How much can an aluminum driveshaft take?

351c-ya

New Member
Mar 2, 2004
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Oceanside, CA
I was considering going to an aluminum driveshaft when I convert the tranny to a 3550; since I'd have to have the driveshaft shortened anyway. First, is this a worthwhile upgrade? 2nd, how much hp/torque can an aluminum driveshaft handle. I've got a 351 Cleveland, currently at 266 rwhp and 327 ft/lbs torque with an FMX and 3.25; and plan on getting it up to 325-350 rwhp. Should I just shorten the current driveshaft, or switch?
 
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I have seen several vendors state in their catalogue that they are not recommended for drag racing, or, has not been tested for drag racing, so, I would say for everyday driving they would be borderline with alot of torque but for hard hits, look out! You would only gain 2-3 in h.p. or torque, so why bother? I would love to lighten my car also, but from what I have read, this is not the way to do it. Look elsewhere for weight savings;e.g., flywheel,flexplate,aluminum heads and intake, al. rad. , etc...
 
an aluminum driveshaft would have no problem handling a good bit of torque. Yes, it is ligther and will allow your engine to rev more quickly. DO NOT lighten your car by adding an aluminum flexplate or flywheel!!! You will lose GOBS of torque!
 
allcarfan said:
an aluminum driveshaft would have no problem handling a good bit of torque. Yes, it is ligther and will allow your engine to rev more quickly. DO NOT lighten your car by adding an aluminum flexplate or flywheel!!! You will lose GOBS of torque!
Aluminum flywheels are advantageous in road racing and autocross where engine RPM varies and you want to spin-up and spin-down as quickly as possible. For stright line performance, steel and cast iron are typically better for getting you out of the hole faster.
 
If your going for a new driveshaft, skip the aluminum and goto carbon fiber.

The carbon fiber shafts are 60% lighter than 2-piece steel shafts, they generate less powertrain noise and vibration to the passenger compartment, and the composite material is protected against driveline deterioration from corrosion leading to longer life.

I don't know a whole lot about them since they are fairly new, but google it for more info and some companies produceing them. Also the carbon shafts can be twice as strong as the aluminum shafts.

Depending on the price, I might ultimatly buy one for my own project. It's an easy way to save an average of 30+ lbs, and maybe a small HP gain from the lowered rotation weight.
 
how do you figure you can save 30 lbs from a driveshaft swap? i dont think my stock steel one even weighs that much.

anyways, if it were me i'd just pay to have the stock one shortened and balanced, it only cost me 40 bucks for that at a local shop.
 
3spd on floor said:
how do you figure you can save 30 lbs from a driveshaft swap? i dont think my stock steel one even weighs that much.

It was a generalized statement I pulled from a carbon fiber shaft website. It said on average, there shafts save about 30 lbs over the 2 piece steel shafts. But this is dealing with all different sized shafts, so the results will definatly varey.

And I'm sure the over exagerated their statement to make the carbon fiber shaft sound more appealing.

At any rate, test results show that the carbon fiber shafts are stronger than the aluminum shafts, but man are they expensive. I dunno if it's worth it for a meak 20 lbs or so.

20 lbs is only gonna make your car go 0.02 seconds faster in the 1/4th mile (every 100 lbs saved = 0.1 second quicker), thats a gain of like .5 MPH on your E/T. Not real impressive if you ask me. But then again when you take into consideration that some people utilize lightweight parts on every aspect of there car, all those little modifications can build up to huge weight saveings of 500+ lbs. So is this gonna be a street car or a strip car? If it's just a street car, don't bother dropping 800-900$ for a CF shaft.
 
Aluminun driveshafts are fine for high horsepower and drag racing applications. The 351 EFI 93 coupe I helped my friend build has one and it produces almost 400 RWP. The car launches on slicks all the time and to this day the only broken drivetrain part was the Tremec he exploded a few months ago.
 
Last year I took out two 3 1/2" aluminum driveshafts during launch on ET Streets, trying to get into the low 10s.
Previously the drag radials cusioned the shock by spinning somewhat.
The manufacture was getting tired of seeing me come back in with the rear yoke ripped off, and then again with a peice of twisted licorice. I'm afraid to go and pound on this last one, welded by Spicer he says.
There happened to be a guy at the track one day doing wheel stands in a 55 Belair wagon, and when I asked him, he said Inland Empire made his 3 1/2" aluminum driveshaft and it had over 200 passes on it.
I believe it has alot to do with suspension/pinion set up, and more so with who makes the driveshaft.
Currently 577 RWHP and 608 RWTQ.
 
one of these composite (carbon Fiber) driveshafts cost how much?

I know you can get an aluminum one, shortened out of an aerostar all for about $150-$175...

Or an aluminum one from street or track.com for $275

Or one from mustangsplus for $375

Carbon fiber costs.....?????

My money is on the one out of an aerostar. no need in having a composite shaft. And, for the record, after swapping an aluminum drivehsaft into my fox chassis, it accelerated much better and took out a lot of vibration at high speeds.
 
I too had Inland Empire Driveline ( http://iedls.com/ )make my original alum shaft and then shorten it and weld on the new yoke when I went to the 6 speed.

Demonic,
Considering using a composite shaft? You will see no benefits over an aluminum shaft with a driveshaft loop for a moderately to highly modified stang. Usually composite shafts are used for HIGH torque applications (industrial trucks and equipment), applications with long shafts (industrial again), applications where you want the shaft to delaminate in a failure, rather than a metal shaft tearing things up (industrial, safety, etc), and HIGH RPM race cars where the RPM exceeds the alum stability range.
 
Thanks for all the replies. I'll be giving Inland Empire a call, they're not too far away since I'm in Oceanside. And thanks for posting what type of torque and HP you've seen aluminum driveshafts handle, I doubt if I'll ever be over 350 rwhp so it appears that I shouldn't have a problem.

Lance