How much e.t/mph loss with 9 inch ?
How much e.t/mph loss with 9 inch ? OK, looked through the old threads and I see that 9 inches cost about 20-30 hp on the chassis dyno. I'm wondering if anyone has any data on e.t./mph loss with the 9 inch ?
I've got a very mild 02 SS M6, 345 factory options, free mods, pulley, filter, synthetic fluids, on BFG DR's. Car is lowered for AX with AX suspension and brakes. I am thinking of upgrading the rear on it because I am scared to death of breaking the stocker. No clunking or whine yet, but I've read the breakage stories.
Looking at a 9 inch with 4:11's and a beefed up torque arm.
Anyone have any thoughts or data to offer ?
I've got a very mild 02 SS M6, 345 factory options, free mods, pulley, filter, synthetic fluids, on BFG DR's. Car is lowered for AX with AX suspension and brakes. I am thinking of upgrading the rear on it because I am scared to death of breaking the stocker. No clunking or whine yet, but I've read the breakage stories.
Looking at a 9 inch with 4:11's and a beefed up torque arm.
Anyone have any thoughts or data to offer ?
TECH Senior Member
Joined: Apr 2004
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From: Texas
I have never seen the 9" lose that much hp. I have seen 15 hp at the WORST case. Im not sure where your getting 30 hp from. I think the differential makes a big difference in hp loss. With a spool you will loose the least.
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From: Minnesota
I don't think your ET will drop at all you may gain, because you will be able to launch at 5500rpm, as long as you have stickies out back. But I will let ya know by spring, I have a 9" with detroit locker and 4.30 gears on the way 
Dan
Dan
Going from stock 3.42 gears to 4.10s should pick up 2-3/10ths (faster) and lose 10-15hp. At least that is what they did for my car, & I went from 3.23s to 4.10s. (-3/10ths & -14hp)
Teching In
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From: San Diego
If you plan on adding more HP later, the 4.11 gears will cause you to need to shift into 5th gear before the end of the quarter mile. Additionally, on the street 1st gear will be worthless as you'll just break the tires loose. You might want to review your gear selection (I found out the hard way).
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From: Texas
Originally Posted by obe1 95Z28
If you plan on adding more HP later, the 4.11 gears will cause you to need to shift into 5th gear before the end of the quarter mile. Additionally, on the street 1st gear will be worthless as you'll just break the tires loose. You might want to review your gear selection (I found out the hard way).
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Verdad Gallardo 12 Second Club
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From: Minnesota
Originally Posted by obe1 95Z28
If you plan on adding more HP later, the 4.11 gears will cause you to need to shift into 5th gear before the end of the quarter mile. Additionally, on the street 1st gear will be worthless as you'll just break the tires loose. You might want to review your gear selection (I found out the hard way).
Or you could just put on a taller tire too
Dan
I plan to get up to about 400 rwhp max. I will raise rev limiter if need be. I plan to trap about 117-118, which would be 4th gear. I'm already in 4th stock, trapping about 109, so no big loss going to 4.10's, I'll just be at a little higher revs.
Thanks for the response WAHUSKER, I knew I would be quicker because of the 60 ft improvement, I should have asked how much mph I would lose with just the 9".
This was an old thread, I have already decided against the 9" and the 12 bolt because of weight and hp loss. I'm building an 8.8 hybrid this winter, launching off the limiter in the spring. YEEHAA
Thanks for the response WAHUSKER, I knew I would be quicker because of the 60 ft improvement, I should have asked how much mph I would lose with just the 9".
This was an old thread, I have already decided against the 9" and the 12 bolt because of weight and hp loss. I'm building an 8.8 hybrid this winter, launching off the limiter in the spring. YEEHAA
On The Tree
Joined: Oct 2004
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From: Texas
you dont need a 9"...and if you put one in you wouldnt see any loss...yes they are not as efficient...but i've seen plenty of 10 bolts takin slicks & 1000hp...nobody on this forum makes that kind of power...9" are nice...12 bolts are nice...believe it or not, your 10 bolt is tuff enuff...c-clip eliminator, brace/girdle, good posi unit, & dont weld the gears...it does help to weld the tubes to the housing tho...spend your money elsewhere, on something that will make a diff
Are you saying that the 10 bolt is strong enough to handle any car on this board? Give me a break, there have been TONS of people break 10 bolts with a stock car, M6, and nittos (maybe even street tires). You seriously think they can handle 1000 hp with slicks? Please tell me you're joking.
If you drag race, have a 6 speed, and plan on any serious mods in the future (heads, cam, blower, nos, etc.) you will need an upgraded rear. No ifs, ands, or buts.
If you drag race, have a 6 speed, and plan on any serious mods in the future (heads, cam, blower, nos, etc.) you will need an upgraded rear. No ifs, ands, or buts.
Originally Posted by Bryan TTM
you dont need a 9"...and if you put one in you wouldnt see any loss...yes they are not as efficient...but i've seen plenty of 10 bolts takin slicks & 1000hp...nobody on this forum makes that kind of power...9" are nice...12 bolts are nice...believe it or not, your 10 bolt is tuff enuff...c-clip eliminator, brace/girdle, good posi unit, & dont weld the gears...it does help to weld the tubes to the housing tho...spend your money elsewhere, on something that will make a diff
TECH Senior Member
Joined: Apr 2004
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From: Texas
Originally Posted by Bryan TTM
you dont need a 9"...and if you put one in you wouldnt see any loss...yes they are not as efficient...but i've seen plenty of 10 bolts takin slicks & 1000hp...nobody on this forum makes that kind of power...9" are nice...12 bolts are nice...believe it or not, your 10 bolt is tuff enuff...c-clip eliminator, brace/girdle, good posi unit, & dont weld the gears...it does help to weld the tubes to the housing tho...spend your money elsewhere, on something that will make a diff
What are you talking about? I have seen 12 bolts break with 400 hp with m6 cars. If you did see someone dump the clutch with slicks with a 1000 hp and their 12 bolt didnt break, they were lucky. The 10 bolt is enought??? This is getting more and more rediculous.
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From: Minnesota
There is no way that a 10bolt will hold up to a modded 6spd. My car with only 340RWHP and 350RWTQ broke the 10bolt on nittos 
And I have also herd that some 400RWHP M6s are breaking 12bolts and thats sad I think I would go the safe route get the 9" with the 4.11 or 4.30s with the locker Dan
420rwhp snapped the 10 bolt. Now I have a Moser 9" with 35 spline axles, 3.73's and a locker, this rear end is awsome. But with my 408 I can't get any traction.This is my only complaint. I still have not even used my 300 shot. Oh boy.