true or false: 9inch and 12 bolt
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From: strong island, NY
true or false: 9inch and 12 bolt is it true that the 9 inch is a "power robber?" And does the 12 bolt retain ABS, but eliminate TCS?
I have heard and reSEARCHed the facts on power reliability, and streetability of the two... FYI my reference point would be a 99 Trans am with a ls2 402, and a turbocharger system... daily driver.
I have heard and reSEARCHed the facts on power reliability, and streetability of the two... FYI my reference point would be a 99 Trans am with a ls2 402, and a turbocharger system... daily driver.
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Joined: Jun 2005
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From: Kansas City, MO
yes the 9" does rob a tad more power due to it's larger ring gear, but the stronger gear makes up for the loss IMO.
ring gear sizes
stock 7.5
12bolt 8.75
9inch 9
dana60 9.75
the bigger the tougher and more power loss
ring gear sizes
stock 7.5
12bolt 8.75
9inch 9
dana60 9.75
the bigger the tougher and more power loss
I don't agree completely with the statement above, but he's on the right track IMO.
The 9" will rob more power than a standard rear end (like a 12-bolt or the 10-bolt) due to its design. The pinion rides lower on the ring gear for more tooth contact. From my understanding, that's where any excess power loss comes from. But the design is stronger, so you aren't giving up the power for nothing. Plus, a 9" with a removable center section is much easier to set up gear-wise.
As for not being able to retain ABS/TCS, that's false. And actually, if you have both on your car, they use the same sensors to work. My Strange 12-bolt had the option to retain 3-channel operation (ABS only), or 4-channel (ABS and TCS). The 3-channel uses a reluctor gear internal to the pumpkin with a sensor on top, and the 4-channel uses two reluctor gears, one at the end of each axle (with sensors at each end as well). You can also opt for none like I did, and get rid of ABS and TCS altogether.
The 9" will rob more power than a standard rear end (like a 12-bolt or the 10-bolt) due to its design. The pinion rides lower on the ring gear for more tooth contact. From my understanding, that's where any excess power loss comes from. But the design is stronger, so you aren't giving up the power for nothing. Plus, a 9" with a removable center section is much easier to set up gear-wise.
As for not being able to retain ABS/TCS, that's false. And actually, if you have both on your car, they use the same sensors to work. My Strange 12-bolt had the option to retain 3-channel operation (ABS only), or 4-channel (ABS and TCS). The 3-channel uses a reluctor gear internal to the pumpkin with a sensor on top, and the 4-channel uses two reluctor gears, one at the end of each axle (with sensors at each end as well). You can also opt for none like I did, and get rid of ABS and TCS altogether.
THe 9 inch does also lose to the pinion angle, but the size does affect it too. THat is why the Dana 60 loses a fw hp as well. THe 9 inch is only available as 4 channel (TCS) but I heard someone was making a 3 ch kit for it. THe 12 bolt can be ordered as either 3 ch or 4 ch.
true and false, like meentSS said, the 9" pinion rides low on the ring gear, it's almost like a worm gear....
The 12 bolt has the beauty of being used in a 3 or 4 channel application (if you have a car with no Traction control/ASC/TCS) then you have a 3 channel car. if you have a 3 channel car, your ABS will no longer work if you use a 9". if you have a 4 channel car (car with Traction control/ASC/TCS) then both your ABS and TCS will work with a 9".
the beauty of a 12 bolt is you can order it either 3 or 4 channel meaning no matter what, your ABS and traction control will still work.
i am one of those few people that have a 3 channel car and a 9"...i said **** ABS i don't need it. my car only goes out on nice days, and never in the winter so i really don't need abs, that and if i do have them lock up, it's not like cars have had ABS forever...just pump the brake and your fine.....
my $0.02....if your car is the one i'm thinking of, it's a BAMF...and a few extra HP isn't going to kill you lol....for the record i lost 8rwhp when i went from the 10 bolt to the 9". i was bored enough to "dyno test" it on my friends mustang dyno
The 12 bolt has the beauty of being used in a 3 or 4 channel application (if you have a car with no Traction control/ASC/TCS) then you have a 3 channel car. if you have a 3 channel car, your ABS will no longer work if you use a 9". if you have a 4 channel car (car with Traction control/ASC/TCS) then both your ABS and TCS will work with a 9".
the beauty of a 12 bolt is you can order it either 3 or 4 channel meaning no matter what, your ABS and traction control will still work.
i am one of those few people that have a 3 channel car and a 9"...i said **** ABS i don't need it. my car only goes out on nice days, and never in the winter so i really don't need abs, that and if i do have them lock up, it's not like cars have had ABS forever...just pump the brake and your fine.....
my $0.02....if your car is the one i'm thinking of, it's a BAMF...and a few extra HP isn't going to kill you lol....for the record i lost 8rwhp when i went from the 10 bolt to the 9". i was bored enough to "dyno test" it on my friends mustang dyno
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The robbing power is kind of a moot point. If you are making decent power and going to the track enough to warrant a 12 bolt or 9 inch, you are not going to miss the miniscule hp it "robs".
Originally Posted by keliente
The robbing power is kind of a moot point. If you are making decent power and going to the track enough to warrant a 12 bolt or 9 inch, you are not going to miss the miniscule hp it "robs".
that's what i've gathered from a lot of searching around here, and since i actually back to back tested it on my friends mustang dyno just for ***** 'n' giggles proved to me that the loss was not noticable at all. hell it "feels" faster because i went from 3.73's in my 10 bolt to 3.90's in my 9"
on the other hand, had the S60 been out a little longer when i ordered my 9" i probably would have gone with it
