View Full Version : Carbon driveshafts?
12-13-2004, 12:35 AM
Is it true that driveshafts can now be made out of Carbon Fiber? I heard something a while back about it... eyes got real big... just curious to see if anyone knows anything else about em. I could see them being really good, barely half of the rotational weight of an aluminum driveshaft... wonder how well they'd hold up.
12-13-2004, 12:48 AM
They have been around for quite a while. I have never really investigated them too much. You can get a pretty light chromemoly one for a lot less money. I do know that one recently exploded in a heads up Mustang on the starting line. It shattered his elbow and lodged a whole bunch of carbon fiber splinters into his body. I can't say for sure a metal shaft would have been any better, but it makes you wonder. They are now requireing driveshaft tubes instead of just loops.
12-13-2004, 11:52 AM
Just sold me on NOT getting a CF driveshaft....chromemoly or aluminum sounds like a plan, IMHO. I value my extremeties.
12-15-2004, 08:27 PM
who is reguiring the use of driveshaft tubes over them?
12-16-2004, 04:04 PM
Most of the major sanctioning bodies including NHRA and FFW have either passed or are in the process of passing the rule changes. I don't think they are requiring them just for Carbon Fiber, it is for all materials.
12-16-2004, 04:11 PM
1990-2002 Camaro, Firebird LPE 3 1/2 Inch Diameter Aluminum Driveshaft
The 3.5” diameter LPE driveshaft has a critical speed of roughly 11,000 rpm (over 50% higher than the factory driveshafts). This aluminum driveshaft is 3.5" in diameter and weighs 12.2 pounds. The U-joint centerline to centerline length is roughly 40-9/16”.
In testing performed by General Motors on our 3.5” driveshaft, this driveshaft did not show resonance (hit critical speed) until roughly 237 mph (tested in a 6 speed LT1 equipped F-body with 3.42 rear end gear).
The LPE driveshaft also includes an internal driveline noise suppression system and is high speed balanced to reduce vibrations. LPE recommends this heavy-duty driveshaft for virtually all high speed and racing applications
I bought this one and like it a lot !!! It's come down in price $50.00
12-16-2004, 06:57 PM
where did you get the info on the carbon fiber one breaking? i have never heard this before.has anybody else heard of this happenning>?
son of a vit
12-16-2004, 07:58 PM
i remember people being skeptical they would break...but never one breaking
12-16-2004, 10:23 PM
other than a defective peice, it chould not break,given carbon fibers strength properties and how much stronger than steel it is. it must have been a fluke anyway.im still gonna buy one.
12-17-2004, 12:11 PM
Like I said in my posts, the tubes that are required are not just because of carbon fiber driveshafts and the guy who was injured may have benn injured just as bad or worse by a metal shaft(who knows?). I know plenty of guys who run the CF shafts. My only advice would be to buy one from a prominent company that you can research and make sure they build god stuff(just like anything else). I say this because their are alot of companies these days building stuff like this and selling it for "bargain" prices. A good CF shaft will run about $1000 and up(a chromemoly one can be had for like $300). If you find a CF shaft for less, I would be a little leary of it.
12-17-2004, 02:45 PM
ACPT Carbon Fiber Driveshaft
Driveshaft failure scares us. The thought of the car pole-vaulting at high speeds on a severed driveshaft gives us chills, as does the thought of a flailing broken driveshaft sawing through the car's thin sheet metal floor, and then through our legs. As Project Z has big, sticky tires and lots of power, the strain on the drivetrain is several times greater than that of a stock car. Although the Z has a very strong and robust powertrain, we would still like to eliminate some risk.
Although an NHRA-approved driveshaft loop would help prevent the bad side effects of some of these accidents, the way in which the driveshaft is buried under the exhaust system, deep inside the Z's transmission tunnel, makes such a driveshaft loop impossible to mount in the car.
On the advice of our friend, Adam Saruwatari, we looked up ACPT to make a custom carbon fiber driveshaft for us. The carbon driveshaft has many advantages over the stock steel shaft. First, carbon fiber is eight times stronger, in tensile strength, than steel. It is also much stiffer. This gives carbon composites the potential to be stronger, lighter and stiffer than stock. Our driveshaft weighs 13 lbs., which is more than 14 lbs. lighter than the stock driveshaft. We became well aware of the shaft's weight difference when we dropped the stock driveshaft on our chests and foreheads while removing it from the car: Ouch!
Second, carbon fiber has a soft failure mode. That means, when a carbon driveshaft breaks, it breaks up into a soft, broom-like mass of carbon fibers that merely brush the underside of the car, rather than ripping it-along with your legs-in half, like an enraged buzz saw. This mass of straws is not able to support the car in pole-vaulting maneuvers either--another big gain for safety. Audi recently went to a carbon rear drive shaft in some of its Quattro models for these very reasons.
Third, a carbon driveshaft has give in it. This give can cushion the transmission, clutch and differential, lessening the chance of these parts failing. With the huge amounts of power that we anticipate from our new motor, we need all the help we can get to improve drivetrain durability.
Forth, the woven carbon laminate with its cross plies is virtually non-resonant. Driveshaft resonance is a bad problem with modern cars. If the driveshaft is spun at an speed close to its natural frequency, vibrations can build up to the point where it can shake the whole car, even destroying the driveshaft. Because of resonance, all driveshafts have a critical speed that should not be exceeded. The non-resonant, very stiff carbon shaft is not bothered by resonance-related problems to the same extent as a metal driveshaft. Because of this, staying away from the shaft's critical speed is not as important for a carbon driveshaft.
Finally, a carbon driveshaft can absorb vibrations. The Z is sensitive to driveshaft vibrations. The carbon shaft goes a long way to dampen out these vibrations. For safety and other reasons, carbon driveshafts are making big inroads in both race cars and all-out street cars.
The ACPT driveshaft is a one-piece driveshaft, unlike the Z's stock two-piece driveshaft with its sometimes-troublesome center bearing. The center bearing is known to cause vibrations in higher mileage Zs. The driveshaft has two Spicer U-Joints mounted to an aluminum yoke for further weight savings. If you are into domestic performance, Spicer U-Joints are know for their strength and durability, as well as the ability to be rebuilt.
12-27-2004, 11:28 AM
thanks...but i have never seen a 2 piece drive shaft in an fbody....
12-27-2004, 11:44 AM
I agree...wasn't it the old Imapalas that had a center bearing/2 pc driveshaft?
12-29-2004, 03:04 AM
My 93 camaro has a 2 piece.
12-30-2004, 02:18 PM
I think the V6 camaro has a 2 piece but I'm pretty certain the Z's have a one piece. I know my 2 Z's are one piece and all the other Z's I've come into contact with have a 1 piece also.
01-02-2005, 04:22 PM
i have never seen a 2 pc shaft in an fbody....
01-29-2005, 04:10 PM
The only issue that I see with carbon driveshafts is that they will probably not hold up as well as aluminum or steel. There is no doubt that they're better from a performance aspect but when exposed to oil, road debris, and garbage picked up by other cars. IMO this will eventually eat away at he carbon, causing an early failure in street applications.
02-27-2005, 03:32 PM
Just from that story I read above I dont think I would trust one but the light weight sounds awsome but I would just stick with an alum. one myself and just to make sure I didn't hurt myself or anyone that was close to me or something
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