F8X M3/M4 CF Drive shaft mod

[0-60motorsports]

I saw in the What did you do for your M3 today? Thread that member Altaran is installing a modified F8X M4 Carbon fiber Drive Shaft on his E46 M3. I would love to do this for my SMG car and it also looks fund doing this mod myself. Would love to hear everyone's thoughts for this Cost effective mod. I just want to eliminate the CSB on my car.

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/684-what-did-you-do-for-your-m3-today?p=243075#post243075

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/684-what-did-you-do-for-your-m3-today?p=243079#post243079

https://nam3forum.com/forums/forum/main-forum/e46-2001-2006/684-what-did-you-do-for-your-m3-today?p=244004#post244004

[RazorM]

I am also keenly waiting for the feedback after I saw it in the thread.
Its very interesting since you can source these used shafts very cheap and they are OEM quality.
I am wondering if SMG car would need longer flange from transmission side because of SMG actuators, since the shaft is bigger diameter than stock. The CF shaft from euroconnex also have this design

[0-60motorsports]

I am also keenly waiting for the feedback after I saw it in the thread.
Its very interesting since you can source these used shafts very cheap and they are OEM quality.
I am wondering if SMG car would need longer flange from transmission side because of SMG actuators, since the shaft is bigger diameter than stock. The CF shaft from euroconnex also have this design

Yeah should be interesting especially if i can use parts off of my existing DS to make the F8X CF DS work. Just need guidance and instructions so I can ask the workshop here.

[0-60motorsports]

Bumping this up! If anyone knows what Modifications I need to make to install this on my SMG M3 hit me up.

Altaran Any updates brother?

[EthanolTurbo]

In for this. These driveshafts are cheap and easy to get. I have a spare E46 M3 driveshaft to pull flanges from and use for mockup/dimensions with the F8x driveshaft.

[0-60motorsports]

In for this. These driveshafts are cheap and easy to get. I have a spare E46 M3 driveshaft to pull flanges from and use for mockup/dimensions with the F8x driveshaft.

If you do it please post up here…. I have DSs here to use the the flanges off of. I am SMG so I'm sure the length will be different.

[Altaran]

I already sent this to a couple of people via PM, figured I would post it here in case others are interested in the future:

I did not do the actual welding, so I can't comment on that, the rest was fairly simple.

I bought the M4 driveshaft and a 330 driveshaft as donor for the flanches. Make sure you buy a 330 shaft that has the same end links as the M3. There are some weird different shaft variants out there for x drive or automatics.

I measured the OEM M3 driveshaft length in two dimensions: with the rear joint compressed and with the rear joint stretched and gave that Info to the welding company. They then mated the flanches to the m4 driveshaft and balanced it.

My measurements were:
1364 mm with joint compressed
1376 mm with join stretched

Installation was straightforward. The shaft is a bit thicker than the OEM steel pieces, but everything cleared fine. I did not have to do any changes to other parts. You will have to loosen your diff mounts to push it back and mate it to the shaft.

Unfortunately I did not weigh the part when I got it. The M4 shaft weighs 7,6 kg. it did feel considerably lighter with the E46 flanches on it (I would guess 5kg)

Also make sure to install a new ball joint and dont reuse one from some 330 shaft you buy used. It is BMW part 26117841003.

[EthanolTurbo]

I already sent this to a couple of people via PM, figured I would post it here in case others are interested in the future:

I did not do the actual welding, so I can't comment on that, the rest was fairly simple.

I bought the M4 driveshaft and a 330 driveshaft as donor for the flanches. Make sure you buy a 330 shaft that has the same end links as the M3. There are some weird different shaft variants out there for x drive or automatics.

I measured the OEM M3 driveshaft length in two dimensions: with the rear joint compressed and with the rear joint stretched and gave that Info to the welding company. They then mated the flanches to the m4 driveshaft and balanced it.

My measurements were:
1364 mm with joint compressed
1376 mm with join stretched

Installation was straightforward. The shaft is a bit thicker than the OEM steel pieces, but everything cleared fine. I did not have to do any changes to other parts. You will have to loosen your diff mounts to push it back and mate it to the shaft.

Unfortunately I did not weigh the part when I got it. The M4 shaft weighs 7,6 kg. it did feel considerably lighter with the E46 flanches on it (I would guess 5kg)

Also make sure to install a new ball joint and dont reuse one from some 330 shaft you buy used. It is BMW part 26117841003.

Thanks for the update.

Update of my own: I have sourced the OEM F8x M4 carbon fiber driveshaft for $300. I will be taking it to a driveshaft specialist shop to get the flanges swapped. Will post up what they say, costs etc.

[bimmerfan08]

Thanks for the update.

Update of my own: I have sourced the OEM F8x M4 carbon fiber driveshaft for $300. I will be taking it to a driveshaft specialist shop to get the flanges swapped. Will post up what they say, costs etc.

Can you gather weights throughout the process? I.e., initial weight (of both driveshafts), final weight of modified driveshaft, etc. Thanks

[heinzboehmer]

Can you gather weights throughout the process? I.e., initial weight (of both driveshafts), final weight of modified driveshaft, etc. Thanks

And radii too! Sometimes more important that the weight for this kind of thing.

[Cronenberged]

I would like to know where these are being sourced so I can grab one if this a viable option to the YCFM one.

[0-60motorsports]

That's some great progress and info gents. Hopefully someone here does this mod on an SMG and posts measurements.

[EthanolTurbo]

Another update: spoke to a driveshaft specialist. They said they can do it with new flanges or existing ones to save money. They also make custom CF driveshafts so they're very familiar with modifying them. He said he hasn't seen this application before but that it should work fine with the much reduced WTQ the S54 puts out vs the S55.

I will drop off both driveshafts either this week or next to get an estimate. I will also make sure to get measurements and weigh everything. I'm thinking.the CF driveshaft should be roughly half the weight of stock. That + lightweight flywheel should make revving much faster than stock.

[0-60motorsports]

Another update: spoke to a driveshaft specialist. They said they can do it with new flanges or existing ones to save money. They also make custom CF driveshafts so they're very familiar with modifying them. He said he hasn't seen this application before but that it should work fine with the much reduced WTQ the S54 puts out vs the S55.

I will drop off both driveshafts either this week or next to get an estimate. I will also make sure to get measurements and weigh everything. I'm thinking.the CF driveshaft should be roughly half the weight of stock. That + lightweight flywheel should make revving much faster than stock.

That's awesome news! Thanks for the update.

[EthanolTurbo]

Just picked this up today. Here is the CF driveshaft, still looks to be in really great shape and condition.

If this turns out well, I will also try to retrofit another CF driveshaft onto my E90 M3.