i have a 1988 iroc-z and it has 2:73 gear in it, but i wanted to know if i could fit anything else in the 9 bolt borg warner?

 

if you have a 9-bolt then its a 2.77 gear, you have the option of the 3.27 and 3.45 gear that came factory but you have to change the carrier, also you can talk to miles on this board, he has plenty of other gear ratios for the 9-bolt.

 

I was thinking about changing my gears in my BW 9 bolt but it's cheaper to just get a whole new rearend. The gears and install kit are like 455 then labor is between 225 and 300, unless you install yourself. If your lucky, I'm tryng myself, look for a complete fourth gen posi rearend with 3.42s. People say these are geat and its the most cost efficient way. In addition you may want to get a stall converted (also costly about $300)

 

A full breakdown on pricing and possibilties can be found over at http://www.diffsolutions.com/ A guy named Miles run this site (and is here quite often) and can tell you what your options are.

Good luck.

PS I gave up and stuck with my 2.77 in my 88 IROC. I didn't want to spend the money and can't convert to a 10-bolt (SCCA Stock competition rules).

 

What do you want? It's all at www.diffsolutions.com

Miles

 

Stick with the 9 bolt, the ten bolts are weak pos.

 

Since nobody else has mentioned it yet...

The BW 9 bolt isn't a 8.5" ring gear. It's only 7.75". Still better than the 10 bolt.

 

didn't even notice that in the thread title..

 

Sorry to jump on someone elses post but I have some ?s that could benefit everyone.

If these are so much better than the 10 bolt than I think I will start looking for a used one. But the gears and all other parts are ridiculously expensive.

So If I could find one with 3.45 gears how much more ? would I need to put into it to keep it together with about 400 hp and slicks/suspension work.

What year car, tranny,other options, vin #s axle codes or whatever should I look for? does anyone have pics of the 9 bolt and a 10 bolt or have a good way to distinguish them apart.

Mainly If I can find one what can I expect out of it and to put into it?

Thanks

 

Easiest way to tell them apart is to count the bolts on the rear cover. An even quicker way is to just look at the cover. A 9 bolt has a rubber filler plug on the cover. The 10 bolt is a smooth cover.

I had no problems keeping a stock 3.27 geared posi 9 bolt from running high 11's with slicks when I was still running a SBC.

 

9 bolt are expensive because they were only available for ~ 5 years. Hot Rod claims they are stronger than a Dana 44 (available in the firehawk). GM tried to improve the 7.5 10 bolt by making it 28 spline axles and a 7.625 ring gear, but fell far short of the 9 bolt. More information is available at www.9bolt.com

I have been running my 9 bolt for almost 4 years now behind my big block 427 (500hp/520lbft). It runs 1.72-1.75 60ft times with slicks and I beat the **** out of it on the street. It is completely stock! I don't even have one of my "prototype" rear girdles on it yet (or other parts .

They were available from 85-90. Just count the number of bolts on the rear cover (ie 9).

Miles

 

I gotta agree. The 9-bolt is obviously the "hot ticket", but expensive. Two weeks ago, I tracked my 88 IROC at Watkins Glen. One of the instructors had a full-race-preped IROC and the only thing that was stock on the car was the 9-bolt. (This car had two racing seats/harnesses and I was lucky enough to get some hot laps as a passenger. Yikes!).

This guy pounded the drivetrain lap after lap before damaging his engine (oops). Afterwards, he just went on and on about how great the 9-bolts are (as he loaded his broken car onto the trailer).

Good? Yep. Expensive? Yep. What things in life aren't?

 

ive looked at the sites there are tons of expensive parts but very little of anything I can gain knowlege from by reading.

ok, So how long and hard will I be searching to find one w/ the 3.45s. Is this a fairly common or extremely rare ratio?

Is the junkyard gonna charge a lot more because it is a 9 bolt or do they just go by car/ posi/non and miles.

How strong is a 4th gen rear?

 

The 3.45 ratios only came in the 5 speed cars with the high performance gear ratio option and of course the option for the 9 bolt. They are fairly rare, but I dont know if you will get charged more by a junkyard or not. I bought a 2.77 posi 9 bolt for 200 from a local junkyard but have since got a 3.45 from an individual. It cost me $375. You will just have to look around and see what you can find.

Ben

 

GTAs, Formulas , and (i think) T/As came with borg rears. flip a rear over and under the pinion it will say "borg warner" logo and all.
look for the codes with GM3 (3.45) ,GW6(3.27), GH3(2.77)in a cars RPO sheet if its still there when in the salvage yards. you can also look on the classifieds here and every now and again someone is selling a borg rear.
buy it and put a good carrier ,R+P in it from miles and you are set.
you can also call house of camaro in cali to see if they have anything.
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