[trackbird]

I know there was some interest in these on the board, and we have a thread about it in one of the forums right now. So, if anyone is interested.

I just hung up with ACPT. If we can GP 5+ of these, they will be $200 off of the regular $795 and $40 freight (48 states of the US only). Meaning, $595 each (plus shipping).

The tech info is this:

Aluminum yokes.
800 ft lbs torque rating
3 1/4" OD
12,500 RPM critical speed

For an additional $100 you can have (and I know you guys will love this one).....

3 3/4 OD
2000 ft lbs torque rating
14,500 RPM critical speed


Anyone interested?

[trackbird]

I just hung up with the tech guys at ACPT. The info you seek is this.

The 3" version (3 1/4") broke the yoke ears off at 2500 ft lbs of actual applied torque (in a test fixture), they've never been able to break the actual shaft, the U-joint or yokes break before the carbon tube. It weights about 11 lbs

The 3 3/4 inch version handled 6000 ft lbs applied to the actual driveshaft and something (besides the shaft) broke in that case also. It weights about 13-14 lbs.

He said they set the limits based on the limits of the U-joints that fit these shafts. It's not so much a function of the actual shaft, but the attaching hardware. Meaning, if you're u-joints fit it, and you haven't broken them, you won't break it.

All better?

(IMG:http://www.frrax.com/rrforum/style_emoticons/default/beerchug.gif)

[johns68]

I just hung up with the tech guys at ACPT. The info you seek is this.

The 3" version (3 1/4") broke the yoke ears off at 2500 ft lbs of actual applied torque (in a test fixture), they've never been able to break the actual shaft, the U-joint or yokes break before the carbon tube. It weights about 11 lbs

The 3 3/4 inch version handled 6000 ft lbs applied to the actual driveshaft and something (besides the shaft) broke in that case also. It weights about 13-14 lbs.

He said they set the limits based on the limits of the U-joints that fit these shafts. It's not so much a function of the actual shaft, but the attaching hardware. Meaning, if you're u-joints fit it, and you haven't broken them, you won't break it.

All better?

(IMG:http://www.frrax.com/rrforum/style_emoticons/default/beerchug.gif)

Based on this, I have a question: The main benefit here seems to be the safety involved in a catastrophic failure, but the testing indicates that the u-joints or yoke ears will fail long before the shaft. So in a real world failure, you will not broom the shaft, but break a u-joint or yoke ear and drop the driveline just like with a metal unit. Assuming a driveshaft loop, it seems to me a cf tube rattling around in the tunnel will wreak as much havoc as an aluminum one. Assuming no loop, and a broken front joint, wouldn't you now have a better and stronger lever hitting the asphalt and lifting the car? One with a lot more flex and rebound potential so it is less likely to bend or break and therefore more likely to lift the car?

I'm not a materials science guy , so don't know if the linear force from an impact will effect the cf differently than the torsional force it is (well) designed to resist, but it seems any safety benefits would be non-existent over aluminum or steel.

So how far off base am I?