aluminum driveshaft install

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el_kid_1 said:
May be :OT: But, what's the real benefit of installing an aluminum drive-shaft (besides the fact that it eliminates some weight)?

Its more than just eliminating weight...its about eliminating rotational weight. I have read that removing 1 lb of rotaional weight is equivalent to 4 lbs. of dead weight. Im not sure if this is totally accurate....but you get the idea. I think it was on this forum, but there was a guy stationed in Germany through the military. Anyways he said he actually picked up some top speed by doing this mod. It makes sense. My 4cyl jeep is extreamly sluggish....and when its in 4wd you can feel how much slower it is. Turning all that extra weight requiress power. This is the power you can free up by istalling a lighter driveshaft.
 
Premium Speed said:
4th or 5th will hold better, but 1st is fine for this. :nice:

Actually lower gears hold better. Say for instance you have a 5:1 ratio first gear, and a 1:1 ratio 4th, for simplicity's sake. If the car tries to move, in first, the engine has to go around 5 times to move the car the same amount of distance that 4th would need to spin the motor only once.

So say the motor is not on locked on a compression stroke, in fourth, the car will move 5 times as far as it would in first. (to get to a comp-locked state)
 
cjist1 said:
Its more than just eliminating weight...its about eliminating rotational weight. I have read that removing 1 lb of rotaional weight is equivalent to 4 lbs. of dead weight. Im not sure if this is totally accurate....but you get the idea. I think it was on this forum, but there was a guy stationed in Germany through the military. Anyways he said he actually picked up some top speed by doing this mod. It makes sense. My 4cyl jeep is extreamly sluggish....and when its in 4wd you can feel how much slower it is. Turning all that extra weight requiress power. This is the power you can free up by istalling a lighter driveshaft.
you're right...its simple physics...it takes more energy to rotate a heavy weight than a light weight, for example, if you have a weight on the end of a pole and you try to start spinning it, it will be easier if it is 1 lb instead of 20 lbs...
 
it's not even physics really, just maths.

If the engine sees it is easier to spin the wheels than 1:1, then the wheels see that it is the inverse of this, that it is harder to spin the engine than 1:1, and by the same proportion.

For this application it shouldn't matter though, 1st, 5th, 9th, whatever. :)
 
Route666 said:
it's not even physics really, just maths.

If the engine sees it is easier to spin the wheels than 1:1, then the wheels see that it is the inverse of this, that it is harder to spin the engine than 1:1, and by the same proportion.

For this application it shouldn't matter though, 1st, 5th, 9th, whatever. :)

Yeah, 4th or 5th will "hold better", but good luck moving it in 1st from 1 inch away from the center of rotation.

-Jim