9" Mpg

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Aug 15, 2008 | 12:55 AM

smurray

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9" Mpg

Is it true that a 9" has a lot more parasitic drag than a 10 bolt? I know I will be looking at a new rear end somewhere in the future. Right now my car makes 430 at the wheels, so the 10 bolt wont last forever. At the same time though its my DD, and I dont want to lose efficiency. Are fab 9"s the same way? My other main concern is weight, I try to keep the car as light as I can.

Thanks

Aug 15, 2008 | 09:19 AM

jmm98LS1

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From: KS

It's a much bigger piece than the stock 10 bolt so it will take more power to turn it.......but I still knock down 24mpg on the highway with a Moser 9", 4.56 gears and heavy 17x11 rims.

Aug 15, 2008 | 09:36 AM

strokedz383

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I agree it is beefier and will add more drag but well worth it. If total weight is a problem a midwest fabbed 9" with the aluminum carrier is about the same weight as the 10 bolt. My car was a cammed LT1 last year with 4.10's, 3600 vig, DR, and and auto and would get 16mpg. So not great compared to a LS 6 speed but I wasn't complaining.

Aug 15, 2008 | 10:44 AM

TT632

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From: Any dragstrip any time

The main complaint with the 9" has been with the offset pinion gear compared with a 10 or a 12 bolt. Ive never seen a big difference in power loss but some people say they have. I'm sure there are some before and after dyno numbers you can find here.

Aug 15, 2008 | 11:29 AM

LM97Z

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From: S.W. Missouri

Don't sweat it, i still get great gas mileage from my bolt-on LT1, as for power loss, well i can't tell it, now that i can hammer on it alot harder with the 9", its gone faster, even in the MPH, & i'm at FULL weight in this pig, still have the jack/spare with 158K mile to boot, go for it & don't look back & don't listen to the myths lol.