The elephant in the room
"These build journal entries are part of a Special Series on the E9x M3 V2 carbon fiber driveshaft by YFCM Technologies.
I cover the bizarre backstory to uncovering the manufacturer of the renowned and authentic V2 product with its comparaison to the counterfeit unit. I then cover the installation procedures and discuss my driving impressions.
In this entry, I cover the elephant in the room: will this V2 really be all it's hyped to be - or will it vibrate? I share my driving impressions along with David's, the original 6spd V3 tester who also tested the V2."
- Matt
Let's get the elephant in the room out of the way.
There is absolutely no vibration or added NVH coming from the YFCM carbon driveshaft on my DCT S65.
Zip, zero.
Where the previous MFactory V3 vibrated the whole car like riding on a cobble road at 180 to 200 kph.
This is silky smooth.
David's impressions.
David (@ds_e92m3) mentioned in his initial MT review that the felt the car was slightly more responsive and felt "tighter" than equipped with MFactory's V3.
"To be honest, I wasn’t expecting a difference in drivability – as I was pleased with what the “v3” offered outside of the issues listed above.
However… I was pleasantly surprised; throttle was more responsive. The whole drivetrain feels even tighter. I don’t have data to go by, but it feels faster across the rpm range.
Clutch engagement is much smoother, which I assume is a by-product of the lighter rotation mass the shaft now carries. Mashing on the throttle is instantly translated to power – it’s like driving an electric car. I was able to take it to 110 MPH (in Mexico) with 0 vibrations or humming.
I’m ecstatic!
Here’s a weird one: coming to a stop is also smoother; where you’d have to apply brakes and back-off a bit as the car comes to a stop, is no longer needed. Simply holding the brakes steady will do now.
When I first received the YFCM shaft I inspected it closely; weighted it on my bathroom scale (just shy of 11 lbs for the 6 speed) and then went looking for any imperfections, the number of weights, the build quality, any anomalies that would jump out at me – all I found was a single balancing weight and a build quality that is beyond what you or I would expect.
It’s superb - which is also unfortunate because that it is a piece you don’t get to see again."
My impressions.
I wanted to throughly test this over the last week and do various back country runs to better feel it for myself.
David was right.
Everything feels tighter, better - there's less play, no clunk. The S65 feels bolted straight to the rear diff more than ever - the connected feel is incredibly precise and tactile.
You will more easily chirp tires on shifts into 2nd and 3rd. Power is more quickly transferred to the rear wheels.
I can now trust the car & drivetrain once more to not rattle itself to pieces.
It's all about stiffness.
The benefits to this upgrade are derived from the one piece carbon tube. By having a higher tensile strength than steel, the V2 one piece design eliminates the center support bearing.
Considering this, you should approach this modification with a similar mindset that you would for solid subframe bushings:
- No added NVH.
- Improved chassis response.
- Improved throttle response.
Throttle response is a function of time.
By directly connecting the differential with the transmission, the entire powertrain moves around less than OEM. It makes the connection between the engine, flywheel, clutch, driveshaft and diff simply faster to respond.
We conflate weight reduction with rotational inertia.
Many often misunderstand carbon driveshafts: I did too! We expect them to feel like lightweight flywheels: we are used to these drastically improving low to mid range engine response.
While the driveshaft does lose 10+ lbs over stock, it does so on a much smaller radius compared to the flywheel.
My car is fitted with a lightweight forged carbon steel flywheel.
This wraps up the Special Series about the E9x M3 V2 Carbon Driveshaft.
It's a must-have modifications for our chassis, and it's no wonder BMW M fitted it from the factory to early generation F8x M3 and M4s.
It improves the analog experience and our connection to the chassis: it's why we do this.
You can order the driveshaft year long here.
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