carbon fiber driveshaft???
I just ordered some heads from them not too long ago and asked about it repeatedly over the last few months and got nothing of substance in return. One guy said supposedly they are being made but who knows. I dont know who is doing them for them. I couldn't wait any longer so I ordered one from ACPT/Powertrain Industries today. Their kit price has dropped from $1450 to $1250. I spent an extra $50 on the high strength, high modulus carbon fiber because I will be boosting on top of the nitrous I am already using soon. I thought you guys might want to know about the revised pricing and high strength option. As for weight, he said a few grams difference. Its a no brainer unless you are NA, in which case I couldn't justify the extra expense with 250-300rwtq.
if you guys want i can host a group buy on carbon fiber driveshafts, im hosting one right now on the facebook forum for aluminum driveshafts through the same people that made my carbon fiber driveshaft. we'd need 5 people though. if they are out there post up and ill make it happen. i have one guy who would get in for sure, so you really just need four.
it took them about 2 weeks to make my cf shaft. price for one unit was 1250 (1300 if you want the high modulus, high strength option i got), so i would suspect something in the range of 1150-1200, shipped. minimum number of deposits would be 5.
def looking forward to my alu shaft from jakes group buy. I wanted a carbon shaft but would rather put the extra cash into other upgrades/issues. I wonder how much of an actually difference the two would have anyways.
My understanding is the only main difference is power holding. IMO if the AL will hold your power plus 15% buffer I would go that route. The cost is the main thing holding me back from getting a CF one but none of the AL ones will hold enough TQ for my car.
the difference comes from reduced drivetrain loss... its as simple as that. power holding might be a result of that, but its certainly not the only mechanism for increased power. rotating losses arise from moments of inertia... of which M (mass) and R^2 (radius squared) are the primary factors (along with a shape constant). if everything in the drivetrain weighed nothing, or very infinitesimally small, then there would be no drivetrain loss and a chassis dyno wouldnt read any different than an engine dyno, assuming the same type of dyno and calibration settings and whatnot. since neither situation is possible, the best thing you can do is to reduce it. fwd cars, like the maxima, show greater hp/tq numbers with the same motor/combo than the rwd g35's do. the reason is there is less power lost in the drivetrain. there is less mass tied up in the sum of the rotating parts that ultimately drive the wheels and that is the difference. the engine is making the same power in either case, it just that more of it gets to the ground. if you go put heavy, wide, cast, chrome 20's on your car, you will slow down due to increased rotating mass. if you go put lightweight 15's and race slicks on your car, you will speed up. in a perfect world this would mean a consistent across the board gain, and is best explained like that, but thats not the case in reality, as the loss generated by some rotating components increases with rpm more than others. as i have seen in denchan350gt's dynos with his aluminum shaft, there was a solid 10-20rwhp from 4000-7000 on hill's garage's dyno (i believe dyno dynamics). for reference, this was on a 300rwhp na de combination. i suspect a turbo car would benefit from increased turbo spool times due to the car being more responsive in the lower gears.
