Just wondering if anyone has/had a carbonfiber driveshaft and any good/bad comments. Thanks

 

I've just installed one, so can't comment on it doing anything for the car. Cool having one though for that thought in the back of your mind, knowing you've went over the edge in mods and if your wife found out the cost of it, your sleeping in the car

Tim

 

lol
how much and who makes it?

 

www.rx7.com almost 1k. Does anybody know what the factory d/s wiegh??

 

http://www.rx7.com/cgi-local/3catalog.cgi?cat=2&part=6
10.6lbs
Thats sweet.

No idea on the weight of stocker.

 

Tim have you been able to drive with it on yet

 

Rx 8 is suppose to have a CF driveshaft stock

and the new 350Z has one too

 

Wael El-Dasher has one. E-mail him for his experience with it. His website is efini.net

 

Stock driveshaft is very small and light. There is no need what so ever to get a carbon fiber one with the exception of saying that you have one. If you drag race, you'll never break the stock one so don't worry.

 

Here's where you can get the made.

http://www.iedls.com/driveshafts.html

 

so ernieT even if you upgrade all of the other driveline components that break, the driveshaft wont break at 600+ whp and slicks?

 

Nothing is impossible, but Ari, Demetrios K., and Ray Wilson (all have low to mid 9sec cars with well over 600rwhp) have not broken a driveshaft. Ari, Im not positive, but Demetrios and Ray, Im certain of. The driveshaft is so small on our cars, everything else would break prior.

 

ErnieT i was thinking that the reduced weight of the driveshaft would be able to transfer more power similar to a lightened fly, pulleys axels, etc. I thoght that any moving parts that could be made lighter would be benificial. Please correct me if im wrong but every lb saved on a moving part is like saving 3 lbs on a non moving part. I could be wrong. Please write back!!!

 

You are correct......but, is it a couple lbs. worth $1000?? If you were a hard core drag racer, then I'd say yes, otherwise your money is best spent somewhere else.

 

Jahoo88 did this too when he converted to a TII, If memory serves me right. You might want to PM him for his experiences.

 

isnt is also good because it absorbs some shock when the clutch is released, i though that and when they break they feather out and dont tear stuff up compared to a steel shaft where they just shear apart and bounce off stuff under the car.

btw how do i fix that my sig comes up everytime when i reply to a message

 

Had mine on for a few weeks now and can't say that it was worth it since I did a 4.33 gear at the same time. Total weight savings, not even 3 lbs. So there is a reduction in rotating weight, but since its so close to the center, unlike a flywheel whose weight savings are from the out edges, further away from the center, it won't free up as much hp.

I was running out of things to buy for the car so I got a CF driveshaft. I would do it last and spend the 900 on something else, either for power or the reliability mods.

Tim

 

If it breaks it will shred apart, not catapolt your car into the air like a metal one, Or come through the floor and hurt you. Thats why they make them.

 

If you are running that fast, as to where you drive shaft would break, you should have a DS Loop installed. These basically cradle your DS without allowing any damage to be done. Good mod IMHO.

Jeremy

 

Carbon shafts are supposed to reduce the shock on the drivetrain when you dump the clutch (which might help reduce diff/axle breakage). I doubt the rotational inertia difference is a very significant effect since the diameter is pretty small. sbertolone posted this same info already, I am just agreeing with his post on the theory side of things. Perhaps these factors aren't that important if the big drag racers aren't using carbon shafts, however.

-Max

 

CF driveshaft will have practically no effect at all on the rotational inertia / driveline losses. First, the diameter is incredibly small and close to the center of rotation. Secondly, the stock piece is already quite light. Third, the weight is after the clutch and tranny which makes the effect even smaller than if the couple of pounds were on the flywheel. The effect of heavy wheels on acceleration is usually overstated, and the effect of the CF driveshaft would be far, far less than wheels.

Even on a couple of equivalent RX-7's (one with the CF and one with the stock steel shaft) jacked up so the rear wheels spin freely - I'd be VERY surprised if you could measure a difference in acceleration of the rear wheels.

There's really no reason to use one in a FD unless you're just looking for something to buy for it. No measureable performance benefit.

Wade

 

alot of auto manufactures use them as a kind of energy absorber for the engine/trans in a head on collision, of course the car would half to be designed around this.

 

The rotational mass difference between the two drive shafts is not EVEN worth bothering with. The only benefits of a Carbon fiber drive shaft are -
1)It will absorb shock loads from the trans to diff. A very good thing
2)If it breaks, it should not catapult your car into the air, destroy the drive shaft tunnel or chew up your ARSS A very very good thing ( No drive shaft safety loop necessary. )

 

I'd read somewhere that those cars only have carbon reinforced driveshafts.... I'm guessing that means that they're not fully carbon?

 

I think my stock unit weighed right under 14 lbs, say 13.5. The CF was at 11 lbs. Maybe 2.5 to 3 lbs saved.

Tim