THEBEAST94TAGT

What are your thoughts regarding 9" vs 12 bolt? Is there any benefit to the other? alot of guys around here are running 9" (looks cheaper from what I have seen). If I go with that am I gonna have fitment problems, abs problems etc or is this a direct bolt in just like the 12 bolt.

What type/brand of posi unit have you guys found to be very good to hold up to the abuse of the track?

Opinions please.

rskrause

12-bolt: lighter (unless a much more expensive and not as strong fabbed 9" with an aluminum, center section is used), less parasitic hp loss, less bulky, better choice of limited slip diffs.
9": stronger, easier to change ring and pinion.

Price is ~ the same in an apples to apples comparison. Both can be confgured to work with ABS. I have a 12-bolt in mine with an Eaton posi..

Rich

Injuneer

Some 12-bolts work with astock DS length, the 9-inch may not. The 9-inch lowers the pinion shaft height (potential pinion angle and U-joint problems if you don't address it), and offsets the pinion to one side of the centerline of the car. Reuires a torque arm with offset mounting holes (most aftermarket now include them) and frequently requires pounding of the tunner to keep the TA mount from hitting the body. I don't think you can get posi units for the 9-inch when you get above 33-spline axles, and need to use a locker or a spool.

Personal preference would be the 12-bolt up to 800 flywheel HP.

THEBEAST94TAGT

Thanks guys, now where (if you live in KY) would you try to buy the 12 bolt. I'd like a nice combination of quality/service/price on the piece, can I get all three at one place (from what I have seen on-line, they are all priced about the same with the same options).

PS is there any specific options I should go with, ex. how many spline axels, studs? etc.

SABLT194

A4 = 12 bolt
M6 and slicks = 9"

Steve

joe-96z1le

I've got the Strange 12 bolt and I'm happy with it. I purchased all the upgrades for the unit. Well worth it IMO. Also, don't forget Strange makes the Dana S60 now. Should be a direct bolt in also.

FastLt1

Everything I've heard is Go with Strange on the 12 bolt. Moser bolts back out at torque arm.

Kyle@CSS

12 bolt unless your going full drag. I have a 9 inch and it hurt my et a good bit.

THEBEAST94TAGT

Everyone around home is telling me the 9" is bulletproof. If you are going to launch 5-6Krpm your gonna want the 9. Several people have broke things in their 12 bolt. I hate to loose my ability to run abs, but I also don't want to be worrying if I drop the clutch from 5K. I will run full slicks at the track, and I will try to launch pretty hard, so I don't want worry's. If I can get that with a 12 bolt that'd be great, but since I have an M6 car, the consensus is 9"...seems like.

Any other comments (what kind of gear are you all running in your M6?)

SABLT194

You'll certainly want the 9" if you're launching hard on slicks. I see your on a single disk clutch. You'll probably toast that at some point in time and be tempted to move up to a Street Twin. That's when the real carnage starts on a 12 bolt. Plus if you get an aftermarket TA that makes things even worse. Every time you stiffen up suspension and drivetrain it adds to shock loading on the Ring & Pinion. I've had good luck on my 9" after a terrible time on 2 different 12 bolts from Manufacturer A and B

I'm running 4.30 gears and there pretty darned nice. A little better 60' time for my heavy car than the 4.11's and still plenty of gear for cruise. However, The more gear you throw to it the more likely you'll start to have driveshaft vibe problems at road speed. F Bodys seem to be very sensitive to driveshaft harmonics even when everything is dead nuts perfect.

Steve

Jim D

I would like to add another question to this " 9" or 12 bolt" topic. Which is better for street/auto cross? Which is better for setting up brakes?

EDS Z28

I haven't had a problem with the torque arm bolts loosening on my Moser. A moser will handle tons of power with the right setup, and a spool. I would be more worried about the tranny breaking in my car than the rearend.