F8X M3/M4 CF Drive shaft mod

[e46IX]

Update: the driveshaft shop (DriveshaftPro) called me and said my driveshaft is ready for pickup. I dropped it off last week explaining the vibration issues.

Here is what they said:

"The original drawing we went off of caused the driveshaft to be too long. We shortened it by 3/8ths of an inch and rebalanced it. This should resolve any vibration issues. The CV joint wouldn't have lasted long due to this."

So whatever specs I posted above for measurements needs to be reduced by 3/8ths of an inch. 53.875 inches needs to be cut down to 53.5 inches.

Going to pick it up today on the way to Disneyland. I have to reinstall it, but it looks like OEM carbon fiber driveshafts might be back on the menu, boys. If it works without any vibration issues, I will get a quote for 5-10 of these to be done to try to get better pricing.

You get any seat time with the revised length drive shaft?

[Projecte46m3]

YFCM carbon fiber driveshaft checking in! Can't wait to install this along with a 3 clutch LSD w/ 4.10s.

[Altaran]

I'm in pending it handles high revs and speeds with no issues. Would be a plus if it we had a track day review

Realistically it will take me another 2 months or so to hit the track, as I still have other things to finish to get the car ready.

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[Cronenberged]

I'm in pending it handles high revs and speeds with no issues. Would be a plus if it we had a track day review

[0-60motorsports]

It's posted on a previous page sonewhere: $776 with parts and labor.

I just would hate to see anyone spend the money I did and have issues. By the end of this week I should be able to test the car out with the shaft.

Sounds good. Please let us also know what they said was the issue first go round. Thanks.

[SQ13]

It's posted on a previous page sonewhere: $776 with parts and labor.

I just would hate to see anyone spend the money I did and have issues. By the end of this week I should be able to test the car out with the shaft.

If take 2 goes well, I am down for the GB. If you still plan on offering it of course.

[EthanolTurbo]

Good, looks like they are fixing it. This is hilarious!

But I have to wonder how much you paid? I was quoted $800 shipped and with only having to supply the carbon shaft. Maybe you can get some money back.

It's posted on a previous page sonewhere: $776 with parts and labor.

I just would hate to see anyone spend the money I did and have issues. By the end of this week I should be able to test the car out with the shaft.

[0-60motorsports]

Hopefully they can figure it out first

[bigjae46]

Update pt 2:

Just picked up the driveshaft from the shop. I asked them how they knew it was too short or too long, they said they opened the CV joint and inside you can see if it's too compressed or not due to the traces and marks it leaves inside. It was running too compressed due to the DS being too long. Their original measurement and drawing was based on the 2 piece length but after seeing the CV joint, they said that 3/8th of an inch reduction was necessary.

Good, looks like they are fixing it. This is hilarious!

But I have to wonder how much you paid? I was quoted $800 shipped and with only having to supply the carbon shaft. Maybe you can get some money back.

[bigjae46]

LOL. This is hilarious. Sorry to rain on your parade but this is the exact place I had my vibrating driveshaft done. 😂

Oh shit…really? 🤣🤣🤣

I asked and they said they’ve never done one before so I assumed it was a different place. I think these guys were split off from the company I’ve dealt with in the past (Powertrain Industries)…or something which is what made getting to this point a massive PIA.

That guy Eric told me there’s a 1 year warranty. Take your driveshaft back and make them fix it. I can try and help I really don’t know these guys. I have a rep I deal with at Powertrain so I can take care of issues.

Sorry everyone!

[EthanolTurbo]

Update pt 2:

Just picked up the driveshaft from the shop. I asked them how they knew it was too short or too long, they said they opened the CV joint and inside you can see if it's too compressed or not due to the traces and marks it leaves inside. It was running too compressed due to the DS being too long. Their original measurement and drawing was based on the 2 piece length but after seeing the CV joint, they said that 3/8th of an inch reduction was necessary.

[EthanolTurbo]

Update: the driveshaft shop (DriveshaftPro) called me and said my driveshaft is ready for pickup. I dropped it off last week explaining the vibration issues.

Here is what they said:

"The original drawing we went off of caused the driveshaft to be too long. We shortened it by 3/8ths of an inch and rebalanced it. This should resolve any vibration issues. The CV joint wouldn't have lasted long due to this."

So whatever specs I posted above for measurements needs to be reduced by 3/8ths of an inch. 53.875 inches needs to be cut down to 53.5 inches.

Going to pick it up today on the way to Disneyland. I have to reinstall it, but it looks like OEM carbon fiber driveshafts might be back on the menu, boys. If it works without any vibration issues, I will get a quote for 5-10 of these to be done to try to get better pricing.

[Slideways]

Who's done it successfully?

I saw one post where someone said they didn't get to drive it much, but didn't notice vibration.

I'd want a little more assurance than that before moving forward.

That driveshaft was fabbed at a shop in Germany, IIRC. It would be nice to see at least 1000 miles and some track abuse before confirming the best shop for this driveshaft mod.

[9kracing]

Who's done it successfully?

I saw one post where someone said they didn't get to drive it much, but didn't notice vibration.

I'd want a little more assurance than that before moving forward.

[Projecte46m3]

Can people who’ve had the conversion done successfully share the name of the shop that did the work? I’m not trying to pay a random place $1k to do questionable work lol.

This!!!