Aluminum driveshaft

[S14DB]

Originally Posted by gearhead55

Yea, but I think he was just attempting to explain what taking out rotating weight does in general, not specifically a driveshaft. The inertia of the driveshaft still applies when the clutch is engaged. Right?

No, Inertial mass is only bolted to the crank(Pulley, Flywheel). Driven Mass(DS, Axles, wheels), the lighter the better.

[bmxer882x]

Originally Posted by Matej

By the way, one of the old Nissan trucks/SUV's comes with a driveshaft that fits the 240SX, though I forget which one. Good for anyone who wants a cheap one-piece steel driveshaft.

Anymore info on this? Im now quite curious if the weight is less than the stocker 2 piece

[Mikester]

Originally Posted by S14DB

No, Inertial mass is only bolted to the crank(Pulley, Flywheel). Driven Mass(DS, Axles, wheels), the lighter the better.

Actually, he is correct- this I DO have experience with as a 21 yr instruments, flight controls and navigation technician. Any rotating mass is inertial mass subject to gyroscopic precession due to Newton's laws of motion (objects in motion tend to stay in motion). With the clutch engaged, everything from the clutch to the wheels technically becomes inertial mass... which is why lightening everything from the wheels to the flywheel to the crank to the pulleys etc makes a difference in how the car responds.

Lighter is not always better- depends on the application. For instance, in drag racing, to a point, heavier is better as more mass tends to stay in a rotational state longer than a lighter one. However, I highlighted 'to a point' because there is also the work required in pushing the total mass of the car down the track- in which case, heavier is NOT better aft of the flywheel lol. This, I believe is where the differentiation as you stated between driven mass (clutch back) and inertial mass (Flywheel fwd) comes into play... but really, it's all inertial mass once put into rotation... Silly point I suppose... but being a geek, it sorta caught my attention

[bmxer882x]

Originally Posted by bmxer882x

Anymore info on this? Im now quite curious if the weight is less than the stocker 2 piece

Ive tried searching but closest I can find is the pathfinder is 2 inches longer than the 1 piece steal or aluminum driveshafts sold by aftermarket companies. Plan on swapping diffs soon so if I could pick up a 1 piece itd be nice to do it at the same time. Im in for more info on this!

edit just realized I only quoted myself. Look 2 messages up.

[S14DB]

Originally Posted by Mikester

Actually, he is correct- this I DO have experience with as a 21 yr instruments, flight controls and navigation technician. Any rotating mass is inertial mass subject to gyroscopic precession due to Newton's laws of motion (objects in motion tend to stay in motion). With the clutch engaged, everything from the clutch to the wheels technically becomes inertial mass... which is why lightening everything from the wheels to the flywheel to the crank to the pulleys etc makes a difference in how the car responds.

Lighter is not always better- depends on the application. For instance, in drag racing, to a point, heavier is better as more mass tends to stay in a rotational state longer than a lighter one. However, I highlighted 'to a point' because there is also the work required in pushing the total mass of the car down the track- in which case, heavier is NOT better aft of the flywheel lol. This, I believe is where the differentiation as you stated between driven mass (clutch back) and inertial mass (Flywheel fwd) comes into play... but really, it's all inertial mass once put into rotation... Silly point I suppose... but being a geek, it sorta caught my attention

Potential energy vs Kinetic.

Drag racers use 40lb flywheels but Carbon Fiber Driveshafts.

[Mikester]

Originally Posted by S14DB

Potential energy vs Kinetic.

Drag racers use 40lb flywheels but Carbon Fiber Driveshafts.

Yup yup... A heavy steel driveshaft initially carries exponentially more potential energy... but when in motion, a 6lbs carbon unit and other lightweight materials on the car enable the car to travel much faster- although the potentialy energy is lower, the kinetic energy all said and done is much higher; while minimizing the parasitic drag on the flywheel... Art at its finest

[bbliss126]

I have one in my track car and at slow speed in first gear I hear a bit of rattle sometimes but nothing that would keep me from using one in a daily driver, just my 2 cents.