'm looking to do this swap but would rather pay for a custom DS vs cutting and welding

[AWDBooSTIn90]

Originally Posted by YO335vert

is there any company that makes driveshaft that can work on the 335 to m3 diff?
I'm looking to do this swap but would rather pay for a custom DS vs cutting and welding

A custom driveshaft shaft shop could do this for you if you provided the correct measurements abd info.

Either way, if you actually did weld the DS yourself, it still needs to be balanced.

Im going to get the M3 DCT and do exactly what Marconi was explaining. Thanks for the info.

I'm most likely going to cut and measure and cut to final length and send it to be welded and balanced..

[YO335vert]

Originally Posted by AWDBooSTIn90

A custom driveshaft shaft shop could do this for you if you provided the correct measurements abd info.

Either way, if you actually did weld the DS yourself, it still needs to be balanced.

Im going to get the M3 DCT and do exactly what Marconi was explaining. Thanks for the info.

I'm most likely going to cut and measure and cut to final length and send it to be welded and balanced..

I see that your in ny, where can I get the driveshaft balanced in nyc.

[feuer]

M3/5 flange fits on the 335i transmission and is 2cm taller. Not sure if that would allow for direct M3 prop shaft swap but perhaps is better deal for some to cut only one prop shaft instead of two.

[marconi118]

Originally Posted by feuer

M3/5 flange fits on the 335i transmission and is 2cm taller. Not sure if that would allow for direct M3 prop shaft swap but perhaps is better deal for some to cut only one prop shaft instead of two.

you can find it on ebay for 200$

better to buy a 320d shaft, cut the flange and use it on the 335i gearbox (check on realoem.com if it is really the 320d shaft, I cont remember exactly, I did it 8 years ago)

[AlexN]

Originally Posted by AWDBooSTIn90

Anyone have any definitive answers, on the shortening needed, on the front section (Trans side of Center Carrier Bearing) of the m3 driveshaft. When doing a 335i > M3 Rear Subframe/Suspension Conversion.
I would like to know the measurements if someone has possibly already figured this out and has ran their set up. That way i can have the Welding done in the meantime, to cut the M3 DS at the very front and join it to the 335i driveshaft properly.

Found the following post on another forum. you can copy the text and google it to get to that thread which also has some photos in it

Bolted the M3 diff to my 12/2008 E91 LCI N54 E91 and the measurements are as follows:

From diff flange to center of centerbearing-bolt: 719mm
From front universal rubber joint to center of centerbearing-bolt: 669mm
Universal rubber joint thickness: 40mm
Total length from inside the bolthole on gearbox-flange to M3 diff-flange: 1428mm (1388mm without stock universal rubber mount).

[AWDBooSTIn90]

Originally Posted by YO335vert

I see that your in ny, where can I get the driveshaft balanced in nyc.

I contacted a well known driveshaft/performance drag racing rear end shop. Its called Nassau DriveShaft Shop. Its in Merrick, NY. In Nassau county, Long Island.
When i called and explained what i was doing for this conversion and what i needed done. He was very familiar of what i needed done, and has done it manyy times for various different cars. ie Cut D.S. and Balance it..
The BMW 335i/M3 D.S. is very similar to a conventional RWD Driveshaft.
Just need to give him the parts and the measurements. Or bring the car witg the M3 subframe in and he can do the work, if your not comfortable doing the job or measurements...

[zero2sixtyZ]

Originally Posted by AWDBooSTIn90

I contacted a well known driveshaft/performance drag racing rear end shop. Its called Nassau DriveShaft Shop. Its in Merrick, NY. In Nassau county, Long Island.
When i called and explained what i was doing for this conversion and what i needed done. He was very familiar of what i needed done, and has done it manyy times for various different cars. ie Cut D.S. and Balance it..
The BMW 335i/M3 D.S. is very similar to a conventional RWD Driveshaft.
Just need to give him the parts and the measurements. Or bring the car witg the M3 subframe in and he can do the work, if your not comfortable doing the job or measurements...

So is there a standard measurement that they can develop for any E9x that is installing an M3 Diff?

If so, would be interested if they could make more of them depending on price. I have family that I visit in Long Island fairly frequently, so I'd be willing to bring or ship parts / pick one up.