You don't really loose power through a drive shaft, unless your uni's are at a rediculous angle cos you put monster truck suspension on your car.

A steel one has a more inertia becuse it weighs more so wil take more power to initially get it spinning, but once it is up to speed the power it "uses" is negligible. Because the diameters are small, the "more inertia" is really a lot more.

Consider a bike wheel and fly wheel of the same dimensions. It takes more power to make the flywheel turn, but once they are both turning it doesn't take make more to keep em both doing the same RPM.

Maybe not a close analogy but it serves the purpose.

Consider again a 6 cyl E series and a V8 E series, both stock. Both the the same transmission. The V8 will have an alloy tail shaft (mine does), and the six has a steel one (as I think "most" do). Put em on a dyno and using the factory pusblished power output, you can measure the drive train loss. I doubt the steel tail shaft has cost any more power.

Drive train loss comes with gear, pulley and bearing friction. A straight drive shaft effectively has neither of these.

I have a spare alloy shaft in the shed from an EB that I am conisdering putting in my coupe. The sole reason is for weight saving. Cheap increase in power to weight.

as far as i am aware, all XR models and all V8 models got the alloy shaft

^ i'll take that back.

Just had a squizz under my DC LTD (3.9L) and the tail shaft looks alloy!! Theres no rust on it and it has a chalky style residue

WTF is going on? where they optional or somthing, or possibly standard becuase its a LTD??

LWB models (LTD/Fairlane/Wagon/Ute) got them.

couldnt you check if its a steel or alloy shaft by sticking a magnet against it?

alloy is not magnetic , steel is. if your tail shaft has a whering sound it needs to be balanced at hardy spicer they glue a weight on to it and you have to wait 24hrs or so to use it . do your self a favour and get rid of the balancer . when it was new it was good but if you dent it ,it is shocking , the balancer then amplifies the whooble and starts to wear out your extension houseing. if you get rid of the balancer and dont balance your shaft it just means you cant hear your extension houseing whairing out.

I got an EL XR6 Manual, steel shaft.. must have been a friday build.

You will find all the EF/EL XR6 sedans had steel as the XR6 was speed limited, except for ex cop XR6's as they were not speed limited so they got a alloy tail shaft (same for Gli ex cop I6's), all XR8 sedans (not sure about utes, you would hope they were limited) were not speed limited.

here in brissy they charged me $50 for one and i could have selected an alloy one.

personally i reckon lighter tailshaft would increase performance just a bit, but definitely not noticeable.
it's almost like putting in a lightened flywheel or lighter diff gears (billet?!) or even lighter rims.

does anyone wanna sell me an alloy xr6 tailshaft before saturday?