Experience with one-piece driveshafts?

[99svtlightning]

i read somewhere, that even though the BMR carbon fiber was lighter then the aluminum, it would not produce the same power gains. this is because for it to be very strong, it has to be thicker than the aluminum one, and this creates more rotating mass. so even though its lighter you will see less gains from it. is this correct?

Intersting idea, not sure how to prove it other than a back to back test. Steel shafts are smaller in diameter than aluminum, but the aluminum is still beneficial. I'm not sure at what point the size vs. weight is becomes practical.

 

[8850]

Intersting idea, not sure how to prove it other than a back to back test. Steel shafts are smaller in diameter than aluminum, but the aluminum is still beneficial. I'm not sure at what point the size vs. weight is becomes practical.

If these shafts were made from 7075 aluminum they could be the same size as the steel. They would be even lighter than the curent 4" diameter aluminum shafts. The price companies are charging they should be made from 7075. It is a more expensive aluminum but as strong as most steels.

 

[official_style]

pulled the trigger on the powerhouse one. are these things any less strong than the stock driveshaft?

 

[PDXStangDude]

i read somewhere, that even though the BMR carbon fiber was lighter then the aluminum, it would not produce the same power gains. this is because for it to be very strong, it has to be thicker than the aluminum one, and this creates more rotating mass. so even though its lighter you will see less gains from it. is this correct?

There is an article in a mustang rag that talks about this. The driveshaft has to be engineered for both weight and diameter. If the diameter is to big then the inertia from the larger diameter driveshaft will reveal no gains in horse power. I'll try to find the rag I read it in.

 

[V8JamesGT]

I would be intersted in knowing how different driveshafts compare as well. Maybe some before and after dyno results and quarter mile times...

 

[red05mustang]

Interestingly enough the BMR weighs in at 20.7lbs vs the aluminum at 19lbs. The question becomes does the added dampening effect of the carbon fiber offset the slightly lighter weight and possibly (unconfirmed) smaller diamiter of the aluminum. The stock weighs about 42lbs. CF about $1000 vs $700 (not the ranger cut down) aluminum. Should it snap the CF will be much safer for both the car and the ocupants. While it dosent seem like much the aluminum's lighter weight probably makes a little more HP if they are the same diamiter. Figure its something like a 7% weight reduction relativly however there wont be a 1:1 corilation with HP gain. So if the CF gains 15rwhp the aluminum might gain 16 or 17. However this is all just speculation. We need a back to back test.

 

[1fastz]

shafts.

All you have to do is get it. There is no reason for any more questions about it. Your drivetrain will lighten up substantially. We raced a guy with a Kenny bell blower and nearly the same hp, same gears only he had a stock shaft and a steel flywheel. The guy's car had QA1 high end shocks, control arms, and other suspension work. We consistantly killed his 60 ft times all day with nothing more than Steeda springs on my car for suspension mods. All because of the lighter rotating mass.

UM actualy you are dead wrong lighter rotating mass is WORSE for sixty foot times and better for acceleration when the cars moving.

the most likely reason your sixtys were better is the severe torque the KB makes causeing him to spin some.

when you leave on slicks the heavier rotating mass of the heavier drive shaft would hit the tires harder and there for if you have enough traction the car would sixty foot quicker..

however the stock shaft is crap and tends to come apart with hard use on drag tires.

psiperformance.net is a local shop to me that sells them as well 549 for complete kit everything to install it.

I run one of the aluminum shafts they sell and I regularly cut 1.50 sixty foots on 28x10.5 slicks leaving at 5500 rpm with no issue as of yet behind my cars 549 rwhp.

they also offer a full steel shaft for 409 wich is so much smaller in diameter then then aluminum that it only weighs 4 pounds more and is prety much indestructable and capable of 1000 horsepower all day

 

[anthony05gt]

The Kenny Bell car and my car barely spun at all on the launch. Englishtown's track was prepped like no other and we both had Mickey's. Justin Burcham and I both attribute the better 60 ft times to the aluminum flywheel and driveshaft. These cars just love that combination. Most drivetrain specialists will tell you not to use an aluminum flywheel until you're at or around the 600hp level. Justin talked me out of that way of thinking for this very reason.