I have an 89 IROC with a 5.7L (stock) and BW 2.77 posi rear. Obviously this rear doesn't do me any favors off the line, but I don't want to change it because I like how it keeps the revs down on the freeway compared to my friends 92 Z28. Will switching to an aluminum driveshaft, having less inertia/weight, have any noticable effect. Also how many RPM's do most of you with 2.77's turn at about 70mph?

 

i have an 88 IROC-Z with 2.77 gears, 700r4, stock aluminum driveshaft, and run about 1800 @ 70MPH and 75 @2000RPM. the aluminum driveshaft is supposed to reduce vibration especially at higher speeds. i guess it does because my 88' it doesn't vibrate like my 86' IROC(stock steel driveshaft) does @ 120. besides it looks cool when i get under the car.

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88' IROC-Z, 350 TPI, 700-R4

[This message has been edited by mystikkal_69 (edited August 30, 2001).]

 

An aluminium driveshaft wont change your cruising RPM's any, if thats what you're asking, but it will help some things. First, like mystikkal said, you have less high speed vibration, but its also alot lighter than a steel driveshaft, so you have less rotating mass, and less overall weight. This might not sound like much, but in racing, every ounce counts...

EDIT: By the way, my car does 65 @ 2000 RPM in overdrive with 3.23 gears. Still want 2.77s??

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1983 Firebird
TH700R4 Auto
Small Block 400
LG4 ECM, Intake, Carb, Distributor, etc.
Soon to be non-computer.
Clarion Head Unit 45X4
2 Pioneer 400W 12" Subs
Third Gen Performance
"A four cylinder is half an engine."
"Ponies can run, but birds can fly..."

[This message has been edited by Ward (edited August 31, 2001).]

[This message has been edited by Ward (edited August 31, 2001).]

 

Should anyone be looking for an alum 1LE drive shaft, I currently have two (I sell these fairly regularly on this board). Please e-mail me for details as I won't post on the classifieds until Saturday.

JamesC

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I am with Ward, I have 3.27 gears in my GTA, and at 65 MPH, I am turning 2000 RPM's. Not much difference than your 2.77's. Unless your Tach isn't accurate. I wonder if my driveshaft is aluminum?¿ I never really noticed. But I do know that I have no vibration at any speed up to 125.
Take care
Mike

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Check out My Car Pics http://albums.photo.epson.com/j/Albu...667&a=13599419

Gran Turismo Americano "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber) & AC Delco Rapid Fire Plugs

 

West Coast,

You have much the same car as mine so you have alum driveshaft ... hence the GTA got the goodies everyone else is looking for

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1989 Trans Am GTA, 5.7L TPI, TH700-R4, T-Tops, dual cats, 9-bolt rear, 3.27, Dynomax muffler, K&N
1992 Camaro RS, 5.0L TBI, T-5, T-Tops, 3.08, L69 Dual Snorkel, K&N - Sold