Will I need an alum. driveshaft w/ 4.10's?

http://forums.stangnet.com/showthread.php?t=412750 Here ya go. I did this thread a couple weeks ago about the shaft. I still have some vibrations at about 60mph, so i wouldnt say the shaft fixed anything, but it's worlds better than stock.

R100RT said:

Rotational mass has nothing to do with driveline loss. Absoutely no HP difference between alumn and steel drivelines. If it has less vibration, it's because it's balanced better. Steel driveshafts, balanced correctly, will run just as well.

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Rotational mass has everything to do with drivetrain loss! Example....take a cylinder like a driveshaft that weights 300 pounds that's suspended by ball bearings so it spins. Turn the shaft by hand and you'll see that because of it's weight it takes a good amount of force to move it. If you have the same shaft that weighs 100 pounds, it takes less force to move. Much like with a drive shaft, even thought the aluminum shaft isnt worlds lighter than the stock, you're still going to encounter less drivetrain strain because the meterials are lighter. You're not going to see huge HP gains, if any at all, but the fact that there is less drivetrain weight equals less power required to move the drivetrain.

85_SS_302_Coupe, thanks for backing me up.

Lighter rotating mass in the drivetrain equals less HP needed to turn it resulting in less time to reach a certain speed. Some class racers even go so far as using shaved/lightened rear gear assemblys! As far as the vibration goes my thoughts are the driveshaft will be turning alot faster with 4.10's compared to say a set of 2.73's so the slightly outta balanced shaft would then show-up if the driveshaft is the problem area. I've ran 3.55,4.10,4.56 and 4.88 gears with a stock shaft and never had any problems. Currently I'm using a FMS aluminum driveshaft with good results. I feel like it's a bargain at $159,heck go to any local shop that makes driveshafts and you'll most likely have that much or a lil' more tied up in a mild steel shaft...Just my 2 cents.

Tater

hey tator. how's it going? i hear you about the lightened rear and all. i was down at bills how's last weekend to pick up some parts and he was telling me about shaving and milling his ring gear. he's not wasting his money is he? J/K good for a little weight savings and rotational mass right.

axeman said:

85_SS_302_Coupe, thanks for backing me up.

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**No punn intended!! Nice thread! I love threads that actually teach you something

Hey Mark, yeah when it comes to class racing things will get crazy trying to get the edge over the guy in the other lane. GunDrilled axles, lighted rear gears, light weight drive shafts (carbon fiber), etc...etc...just a tip of the iceburg. Currently putting in a PAracing k-member kit here to lose some weight up front (would've been alot cheaper to go on a diet!!) LOL

Tater