dragline

Any input on the benefits of using an aluminum vs steel driveshaft on a street/strip car? The price I was quoted would be $50-$75 more for aluminum.

VC455

For equivalent strength, aluminum is lighter. The benefit is not only less weight, but less rotating weight to spin up. Both are beneficial to your strip time, the greater benefit of the two is horsepower saved due to less spin-up power required.

On the street, I don't think you will see a benefit.

Another potential benefit is for high-speed applications. Aluminum may be able to handle higher driveshaft rpm without self-destructing--your drive-shaft supplier will be able to tell you if that is the case with their version.

oddball

Aluminum is prettier, but you usually have to go 1/2" larger to get the same strength. e.g., 2.5" is typical for a steel shaft, so 3" is the usual starting size for an aluminum.
I run an aluminum just for the hell of it. Easier on my back to install? Can't really "justify" anything in this hobby, you know?

droldsmorland

I had Dennys whittle me a new aluminum shaft. Very happy. Yes, much lighter and less rotating mass. It sounds different too when the dual fed drum TH400 bangs 2nd.

Battenrunner

I was told by two very reputable suppliers of very good driveshafts that welded Aluminum shafts are more likely to fatigue at the welds where they intersect the yokes. Once they fatigue, the welds crack and the shaft fails. Both suppliers urged me toward either a bonded aluminum shaft or to just go with a Mild Steel shaft and "forget about it" for the street and strip. I was also told that Aluminum will not hold as much power without failure at the same diameter as Mild Steel, notwithstanding the cost. I really wanted aluminum for the weight and E.T. advantages, but not enough to spend more money on something that might fail earlier. Most likely none of you will ever have a problem with your Aluminum shaft, but knowing how "Murphy's law" works for us.....

We just purchased a brand new 3.5 inch Mild Steel driveshaft with 1350 Dana Solid U Joints with permanent lube (No Grease Zerks) for strength, as well as a new Dana Forged 32 spline yoke for the Turbo 400 output. It came out very nice.

With the length of these cars, you have to really watch the diameter of the shaft to make sure it is large enough in diameter to take care of any possible issues caused by harmonics and failure of the tube at "Critical Speed". Reference critical speed chart here : https://www.markwilliams.com/driveshaft-tech.html

The shaft in our 1967 Cutlass is 57.5 center to center of the U-Joints, and we have a 1350 Pinion Yoke in the 12 bolt Chevy rear differential to match up the same strength.

Another topic to speak about when upgrading the driveshaft is the 1310 vs. 1350 U joint issue when you start pushing a car consistently fast, as the 1310's will fail. If you must keep the 1310 series U Joints, go with the Dana Solid non-greasable ones part number 5-1310X (Make sure they fit your application), as the solid U joints will be much stronger than the hollow greasable ones.

Run to Rund

I agree that Mark Williams has some good tech articles and it is worthwhile to visit the website. They also offer very high quality parts such as yokes and universal joints. Drag racers who have tried both steel and aluminum give mixed reviews but aluminum helps e.t. none or very little for most of them. As above, pay attention to critical speed vs. the rpm your shaft will run--Olds shafts tend to be quite long, up to 60" or more.

joe_padavano

As an aerospace engineer, the aluminum vs steel trade is not always clear cut. Yes, aluminum is about 1/3 the density of steel, and quality aluminum like 6061-T6 has about the same strength as mild steel, so if you have a part that is driven by strength, aluminum will be lighter. In the aerospace business, we don't use mild steel, we use high strength steel, and at 180ksi yield for HSS (about 3x that of 6061), the weight is the same. Aluminum also only has about 1/3 the stiffness of steel, so if you have a part that is driven by stiffness, there will be no weight difference between properly designed aluminum and properly designed steel. And as noted above, aluminum has much less fatigue resistance than does even mild steel. The benefits of aluminum come if there are machining or casting thickness limits, where the limitations of the production process prevent you from building an optimally designed steel part.

oddball

Good lord, never use 1310's. Olds used 3R's which are roughly equivalent to 1330's. Use 1330's at a minimum if stuck with using Chevy parts, 1350's if you can swing it. I still like 3R's in the rear as you're less likely to booger the u-joint with 3R straps than 13XX u-bolts.

monzaz

Anything to do with all out torque and power always take the steel drive shaft
We have seen many tow vehicle and Van wallow out the u-joint drive shaft saddles.... So that would probably happen hitting it at the take hard too.

I am not saying there is no place for aluminum ... Road racing and probably circle track where weight and reciprocating acceleration in and out of corner could help shave times. But also remember these types of racing are highly sponsored type of racing and they can afford to changer the shaft ever few races etc.

If you have a Muscle car and like doing hard driving burn puts and drag racing stick with the STEEL aftermarket drive shaft... Will last long time and as someone else mentioned your not going to notice any difference it would
provide.
I am sure all the standard trucks and cars use Aluminum as it is easier to recycle and weight factor for best fuel mileage required by the government standards these days...Especially in trucks!

And finally....as I always say....IT IS YOUR vehicle and you can build it with what ever YOU want. That is why we live in the USA!