Carbon Fiber Drive Shaft Specifications

[casuprock]

The following information is for a one piece 2G carbon fiber drive shaft fabrication. I am providing this data because I had significant trouble ordering the shaft through Vivid Racing and there were communication issues with length dimensions between the fabricator and Vivid. Not wanting anyone else to go through the pain of waiting and/or frustration. I would suggest contacting ACPT directly to have your shaft manufactured. I should add that ACPT was quite good with correcting a length error with this shaft.

- The fabricator will need you to cut your stock transmission yoke off with ~4" of the stock drive shaft still attached. Say goodbye to your stock drive shaft.
- The fabricator can use an aftermarket flange yoke for the rear side. Mine used a Dana Spicer Flange Yoke 1310 series and Dana Spicer U Joint 1310 series.
- The fabricator will ask for distance between the U joints on the fabricated shaft. The dimension used on mine are 76.25" between U joint centers.
- The length of the carbon fiber shaft is 70.5".
- A rear adapter (provided by the fabricator) connects the aftermarket u joint assembly to the stock differential. This connects the stock rear diff bolt pattern to the aftermarket u joint assembly.

Why would you want a composite drive shaft? (Besides a morbid fascination with weight reduction.)
http://www.dsmtuners.com/forums/newbie-forum/382899-stock-drive-shaft-weight.html

How much does it weigh: ~17lb. The stock 3 piece weighs ~36lb

Primary benefit: Increasing torsional damping reducing strain on trans, reducing I*alpha torque loss during acceleration.

What does it look like installed?

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[wishin4nX]

How will it hold up to launches??

 

[hubz91talontsi]

Well, i know we have a hard time finding 1pc shafts because of the pinion angle. Was this improved or is there still a 5 degree difference? 2 in the front 7 in the rear.

 

[casuprock]

How will it hold up to launches??

Will tell you soon... They use these on garbage trucks, etc, so I'm assuming it will be just fine on a little car.

Well, i know we have a hard time finding 1pc shafts because of the pinion angle. Was this improved or is there still a 5 degree difference? 2 in the front 7 in the rear.

The angles are visually minimal, I have not measured. I doubt they're that extreme, it was a very straight connection, certainly not 7 deg... If I had to guess, they're <2 deg.

 

[knochgoon24]

What are the angles between the transfer case and the drive shaft, and the angle between the drive shaft and the rear end? From what I've seen, the reason DSS uses a 2 piece design is because the angles were too different. I can't find the source of that info at the moment though.

EDIT: Looks like I took too long to type.

 

[burkgonzo]

This is one of the things I will stand back and watch, cause if something breaks its going to be violent.

 

[casuprock]

What are the angles between the transfer case and the drive shaft, and the angle between the drive shaft and the rear end? From what I've seen, the reason DSS uses a 2 piece design is because the angles were too different. I can't find the source of that info at the moment though.

EDIT: Looks like I took too long to type.

It's a valid question. Aluminum drive shafts have problems with fatigue, so angles would put a bending load on the shaft and might (postulating here) cause fatigue problems prematurely with a one piece aluminum shaft. Carbon fiber composites have better fatigue properties than any metal.

For better or worse, this is an experiment. We will see what happens and try to answer the question with real info. John Shepard used to run a carbon shaft if I'm not mistaken... I would like to hear his input (i.e. how it fails or if it fails) since he was surely pushing the limits. If I had to guess, the most likely failure mode will be delamination of the yoke bonds into the composite shaft at some unholy torque number.

 

[MY1GDSM]

Just Curious,
It seems like its real close where the rear carrier bearing mounts
Did you have to cut into it for clearance?

 

[knochgoon24]

It's a valid question. Aluminum drive shafts have problems with fatigue, so angles would put a bending load on the shaft and might (postulating here) cause fatigue problems prematurely with a one piece aluminum shaft. Carbon fiber composites have better fatigue properties than any metal.

For better or worse, this is an experiment. We will see what happens and try to answer the question with real info. John Shepard used to run a carbon shaft if I'm not mistaken... I would like to hear his input (i.e. how it fails or if it fails) since he was surely pushing the limits. If I had to guess, the most likely failure mode will be delamination of the yoke bonds into the composite shaft at some unholy torque number.

I found the source:
The Driveshaft Shop | MITSUBISHI 1995-1999 Eclipse GSX / Talon TSi AWD 650HP Aluminum Driveshaft

The front angle was 2 degrees and the back was 7 degrees (not good), the problem is the rear joint would move more than 2 times as much as the front and cause a very nasty vibration. The AE-7 manual of Automotive engineers doesn't recommend any driveshaft to have more than a 1 degree difference from one operating angle to the other (this would be a 5 degree spread). Some of the carbon fiber shaft company makes this shaft but the angle problem still remains and in our opinion will cause the fiber to tear over time and fail.

 

[casuprock]

Just Curious,
It seems like its real close where the rear carrier bearing mounts
Did you have to cut into it for clearance?

I didn't have to cut into the sheet metal, however I cut the bolts out... they were stripped anyway. while i was removing the stock drive shaft, I noticed that the threads on the bolts holding the shaft bearing were gone... I guess from years of vibration and corrosion. the threads just disintegrated when I removed the stock drive shaft.

As it stands, there is about 1.5" of clearance which should be fine. The engine/trans doesn't move much, I have prothane mounts so it's range of motion is a lot lower than normal.

I found the source:
The Driveshaft Shop | MITSUBISHI 1995-1999 Eclipse GSX / Talon TSi AWD 650HP Aluminum Driveshaft

Aluminum shafts have fatigue problems, I could be wrong, but I suspect that this is misinformation about the carbon shafts. I have to figure out how to measure the angles on the joints... find out what they really are.

ACPT has a couple of publications describing the applications and properties in drive shafts.
Composite Driveshafts: Technology and Experience

Here's a SN curve comparing metal shafts to composites:

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[Bender]

Another reason you can't go with a single piece aluminum shaft is the harmonics it will experience during rotation. Carbon fiber's critical speed is higher than any metal/alloy.

 

[Slippi84]

WHy mess with measuring. ACPT has upgraded yolk DS's where you doin't have to mess with measuring or your stock shaft. I own the 1pc CF driveshaft for the 1g with a upgraded yolk and it is a thing of beauty.

Couple things one , it is much thicker than stock much like the DSS Driveshafts so you have to take that into consideration when talking about strength. The WRX guys run these and love them. They have already been proven to be successful and work. Shep ran one (may even still run it) on his purple 1g and Jake H (Topstreet/JHRacing) ran one in his 9.xx red talon(I actually own the unit from his car).

To the guy that said he wants to sit back and watch for when it fails....you really have no idea what your talking about. One these are strong and don't break unless something external is thrown into the equation and two IF it were to break it is 1000000 times safer than stock or aluminum because the CF splinters and would just break apart and if anything give the bottom of your car and the street a very good cleaning much like a drive threw car wash scrubber.

ACPT Advanced Composite Products & Technology

Save up your pennies and here you go
ACPT Carbon Fiber Driveshaft Mitsubishi Eclipse 93-99

 

[MY1GDSM]

WHy experiment there is a company that already makes these and it isn't vivd. ACPT makes 1pc and 2 pc CF driveshafts for 1g's and 1g's. I own the 1pc CF driveshaft for the 1g it is a thing of beauty.

You should Re-Read his first post...

 

[Slippi84]

You should Re-Read his first post...

I read it. I'm aware that he knows about ACPT and that vivid is just a reseller of these and that you can deal with them direct. What I"m not sure is why there was measuring and cutting needed. You can get the shaft with a ugraded input shaft that is the same size needed to hoo up to a shep or dogboxracing tcase and have a badass shaft with all that measuring and cutting.

 

[MY1GDSM]

Oh well, that's not the way what you said read to me

 

[Slippi84]

Better?

 

[hubz91talontsi]

Well, unless a 1g has different angles than a 2g I'm sure that there is a 5 degree difference. It may look small but it's there.