I still have the c/f over alloy tailshaft that I have been using in my race car for over three years with absolutely no problems. I have heat shield and my custom exhaust is not close to tailshaft, no cats or resonator boxes. Running 1.5 bar boost the exhausts get very hot for certainly a shorter time than your ten hour trip, but probably under a much higher strain during that period. IMHO I would go with the moly option for a road car.
Carbon wrapped I think would be less prone to failure as you don't have that torque between the yoke and the shaft. I had a heat shield too made of that ACL heat shield stuff (that you see in Falcon turbos etc) with a layer of thermaflect backed fibre based thermal barrier mat. I suspect heat soak is the issue rather than latent heat. Just hypothesing but I think race car would potentially get away with this as while latent temps may be higher it's running for much less time and less potential for heat soak. I ran the shaft for two years before the issue came back, and both times it has failed the circumstances have been very particular.
And so an end to the saga... I have since fit a massive chrome molly shaft which has been upgraded in every which way possible. On the downside I've put another 5.6kg into the driveline; on the plus side I don't expect to have any problems (with the tail shaft) again. Ever. PST were good enough to accept the carbon shaft back for repairs once again, but upon receiving it and inspecting the failure admitted that they were at a loss as to how to prevent it happening again. They offered me a choice of repairing the carbon shaft or sending over an ally replacement, I took the ally one as I would feel much more comfortable selling it to a member compared to selling a repaired carbon shaft. At least this way I can offset some of the big $$ i outlaid for the busted shaft. I have to emphasise that Mark Veldhuis from PST has been awesome about all of this. I bought the shaft some 7 years ago via a third party and most manufacturers would have simply told me to **** off at this stage of the game. Credit where due and their integrity has been much appreciated. I wouldn't hesitate to recommend their services to anybody needing a Z32 tailshaft (just don't get a carbon one...!).
Both failures were at the same end, he just said that having failed twice he was at a loss at what to do about it. It was very clear that the issue is heat though, the bond had softened enough for the yoke to spin a quarter turn against the shaft before cooling and reselling. No two ways about it heatsoak is what does it.
Didn't know about the difference in bonding . Can you post up the vid? can't find it . 4728nm vs 1376nm wow! expensive string .
That's the one I'm talking about -the fibres are knitted between the yokes. With the shafts like you have and I used to run have the shaft and yokes are separate pieces and are glued together.
This seems to be a problem only with the PST CF driveshafts. I have two ACTP CF driveshafts one on the street car and one on the race car. Both would be subject to the same sort of heat as Rob's car, I have no wrapping or special heat shields. The first one I bought and fitted in 2003 - ten years ago on the street car and it was a daily driver for 5-6 years after that. Its still going strong. The second one I fitted to the race car was actually second hand and had a bit of a gouge in it - I never expected it to last but that was in 2008 and its seen plenty of track time since then. Good to hear PST standing behind their product, but I have heard not of any such problems with ACPT so could be a design or manufacturing problem.
ACPT have a much worse track record here.... A member on this forum has had one shatter as have a few skyline owners.
Ran across this old thread while doing some research, in case anyone is interested it seems that the CF tail shafts discussed here may not have used the most appropriate adhesive to bond the CF to the metal yokes, particularly in regard to heat stress. The best adhesive seems to be a single epoxy type that is cured in an oven using a predetermined heating cycle, as you can imagine the resulting bonds are highly heat tolerant as well as being very strong. I'm guessing that the problem ones here may not have used that process, the oven would not be cheap to buy and install.
