VINCE

iTrader: (1)

I've been reading a lot about rear ends lately. Many run the 12 bolt, but recently I keep hearing the 9 inch is much lighter than the 12 bolt and just as strong. The ford peeps are still saying a 8.8 inch is the way to go and it is lighter than both the 12 bolt and the 9 inch. I know that there is more gear selection with the 9 inch and 8.8, but what would be the advantage of going 12 bolt. The prices seem the same.

So Slow

iTrader: (2)

Vince I pondered on this choice for the past couple of years before deciding on a 9"..My 10 bolt gave me great service and never broke but the possibility was always there of it happening...

Changing gears in a 9" is so much easier then a 12 bolt..9" center sections are sold thru just about any gear vendor and car range in price from $500 to $1200 complete..A couple of hours or less and the center can be changed out from a low gear set for track use to a high gear for everyday driving..

I might have went overkill with mine when I bought it ( 35 spline axels , lightweight spool and aluminum center) but when I go to the track now the rearend is the last thing on my mine that might break or give me problems..

Another selling point is a complete 9" can be shipped UPS in 4 boxes saving a high truck shipping freight bill saving me at the time over $100.00...Plus IMOP they look better then a 12 bolt..

CAT3

iTrader: (9)

Vince, the 12bolt is good for most A4 guys, but the drivetrain shock of the M6 is a killer and the 9" seems the way to go there. I am waiting to get a 9" but thats the saem reasons as Tim pointed out, change a center in a couple hours and drive cross country. Good luck.

SouthFL.02.SS

Went to the track for the 1st time yesterday with the 9" installed and I've never had so much peace of mind when launching. I did long *** burnouts, dry hopped to clean tires, dumped clutch at 4500 rpms and really enjoyed the evening. The 9" is very strong. Posi units are known for breaking on them, but it's rare. I've read too many 12 bolt breakage posts and have a friend who broke his 12 bolt.
Granted, for what I use my car for, a 12 bolt would have been more than plenty, but at least the 9" is extra insurance.

WILWAXU

iTrader: (6)

M6 guys having issues with 12 bolt has more to do with the posi than anything else.

For the weight and HP you will be pushing along with the M6, I'd suggest going with a 9".

Any A4 combination, I'd stick with a 12 bolt.

NastySSoo

I have a 12 bolt in my M6. I think the 9 inch is a stronger piece. But, you do lose a little more HP thru a 9 inch. In hindsight, if I did it again I probably would go with the 9 inch cause my car lives at the track! Made 11 passes yesterday!

VINCE

iTrader: (1)

Sounds like a 9 inch is a better choice. So far no one has said anything about a 8.8 rear..

Hardtop

iTrader: (3)

Vince I just switched from a 12 bolt to a 9". The 9" with 35 spline axles and locker, and iron center section weighs 30 lbs more than a 12 bolt. I went through 3 sets of gears in my 12 bolt, and finally got to the point that I couldn't stand the gear whine any more. Correct setup of the gears was not the problem. If the 9" cost me a tenth or so because of driveline loss I can live with that. Running a 12 bolt with a spool is something I couldn't live with, I drive my car on the street alot. The rear I have now will handle anything I can throw at it. Not the case with a 12 bolt and posi. I've seen a bunch of the posi's and spyder gears do this>>>>>> With what you have planned for your car, I would get the 9" and be done with it.

Bruce

NastySSoo

Hey Bruce, are the 9" gears quiet? How long have you had it in? Been to the track with it? Im interested cause the whine alone may be worth a tenth!Ive already broke my spider gears and the ring gear bolts!

VINCE

iTrader: (1)

Wow!!! I am seriously leaning toward a 9 inch.

Hardtop

iTrader: (3)

So far so good. I've got about 5 track runs on it, and it hasn't gotten louder yet. 4.57's are going to make some noise, but its a bunch quieter than my 12 bolt was with 4.30's. Time will tell though. If it stays like it is now after another 20-30 runs I'll be happy. Evil has a bunch of Nitrous runs on his car and its still quiet.

Bruce

SouthFL.02.SS

Quiet over here too.

AustinL911

iTrader: (-1)

where are you guys buying your 9's from? Can I retain stock ABS and TCS? Direct bolt in? I don't want to have to assemble it if I don't have to. It sounds complicated.

CHRISPY

Vince I would look at Jay Bs lightweight 9 inch housing. It is only 30 pounds heavier than a spooled 12 bolt but it a very slick piece

KGSloan

one thing that i have not seen mentioned, which was THE deciding factor for me. with a 9" you have to have both abs and tcs for them to work. if you only have abs, it will not be operative. i don't have tcs, so i opted for the 12-bolt so i could keep my abs (has saved me many times). just something i wanted to make sure people realize

HumpinSS

iTrader: (1)

93-02 LS1/LT1 MOS293 DIRECT REPLACEMENT 9" WITH EATON POSI $2169.99 Add
93-02 LS1/LT1 MOS233 DETROIT LOCKER OPTION $45.00 Add
93-02 LS1/LT1 MOS101 FOR FUNCTIONAL ABS AND/OR TCS $100.00 Add


LS1Speed offers provisions for functional abs and tcs on the 9"

Tack25

I'm getting an 8.8 with 4.10's installed on thursday. I'll post when I give it a wee little test run.

Cal

iTrader: (1)

The 8.8 is a good one also, but it has fewer ratios available for it. To keep your ABS with a 9 inch, you need to already have a four-channel system, meaning a sensor on both rear wheels, not just one into the center section of the axle. I got my 9 inch from Moser, and it bolted right in with no problems.

35th SS

iTrader: (2)

9inch. here.no problems .so far 4500rpm clutch dump.still going strong.

gator's 99TA

iTrader: (2)

i have a 12 bolt and never had problems when it was in this automatic car. but it doesnt hit the tires that hard. i broke the ring and pinion on a hard launch in a manual car it was in before. i was launching 6000 rpms or more. if it were me and i had your combo, NO DOUBT i would do a 9" for piece of mind. i doubt you are a dyno queen and it really only robs a few more rwhp over a 12 bolt. gear changes are way easy.

i would seriously look into Jay Billingsley's 9" esp with that bad *** rear sway bar they have designed. i think that is the ultimate combo. esp if you are serious about that nitrous shot on a big cube motor! good luck bro!