GofasterFirebird

iTrader: (3)

I can get a stock 9 inch carrier for cheap and a currie bolt in 9 inch rear complete minus carrier. I am sure the currie housing can hold but what about the carrier? Also, who makes the detroit locker? Thanks in advance.

Also, I am very slowly building a 406 with 10.8 to one compression and a roller cam with all the other mods in sig. If this helps you decide on the poll...

Dragroc

I have already been through this, and if I could go back, or just had another $2200 dollars to spend, I would definately put the 12 bolt in instead of the 9 inch. Don't get me wrong, I like the Moser built 9 inch(no whine at all, and strong as hell), but the 12 bolt takes less horsepower to turn, and will hold up to anything that I will put to it. I have had vibration and wheel-hop issues with the 9-inch, and I have LCA's, a Spohn torque arm...I also have a Inland Empire aluminum driveshaft, and still have a little vibration. Plus that rearend is heavy as hell. I could hold the stock rearend (9-bolt) up with one arm, and just the carrier of the 9-inch seemed to weigh as much as the stock rearend. I have also heard that the 9-inch takes 20 rwhp to turn compared to the 12 bolts 8-10 rwhp; granted this is just what I heard, it came from a pretty reputable source. One other problem I had with the 9-inch is that the vent for it is right up above the gears, so any form of vent that I tried ALWAYS leaked oil. I gave up and called Moser about it, and they couldn't tell me anything other than if I can't get it to stop leaking, cap it off. So I did that and haven't had a problem since. I have rear disk brakes, and had to get the backing plates sent to a machine shop to be bored out to a certain depth to work, and then had to drill the 4 holes to bolt them to the rear (the biggest pain of the installation.). But now it is in there, and I can do whatever and not have to worry about the rear. This is just my insight anyways.

GofasterFirebird

iTrader: (3)

Thank you for the informative reply. I have a few questions:

1. Why do you think the rear end contributed to wheel hop?

2. You compare the stock rear end weight to the 9 inch. Aren't the 12 bolts almost as heavy?

3. Rumor has it that the 9 inch takes 20 hp, the stock one 10 hp. I would assume the 12 bolt takes between 10 and 20, probably closer to 20. Maybe someone can clear this up.

4. How fast is your car, 60 ft and 1/4 mile trap speed?

5. Are you saying you think the 9 inch has vibration?

AlkyIROC

There are 3 different 9" carriers. The weakest is called the WAR carrier. It was made before 1965 and has the casting WAR on the inside. The most common is just a typical 9" carrier. You can find it in just about anything with a 9" after 1965. It should be able to handle 600hp with no problems but it depends on too many factors to say if it will or not. The last and best carrier to get is a Nodular. It has a different metal content and will flex instead of break when under load.

The most popular nodular carrier was made between 1970 and 1976 (maybe until 1985). It has a large N cast on the outside and will have casting numbers D0OW-B or D0OZ-B cast on the inside. These are the most sought after and highly prized 9" carriers.

Just as good are the 1965-1969 nodular carriers. They don't have the large N cast on the outside but the inside will have C4AW-B cast into it. These are a bit easier to find.

Just stay away from the WAR casting and a factory carrier should survive with no problems. If you put out enough HP to break a factory carrier then better start saving for a billet aluminum one.

Jay 727

Incorrect pinion angle.

JoelOl75

[/QUOTE][/B]
3. Rumor has it that the 9 inch takes 20 hp, the stock one 10 hp. I would assume the 12 bolt takes between 10 and 20, probably closer to 20. Maybe someone can clear this up. [/B][/QUOTE]


It's due to how high up on the ring the pinion rides. I heard the only difference is in the 4-5 hp range but I may be mistaken.

Dragroc

1) The wheel hop was never there with the stock rear, and after I put the rear in it started. I ordered LCA's, the swaybar relocation kit, and the torque arm immediately after I put the rear in, and this only helped the problem, but didn't eliminate it.

2) In the new CHP(I think that's the mag, a friend has it.), they put a 9-inch in a Chevelle, granted it doesn't have the same mounting points, it should still be close. They weighed a 9-inch, and a 12 bolt, and came up with the 9-inch weighing in at 230#, and the 12 bolt being 175#.

3) Already answered somewhat.

4) I haven't ran at the track in a while, and have done a crapload of stuff since then, but back then when I put the rear in, before it ran a 13.7 at 102.8 with a 1.9 60 ft. time on street tires. After it ran a 13.7 at 100.9 with a 2.1 60 ft. time on street tires. The stock rear had a 2.77:1 gear in it, and the 9-inch has 3.70:1 gear in it.

5) Not the actual rear itself, but somewhere along the driveline it has contributed some. And YES, the pinion angle was set. The torque arm came with a pinion angle finder, and I put it to good use. So angle is not the problem. I put an aluminum driveshaft in, with the stock driveshaft diameter at 2.75", the aluminum at 3". This helped out alot, but not totally. Other manufacturers sell aluminum shafts with a 3.5" diameter, that probably would have solved the problem totally, but I was looking more along the lines of a strong aluminum shaft.


I'm not saying don't put a 9-inch in, or that this rearend is a piece of ****, I'm just telling you my experiences with it. I am very knowledgeble about mechanics, and know what is involved in something before I get into it...hint: incorrect pinion angle. I actually think that I am going to sell it, and put a 4th gen rear in until I can spend money on a 12 bolt. Know anyone who might want it?

GofasterFirebird

iTrader: (3)

Did you buy it new? I want it. Where do you live? Also, since you think the pinion angle is incorrect can't you use your torque arm to change that?

Dragroc

I don't think that the angle is incorrect, I said in the post that I set it with an angle finder that came with the torque arm. I live in Ridgeland, Mississippi. I bought the rearend brand new from Moser...I still have the reciepts...I can't remember the exact mileage, but it is around 12,000. I am going to buy a 4th gen rear from a friend, so when I get it in I am putting it up for sale.

AlkyIROC

The weight of the 9" depends on what gears are in it. Since there's only one series of carrier the ring and pinion size changes as the gear ratio changes. 3.00 gears are lighter than 4.56 gears. A 5.13 gear is huge.

With a 12 bolt the ring and pinion size stays relatively the same. The different series carrier compensates for having to use a thicker gear.

GofasterFirebird

iTrader: (3)

Dude, really. The gears weighing more? Maybe a pound or so. IMO, that is really not an issue. Maybe plus/minus 10 pounds total weight accuracy would be fine.

GofasterFirebird

iTrader: (3)

ttt

Jay 727

Get the 9" since you can get a good deal on it, it's the most poular rear out there and parts are cheap. It's a very strong rear especially in a light car.

gtabadboy

Im trying to decide between a 9 inch and a 12 bolt rear for my 88 GTA. I am running about 600HP and 530LB TQ. I also plan on getting a 300HP nitrous boost. What rear will work better for me. i know that strange sells 12 bolts for about 1400. Is it worth it to spend the extra 1000 on a nine inch? I know the 9 inch weighs more and takes more HP. What's your opinion. Please help I want to order ASAP. Specs in sig