Aluminum driveshaft Whats the deal?

[bigbadjim]

So whats the big deal with an aluminum driveshaft?

Weight saving is the obvious reason. But are they stronger? I presume they use the same u-joint as a stock driveshaft? So other than a lighter driveshaft, what am I gaining by spending $300 on one?

Also which brand to go with? Has anyone bought one lately, and where did they get it?:SNSign:

 

[Gearbanger 101]

Stronger, lighter and don't fly apart at high RPM like the "stock" steel drive shafts do. They also reduce or eliminated the inherent driveline vibration often associated with steel drive shafts.

I lucked out and got one from a Lincoln Mark VIII, but you Mustang guys won't get off that lucky. You'll have to get one from the aftermarket.

Try this....
http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=1170

 

[TweekedGT]

It depends on where you want the car to be. If you are looking for a full weight, high horsepower street car, or an all out race car I wouldn't go aluminum. For just a fast street machine you can go with aluminum. Here's what a manufacturer of aluminum driveshafts cautions:
"not all applications can utilize an Aluminum driveshaft successfully. We do not recommend that you use a 6061-T6 aluminum shaft in heavy high performance vehicles or race cars with clutches or trans brakes. The HD Aluminum driveshaft is better designed for that kind of abuse. High performance street cars and race cars can reap the benefits of DENNY'S HD ALUMINUM at a very reasonable cost. Heavyweight vehicles, 3400 lbs or greater, with clutches or trans brakes should seriously consider the track proven abilities of our NITROUS READY steel driveshafts for total reliability."

http://www.dennysdriveshaft.com/html/hd_aluminum.html

Don't mind the sales pitch in there. I know many drag racers will not use aluminum drive shafts due to there inability to handle big torque levels. What that means is relative I guess. What is big torque. I'm guessing you can probably get away with 500tq+ with no problems, just a guess though, the yokes will end up being the weakest link. I watched an aluminum driveshaft shatter on a 750hp Chevelle right off the starting line 2 years ago.

 

[bigbadjim]

I'm still not convinced about the aluminum driveshaft. I'm thinking they are mass produced and probably not much stronger than the stock one. Just lighter....

So how long will my stock driveshaft hold out? Stroker engine making 300-400hp plus a 100-200 shot of nos?

Hmmmmmm..... I do have a safety loop installed...

 

[351LX]

I read somewhere that the AWD Aerostars used an aluminum driveshaft the same length as a fox Mustang one.

 

[Red2000GT]

I don't think you gain any strength,just slightly less rotating and static weight. Biggest difference I've heard about was the reduced driveline vibration. That's gotta be better for the engine and trans and rear end.

 

[RAD]

with aluminum driveshaft do I lose MPG on the highway ? and you guys consider carbon fiber driveshaft? I know is expensive but what about strength ?

 

[bigbadjim]

I don't think you would gain squat for fuel economy...

As for carbon fibre, thats another part for weight saving only...If you read in the above link from that shop selling custom shafts, the guy says that carbon fibre driveshafts are pressed together with glue. Glue? Thats what I was thinking.... Can't see those being strong??

 

[Gearbanger 101]

I don't think you would gain squat for fuel economy...

As for carbon fibre, thats another part for weight saving only...If you read in the above link from that shop selling custom shafts, the guy says that carbon fibre driveshafts are pressed together with glue. Glue? Thats what I was thinking.... Can't see those being strong??

Yes, but what makes them so strong isn't necessarily how the pieces are put together, it's their design and the carbon fiber material that makes them work so well. Not only are they the lightest of the bunch, but when you dump the clutch while using one, not all of the energy is transferred through the shaft all at once like it is with a steel or an aluminum shaft. The carbon fiber units tend to absorb a lot of the initial shock through that’s sent through the drive line. Shock that could normally break the slicks loose on a hard launch pr to a more serious extent, the U-joint or the shaft itself!

 

[RAD]

Yes, but what makes them so strong isn't necessarily how the pieces are put together, it's their design and the carbon fiber material that makes them work so well. Not only are they the lightest of the bunch, but when you dump the clutch while using one, not all of the energy is transferred through the shaft all at once like it is with a steel or an aluminum shaft. The carbon fiber units tend to absorb a lot of the initial shock through that’s sent through the drive line. Shock that could normally break the slicks loose on a hard launch pr to a more serious extent, the U-joint or the shaft itself!

hmmm so carbon fiber shaft isn't better then aluminum? oh and I thought with either one cruising on the highway when you let off the throttle car will slow down faster due to lighter shaft which will lead to burning more fuel cause you have to keep your foot on the gas

 

[Gearbanger 101]

hmmm so carbon fiber shaft isn't better then aluminum? oh and I thought with either one cruising on the highway when you let off the throttle car will slow down faster due to lighter shaft which will lead to burning more fuel cause you have to keep your foot on the gas

I wouldn't say that the carbon fiber shaft isn't any better than the aluminum....just more suited to a different purpose. The carbon fiber shaft would be better IMO for a road racing style application, where power application remains more constant and every little reduction in weight to the power and drive train counts….not to mention the carbon fiber shafts critical speed is higher than both the Steel and aluminum shafts, which would make it better suited for high RPM application. An Aluminum shaft would be better suited to moderately high powered cars (under 700hp or so) and daily drivers, for its ability to combine both high strength, and high critical speed, while still providing lower rotational mass. The custom steel shafts (and no, the stock steel drive shaft doesn’t fall under this category) should be held at bay for the ultra high horsepower cars that will really be shocking the system with high horsepower and high traction applications. And since their usage is limited to short, quarter mile blasts, and not sustained duration of high RPM, the trade off of it’s lower critical speed characteristics isn’t a problem.

Another point to bring up, is as great as the carbon fiber shafts are, they're still subject to rot over time under continuous exposure of the elements (unlike the aluminum or steel shafts) and carbon fiber has a tendency to shatter with impact (which wouldn't bode well in the accidental case the driver encountered some road debris). Yet one more reason they probably shouldn’t be considerer for daily driving status.

As far as reduced fuel economy is concerned.....I'd say your theory is a stretch at best. The lighter rotational weight of the shaft would have next to no affect on the vehicles fuel economy. Factors such as total vehicle weight, wind resistance, gearing, wheel/tire weight, etc would far overshadow the effects upon deceleration that the usage of a slightly lighter drive shaft. On the other hand, any additional weight you can eliminate upon acceleration (aluminum flywheel, lighter wheels, lighter drive shaft) all have shown a measurable advantage in performance.

...and besides, whatever theory presented that the lighter shaft might reduce fuel economy upon deceleration can also be used in order to improve fuel economy upon acceleration, since the lighter drive train components would require less horsepower from the power train to operate. The requirement of less horsepower, would also mean the consumption of less fuel.....however slight.

 

[RAD]

Looks like I gonna get an aluminum one , thanks for info