"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 get my hands on the authentic E9x M3 V2 carbon fiber driveshaft and compare to MFactory's V3 counterfeit unit."
- Matt

The core issue: vibrations. 

The fundamental problem with the counterfeit V3 is simple: it doesn't work. Carbon driveshafts developed to be used with the original flexdisc should not have any vibrations. From the previous entry, all counterfeit V3 units experienced critical levels of vibrations. 

Upon receiving the authentic V2 carbon fiber driveshaft, I was able to better understand the quality differences leading to vibrations. 

At the core, it's a balancing issue derived from poor design and manufacturing on the V3.

The counterfeit unit made use of balancing weights across the tube. In similar logics to balancing wheels & tires, excessive weights can be indicative of poor quality standards when new.  

In the case of carbon driveshafts, I discovered that using weights at all was a sign of poor design. 

3x glued on weights were used across the tube and another balancing weight was found on the middle of the tube. 

2x balancing weights by the CV flange, the heaviest section of the driveshaft. 

The V3 also had this riveted on weight by the flange. 

The V2 has no balancing weights. It never uses any, as balancing is not achieved using weights, but rather subtle machining of the flanges. 

The culprit: the carbon tube. 

The need to use balancing weights arise from poor carbon tube manufacturing techniques. Upon comparing the two units, this was made obvious. 

The differences in manufacturing techniques have a visible impact of the design restrictions of the carbon tube, I cover these below.  

The original V2 is winded from pre-preg carbon filaments, a similar process as used in the Lexus LFA. Interestingly, the filaments are sourced from Toray Industries in Japan - who was a key manufacturing partner for Toyota in the production of the LFA.

You can discern the various layers of the carbon tube, and the difference angles at which the tube is winded together. 

The V3's unidirectional carbon is actually made from a lower quality carbon process: the rolling & pasting method used is similar to golf club manufacturers.

It'll be obvious to anyone that golf clubs don't spin to 9,000 RPM and its manufacturing techniques were never intended for such an application.  

The unidirectional weave can be discerned below. 

The V3 carbon tube manufacturing process imposes has a wider diameter to achieve its rigidity rating. The diameter increases is a bad design choice for two main reasons: clearance, and rotational inertia. The latter imposes further balancing weights to be used. 

The larger diameter increases risks of failure from “cut conditions” by hitting screws along the transmission tunnel - or the tunnel itself. 

The V2 tube is smaller in diameter, reducing potential risks of failure.

The underlying issue: the transmission flanges. 

Vibration issues are obvious, they can rapidly be experienced on the first drive with a faulty driveshaft by hitting its problematic speed range.

Beyond vibrations, there is an underlying long term issue to the V3's design: ungluing of the transmission flange. Ungluing risks have plagued most carbon driveshafts manufacturers, even BMW M on the F80.  

The risks come from using the original guibo / flexdisc as part of the driveshaft design. It is a mission critical component to reduce NVH and vibrations across the driveline for an OEM experience.

Race derived driveshafts solve the ungluing issue by most often using u-joints that bolt directly to the transmission flange, leaving to increased NVH unsuitable for a street car. 

The V2 solved this problem by using a patented self-locking flange design, whereas the V3 does not. 

Below is a direct comparison of the two transmission flanges. 

The V2's tube is sealed, glued and locked within the transmission flange to eliminate ungluing risks.

The flange is machined with internal tabs that align with notches in the carbon tube to create the mechanical locking effect. 

The notches on the tube are cut to align with the flange, with some play to allow adhesives to seep through. 

The V2's flange is anodized and further machined for weight reduction. Most importantly, it's made from 7075 forged aluminum. 

The V3 is a crude design in comparaison. Simple machining work can be seen, along with using lower rated 6061 aluminum. 

Interestingly, you'll find hand engraved serial numbers on the V3s. 

The V3's carbon tube needs to be larger in diameter as it slips over the flange. Adhesives are used as the sole locking mechanism. 

The V3 and V2 share the same commercially available CV flanges - but the V2 is a step beyond with in-house heat treatment to improve durability. 

Up next: we complete the installation and share our notes. 

There are a few key indicators to validate your installation before driving.

I will also suggest while you're in there maintenance.