I just had the driveshaft shop make me a carbon fiber driveshaft (before their prices went up). On the driveshaft are stickers that say not to exceed 300f or the driveshaft can be damaged and warranty is voided.

On my FD, I have a custom 3.5" exhaust system and as you know, the exhaust runs close to the driveshaft location. Will it heat the driveshaft to over 300f? If so, what are the best options? I'm thinking I could use exhaust wrap on that section of exhaust that runs near the driveshaft. My downpipe is already wrapped.

 

300f sustained would be hard to do on a driveshaft in the fd. It lives tucked into the ppf and it spins. I don't see that being an issue. If you're worried about it then you can heat wrap the exhaust in that section or make a little heat shield. I don't see temps that high being possible through convection on a rotating object with active air flow, the ppf acting as a barrier and at least a foot of distance between it and the exhaust.

300f is really hot and even on a glowing turbo manifold the radiant heat isn't anywhere near that high. The section of the exhaust thats closest to the driveshaft is so far downstream I wouldn't really worry about it.

 

the other data point is the Rx8 which has a CF drive shaft, and it gets so hot under there they have had at least 2 recalls to keep them from catching on fire, but the drive shaft is fine.

if you're worried a little exhaust wrap would be the easy solution

 

Curious…is there any noticeable difference with a CF driveshaft? IMO our stock DS already seems pretty light, it’s not all that long or big in diameter.

 

I sold an FD and decided to pick up some goodies. Plus I was able to get in on prices before they went up and they offered a military discount. Still wasn’t cheap tho.

There is a lot of feedback about CF driveshafts from other car forums and racing sites. Basically it’s supposed to be a lot smoother and better power transfer to the wheels. Less vibrations and noise. Easier on the drivetrain.

it’s supposed to have all the benefits of an aluminum driveshaft plus more.

from Banzai site:

Aluminum Driveshaft 93+ RX-7 93+ RX-7 3" Aluminum shaft. The 1-piece driveshaft that we offer for the RX-7 is lighter than the stock driveshaft, but is also considerbly more torsional. A steel shaft can torsionally twist 5-7 degrees, where an aluminum shaft can twist as much as 15-20 degrees. This means a smoother ride and better response. Comes completely assembled, balanced and ready to install. Uses Spicer Heavy Duty replaceable U-Joints.

 

the biggest factor re the FD DS is that the U joints are not replaceable. next time yours is out play around w them and you will find they are notchy. as in not good. i was delighted to throw mine in the trash barrel when i switched to a Tremec 6 speed in 2013. i run an aluminum DS from Quartermaster and love it.

 

I had mine out just a year ago in May. I recall checking the u-joints and despite about 132k, they still felt tight. I guess I didn’t notice anything ‘notchy’. I chalked it off to the car living life in a relatively clean environment, not doing any hard launches, and the fact that it’s an IRS and there didn’t seem to be a lot of deflection involved at either end.

 

Since the FD's driveshaft moves very little due to the power plant frame it really doesn't wear out U-joints. I don't think I've ever heard of a case of bad U-joints.

Dale

 

i think i have seen every part of the FD break, except the drive shaft.

 

The notchiness shows when they’re moved to a slightly different angle. As noted it doesn’t move much, especially with a ppf locking the trans and diff alignment. So they tend to just be at the usual spot forever. They wear to that spot and when moved to a different angle then they tend to bind and let go, bind and let go; sort of a notchiness. When the PPF is not adjusted/aligned properly it shows up as a drivetrain vibration. That’s what I always noticed any way. Same with my 2005 RX8 cf driveshaft that has less than 40,000 miles on it. So they don’t fail in a classic sense.

 

Decided to play it say. This should do it. However, I hope that the small magnaflow race muffler doesn't overheat and burn out from being wrapped.

 

you overestimate the insulating power of the heat wrap....

youll be fine

 

FWIW I’ve had good luck with DEI’s HT coating over the wrap. Keeps it cleaner longer and makes it a lot easier to work around if needed.
https://www.eastwood.com/dei-ht-sili...299281180f2592