Carbon Fiber Driveshaft coming soon!

Epiphany said:

I had the opportunity to talk to Jamal Hameedi about why the factory didn't pick up where the last GT500 left off and include a CF shaft on the GT350 as well. He was clear that fiber shafts weren't stiff enough, hence the two piece. So I'd love to hear DSS' point of view and what they are doing differently with this specific application to make it work - properly.

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Not stiff enough? Why do all the exotic car brands have them then? It's cost related... Has to be.

I have one and noticed a difference right away. Throttle is a bit snappier. Less slop and weight. 36 vs 18 lbs difference

Spacebird said:

He immediate felt the difference of being $1500 poorer.

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The factory shaft was quite a bit less that $1,500. The hard part was coming up with a fixed flange that adapted to the front CV joint of the '13/'14 shaft. I worked with a top notch machinist that also works for Dean Martin's Pirelli World Challenge Team on a solution. I ended up selling 30 or so adapter flanges to fellow GT500 owners. So to your "point" Spacebird, the mod paid for itself.

stanglife said:

Can you elaborate?

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Certainly. The reduced rotational mass and elimination of the center joint allows for faster acceleration over that of a steel driveshaft(s) or aluminum driveshaft. CF shafts are easier on the driveline as they twist and then return to their original state, reducing dynamic "shock" under certain circumstances. In essence, their NVH qualities are much better than that of steel. CF shafts also have much higher critical speeds, the point at which a shaft can bend or whip.

There is a certain "smoothness" to a well done CF shaft that you won't feel in a steel or aluminum shaft, especially in the upper rpm ranges, which is exactly where the GT350 wants to be. Much like the Cf wheels on the R model, a CF driveshaft has the potential to offer a substantial weight reduction, an increase in driveline durability, as well as smoother driveline altogether. As I mentioned, if DSS can come up with a stiff enough design that is robust enough to live behind the high winding 5.2 (and its inherent vibratory potential) it'll definitely be a part worth taking advantage of.

Super Werty said:

Not stiff enough? Why do all the exotic car brands have them then? It's cost related... Has to be.



I have one and noticed a difference right away. Throttle is a bit snappier. Less slop and weight. 36 vs 18 lbs difference

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It's likely a combination of both; adequate stiffness costs money. A simple CF tube likely isn't going to cut it. It has to have lots of cross-lattice layers of high quality CF which is expensive. One of the advantages of CF is that it does flex a bit: it's strong, but not super stiff. Remember, stiffness and strength aren't the same.

I buy that CF shafts are good for a few lbs of overall weight savings, but the reduction in the moment of inertia is not very substantial as the radius of the driveshaft is so small.

Spending the $1500 on some lighter weight rear wheels is a vastly more cost effective way of reducing driveline inertial moment and overall weight PLUS you get the added benefit of reducing unsprung weight.



Sent using the protocol module of my R2 unit.

The GT350 with less power and tq will not break a damn carbon DS. The GT500 sporting one is pushing 600rwhp and about the same TQ. I believe its also cost related, just like ditching the Carbon rotor and going with a two piece rotor.

If you can afford this bad ass mod go for it! An aluminum DS is a good alternative too.

Super Werty said:

Not stiff enough? Why do all the exotic car brands have them then? It's cost related... Has to be.

I have one and noticed a difference right away. Throttle is a bit snappier. Less slop and weight. 36 vs 18 lbs difference

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I was in agreement with you - one hundred percent. It simply didn't make sense that the GT350 wouldn't take advantage of the development that took place on the GT500 unit. Hameedi's comments seemed to contradict some of the reasons why Ford chose CF for the GT500 but after talking to him about I could see his point. They tested CF shafts on the GT350 and it didn't work out. Part of that may have been a cost ceiling, I agree.

And nice to see someone else that actually had one make the same comments. So to those up above, lol indeed.

It's 100% cost related. They can make a carbon shaft strong enough. FYI the one I have is rated for 1000 hp.

1mic said:

The GT350 with less power and tq will not break a damn carbon DS. The GT500 sporting one is pushing 600rwhp and about the same TQ. I believe its also cost related, just like ditching the Carbon rotor and going with a two piece rotor.

If you can afford this bad ass mod go for it! An aluminum DS is a good alternative too.

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Ford has said its a RPM issue with why the GT350 doesn't have a CF driveshaft stock. 3.73 vs 3.31.

xt6wagon said:

Ford has said its a RPM issue with why the GT350 doesn't have a CF driveshaft stock. 3.73 vs 3.31.

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Yep. Not to mention the higher redline. The longer the DS is (ie one piece), the stronger it needs to be to have an acceptable critical speed (8250rpm essentially)

xt6wagon said:

Ford has said its a RPM issue with why the GT350 doesn't have a CF driveshaft stock. 3.73 vs 3.31.

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Which is a complete contradiction of their reasoning for using it on the gt500. It was stated that to reach their 200mph goal they had to use a CF shaft to handle the extreme driveshaft rpm.

Of course he had a reason prepared for why they didn't use a CF shaft. What do you think his response is going to be? "budget didn't allow it"

For what it's worth I did mention Jamal's statement on why they didn't use a CF shaft to Frank at DSS, and I literally got a 15 minute ear full. A lot more than Jamal offered on the subject...

Spacebird said:

Remember, stiffness and strength aren't the same.

I buy that CF shafts are good for a few lbs of overall weight savings, but the reduction in the moment of inertia is not very substantial as the radius of the driveshaft is so small.

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The above was with respect to the '13/'14 CF shaft. Typical aftermarket CF shafts often see even greater weight savings. Just what an engine like the 5.2 is looking for and for many of the same reasons that Ford went with a smaller, dual mass clutch. Less rotational mass, allows the engine to rev quicker. Perfect for the Voodoo. Every bit counts, and 15-20lbs of rotational weight reduction ain't too shabby.

1mic said:

The GT350 with less power and tq will not break a damn carbon DS. The GT500 sporting one is pushing 600rwhp and about the same TQ. I believe its also cost related, just like ditching the Carbon rotor and going with a two piece rotor.

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It isn't about "power and torque" but rather what Spacebird rightly pointed out up above that "stiffness and strength aren't the same." Ford spent quite a bit of time and money making the FPC livable, including (for example) adding over 12lbs worth of mass dampers at the base of the TR3160 where it mates with the crossmember. They tested TR3160's with '13/'14 GT500 fixed (cup-style) flanges and found a "tail wagging the dog effect" due to overall transmission length. They subsequently went with a much shorter flange. Here's a shot of just such a flange behind a development TR3160. The flange being held is what Ford ultimately went with since they didn't use a CF shaft.





ON EDIT...Hameedi is quoted in an interview as saying...

We needed the stiffest driveshaft we could get. We looked at a carbon-fiber driveshaft and we couldn’t get it stiff enough, so we went with the two-piece steel.

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They didn't test them only to round file the idea due to cost "100%." The monies spent developing the '13/'14 shaft on things such as the splined ends (DSS bonds their ends on) wouldn't have to be amortized by GT350 production.

Well when your constraints are cost and driveshaft critical speed, technically you can blame either aspect on not being able to do it

Did the DSS have any comments on potential NVH issues?

Epiphany said:

They tested TR3160's with '13/'14 GT500 fixed (cup-style) flanges and found a "tail wagging the dog effect" due to overall transmission length. They subsequently went with a much shorter flange. Here's a shot of just such a flange behind a development TR3160. The flange being held is what Ford ultimately went with since they didn't use a CF shaft.

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So Maybe if there was an issue with the CF shaft they tested, it was actually caused by the dual cv configuration. The DSS shaft will mount to the trans using a u-joint just like the stock gt350 shaft.

In the case of the GT350 it'll have to be a u-joint up front unless the flange is changed or an adapter ring is used. The dual CV jointed shaft is the way to go - if you can. The Neapco joints proved to be very robust on the GT500.



I look forward to seeing what DSS comes up with beyond just balancing to a certain rpm threshold. How it behaves behind the 5.2 may prove to be another story.

I'll say it again. It's 100% cost related. Making a carbon shaft for the car is 100% possible and has been done before on much more demanding cars. The gt350 is not some new insanely fast revving engine that cannot accept anything but steel two piece driveshafts lol

Nobody implied that the GT350 could only use a two-piece steel shaft. And saying it is "100% cost related" simply isn't accurate.