good idea? worth the price? worth it at all? lol leme know guys thanks.

 

its worth it if u have a decent amount of things done to your car....

 

+1

 

if i add gears and a tune to my mod list is that enough? or your talking about getting into superchargers and turbos

 

If you plan on adding a power adder down the road, i would save that money for that, if you don't, then i would say go ahead and get the driveshaft.

 

it won't help a lot with anything in particular. a little tiny bit of power will be freed up but that's about it... even the weight savings is kinda small at 8-10lbs. I wouldn't bother until your ride is pretty heaviy modded otherwise, then it becomes a might-as-well thing.

 

if you drop 10lbs off the DS, that 10lbs of rotating mass equates to about 100lbs of dead weight, which is roughly 1/10 in the 1/4 mile

(lots of generalisations up there, but it gives you an idea)

 

Agreed in principle but, that would heavily depend on the diameter and sectional density of the starting and ending parts. In some cases an aluminum ds will have identical or even more rotating mass (above a specific rpm) than a steel DS.

Case in point:
In one instance, I had a 4" aluminum DS and a 3" steelie. The steel was 8lbs heavier but due to the location along the diameter of the bulk of the steel DS's weight; which was completely contained within 3" of the center, the aluminum had higher rotational energy at it's curcumference after some few thousand RPM, since almost all of the weight of the aluminum DS was more than 3.5" from the center line. The centrifugal forces were higher despite the literal weight being significantly less. This is all 100% academic but it shows that design and diameter are as significant a factor as gross weight.

While teals math may not be totally accurate he brings up an important point that works both ways, so be sure of what you're getting and what problem you're solving with your mods.

 

I'd say go ahead and get the Alu. Driveshaft after your get the gears and a tune...

I basically have the same mods as you, and I also plan on getting one after my gear swap and axle/differential upgradez. Also. I have heard in SOME cases that after a gear swap as been done, I noticable vibration from the stock driveshaft started. And when they changed it out with a new Alu. Driveshaft the vibrations went away. so..yea..you might as well get the driveshaft..it will free up drive train HP loss by about 2hp also..

 

Is this with a stock driveshaft?

 

are those vibrations what they mean when they say 3.90's tend to make noise. cause im still undecided on 3.73 or 3.90

 

when they say noise it's usually the whinning noise that some gears might make. Usually if you shim it right it won't whine, and if you shim it to tight it'll usually howl. I've had motive and Ford racing gears and they didn't whine but some will say motive will whine. not sure what brand my saleen has but it doesn't whine.

 

To simplify this, basically, the larger the diameter of the driveshaft, the larger the intertia (resistance to change in acceleration). Think of it as comparing 14" steel wheels w/ normal profile tires to 18" aluminum versions w/ low profile tires. Though the Aluminums might weight less, since more of the mass is concentrated further away from the center, the interia is increased, therefore requiring more torque to turn than the heavier steel version.

 

sorry... didn't see the post.

The 3" was a stocker but the 4" was a custom job I had made at a local driveline shop.

bassman... you're the ginchiest. Way to simplify it.

A properly set up gear set won't whine. Motive have had complaints but I've come to the conclusion that those were caused by guys cheaping out on the install and letting some two bit hack set them up instead of paying someone that knows what they're doing to do it right.

 

I installed a Alum. DS on my son's stocker 1996 GT Conv. I certainly could not tell a performance difference, but the overall "smoothness" gained was definitely noticable.

Luckily, I got mine from partsamerica.com for $170.99 shipped before they jacked the price up. I should have ordered a dozen of them.