"These build journal entries are part of a special series on the development of the E60 M5 & M6 Carbon Fiber Driveshaft by YFCM Composites. 

This specific journal entry covers the preliminary checks, while-you're-in-theres, recommended hardware and installation notes along with final validation checks to fit the the carbon driveshaft to your SMG3 and 6spd V10.

These entries are written in collaboration with M Lee: lead engineer and patent holder to YFCM's innovations."
- Matt

Preliminary checks.

Inspect & Replace worn bushings and mounts!

If your bushings and mounts are worn - I highly recommend you change them. The M5 is prone to wheel hop, it's a smart while you're in there. 

I upgraded my rear sway bar bushings [...]

and the sway bar itself with Dinan's adjustable bar in the Sport Chassis Kit.

Recommended hardware. 

• 1x Flexdisc "guibo" (SKU:  26112282573) 
• 3x Self Locking Nut for Guibo / Transmission flange (SKU: 26127536563)
• 6x Hex Bolt for Guibo / Transmission flange (SKU: 26117527475)

Installation Steps.

Get to the driveshaft. 

You need to remove the center exhaust bracket, disconnect 02 sensors off the exhaust and remove the entire exhaust systems. 

The OEM steel driveshaft and center support bearing can then be removed. The transmission then needs to be supported for the transmission mounts to be removed.

It's a tight fit! 

1. We needed to lift the transmission all the way up with the engine supported.
2. We also loosened the differential bushings and pried off them to get the YFCM to fit.

We first fitted the guibo to the driveshaft instead of the transmission flange. Make sure the Guibo points in the correct direction. 

Validation Steps.

You need to meet these clearances before completing the installation as it may otherwise lead to catastrophic failure of the tube.

"After having sold 100 + driveshafts, and over 500+ of these being around, I have yet to see a carbon tube ungluing."
- Matt

Telescopic Flange Measurements

The CV flange is telescopic and allows for some play for the rubber bushing in the powertrain such as the engine mounts, transmission mounts, diff and subframe bushings.

As the 1 piece carbon tube design is engineered to flex and move with the drivetrain, YFCM carefully engineered the tube length to match with the CV flange.

It must have a 64mm / 2.52 inches distance between both points pictured. 

If you installation does not come within the specifications listed below, you may have worn bushings and/or mounts across the powertrain. It's ideal to have had the car under the load if you changed any bushings. 

Here's how we took the measurement on the M3 V8. The car was still on the lift. 

Carbon Tube Clearances

Carbon tubes are larger than steel driveshafts and more susceptible to being damaged by screws and bolts that are at the top of the tunnel.

Careful attention to clearances and free range of movement of the tube must be validated. There are 2x bolts and 1x screw by the CV flange that are to watch for.

There should be at least 20mm / 0.8 inches separating the tube from any physical element across the driveshaft valley.  

Up next: the hype is real and the effects are felt even more than on my DCT V8. 

The SMG needed this.