I can understand my F250 crew cab pickup having a two piece drive shaft with 13 foot wheelbase.

Why does my '11 5.0 have a two piece setup? Seems like a lot of extra rotating mass with this set up.

How does a one piece shaft affect the exhaust placement?

How does a one piece affect pinion angle?

 

Well I have a one piece aluminum drive shaft on mine and it didn't effect the exhaust placement at all. My car isn't lowered so I didn't need to change the pinion angle. Honestly, its the best mod I've put on my car so far. I love it. I'm not sure if there are any companies offering a one piece for the 11 yet, but it would be worth it to get one. Mine dropped 26lbs off the weight of the stock clunker.

 

No manufacturer would design the Mustang with a one piece shaft. It doesn't meet the correct geometry and design criteria for OEM. The problem is many fold you can not properly align a one piece shaft with hook joints at both ends. It can't be done. Normally the slip joint would be contained inside the tail shaft of the transmission allowing a true one piece shaft unfortunately the transmission Ford used doesn't have a slip joint so the slip joint is placed in the shaft creating a huge potential for the shaft to have run out, not be straight, bind or be loose and cause vibration issues. Ford uses CV joints these are superior joints to the common Hook or T type universal joint they take increased loads don't have alignment issues and have built in length compensating capabilities. Unfortunately Ford doesn't build the two piece shaft light they fill it with shot.

 

Why is that? What is the benefit of the shot? More precisely, what is the benefit of having so much more weight? Both linearly and moment-wise?

This seems like an absolute waste of material as I cannot fathom what the benefits would be of filling it with shotgun birdshot.

 

Dampen vibrations / noise. Same deal with the stock panhard bar.

 

Wouldn't balancing it correct the vibration and therefore noise?

Afterall, filled with birdshot or not, an unbalanced shaft will vibrate. Make the shaft heavier, and the vibration becomes worse.

 

It is balanced to correct for vibration that you would FEEL. However, the vibration that you would HEAR is on a different frequency and that is corrected by the bird shot. The stock driveshaft is a heavy pig, and the addition of a few ounces of mostly free-floating birdshot is minute to the overall balancing of it. However, it is enough to absorb the NVH that would cause noise.

A few free-floating ounces is nothing when the shaft weighs close to 40 pounds.

 

Then why not make the stock shaft lighter, and to correct noise, you would have to put in even less birdshot?

That way, the materials cost goes down considerably over thousands of cars made, and you also get a slightly lighter car and also a bit less moment of inertia from the shaft?
The moment of inertia being the more considerable property over linear weight in this case.

 

Probably partly because the know that guys like me will modify the car to put more power through the stock drive shaft

 

LOL, good point! Alot of use go with the minimum mods of CAI and tune, which puts a little more stress to the drive shaft! I wounder just how much torque the stock shaft can take before it fails?

I think Axle Exchange rates their shafts to 800 ft-lbf torque at the crank, but I am sure the safety factor is huge and probably it could take 900 ft-lbf before any failure.