help choosing my rear... - NJFBOA - Home of New Jersey's Camaros and Firebirds

transmaro93 · 09-09-2009, 10:32 PM

OK... so the time is going to come sooner or later that im going to have to figure out what rear i want to go with.... choices are usual suspects 12 bolt, 9 inch, or dana60 (s60).... now im looking for opinions and facts on all 3... from what i understand the 12 bolt is the lightest but weakest... 9 inch is strong but has the most power loss.... and the s60 is the strongest but also the heaviest of the bunch, but has less power loss than the 9 inch... i think the s60 is overkill for my car.... roughty 550 flywheel HP lt1.... (give or take).... now i dont like the diff options for stranges 12 bolt... only offer spoool and eaton... no good... mosers 12 bolt offers spool eaton and trutrac.... but i really wanted a locker... i can get the moser 9 inch or s60 with a locker.... but moser 9 inch is really expensive and i still think s60 is over kill and just dead weight back there for a car at my power level.... any input is greatly appreciated.... i know 9 inches are like bullet proof... how strong are the 12bolts... and whats the power loss like on the 12 bolt... after i figure out what rear im going to be looking to buy one if the comming months so sponsers if you want to chime in feel free....i already checked pricing on spohns website and stranges so i know what they are looking for... see if you guys can do better..... thanks for any help guys!

BigAls87Z28 · 09-09-2009, 11:00 PM

S60. It seems that its becoming the big winner in a lot of places.

NastyEllEssWon · 09-10-2009, 01:43 AM

i loved my 9'' in the t/a. you can really feel it back there. the peace of mind is also nice. beings its a front loader too its pretty easy to work on. if you get one i hear the trutracs are better than the detroit lockers. full spool on the street is gonna suck really bad. dont cheap out either with the axles. >31 spline

98tadriver · 09-10-2009, 02:33 AM

i had a 12 bolt with 33spline axles and an eaton HD posi in my car, and it was in my friends car before mine, and now its in 86formulas car (another friend of mine) it has been launched on slicks/drag radials by me and the previous owner and its working perfectly fine. demonicbird and jersey_ta also have 12 bolts sitting under their cars and i too plan to get another 12 bolt rear. demonicbird aka brandon makes 430-450 to the wheels, jersey_ta aka rob makes quite a bit of hp as well

mc73nova · 09-10-2009, 02:22 PM

My brother Al has a Moser 12 bolt and has been a 1.36 60' on slicks with no issues. Not sure how fast you are planning to go.

I still have my stock GM 10 bolt (8.5) with Moser internals and have been a 1.40 60', they dont make em like they used to

transmaro93 · 09-10-2009, 06:20 PM

thanks for the replies guys... im shooten for mid low 11's with the car... im hopen to put down 450+ to the wheels with the right gearing.... i dont think the car will be able to go 1.3 60's but if i can that would prob be the best it would get... id probably be looking more at like 1.5's with what ever i do.... going to most likely run radials (m.t's, or hoosier) unless i have trouble with traction (which i dont think i will) then ill switch to regular slicks... i think im going to scrap the s60 idea... i just think its overkill for my car (9 3/4" ring gear is massive)... anybody know the weight difference from a 9inch to a 12 bolt?? just trying to figure out if the power loss of the 9 inch is made up in being lighter than the 12 bolt... i think any of the 3 will handle my power range... OHH BTW.... car is an M6 and will probably be launched at 5K+ traction pending....

Czop418 · 09-10-2009, 08:57 PM

... i belive the 9ich is about 120 lbs. I could be wrong though

NastyEllEssWon · 09-10-2009, 09:17 PM

9'' are a big rear. as for the weight i dont know. you wanna know when i felt comfortable adopting the 9'' rear as my rear of choice???? the moment i laid down on the ground and looked under bills car and saw the same rear sitting there

Saitin · 09-10-2009, 10:21 PM

12 bolts are good for 450-500HP after that you need a 9" a s60 is pretty much a race rear 1k+ hp.
and a general rule I've come to believe in is 12 bolts are for auto's and a M6 needs a 9" when launching over 5k with a built motor.
There is some one on here I can't recall there user/name but they have broken a 12 bolt 3 or 4 times within a year or so. mike iirc??
That is my 2 cents

BarneyMobile · 09-10-2009, 11:16 PM

I say go with the 9inch but I'm bias toward the 9inch since I have one. I feel I made the right choice in going with the 9inch since I leave off the limiter. My self and many others have made pretty good power through a 9" Plus they're easy to work on. I got mine new with 35 spline axles, 3.89 gears and a locker. The only thing I would change is locker and go with a spool if I had to do it again.

JSPERFORMANCE · 09-11-2009, 03:29 AM

My reccomendation would be the Strange 12 bolt, for your application it will be the most direct swap and be more than strong enough. Give us a call when you are ready we can get you set up.

WildBillyT · 09-11-2009, 08:57 AM

Quote:

Originally Posted by Saitin

12 bolts are good for 450-500HP after that you need a 9" a s60 is pretty much a race rear 1k+ hp.
and a general rule I've come to believe in is 12 bolts are for auto's and a M6 needs a 9" when launching over 5k with a built motor.
There is some one on here I can't recall there user/name but they have broken a 12 bolt 3 or 4 times within a year or so. mike iirc??
That is my 2 cents

You can't generalize on the strength of a rear based on it's design style. It depends on its components. Any of them can be built to handle a lot of power, it just depends on what you put in it.

There is a big difference between a stock GM 12 bolt with 30 spline axles, a posi, and c-clips and an aftermarket 12 bolt with the tubes welded, 33 or 35 spline axles, no c-clips, and a spool. Just like there is a difference beween a stock Ford 9" with 28 spline axles, a WAR center section, and an aftermarket one.

I recognize that nobody puts factory HD rears in their 4th gens since they need to be modified first. But ANY of the rears should be able to handle what most of people will throw at it. Aftermarket support is good for all 3.

JSPERFORMANCE · 09-11-2009, 09:05 AM

Yeah, I have a few 3400lb cars running deep into the nines on 12bolts.. Do the math, its alot more than 500hp..

Saitin · 09-11-2009, 10:04 AM

Quote:

Originally Posted by WildBillyT

You can't generalize on the strength of a rear based on it's design style. It depends on its components. Any of them can be built to handle a lot of power, it just depends on what you put in it.

There is a big difference between a stock GM 12 bolt with 30 spline axles, a posi, and c-clips and an aftermarket 12 bolt with the tubes welded, 33 or 35 spline axles, no c-clips, and a spool. Just like there is a difference beween a stock Ford 9" with 28 spline axles, a WAR center section, and an aftermarket one.

I recognize that nobody puts factory HD rears in their 4th gens since they need to be modified first. But ANY of the rears should be able to handle what most of people will throw at it. Aftermarket support is good for all 3.

that's just what I've found from almost 6 months of digging and researching on rears.

WildBillyT · 09-11-2009, 10:12 AM

Quote:

Originally Posted by Saitin

that's just what I've found from almost 6 months of digging and researching on rears.

I think you may be misinterpreting the data. Plenty of people run a lot more than 500hp through 12 bolts. And don't put too much weight in cases where people buy used 9" and 12 bolt rears and have them fail. It depends on how they were cared for, installed, set up, etc. If somebody has Jo Blo automotive set up a gearset or change bearings and they are poorly done, the setup can still "work" but at reduced capacity.

JSPERFORMANCE · 09-12-2009, 07:56 AM

But if someone posted it on the internet, it must be true..
12 bolts have been (and are still) in some really fast cars for the last 40+ years. They are now garbage? Should everyone with a 12 bolt that has been running it with no problems yank it out and buy dana rears or the amazing exploding 9"?
All three styles of differentials are plenty stout for 90% of the cars out there it is just a matter of weighing the pros and cons of each design.

Only one guarantee in racing/performance work.. Stuff WILL break.

transmaro93 · 09-12-2009, 08:54 AM

yea im just leaning more 9" over the 12bolt for the fact that im going to be on slicks and im a M6 car and will be launching like a madman (hopefully).... im going to start reasearching prices... so if you want to PM me some basic prices josh go for it.... i know price changes with options...

JSPERFORMANCE · 09-12-2009, 11:53 AM

Once they are optioned out they all come out to be around the same cost but the the base price for the 12-bolt is $2600 and the s-60 is $2350. One of the main differences in cost is that with the 60 your driveshaft will either need to be shortened or replaced the 12 botl will bolt right in with your existing parts.
I do not sell the 9" because in my opinion there is very little benefit to running it. It is definately NOT bulletproof as everyone seems to think. Most will not benefit from any of the pros that come with running one as opposed to the 12 or s60.
Also be forwarned, in my experience all of the aftermarket rear ends have a higher level of gear noise than the stock 10 bolt not a problem, just seems to be a quirk they have.

NastyEllEssWon · 09-12-2009, 12:09 PM

Quote:

Originally Posted by JSPERFORMANCE

Once they are optioned out they all come out to be around the same cost but the the base price for the 12-bolt is $2600 and the s-60 is $2350. One of the main differences in cost is that with the 60 your driveshaft will either need to be shortened or replaced the 12 botl will bolt right in with your existing parts.
I do not sell the 9" because in my opinion there is very little benefit to running it. It is definately NOT bulletproof as everyone seems to think. Most will not benefit from any of the pros that come with running one as opposed to the 12 or s60.
Also be forwarned, in my experience all of the aftermarket rear ends have a higher level of gear noise than the stock 10 bolt not a problem, just seems to be a quirk they have.

the bevy of cars that ive seen sporting a 9'' are well over double the hp as the OP's projected target range and their 9''s seem to be holding up fine. ive only heard of some of them having broken axles (small spline) or posi's/lockers, ive only known one person to say theyve totalled crapped out a 9''.

not saying you're wrong, or anyone is in this thread....just adding my two cents from what ive seen around.

JSPERFORMANCE · 09-12-2009, 12:28 PM

Well now you know two, and I have chunked two of them my self and my car only makes 830hp and has a turbo400 trans. The s-60 is stronger than the 9" by far anyways..

transmaro93 · 09-12-2009, 12:38 PM

12 bolt sounds too expensive since im going with a new driveshaft either way i go... i dont have a stock steel anymore and the ls aluminum i dont trust... after options with the 12 bolt im looking at like $3500 with driveshaft... dont think i want to swing that.... i still think s60 is overkill... how much hevier is the s60 to the 12 bolt... and they are fairly new for the f-body scene... has anybody had any track time on them yet... i know brian (blackbirdws6 i think..) has one but i dont think he races his car (its far too nice for it)...i know he likes it but i want to see some track results too

NastyEllEssWon · 09-12-2009, 02:04 PM

Quote:

Originally Posted by JSPERFORMANCE

Well now you know two, and I have chunked two of them my self and my car only makes 830hp and has a turbo400 trans. The s-60 is stronger than the 9" by far anyways..

hey thats why we have these types of threads, to get more information out there regarding said topic. im interested in what actually happened to your rear...if you wanna post it up or pm me im always interested in hearing the gory details of destruction

the 9'' seems to be a good compromise between the two though. i deffinately enjoyed the one i had in the t/a. it was quite stout feeling to say the least and held up to some use enough to shred my driveshaft. im confident that wouldve been a puked 10 bolt if the 9'' wasnt there.

seems no matter which application you get the consensus is the same. 10 bolts are junk

JSPERFORMANCE · 09-12-2009, 02:13 PM

The 60 has been out for years. Original production dana 60s are found in some of the fastest door cars in the world. I am not sure what proof you want but the strange version of this rear is a beefed up variation on the original unit. The s-60s have been installed in some very fast stock style suspension drag radial cars that dip into the low 7 second zone.. You probably havent read about it because these people are too busy actually racing to go on the internet and post about the rear they have in their car.. Like I said you cant go wrong with either one the 60 is maybe 30 lbs heavier at most than the 12 bolt but it is substantially bigger, you can not use a girdle style cover with the 60, it will hit the panhard bar..

JSPERFORMANCE · 09-12-2009, 02:18 PM

Quote:

Originally Posted by NastyEllEssWon

hey thats why we have these types of threads, to get more information out there regarding said topic. im interested in what actually happened to your rear...if you wanna post it up or pm me im always interested in hearing the gory details of destruction

the 9'' seems to be a good compromise between the two though. i deffinately enjoyed the one i had in the t/a. it was quite stout feeling to say the least and held up to some use enough to shred my driveshaft. im confident that wouldve been a puked 10 bolt if the 9'' wasnt there.

seems no matter which application you get the consensus is the same. 10 bolts are junk

I am sure there is some video floating around. Blew the "bulletproof" nodular center section int multiple pieces, broke pinion and "bulletproof" billet support as well. Only thing left in the rear that was any good was the spool and axles.. Also whipped the driveshaft around bad enough to put it through the muffler and locked the car where it sat. $2000 later it was back together..

transmaro93 · 09-12-2009, 03:06 PM

ohhh i know that the dana60 rears have been around forever... but its to my knowledge that the strange s60 is the first bolt in application of this rear for 3rd and 4th gen f-bods... thats what i meant by fairly new... maybe ill look back into the 60.... uhhggg im so undecided and i want to know before i send my comp out for a quick tune... which ill probably be doing in a few weeks