9 Inch Vs. 12 Bolt

[Enthusiast]

Ive always read that the 12 bolt moser will sap more power than the stock 10 bolt. Ive also always been told that the Ford 9-Inch is one of the best rearends when it comes to putting the power to the ground. So i have some questions. Which one is the least expensive, the most durable, and most the efficient?

[1970judge]

About the same price,ford 9 owns all. I have NEVER broken a 9 ive used them 2 times.

[Enthusiast]

But have you ever broken a 12 Bolt? Which one will sap less power?

[1970judge]

A 9 saps little power a moser does. Pay the money and get a 9.

[Vendetta]

9inch is stronger and saps more power, 12bolt is a direct bolt-in though.

[Chris 96 WS6]

The 9 inch is 3% less efficient than a 12 bolt.

[Enthusiast]

So with a 9 bolt, what kinda drivetrain loss are we talking about? 21%?

[Chris 96 WS6]

So with a 9 bolt, what kinda drivetrain loss are we talking about? 21%?

With an auto, probably yeah.....you just have to make up with it with more HP.

[gettinthere]

This is the way I look at it.

If you have an Auto get a 12 bolt.
If you have a stick get a 9".

[Chris 96 WS6]

This is the way I look at it.

If you have an Auto get a 12 bolt.
If you have a stick get a 9".

Yep!

[C Murda]

Gettinthere has the right idea.

yes a 9" is 3-5% less efficient on putting the power to the wheels over a 12 bolt but when you need a 9" you have plenty of power to worry about that. also they do make complete bolt in 9" rear ends, i got mine from Moser and it was a simple job.

[gettinthere]

Gettinthere has the right idea.

yes a 9" is 3-5% less efficient on putting the power to the wheels over a 12 bolt but when you need a 9" you have plenty of power to worry about that.

Exactly.

M6's put more power straight to the ground and match the 9" better b/c it's stronger.

A4 trans's soak up some power and are alot easier on the rear. This is why a 12 bolt work better.

[Built2Run]

If you want to keep you 3 Channel ABS (Manily For LT1 Guys) You can only get a 12 bolt, Stick or Auto no company has yet to make a 9'' with 3 channel abs (sensor in the diff Housing)

[C Murda]

If you want to keep you 3 Channel ABS (Manily For LT1 Guys) You can only get a 12 bolt, Stick or Auto no company has yet to make a 9'' with 3 channel abs (sensor in the diff Housing)

ya this is true, i forgot to consider that seeing as i own a 3rd gen with a 9" and my car doesnt have ABS so i kinda forgot :homer:

[Mykdiver]

9inch is stronger and saps more power, 12bolt is a direct bolt-in though.

The 9 inch when you get it from Moser for your car and year is also a direct swap in.
The 12 bolt is more efficient, the 9" is stronger.

[Chris 96 WS6]

If you want to keep you 3 Channel ABS (Manily For LT1 Guys) You can only get a 12 bolt, Stick or Auto no company has yet to make a 9'' with 3 channel abs (sensor in the diff Housing)

Actually I've seen this done. If you do a search on LS1tech.com for (9 inch 3 channel) you'll come up with a few posts where guys have mounted a reluctor ring to the pinion yoke and moved the sensor to the front of the housing to measure the speed of the ring. I think the stock reluctor has 177 teeth or something, so you divide that by your gear ratio and that's the number of teeth the new reluctor should have. They've also put them on the trans output shaft.

[gettinthere]

It's possible to make a 9" recieve a 3 channel. It just takes a little fabbing.

[Built2Run]

it may not be worth the hassle to some.. IMO if your not at the track every week or doing 6k clutch dumps daily a 12 bolt will survive in a m6 car. a buddy has a 12 bolt in his 97 Z, hoosier slicks and 4:56 gears hes been dumping at 3-4k for the last year and hasent had one problem with it, i think some people just beat the hell out of there cars and expect nothing to break.

[gettinthere]

I'm not saying a 12 bolt won't hold up in an M6. B/c it will. People have just proven that the 9" can take more abuse in an M6 whereas a 12 bolt can take more from an A4.

[Fastbird]

I think that the problem with M6 guys running a 12 bolt and breaking them is that they're running just a HD posi and ABUSING it at the track (more track than street). The spider gears in there are only going to take so much.

Now on a street/strip car odds are that it'll hold up quite nicely. Watch as I end up eating my words next spring though once I get the 12 bolt. :D

[gettinthere]

That's why Full Spool > Locker > Posi

I would never put a posi in a car I race.

[Lifeisgood]

ive seen one broken, by rob raymore, in his turbo LS1.
but one of the main reasons ive heard for using them was how quickly you can swap gears. i think that the 12 bolt is just as strong.
thats my 2 cents

[99formulam6]

so, if i want to keep the ABS, i have to get a 12 bolt (or a 9inch and fab up some crazy shit)...?

[Chris 96 WS6]

Nope, its possible to get 4 channel or 3 channel on a 9 inch, it just takes some more effort. :D

[Jaberwaki]

it may not be worth the hassle to some.. IMO if your not at the track every week or doing 6k clutch dumps daily a 12 bolt will survive in a m6 car. a buddy has a 12 bolt in his 97 Z, hoosier slicks and 4:56 gears hes been dumping at 3-4k for the last year and hasent had one problem with it, i think some people just beat the hell out of there cars and expect nothing to break.

3-4k dumps are baby dumps... hell a 10bolt will hold more then a few of those;)

[Jaberwaki]

ive seen one broken, by rob raymore, in his turbo LS1.
but one of the main reasons ive heard for using them was how quickly you can swap gears. i think that the 12 bolt is just as strong.
thats my 2 cents

you heard gear swaps are EASYER in a 9" :lol:
i whole heartedly disagree with both statement's

you dont have to remove the DS to get to the 12bolts gears.

you know of ONE 9" breaking to a turbo ls1?

there is a vertual body count of 12 bolts giving up the ghost to the M6... :P

[99formulam6]

3-4k dumps are baby dumps... hell a 10bolt will hold more then a few of those;)
i launch at 3500 :)

[Chris 96 WS6]

you heard gear swaps are EASYER in a 9" :lol:
i whole heartedly disagree with both statement's

you dont have to remove the DS to get to the 12bolts gears.

you know of ONE 9" breaking to a turbo ls1?

there is a vertual body count of 12 bolts giving up the ghost to the M6... :P

How are you going to get the pinion gear out of the 12 bolt w/o taking the drive shaft off? That's a requirement regardless of the rear end you're working on IMO.

[Jaberwaki]

you got me there... i have not had to swap gears on a 12bolt yet... looked like everything came out from the back? why does the DS have to come off?
in the 9" the hogs heads removes from the front...

[Chris 96 WS6]

The DS has to come off because you can't get the pinion nut or Yoke off with it in the way. The pinion does come out the back but there's a bug nut, the yoke and a bearing holding it on from the front :)

[LiquidFire350]

12bolt is the same as a 10bolt, just bigger and stronger, gear swaps are done the same

[Jaberwaki]

The DS has to come off because you can't get the pinion nut or Yoke off with it in the way. The pinion does come out the back but there's a bug nut, the yoke and a bearing holding it on from the front :)

noted.... it is something i should know how to do... i will have to make it a point to find one to do... :cool:

[snakeoilperformance]

it just sucks that the f bodys were givin such a shitty 10 bolt. the 8.5 10 bolt can handle some decent power, if set up properly. ie: welded axle tubes, axles, good diferential and set gears up to take the abuse. oh and dont forget the girdle :thumbsup:
easier than buying a whole differential