I was doing some research on the 3rd gen camaros and i seen that the 89 Iroc Z came with a 9 bolt borg warner rear end. Is this rear end able to stand up to more abuse than the stock 10 bolts that came on the 4th gen. If they can would they mount up easily?
Thanks Mike
They're supposed to be a good amount stronger than a 10 bolt when properly set up and maintained but parts are expensive and hard to come across. They're also narrower than a 4th gen 10 bolt so you might need some wheel spacers or something(not sure).
I mean that pretty much all the parts are supposed to be a little pricey since they weren't produced for that long and they were an australian rear. There's a website called like 9bolt.com or 9bolt.org or something like that, just search for it.
9 bolts are 7 7/8" ring gears instead of 7 1/2". So, they're not that much stronger and like rollinna65 said parts are more expensive and harder to find, not to mention the stock rear disk brakes on these cars really sucked. 3rd gen rears are also about 2" more narrow per side. Everything will bolt in place, but you will need wheel spacers.
__________________ 2001 Z28 --> 10.97@128 on 150 shot
11.44@129 on 8psi.. so far Hardtop, M6, 1SC Stripper
Orange99Z man that 9bolt is stout stuff compared to a junk 10 bolt. The size of the ring gear is not the final word on strength. Think of it more like a dana 44 rear. Problem is it doesnt fit 4 gen or ABS TC and parts are high. The cost of manufacture shipping is why they dont use them in the states much. The rear brakes on the 89 is as the first 4th gens, 88 to 85 were crappy brakes. The axles were common in 3.07 & 3.27 or 3.23 if memory serves me right and just because it was a 9 bolt does not mean it was posi. Many 3rd gen guys refurb these axles since they are tough stuff. You can identify a 9 bolt quickly by the plastic plug on the rear cover. If GM used 9 bolt rear in 4th gens we wouldnt be complaining about failures nearly as often.
The only real advantage to these rears is they come with bolt in axle retention. The rest is pretty much the same poop as a ten bolt; 28 spline axles, 7 3/4" ring gear. The posi units are cone type and burn out quickly.
I never had much luck with them and I snapped a pinion right in two on an 89 Iroc BONE STOCK LB9 ( 305 TPI 5 gear ) Whoooo hooo 225 horse
305?? Snap?? = crap
Some guys have had luck with these rears but I certainly wouldn't go through the effort of trying to get one in an LS1 car. Run the ten bolt til she blows
No such ratio available for the 9 bolt. Its either 2.77, 3.07, 3.27, 3.45, or if you are incredibly lucky 3.70. Thats all GM ever offered stock for the nine bolt. Even if it you swapped them to a holden gear set there never was a 3.77 but its possible to get a 3.90 or a 4.10/11
Regardless i think they suck and it aint cuz I didnt give them a chance. I've run plenty. My 89 IROC 1LE R7U GM Motorsport ex Players Challenge car still has the stock 9 bolt though and it still works although the posi is puked ( big surprise )
No such ratio available for the 9 bolt. Its either 2.77, 3.07, 3.27, 3.45, or if you are incredibly lucky 3.70. Thats all GM ever offered stock for the nine bolt. Even if it you swapped them to a holden gear set there never was a 3.77 but its possible to get a 3.90 or a 4.10/11
Regardless i think they suck and it aint cuz I didnt give them a chance. I've run plenty. My 89 IROC 1LE R7U GM Motorsport ex Players Challenge car still has the stock 9 bolt though and it still works although the posi is puked ( big surprise )
must be 3.70's that I have .There new in the box. I don't have much motivation to do anything to my 3rd gen when my 02 is track ready. I'll work on it someday
I live in Georgia, and have an 88 IROC, and a 2001 T/A. The IROC is my long time project. It came with a 350 and a Brog Warner 9 bolt. I was going to ditch the rear end and get a 10 bolt but after some research found out that only 75 IROCs that year came with the 9 bolt. So I began rebuilding the rear end. Bearings were expensive as hell and took days to get here cause the closest place to have them was like Kentucky. I had to send the axles to Moser and have custom copies made cause no one makes axles for this rear. That cost me $350 for just the axles. Also each axle is a different length, the diff is offset and one axle is about 6 inches longer than the other to compensate. I can't seem to find gears cause mine unfortunately has the 2 series carrier with 2.77 gears. I am wondering if all the 9 bolt carriers are the same and there is no difference between 2 and 3 series. That would help alot. But I love the rear with the 2.77 still in it. I consider it a posi unit because if I punch it from a dead stop the ass end will go sideways as well as my LS1 T/A. I think those rears are alot better then a ten bolt and am always looking for more. Just my 2 cents.
I have the original 9bolt in my iroc. It was a 5speed, now a 6, and has about 800 passes on it launching at 4000 rpm on bf drags. Never broken anything, and nothing whines a bit. I wish my SS had this rear so I wouldnt need a 9".
I had to give one away a couple of years ago. It was the last piece left from an 88 IROC that I parted out. I couldn't find anyone that would give me a dime for it.
Didnt GM performance parts actually sell a 12 bolt or 9" or something that was a bolt in for F-bodys at one time?
I just remember hearing that they sold out of them very quickly and were only used on a few special cars.
There was a D44 available. They were available surplus for a little while from dana at a reasonable price, but they sold quickly. They are a reasonably strong rear with a 8.5" ring gear.
9 Bolt borg Warner Questions 
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