I know the 9" is cheaper
but the 12 bolt uses less HP to turn
the 9" is easier to swap ring/pinions

with a steel center section, is it still lighter then a 12bolt? what about with an alum. center section?

any thoughts would be appreciated. how did you decide?

chris

 

I originally wanted to go with the Moser 9", but I wanted to keep my 3 channel ABS (they can do 4 channel only), then I saw the TA mount which uses bolts that thread into the mount from ther top and into the bottom. The problem is that on some occasions, even with locktite, the bottom bolts can come out and cause a big problem. I went with a Strange 12 bolt because it comes fully assembled, with backing plates installed, has 3 channel ABS, and is run in on a dyno the check for excessive noise before it is shipped, AND it uses the stock style bolt and nut TA mount. All for the same price as the 9".

The only drawback I can see so far is that it takes Strange WAYYYY longer to get your rear built and shipped to you...

You'll get lots of opinions either way...this one's just mine...

--Alan

 

I have a friend in NY that actually picked up a tenth when going from a 12 bolt to a ford 9". check out the link and read.

http://www.ls1tech.com/forums/showthread.php?t=344984

 

The 9-inch weighs more, consumes 3% more power, had the centerline of the pinion offest to one side from the centerline of the car, and 0.75" lower than the 12-bolt. The makes tunnel clearance more of an issue, and put larger loads on the driveshaft u-joints.

There are a lot more options for upgrading the 9-inch to be stronger than the 12-bolt, but there is a cost associated with that. The 12-bolt seems to be able to handle up to 1,000HP. You can also reduce the weight of the 9-inch with the aluminum center section, gun drilled axles, etc. (more $$$). The TA mount looks like its not well designed, with tubes welded to the housing, but I've seen it hold up to 1,325HP in a 3550# 4th Gen, so I guess its a better design than it appears. The TA mount does complicate the changing of the center section, because the mount needs to be removed.

I think there is not much in the way of limited slip units for the 9-inch, once you go over 33-spline axles.

You can see the complexity of the TA mount in this pic, although its difficult to see where the Spohn TA ends and the mount begins, because the whole assembly has bee powder coated.

http://cjcfo.fbody.com/members/injun.../DCP03870a.jpg

There is the possibility of mounting an ABS reluctor on the pinion flange, but I'm not sure if you could get enough teeth on it to replicate the 3-channel's carrier mounted reluctor gear. The one in the pic it a drivshaft speed sensor, but using more teeth would possibly make is useful for the ABS:

http://cjcfo.fbody.com/members/injun.../DCP03821a.jpg

 

well, thanks so far guys, Im not sure I even want to keep the abs anyways. this will prolly help me decide to clean up my eng. bay and get rid of the abs.

fred, is that a special bracket the TA mounts too? Ive put in bmr TA's and it look alot diff. than that setup you got. what TA do you have?