boog

Trying to find out if aluminum driveshaft is worth any time or money whatsoever - i searched already...

maybe someone with the shop manual can find the info....please : )

What do our driveshafts wiegh? Manual and Automatic - An aluminim one from mazdatrix is just under 11 lbs.

Is it possible to have a manual tranny with an auto driveshaft and rearend?(my vert was converted long ago but dont know any details on the swap)


if a light steel flywheel helps - i would think a driveshaft wieghing just 5 lbs. less(or hopefully more) should help in an all motor fc too....

boog

a bump for good luck -

jgrewe

iTrader: (1)

Stick with a stock driveshaft or spend $900 for a carbon fiber one. The stock driveshaft isn't that heavy and it works at high RPM. IIRC the owner of Mazdatrix even uses a stock shaft in his race car, not the aluminum ones he sells.

The rotational mass is what matters, the diameter of the object spinning is where the difference will show up more. A pound off a flywheel is worth more than a pound off a drive shaft because the weight is more likely coming off the outside of the flywheel. If you took the weight off the very center of the flywheel it would be the same as taking it off the drive shaft(we'll skip the difference in RPM's in different gears for now)

boog

that actually makes sense, i didnt think of that - thanks for the input!

85rx-7gsl-se

iTrader: (2)

One of the only advantages I have heard about aluminum driveshafts is that they reduce stress on driveline components on hard launches because the aluminum ones flex a little, reducing the shock on the rear-end.

boog

hmm, thats kinda funny because everyone seems to be all about making things stiffer for the engine/tranny/rear end to improve performance (torque braces for engine and competition mounts) - ive always wondered if stiffer mounts were really a smart addition on a daily driver because the drivetrain should be more impacted by imperfect roads and such - obviously it would be the same for a track only car but a broken daily driver means you cant get to work...

food for thought i guess......

jgrewe

iTrader: (1)

The biggest thing you would notice from stiffer motor,tranny and diff mounts would be more vibration in the chassis. A bumpy road wouldn't hurt anything.

Everything that you can do to stop driveline stuff from 'winding up' will really be noticed in harder launches drag racing and mid corner chassis response at the limit of grip.

If the car is always going to be a daily driver keep it stock, if you are in the middle of a slow conversion to track *****, go for it. One nice thing about the rotary is it's smooth power.

Mechanic

actually iirc mazdatrix claims to use the alumi driveshaft on their drift car. i just.. purchased one just to have one that can be rebuilt, and new, and well.. i'd imagine it helps a little and stuff.. gotta make up the weight of my tranny adaptors (auto to manual swap...) i am slowly... but surely.. stripping as much weight as possible on my car...
i will soon use fresh wrap for my windows... -=x
hahahah...

yeah i just got it to satisfy my curiosity in performance. it wasnt like the carbonfiber unaffordable driveshaft.

the alumi shaft is a pretty nice piece. feels nice and light, the couple of lbs i am sure it will help... but i wont be able to tell anyway i got a alumi flywheel and driveshaft at the same time... hahaha.

im just a little nervous that the counterweight bolts will come undone... haha... i didnt put threadlock on it, i put never seize cos im afraid the aluminium may cause problems.. but i can just be over sensitive.. torqued them to like 35 lbs haha

sharingan 19

iTrader: (16)

And you said all that to tell us the stocker weighs how much.....?

ericgrau

iTrader: (1)

I'm pretty sure an aluminum driveshaft should be the same stiffness or stiffer compared to a steel one. It would need to be a larger diameter than the steel one to have the same strength, and increasing the diameter even a little makes a tremendous difference in stiffness. OTOH increasing diameter also greatly helps its ability to withstand high torque, so it might simply have the same stiffness as the steel driveshaft.

Evil Aviator

I have one, but I won't have the opportunity to try it out until early next year. I figured it was worth a try, as it wasn't much more expensive than a regular driveshaft. However, I don't see much advantage in using one on a street car that will never race, except maybe for the bling factor.

The stock TII driveshaft is about 14 lbs.

Yes, this is a common mod among complete dipshits who do not look at the FSM that plainly shows the AT driveshaft is too short for proper mating to the transmission. Personally, I wouldn't drive the car if it were jury-rigged in this manner, as I consider it extremely dangerous. If a professional shop or dealership sold you the car, you may have good grounds for a lawsuit.