TS6

iTrader: (41)

If you were going to run a posi unit in either rear end, is there a difference in strength between the 9" and the 12 bolt? I know the 9" is stronger but I heard the posi unit is weak. I want to stay posi vs. spool or locker because my car sees 95% street duty, so I don't want to deal with all the tire chirping and popping noises. My car weighs alot (about 3900 with me in it) and makes alot of power, so I'm worried about durability. But I don't want to buy a 9" if its just going to be as weak as my 12 bolt.

I hope that makes sense....

onfire

iTrader: (17)

What's a lot of power?

3900lbs is heavy...can't have it all...If you're plus 700rwhp and hook it with a slick you need a spool at that weight....if you leave drag radials on the car and stay on the street a posi will be fine...an Eaton with carbon fiber disks and 800lb springs will work well.

Pro Stock John

iTrader: (34)

If you let your car leave in the 1.5's you won't tear up much stuff, but if you are looking for 1.3's you are going to go through posi's. I ran a 31 spline locker for a while and it was finally acting weird so I went spool last week and 35 spline stuff. I am at 3400 raceweight.

TS6

iTrader: (41)

I'm making 730+ RWHP.

I run a 325/50/15 MT DR, not sure what posi (came in my Strange 12 bolt).

I'd like to run some 1.4x short times, but I realize its risky. If the car was raced more I'd go spool just for the peace of mind, but I have buddies who occasionally street drive with spools and it sucks.

Pro Stock John

iTrader: (34)

I guess see what happens.

Jakes Dad

If I understand what you;re asking I wouldn't run either. I would buy a whole assembly from someone who builds PERFORMANCE REAR ENDS........................

Matt D

iTrader: (49)

Obviously he did because he said he has a Strange 12 bolt already with a posi. He was asking the stregth difference in a posi 9" and a posi 12 bolt. A spool isn't that bad on the street. My buddy has a 9" with spool and 3.50 gears. He has 17" Z06s with MT drag radials out back. No problems whatsoever, and you can't really tell with the popping noises.

TS6

iTrader: (41)

Yes, obviously I have a "performance" rear end, since no 4th gens came with 12 bolts. I think Matt explained it pretty well.

I dunno, my friends with spools sure seem to make alot of noise. I live next to a state trooper, he is cool but I really don't wanna make tire chirping noises in my cul-de-sac coming home at 2:00 A.M..

vtec

iTrader: (1)

so, the tire chirping would be louder than your 730+rwhp supercharged car? lol....

i will say that i personally know 2 people that broke their eatons. both m6 cars with nowhere near your power. i would probably run a locker in a 9" if its mostly street, or a spool if its mostly track.

Brief Encounter

iTrader: (6)

what about a tru-trac type diff.

TS6

iTrader: (41)

I believe that is the "posi" unit in the 9". Lots of people have broken them, some say they are junk. I have no experience with them, but don't wanna learn the hard way.

vtec: Yes, tire chirping would be louder than my car, its actually pretty quiet for what it is. 3" TD's with Dynomax Super Turbo mufflers (yes, the cheap ones). Made 757 RWHP through that exhaust, I can back into my garage at 2 A.M. and not wake my 2 year old up, his bed is on the same wall as the back of my garage.

Bitemark46

I think any clutch type diff is gonna break especially at your power level. When my car was my daily I drove around with a locker. Wasn't loud at all. You could only hear it when I would turn in sharp places. And in the rain it was fine as long as I kept my foot out of it. But it sure doesn't tear up tires as much as a spool. -Mark

LSInnovations

iTrader: (7)

I think a Detriot Locker might be your best choice if you dont want to go spool

TS6

iTrader: (41)

They don't make a locker for a 12 bolt do they?

I really don't care about tearing up tires, tires are cheap. Smacking the wall because your posi failed while wheels up=expensive.

JL ws-6

iTrader: (50)

thre is no detroit locker for a 12 bolt. DO NOT get one of those tru tack thigns, those are total junk, worse then an eaton posi unit.

A locker will work out for you decent, but those definately make noise when ya try to back up and turn, and are annoying with the locking and unlocking they do. If ya don't want to deal with that, suck it up and put a spool in and then tehre's no worry of stuff breaking, or put an eaton in and just know that it can leave you stranded.

Jaspirr

iTrader: (6)

Don't mean to hijack the thread but..

I see everyone trashing the Detroit True Trac. I have one in my 9" from DLS. I'm hoping to make 550rwhp on spray and run high 10's with Mickey DR's.

Is a True Trac still junk for my goals? The car is 99.8% street time, so I really didn't want a posi or locker.

WFOWS6_IL

iTrader: (3)

Starting to think getting the Eaton posi in mine wasn't such a good idea.

Bitemark46

Honestly, there not that loud. But I will say that my driving habits had to change due to the characteristcs of the locker. But you won't hear any clicking unless I turn into a parking space. The only time its loud is sometimes when your start to hit the gas and the diff is not locked. Which doesn't happen often for me. You will get a loud "bang" as it engages. Its kinda funny actually, cause people think my rear just blew or a driveby shooting is happening. But being able to leave the line at 7100 knowing its not gonna break is the best insurance I ever bought.
-Mark

yak

iTrader: (15)

dude, the posi is not your biggest problem with that weigh. think about your rear end, it has a torque arm that is mounter to hopefully the frame. Now think about the load exerted on the rear when you launch your tank at the track. I would be worried about contorting the case on a hard launch which is more likely with a 12 bolt vs 9".

TS6

iTrader: (41)

I don't run a trans brake, I'm not worried about hurting the housing. The torque arm would break first I think.

Don't spools also kill axle bearings frequently when street driven?

Like I said, I don't care about tires. I just don't want to cringe every time I turn the wheel.