F8X M3/M4 CF Drive shaft mod

[EthanolTurbo]

Did your revised, shortened driveshaft allow you to install without loosening the diff?

Haven't reinstalled it, car has been in the garage for months. I'm guessing the diff still has to be loosened.

[Cronenberged]

So this DS will rub on something or it won't?

[sdwz_m3]

Altaran's worked fine, I got mine re-shortened to the proper length, just haven't reinstalled it yet. I haven't driven my E46 in 3 months so once I get it back on the road I'll resume testing.

Did your revised, shortened driveshaft allow you to install without loosening the diff?

[0-60motorsports]

Installation went well, it really was a breeze. Could not be happier with my decision to opt for the telescoping slip-on joint flange, it was so easy to get the driveshaft into place. Everything else was very straight forward, typical driveshaft job. Only thing that's different is I decided to leave the heat shield off-- a quick fitment check revealed that it's going to be a choice between constant rubbing on the driveshaft being that it's got a larger diameter than stock or an occassional rattle against the exhaust and I wanted to deal with neither of those.

As far as driving impressions go, I can't pretend the car feels night-and-day different, it really doesn't 😂 but I am happy to have rid myself of and never have to worry about the center support bearing ever again. Was a fun project, I recommend to anyone who is looking for something to do to their E46, especially if their CSB is giving issues.

Thanks for coming back nd posting your feedback. Do you have an SMG or 6MT?

[fattycharged]

You can't tell any difference in engagement?


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[1spool]

Installation went well, it really was a breeze. Could not be happier with my decision to opt for the telescoping slip-on joint flange, it was so easy to get the driveshaft into place. Everything else was very straight forward, typical driveshaft job. Only thing that's different is I decided to leave the heat shield off-- a quick fitment check revealed that it's going to be a choice between constant rubbing on the driveshaft being that it's got a larger diameter than stock or an occassional rattle against the exhaust and I wanted to deal with neither of those.

As far as driving impressions go, I can't pretend the car feels night-and-day different, it really doesn't 😂 but I am happy to have rid myself of and never have to worry about the center support bearing ever again. Was a fun project, I recommend to anyone who is looking for something to do to their E46, especially if their CSB is giving issues.

[0-60motorsports]

Yes, I think they would. Ask for Rob at Nassau Driveshaft located at 2279 Babylon Turnpike, Merrick, NY 11566, tell him John sent you.

Awesome! Thank you!!!

[fattycharged]

Yes, I think they would. Ask for Rob at Nassau Driveshaft located at 2279 Babylon Turnpike, Merrick, NY 11566, tell him John sent you.

Seems like this should be simple for any competent shop now with this version, no? Hopefully so, I just ordered one and would prefer not to send it off again

[1spool]

Awesome post! Thank you for all the data. Would the shop you used do this for us if we shipped them the DS and parts?

Yes, I think they would. Ask for Rob at Nassau Driveshaft located at 2279 Babylon Turnpike, Merrick, NY 11566, tell him John sent you.

[fattycharged]

I keep finding part # 7632 and hopefully this works as well


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[Cronenberged]

$480 would make this worth it.

[0-60motorsports]

Hello everyone. Stumbled across this thread about a week ago and was inspired to get to work.
Would like to preface the following by saying that I was the first (at least to document it) to retrofit an F8x driveshaft onto my E82 back in September 2021 so I had a good idea of what I'm up against here. All measurements and weights posted were taken by me as in the past I've learned (the hard way) that internet measurements can be misleading.

Began by purchasing an F8x driveshaft off of a 2016 M4 coupe, part number 26107857629. It's important that you get this one, NOT part number 26117855000 as 7629's transmission-side flange is a slip-on joint that allows for 2" of travel, thus absorbing any play in the drivetrain (also making installation easier) instead of the now-missing center support bearing. 5000 does not feature the slip-on joint but instead is a fixed, welded piece. Our OEM E46M3 guibo does not fit this F8x flange so some modifications had to be done-- a local machine shop ovaled out the flange holes to accomodate the guibo holes. Worth mentioning that I ran the same style modification on the F8x driveshaft that ended up on my 790whp 8k RPM 200mph 135i 3 years ago-- no issues. Local driveshaft shop welded shortened the F8x driveshaft to my desired length and welded on the diff-side portion of the E46M3 shaft allowing for the traditional OEM CVJ to be used.

Now some measurements--
OEM guibo: 32mm
Fully dressed E46M3 DS: 1,403.5mm
Naked E46M3 DS (no guibo): 1,371.5mm
Resting position F8x DS (with guibo): 1,463.5mm
Fully compressed F8x DS (with guibo): 1,433.5mm
Fully expanded F8x DS (with guibo): 1,483mm
F8x slip-on joint play: 54mm
Modified F8x DS resting position: 1,397mm
Modified F8x DS fully compressed: 1375.5mm
Modified F8x DS fully expanded: 1,429mm

Weights:
Guibo: 1.4lbs
CVJ: 3.1lbs
Install-ready OEM E46M3 DS: 18.7lbs
Install-ready F8x DS (+E46M3 CVJ): 18.3lbs
Install-ready modified F8x DS: 17.6lbs

Cost:
F8x DS: $180
Flange holes machining: $100
DS shortening/balancing: $200
OEM CVJ: $360
OEM Guibo: $90
Donor E46M3 DS: $100
Total: $1,030
If your guibo and CVJ are in good shape and you don't mind sacrificing your existing E46M3 DS this mod can be done for $480, worth it in my opinions considering you never have to worry about your center support bearing ever again and frankly, it's just plain cool.

In conclusion, I was definitely surprised to learn about the weight differences between the F8x CF DS and our oem (steel by the way, surprisingly not aluminum!) E46M3 DS. I thought they would be more drastic. Either way I'm gearing up to install the new piece tomorrow and if all goes well I've got a spirited drive planned for Thursday morning, will update regarding installation difficulty and driving impressions.

Awesome post! Thank you for all the data. Would the shop you used do this for us if we shipped them the DS and parts?

[Bry5on]

Wonder if you could just swap the transmission output flange and use the bigger guibo instead of redrilling while still avoiding shift selector contact. Interesting info on the telescoping version of the shaft.

[1spool]

Hello everyone. Stumbled across this thread about a week ago and was inspired to get to work.
Would like to preface the following by saying that I was the first (at least to document it) to retrofit an F8x driveshaft onto my E82 back in September 2021 so I had a good idea of what I'm up against here. All measurements and weights posted were taken by me as in the past I've learned (the hard way) that internet measurements can be misleading.

Began by purchasing an F8x driveshaft off of a 2016 M4 coupe, part number 26107857629. It's important that you get this one, NOT part number 26117855000 as 7629's transmission-side flange is a slip-on joint that allows for 2" of travel, thus absorbing any play in the drivetrain (also making installation easier) instead of the now-missing center support bearing. 5000 does not feature the slip-on joint but instead is a fixed, welded piece. Our OEM E46M3 guibo does not fit this F8x flange so some modifications had to be done-- a local machine shop ovaled out the flange holes to accomodate the guibo holes. Worth mentioning that I ran the same style modification on the F8x driveshaft that ended up on my 790whp 8k RPM 200mph 135i 3 years ago-- no issues. Local driveshaft shop welded shortened the F8x driveshaft to my desired length and welded on the diff-side portion of the E46M3 shaft allowing for the traditional OEM CVJ to be used.

Now some measurements--
OEM guibo: 32mm
Fully dressed E46M3 DS: 1,403.5mm
Naked E46M3 DS (no guibo): 1,371.5mm
Resting position F8x DS (with guibo): 1,463.5mm
Fully compressed F8x DS (with guibo): 1,433.5mm
Fully expanded F8x DS (with guibo): 1,483mm
F8x slip-on joint play: 54mm
Modified F8x DS resting position: 1,397mm
Modified F8x DS fully compressed: 1375.5mm
Modified F8x DS fully expanded: 1,429mm

Weights:
Guibo: 1.4lbs
CVJ: 3.1lbs
Install-ready OEM E46M3 DS: 18.7lbs
Install-ready F8x DS (+E46M3 CVJ): 18.3lbs
Install-ready modified F8x DS: 17.6lbs

Cost:
F8x DS: $180
Flange holes machining: $100
DS shortening/balancing: $200
OEM CVJ: $360
OEM Guibo: $90
Donor E46M3 DS: $100
Total: $1,030
If your guibo and CVJ are in good shape and you don't mind sacrificing your existing E46M3 DS this mod can be done for $480, worth it in my opinions considering you never have to worry about your center support bearing ever again and frankly, it's just plain cool.

In conclusion, I was definitely surprised to learn about the weight differences between the F8x CF DS and our oem (steel by the way, surprisingly not aluminum!) E46M3 DS. I thought they would be more drastic. Either way I'm gearing up to install the new piece tomorrow and if all goes well I've got a spirited drive planned for Thursday morning, will update regarding installation difficulty and driving impressions.

[TheElite///M3]

i'm waiting on a new guibo and diff bushings and then i'll share my findings