9" or 12 bolt.... which and why?
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9 Second Club
iTrader: (14)
Joined: Nov 2003
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From: St.Louis, Missouri
9" or 12 bolt.... which and why? I'm gonna be getting one of these for my car in the next month or so. I'm wondering which one is better and why? Things I need to watch out for? Certain options I should get? This will be in my 3rd gen with a 400-450RWHP N/A LS1 and T56 in front of it with a SPEC 3 also. It is mostly a street car but it will see the track. I might spray it also. Not sure yet. Thanks for any info!
I'd go 12bolt if it's mainly a street deal. With the 12 bolt, you'll have close to factory install (on fitment, ride height) and you can set up the abs in the pumpkin (if needed) where as the 9" you'll need a 4 channel (reluctor rings on the axles) if you need to run abs. I see the 9" being good if you're a heavy track person. The ease of gear changes, etc. The strengths should be pretty close.
It really depends on how much you want to pay and what you want to do with the car in the future. The plus of the 9 inch is its stronger and CAN be cheaper if you want to do it cheaply. Not to mention EVERYONE makes parts for the 9 inch.
The advantage of the 12 bolt is it takes a lil bet less power, weighs less and is very friendly for the F-body.
For a real High HP car or a stick car a 9 inch is a good idea. I think you'll be more than happy with a 9 inch for you setup.
The advantage of the 12 bolt is it takes a lil bet less power, weighs less and is very friendly for the F-body.
For a real High HP car or a stick car a 9 inch is a good idea. I think you'll be more than happy with a 9 inch for you setup.
Both rears are a pretty good option for our f-bodies. Moser has numerous 12-bolts running 7's/8's. The 12-bolt spools can handle some good abuse. Both posi units (Auburn for 9" and Eaton for 12-Bolt) are good units. I would recommend the 33 spline upgraded posi/axles for the 12-bolt and I would go with the auburn 31 spline for the 9".
For sheer strength, of course consider a spool but not many people are willing to run
these on the street.
We have a sale on all Moser 9" and 12-Bolts, you can check it out in the sponsor gp section, PM, call or email us about it.
- Matt
For sheer strength, of course consider a spool but not many people are willing to run
these on the street.
We have a sale on all Moser 9" and 12-Bolts, you can check it out in the sponsor gp section, PM, call or email us about it.
- Matt
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Verdad Gallardo The 9" has always supported traction control cars... They just don't support non-traction control abs cars.
You need to order the rear optioned with 4-channel ABS + exciter rings pressed on or press on your old rings to have the tcs/abs working.
- Matt
You need to order the rear optioned with 4-channel ABS + exciter rings pressed on or press on your old rings to have the tcs/abs working.
- Matt
i went with the 9" myself, stronger , easy to change gears if needed, i do have tcs/abs whicch also was a factor granted the tcs is never on 
also got the locker which is nice too
daily driven and draged for fun , no complaints yet
also got the locker which is nice toodaily driven and draged for fun , no complaints yet
Thread Starter
9 Second Club
iTrader: (14)
Joined: Nov 2003
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From: St.Louis, Missouri
Thanks for all the info guys.... I think I'll go with a 9"... just not sure from where and how much. Guess I really need to start looking now. I could finish the LS1/M6 swap right now, or I could spend about the same amount of money on a rearend. I think I'll do the rearend, b/c I know if I finish my LS1 swap, the rearend is gonna go in about 10 minutes. 
I just did my 9" swap this weekend, and I couldn't have made a better decision. I am so happy witht the way this rear end is. No whine whatsoever, can tell this thing will take a beating, very easy swap, and the best thing is that even with the spool, I can drive everyday on the street with hardly any issues at all. The only time that you even know that the car has a spool in it is when you have the wheel cranked and you are going very slow.(Like in a parking lot going very very slow trying to cut into a tight spot with the wheel cranked.)
Launching!
Joined: Nov 2001
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From: Viginia Beach, VA
Originally Posted by heyitsTaJay
are any 12-bolts a direct bolt-in replacement?
TECH Fanatic
Joined: Sep 2002
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From: DETROIT MUSCLE
i have heard of strange, but wasnt sure where to find info on them.
Since i need a rear for an A4 is there something specific i need or should get when going with a 12-bolt?
is it just as strong as a moser?
Since i need a rear for an A4 is there something specific i need or should get when going with a 12-bolt?
is it just as strong as a moser?
The strange and mosers are similar strength-wise. Most people, from what I've read, claim that the fit and finish of the strange is better. The strange is a direct bolt-in, whereas the moser needs some assembly and has a bad track record for gear whine. The strange also comes with 33 spline axles and posi. You can get the strange at TByrne for a good price, but keep in mind - Strange is only installing the HD posi units from now-on, so that will be an extra cost.
Launching!
Joined: Jan 2004
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Originally Posted by TTPMatt
The 9" has always supported traction control cars... They just don't support non-traction control abs cars.
You need to order the rear optioned with 4-channel ABS + exciter rings pressed on or press on your old rings to have the tcs/abs working.
- Matt
You need to order the rear optioned with 4-channel ABS + exciter rings pressed on or press on your old rings to have the tcs/abs working.
- Matt
