Bman1320

Hey everyone. Just like many others on this forum, I blew up my rear differential. I have purchased a 9". This differential is totally stock and straight out of an F150.

My questions to you:

1. What kind of carrier should I go with? The car is going to be on the strip occasionally, but mostly street driven and possibly an autocross car.

2. What type of rear suspension setup should I go with?

3. Since I can shorten my axle now, what is the widest tire that I can go with? (without tubbing the car)

Any input is appreciated.

big gear head

There are many differentials for the 9 inch that work very well for auto cross and road racing. The Truetrac is probably the cheapest one. There are some others, but I can't recal their names.

abray1

Get a detroit locker and be done with it. They make clutch type posi units like most do but they arent quite up to a lockers standards. You can get a locker for about the same price as the others also. Most wheels are made for a stock length rear so if you shorten it you will be looking at custom one off wheels. With a ford 9 you should look at some nascar (used) parts which is what I did and I got my stuff for half price. Look at autoweldchassis.com and you will see the torque arm and crossmember they use. I got my rig from them after seeing how they make it. The torque arm mounts at the very top and very bottom of the rear making the leverage factor work much more effectively. You will see what I mean when when you look at it.

big gear head

The Detroit Locker is great for drag racing, but not the best for auto cross, or even street use. The Truetrac, Gold Trac and other gear type differentials are a lot smoother in turns and don't cause the tires to break loose by locking and unlocking.

Bman1320

Wow, That site has some pretty neat setups. After a little reading, it sounds like the Truetrac might be the way I'll go. They seem pretty reasonable in price, and that style will probably fit my driving style a little better.

AlkyIROC

Since you're going to upgrade the posi, invest in 31 or 35 splines. The axles will need to be ordered anyway to match the narrowed diff.

Suspension choices are very limited. Currie should still sell a mount bracket for the torque arm. All the rest of the mounts can be cut off the 10 bolt and welded onto the 9" tubes.

Your only other real option is to convert to ladder bars to eliminate the torque arm. Ladders bars however have other challenges since the floor is so low in a third gen.

There's a lot of work involved to swap a junkyard diff into a third gen. You could pick up a direct bolt in housing package with axles for around $1000 and you only need to supply the center section and brakes for it. It uses all the stock suspension parts.

LB9GTA

iTrader: (1)

Unless you are really good with fabrication, I wouldnt use a generic 9"

I bought a 9" from Quick Performance. You can use the stock torque arm and lower control arms.

I had mine upgraded to 35 spline axles with a spool with a aluminum centre section.

vetteoz

iTrader: (13)

Won't make any difference
Shorter diff doesn't change the amount of room available under your guards ;only changes where the
center of the wheel will be ( backspace )
Google wheel backspace for explanation

articwhiteZ

iTrader: (56)

i dont know how this RUMOR about the detroit locker ever got started.

a detroit locker working right, is as smotth has glass to drive on the street. has a non locker. (Fact)

and they feel kewl when driving into and out of a turns.

Bman1320

So i'm going to end up having to basically tub the car a little?

big gear head

Not a rumor. I had a Detroit Locker in my Camaro for more than 10 years. It upset the car in turns and it jerked a little when transfering power from one side to the other. I've had a locker in my truck for 15 years and it does the same thing. I've put over 140,000 miles on that one, so I've got a little experience with lockers. I also installed lockers in several customer's cars and trucks and they all work the same. They work great off road and on the drag strip, but there are better choices for a street car and auto cross.

vetteoz

iTrader: (13)

Depends how wide a rim you want to run and where the tire to suit that rim hits something

articwhiteZ

iTrader: (56)

well i dont know what to tell ya, iv also had more then a hand full of Detroit Lockers. all set up by compys who do it, for a living. and have never had any of that, silly stuff go on.(back in the 80's i was a Ford Guy)

and driving a 10 sec car with one on the street. it is as smooth as glass.
and running 29x13x15 tires on the same car. it's the only thing i would drive even on the street,

the only thing i do no like is having to drive the car 10 feet straight, after a turn. to get it locked up.
turning in from staging lanes ya know.

have had one in my 92 camaro, for the last 19 years,and it's still glass smooth..with that kewl power push, when coming out of a Turn.

have had them with 3.55 4.11. 4.56 and 4.86 gear sets. and still do... street car gear sets ya know..

UnstableAviator

Detroit locker with an automatic trans, no problem. Locker with a manual...yikes. Big difference depending on the transmission in use.

abray1

The nascar guys use lockers on road courses which is one of the reasons I chose a locker since I mainly drag race and do a little street racing. Mine isn't violent when it engages and disengages and I can't really feel it. I bought it used from Hendrick motorsport along with the daytona support and 3.75 polished gears. It is a little loud when it opens and closes and maybe the nascar guys modify them but mine transitions well. It is my first locker and my first ford 9 but I have had as many 9, 10 and 12 bolt posi rear ends as anyone. But if the nascar guys use them then there has to be something to it because they only use the best and that is what I based my decision on.

87350IROC

iTrader: (2)

Well that's strange logic. You must also then think 15" steel wheels and tiny 12" iron brakes are the best of the best as well?

Nascar teams use what they use because because it the best option available to them within their very strict rules. We don't have to abide by those rules on the street.

87350IROC

iTrader: (2)

With all do respect, your car sounds a lot more like a strip car than those of us building for road racing. I'm sure you will be fine driving a locker on the street. But driving 10/10th around a corner seems very twitchy going power on to power off and power off to power on around a corner.

big gear head

NASCAR rules only allow 2 differentials, the Detroit Locker and the 4 pinion standard differential. If they were allowed to use something else they would not be using the locker on the road coarses. There are much smoother and better differentials for that, like the Diamond Trac, Gold Trac and others.

UnstableAviator My Camaro is a 4 speed manual and my truck is a 5 speed manual. I don't like automatics.

abray1

Well 87350iroc you missed some of the info. We are not talking wheels or brakes and I am sure I have not mentioned them so I have no idea what you are talking about other than your attitude and you trying to put words in peoples mouth. We are all sharing what we have tried and seen and some of the logic behind it. We are just talking rearends which doesn't mean you have to BE ONE!

87350IROC

iTrader: (2)

Ah, so what you meant to say was that Nascar is the epitome of rear end technology.

You said, direct quote.
"But if the nascar guys use them then there has to be something to it because they only use the best and that is what I based my decision on."

So I actually didn't put any words in your mouth.

So to keep this on topic. You are still saying that given NO RULES, Nascar teams would run a locker on a road course?

I disagree and that is merely the point I am making. But as usual, if you don't agree with someone here, it must be a personal attack.

abray1

A tissue for your issue.

articwhiteZ

iTrader: (56)

look..if i was going to only have 275 to 350 HP and drive a road course.
and street driving. the the stocker would be fine.and so would the clutch type units.

but when adding a bit over 550hp. and wanting it to stay together.
the 9" and a locker is the way i want to go.. there are cheaper units out there
for the guys who want a hotrod/corner car. to drive like Grammys buick.

but.. i dont use stock blocks/heads/OR a blower without a Cog Drive!

and i Love Lockers..they drive sweet on the street for me, and always have.

some guys dont like them. it's a ford chevy thing.

buy them new, set up by the guys that Know How..and never look back!
after all, the weak link is the first thing to go.. and i have run alot of diff "posi" units...(suck).. and i know what works with HP. and long life..just me

if you want a locker... get one..get the hand book/info packet that comes with them, when getting the unit new. read it.
it will give you some good info. Have fun!

87350IROC

iTrader: (2)

I knew a guy with a C4 that had big horsepower and ran road courses and he swore by his locker. It certainly went against convention for a road racer, but it worked for his driving style.

abray1

As fas as tubing the car mrirocz went to some crazy huge back tires a few years back and had to have some surgery on his rear inner fender wells. He is the guy who had the April car of the month this year (black 90 iroc vert) His car is amazing and he should do a short seminar on what he did to get his aftermarket wheels and tires to fit. I have heard a few people discuss having to move the rear control arms inboard some to clear the tires.