Carbon Driveshafts: lets talk!

So lets talk Carbon Fiber Driveshafts:

Whose running them. The good, the bad, and the ugly!

Which ones? (Noting offerings from VAC, Fall-Line).

The entire Mfactory, or Yfactory thing I dispelled a long way ago. That debacle got so far out of hand, I don’t even know Id trust a “GOOD” or signed off product from all that nonsense that went on.

DCT/or 6MT?
How long? Mi/or Trackhours

Should note this would be 6MT application.

Most importantly weight saved.

Thanks guys! Hoping something good can come of this, for everybody.

MFactory V1 DCT, 4.5 years 40k kms (mainly street with weekly WOT hill runs, and 1-2 trackdays per year). Before it came to me it spent 1-2 years in someone else's dedicated track car. Zero issues, zero NVH, zero downsides.

You will feel slightly better acceleration, rpms climb more freely, and the WOT upshifts are much more raw and give you a nice kick in the back. Bonus is no more M clunk from the propshaft center bearing. I love my CF DS and would definitely do it again.

Recently some local E9x M3 guys have installed JFiber CF DS and have reported zero issues as well. Maybe they've gotten their quality issues sorted?

The MFactory/YFCM debacle is just drama between competitors. The products appear to be good so don't let that scare you off from getting one.

I have the v2 YFCM/mfactory 6 spd cf drive shaft. Haven't had any issues with mine and I track my car and do street duty on occasion. I've gotten it up to 150mph with no vibrations or noise.

It's been on the car for 1.5 years now and I've gotten so use to it that I don't notice it much anymore. But I know it's working.

If you're able to get one do it, I know the other drama was just that drama. I didn't even know those other companies offered cf driveshafts. Good to know but if I need a replacement for any reason I won't hesitate to get another one as it's been good.

Redd wrote

MFactory V1 DCT, 4.5 years 40k kms (mainly street with weekly WOT hill runs, and 1-2 trackdays per year). Before it came to me it spent 1-2 years in someone else's dedicated track car. Zero issues, zero NVH, zero downsides.

You will feel slightly better acceleration, rpms climb more freely, and the WOT upshifts are much more raw and give you a nice kick in the back. Bonus is no more M clunk from the propshaft center bearing. I love my CF DS and would definitely do it again.

Recently some local E9x M3 guys have installed JFiber CF DS and have reported zero issues as well. Maybe they've gotten their quality issues sorted?

The MFactory/YFCM debacle is just drama between competitors. The products appear to be good so don't let that scare you off from getting one.

very similar experience/use, but i'm an original owner.

I have the latest Mfactory V3 shaft installed recently. Did 2 track days and around 3000km of driving. Zero issues whatsoever so far.

At my last track day I was consistently hitting 210km/hr at the end of the main straight. Whereas prior to the cf shaft I was only able to get up to 190km/hr or so. My entry speed into the main straight is about the same before and after the V3 shaft.

I left a more detail review in the Mfactory GB thread.

Interesting responses. Nobody on here running VAC offering? or Fall-Line?

Also do believe there was a post today of rhyary posting about an exploding driveshaft in the vendor forum thread?

Exclusivs wrote

Interesting responses. Nobody on here running VAC offering? or Fall-Line?

Also do believe there was a post today of rhyary posting about an exploding driveshaft in the vendor forum thread?

Rhyary's CFDS was 6 years old on a track car with 150 track days, and he's got a new one going in immediately. If anything, it's an indication of how reliable they are.

Redd wrote

Exclusivs wrote

Interesting responses. Nobody on here running VAC offering? or Fall-Line?

Also do believe there was a post today of rhyary posting about an exploding driveshaft in the vendor forum thread?

Rhyary's CFDS was 6 years old on a track car with 150 track days, and he's got a new one going in immediately. If anything, it's an indication of how reliable they are.

Is it catastrophic if they break? Will it damage the engine?

Battle wrote

Is it catastrophic if they break? Will it damage the engine?

No, if it break your car simply won’t drive because it can’t send power to the wheels. I suppose your rpm will spike really quick if you’re at redline.

Redd wrote

Rhyary's CFDS was 6 years old on a track car with 150 track days, and he's got a new one going in immediately. If anything, it's an indication of how reliable they are.

This. 150 track days, supercharged and at times running on r comp tires.

I’d be happy if I can get 150 track days out of my V3 shaft. Since I do only 5 track days a years, that’s like 30 years of usage for me lol.

Battle wrote

Is it catastrophic if they break? Will it damage the engine?

When mine delaminated it was isolated to the rear where the DS connected to the differential. Coming out of a heavy braking zone I went to the gas and had nothing but revs. Slight grinding noises had me thinking clutch or transmission, but sure enough it was the driveshaft. On my second one now (both MFactory).

No collateral damage.

Battle wrote

Is it catastrophic if they break? Will it damage the engine?

no, its less destructive than the steel driveshaft.

the weak point of these carbon driveshafts is the bonding agent between the metal flanges at the ends. if it breaks, it will likely break the bond and the carbon shaft will just rotate on the cv coupler. the car will probably just feel like its in neutral and nothing else will get damaged unless you over rev the car.

Any more updates from those with CF Driveshafts? Anyone try the VTT one that forgoes the Guibo all together? Would love to hear some updates.

I have the newest YCFM CF driveshaft in my 6MT. Shaved 11lbs compared to the stock unit and has handled two back to back days at Buttonwillow effortlessly. No issues to report. Feels good paired with a lightweight clutch.

V1 mfactory over here, DCT. 4 track days so far, including road america where I get to the mid 140s. so far so good ¯\_(ツ)_/¯

Several owners here have been using JFiber CF DS with no issues.

Mfactory V4 shaft here. 14 track days and counting, no issues whatsoever.

Mfactory V2 6MT here. 12k miles with 6 track days. All good, love it.

roastbeef wrote

no, its less destructive than the steel driveshaft.

the weak point of these carbon driveshafts is the bonding agent between the metal flanges at the ends. if it breaks, it will likely break the bond and the carbon shaft will just rotate on the cv coupler. the car will probably just feel like its in neutral and nothing else will get damaged unless you over rev the car.

Adhesive failure should be an easy failure mode to address. Adhesive failure with the adherend is the weakest and most undesirable mode of failure (inconsistent failure load). Cohesive or adherend (composite tube) failure modes are more desirable and have a higher failure load than a pure adhesive failure. Adhesive failure can point to bonding contamination and/or workmanship issues and/or insufficient bond area. Ideally you want an adhesive or bonded joint design that results in a failure of the composite tube itself which means you’ve developed the full strength of the joint. If most or all failures of the CFDS are the adhesive separating from the composite tube then the joint should be redesigned.

Manual MFactory v2 driveshaft with 3+ years & 20K+ street miles never have been happier with this lightweight purchase

I have the Mfactory V3 driveshaft and it's done a full year of competition (some 14 or so track days). No issues, absolutely flawless.

I've had an Mfactory driveshaft in the car (6MT) for a while now, several track days and almost 20,000 street miles. It really improves the car a lot more than you'd expect

Plus it was always the first mod in Gran Turismo back in the day, which makes it worth +1,000,000 cool points