Composite drive shafts have been used in formula cars for years. The most common reason for their use is for high strength and stiffness with very low weight. To reduce vibration due to the length of the driveshaft, sometimes it has to be split into a drive shaft and coupling shaft, which introduces a support structure, bearings, u-joints, etc. These extra parts not only add to the weight of the car, but are also more expensive. Therefore, a composite drive shaft can be less expensive than a traditional steel/aluminum material.

Typically, carbon fiber parts are made up of several different layers to form a laminate. These layers are oriented with the carbon fibers running in various directions to be able to withstand the load as efficiently as possible. There are often several layers with fibers that are oriented at a 45 degree angle to best withstand the torque.

Also, carbon fibers are usually infiltrated with a thermoset resin. Both of these materials perform very well under high temperature and corrosive environments.

To get back to the point, your stock driveshaft will do the job, but a well-designed aftermarket carbon fiber driveshaft will do it even better, resulting in better performance.

-SLCevo

 

Funny, Kam and I were just talking about something like this today. The only experience I have with aftermarket drive shafts is with my friends 93 Mustang GT, it actually helped driveability tremendously in that application.

 

I do not mean to offend anyone here but what is the f**king point in spending 1K plus on a carbon driveshaft (which I think are grate by the way) and saving 10 to 20 Kg when you still have a full interior in the car? I mean if you want to save some weight ditch all the sound interior and sound deadening and fit some nice fibreglass seats and you will loose a lot more than any driveshaft could ever do. And it’s not as though the drive train is exactly weak on the Evo anyway (apart from the transfer case)!
As I said I don’t want to offend anyone but I guess what I’m trying to say is it seems extreme when there are many other things you can do to give much better performance gains at a much lower price. Race or competition car I could see the point but a road car? I don’t think so!

 

from the dsm world, cf driveshafts from ACPT were said to reduce ET's by up to .3 in the 1/4. That's coming straight from ACPT's website.

However, they've been less than helpful in setting up a decent buy in for most dsm guys, we'll see what they do for the evo's.

Another thing is that the CF driveshafts they sell replaced all three sections on the dsm's, causing bad pinion angles. An aluminum driveshaft sold by the driveshaftshop.com people just replaced the first two sections. I question the CF durability from stuff like rock chips that would initiate the mentioned brooming effect. The CF people at ACPT say that CF 'soaks' up the vibration so well that pinion angles don't matter and it's safer in the event of a break. However, the people at driveshaftshop say that the pinion angle can't be cheated on and would accelerate wear in a single peice unit and their product is cheaper too (~750).

Basically, it seems like a great item for the car, because it reduces mass and should prevent damage to the rest of the drivetrain. But the drawbacks appear to be durability and cost.

 

yeah, losing weight in the driveline is better than just losing some weight in the interior anyways... any weight that you can drop from the drivetrain is good in terms of acceleration and what not

 

I understand the benefits you will see in the response by using a lighter prop, but by lightening the car as a whole you will not only see gains in acceleration but also braking and cornering. Don’t forget a racers worst enemy is weight, and there are much easier and more effective ways to do it than a prop! But the whole carbon prop shaft thing is a good idea on something like a stripped out road racer. What about half shafts? Anyone do them in alloy or even produce hollow ones?

 

so my question then why would car manufacturers like mazda use them in their rx-8 ? if there were no significant benefits?

 

Every rotating part in your driveline contributes to drivetrain loss in some way. The driveshaft is one of those parts. Lose weight on the driveshaft and you not only lose some rotating mass, but gain wheel hp. It's just one step in making the car and/or drivetrain lighter and I agree that it shouldn't be the ONLY step, but it's a good one.

 

For one thing, if you keep the interior and lose weight in the drivetrain, you are seeing improvements by lightening some rotating drivetrain parts, you are benefitting from an overall lighter car, but you are also benefitting from still having a full stock interior in the car.

I drove my Evo 28,000 miles in the first 12 months. If I was to lighten up the car, I would want to do it in ways that don't make the daily commute painful or louder. Unless your Evo is a weekend car, having an interior is a big benefit!

SC~

 

yeah i agree secret chimp and phenix, does anyone know if they have lightened half shafts?? that is another part that would be great to get. Somebody said that Mine's is either working on a carbon driveshaft or makes one, does anyone know for sure?

 

Lightened Brake Rotor - Carbon Ceramic anyone?, Lightened Flywheel & Clutch, Lightened Rims & Wheels, Lightened Driveshafts, Lightened Half Shafts all offer near total improvements in the car performance without any downfall.

The only downfall is subjective and that is throttle response is much quicker, so letting off the gas results in less momentum driving the car and will not hide abrupt throttle application. You're smoothness or lack of is apparent, no longer hidden.

I think all those lightened along with some Titanium bits, exhuast, strut bars, lug nuts, I'm hoping to get an MR below 3000 lbs and retain all functionality and comforts.

Lightening is easy. Lightening while retaining all functionality is the trick.

I can get your car down to about 5lbs if you want. I just hope you like running down the street holding your car inbetween your hands and making engine noises with your lips... Bttthhhhttttt, Bttthhhhtt, Pish, Pish, Errrrrr, Vroooom, Pish,.. at least I think the steering wheel only weighs 5 lbs.

 

bump.. does anyone know??

 

I see your points and I knew that my statement would course some of you to get all up tight. It wasn’t intended to do that, it was merely to out that there are much more effective ways to reducing the weigh of your car. I agree that any weight loss in the drive train will help in acceleration and response of the engine, and I understand how important that response is in a quick turbocharged road car. I am sorry! Honest.

 

I just spoke with DriveShaftShop.com and they are working on a two piece aluminum replacement rear drive shaft for the EVO VIII. The factory piece is a three piece design. They claim it should weigh around 15lbs less. This will be a great mod!

 

cool