Jono4820

iTrader: (1)

1

darkhorse91

how much hp/tq can the stock 10 bolts handle?

z 28 jari

iTrader: (1)

Just reconiced that axle flange diameter at 28 splines axle is bigger than 26 splines axle.Both were GM axles.26 spline axle flange dia. is 147mm and 28 splines axle dia is 156mm.
So if you have old delco moraine disc rear brakes,you must grind down some millimeters from flange that you can put disc rotors to axle.Ask how I noticed that...

ownor

iTrader: (5)

curious if there's any updates as to how your 10bolt is holding up? purchased some of the LPW stuff as well.

CamaroIROC88350

iTrader: (1)

Okay, so I'm thinking about swapping out my Borg Warner 9 bolt rear end for a 10 bolt rear end with anywhere from 3:43's to 3:90's. Is this possible because I'm going to replace my transmission with a 2wd turbo 700r4 tranny from a 1982 or 1983 Chevy truck?

ownor

iTrader: (5)

first, imho your options are either 3.42 or 3.73 with a 10bolt. second, as from my experience (i went from 2.73 to 3.27) the gain from 3.27 to 3.42 is negligible. third, i'd think you'd be better off with a dedicated thread on your own

CamaroIROC88350

iTrader: (1)

Thanks and I put up a thread since I had alot of questions.

Ron U.S.M.C.

ownor,
As far as the LPW support cover is concerned its one of those upgrades that goes unseen. But its nice to know its there.
The main thing I noticed was the gear change from 2.73 to 3.42. and the Eaton posi. ,a lot more responsive .And with the posi. It grabs real nice even with the street tires I'm running. I'm not pushing a gang of torque/horse power with my 305 but am happy with what I have for now. My car is not a light car .Ive got a Goodmark steel hood that weighs 80 lb. And Ive got about that much in tools in the rear.
That being said, I bark them going into 2nd and chirp them going into 3rd. with 295/50r15s.Thats with me and my girl in the car. So the gear change was a tremendous asset. If your going to run a 10 bolt why not give it the best support cover there is . “LPW”
So ownor what LPW products did you buy?

ownor

iTrader: (5)

i can vouch for gains of a gear change like that, recently did a 2.73 to 3.27 swap, although i would have personally expected to be pushed in the seat harder than it does now.
i got the ultimate cover, main studs and their girdle. it'll take a while till i get that all installed, first gotta rebuilt the 10bolt and install posi and 4.10 gears to go with the T56

camaro1122

iTrader: (1)

Hey since this is a rear end thread i was just wondering since i just bought a rear end for my camaro is it posi or non posi? They both spin the same way but in some pictures that look similar people say that its a non posi rear. If anyone can help id appreciate it, thanks.

SR-71

That is an open differential, or "non-posi." An Auburn or Eaton will have a set of springs between the axle ends. A gov-lock will have a more extravagant mechanism in there.

camaro1122

iTrader: (1)

Would you reccomend putting this on my car? or should i just save and buy a posi carrier? right now i have a 2.73 drum brakes and the guy thats sold me the cars a mechanic so i hope hes right he said its a posi. That one i just bought from a guy and it has disc brakes, 3.23, and non posi. Also what is the difference between a open differential and a posi rear? Like whats the advantage, what does it actually do as for being called a posi trac, and what is the better one to have?

SR-71

I'll answer your last question first. It all depends on what you want from the car. Decide what you want first, then start making mods. Just because someone says something is better than another, does not mean it's better for YOU.

If you have traction problems; If you are constantly spinning one wheel; If you find yourself in low-traction situations (ice, mud, etc.) where you may get stuck from just one wheel spinning; then you will definitely benefit from a posi.

If you're a street/drag kind of guy, always getting on it and you spin one wheel too easily, then you want a posi.

An open differential will apply all the engine's torque to the wheel that has the least traction. It's great for going around corners, and fine for street cruising. But if one wheel starts to spin, it's going to spin freely.

A posi puts a pre-load on the axles, that makes the engine torque be distributed more evenly between the axles. So it's more difficult to spin just one wheel. And even if one wheel spins, some power is going to the other wheel, too, so it may be able to pull you out of a slick spot.

For acceleration off the line, a posi is indispensable. But you have to decide on what you want. I definitely need a posi with nearly 500 ft-lbs of torque, or when I punch it, I would just sit there and smoke one tire. With posi, my car either launches like a rocket, or smokes both tires and leaves a double stripe on the pavement.

The unit in your pictures is definitely an open differential. It won't hold in slick conditions, and one wheel will spin when you put enough power to it. The only sure way to tell if you have a posi is to take the cover off and look. Don't take a mechanic's word for it, unless you just know he's been inside it.

Here's a fairly good picture of a posi. See those yellow springs? There have to be springs like this, or some sort of other mechanism in the same place, for it to be a posi or a locker. When all you see are the main gears, like in your pictures, it is definitely an open differential.

As for the two diffs you mention, regarding drum or disc brakes-- Again, it comes down to what you want. When you really lay on the brakes, nearly 100% of the stopping force is from the front brakes. The rear brakes are primarily to aid in control. If you have two property set up cars, all things being equal except the rear brakes, there is no measurable difference in stopping distance between them. So disc vs drum is mostly a matter of if you just want rear discs.

camaro1122

iTrader: (1)

On my car right now the 2.73 gear rear end is a posi because i did hit the gas hard and had two lines from the tries. As for what i want, well im eventually going to build my 305 up and be around 350 hp and 300 rwhp, and then maybe add on a turbo or supercharger later on. The engines going to be built and have some power, but yea i like the looks of disks better with the bigger wheels. I guess i want to have a car that when i punch from the line ill have both tires spinning and have a takeoff. I like to show off the power of the car and i mostly have a heavy foot when it comes to driving, so i wouldnt want one tire bold before the other. I dont know if this is good but i just had someone tell me if i wanted posi all i needed to do was put a mini spool in...never heard of that but what do you think?

SR-71

From what you say, you definitely want the posi.

On your existing diff, you can only go as far as 3.08 with the gearing. Two different series, "3.08 and below" and "3.23 and above." Unless you get a posi unit made to fit either series, you can't mix and match.

On your other two diffs, if you open them up and find they're open diffs, then you want to get either an Eaton or Auburn posi unit. Best price I've found was 360 for an Auburn, 420 for an Eaton.

The difference? Auburn has more "bias," meaning it's more resistant to slip, but it (usually) cannot be rebuilt when it wears out. Eaton will let go sooner, but it can be rebuilt by just replacing the clutches. You can do some adjustment with either one by using heavier or lighter preload springs. For me, it's advantage Auburn. It only took 200,000 miles to wear mine out, but others have not been so lucky. "Ya pays yer money an' ya takes yer choice."

If you're going to drive on the street or want any kind of handling, you do NOT want a spool. A spool turns it into a solid rear axle, with no difference in turning rates when going around a corner. That means when you go around a corner, the car will oversteer severely, or kick the rear end out, depending on speed and power. A spool is only good if you only intend to run in a straight line. If you want more lockup than you get with a normal posi, then get a locker. Detroit Locker would be my recommendation in that case.

About getting that kind of power from a 305--
My previous engine was a 305 that I built to make 340 ft-lbs torque and 360 horsepower. For a 305, it was awesome. When I could get the traction its ET was about 13.2. But the camshaft required to get that out of it took away all its street manners. With a manual transmission, I had to spin the motor faster and slip the clutch more. Low-rpm cruising was out of the question. If you build your 305 for 350 horses naturally-aspirated, you'll get the same result. If you want it to have good street manners, shoot for 300 horses, then add a turbo or nitrous.

Also consider that your 10-bolt rear axle will be fine with a 305 built as you suggest, but add a blower or nitrous with slicks at the strip, and you're asking to break it, unless you delay the boost or nitrous shot until after the launch. (Rear ends break on launch. Transmissions break on upper-gear shifts.) 400 horses is about max for a properly-built unmodified 10-bolt.

My 10-bolt holds up to my 406 (530 ft-lbs/420 hp) only because I don't take it to the strip. I'm building this car for handling and flat-out speed. Slicks are never bolted onto the rear! For test & tune, I only run "rolling-start" quarter miles using software for measurements. On the street with normal tires, I can spin freely on 2nd gear shift, bark'em on 3rd and 4th shifts, and chirp'em shifting to 5th (at over 100 mph). If I do a standing launch, traction is impossible. I smoke'em well past the 100-ft line. If I were to do a standing launch with slicks, my 10-bolt would become a great big grenade. Even with not doing hard launches, I'm still about to add a new girdle cover to make it stronger, once the budget allows. (I say all this just to illustrate the limitations of the 10-bolt. Well... yeah... I like to brag a bit, too.)

Lucid

iTrader: (4)

I have a G80 and GU2 package on my IROC, its an 87 with a 2.73 positraction unit. I know its got the series 2 carrier.

I have seen spacers for running 3.23 or 3.42 gears on a series 2 carrier and wondering if that would work?

Example:
http://www.speedwaymotors.com/7-1-2-...olts,7534.html

Does anyone have any experience running this spacer? I dont really want to buy a $200 aftermarket ring and pinion to fit this carrier if I dont have to.

Ron U.S.M.C.

In the beginning of this thread it says (Always replace the axle bearings and seals when installing new axles.) OK that's what I did including a master bearing kit when I did the up grade. My question is do all of the guys here that are changing gears have to replace with a master bearing kit and axle seals/bearings when they are putting in a new/different ring and pinion/etc. ?

big gear head

Don't use a ring gear spacer. There are thick 3.42 gears for the 7.5 10 bolt that will fit on the 2 series differential. The 7.5 rear end is the only one that has thick gears for the 2 series differential. You can get them all the way to 4.56 if you want.

big gear head

Not sure I understand the question, but I always use new bearings when changing gears. It's not worth taking a chance on used bearings when doing all of the work to change the gears. Just be sure that you squirt oil into the axle bearings before you put the axles back in.

ownor

iTrader: (5)

Anyone in the know if the thick gears for a 2 series are stronger than the 3 series? E.g. if you compare 3.73 thick 2 series vs. 3.73 standard 3 series gearset.
thanks

big gear head

I don't think there will be any difference in them. The thick gears are going to be a little heavier, but I don't think they are stronger.

Squidbillies! Don't touch the trim!

rads84n94camaro

Quick question. When you say with the t5 transmission and 3.73 gears at 70 mph its around 2500 rpms. Is that 5th gear right?

SR-71

Quick answer: That's correct.

Middle-size answer:
There's a great gear ratio / tire size / speed calculator on the F-Body.org site:
http://www.f-body.org/gears/
It's a great tool for deciding how to select your rear-axle gearing.

Long answer, if you want to know what's going on:
It all depends on your tires, and which T5 you have.

The standard-size tires on our cars are typically 26 inches tall, and average 800 rotations per mile. The optional 16-inch tires are 25-1/2 inches tall, and average 810 rotations per mile. Aftermarket wheels and tires will vary. If you look up your tires on TireRack.com, it will tell you the rotations per mile for your tire.

Most T5's have a top gear ratio of 0.74:1. There was an option with a top gear of 0.61. (I know this is true, because mine has this option.)

The math isn't too hard. Divide the engine speed by the transmission gear ratio, by the rear axle ratio, to get axle speed:
For a standard T5 with 3.73 rear gears, at 2500 rpm:
Then, divide axle rpms by the tire's rotations per mile to get miles per minute. Then multiply by 60 to get miles per hour:
For your example car with standard tires:
With the optional 16-inch wheels:

rads84n94camaro

Well i have the torq thrust IIs with the 17X8's with the standard T5 top gear ratio of .74. unfortunately tirerack.com doesnt give the rotations per mile but all in all that was some more very helpful information. Thanks

K2000

I want to rebuild the 10 bolt i have in my 1990 Firebird. Its the 'newer' 7.6 inch with 28 spline axles. Can it handle 500 horses? i want good simple answers with good reasons to back it up.


Also i was wondering if it is possible to swap a Dana 44, since the 1991 SLP Firehawk had one under it. Ive found very affordable dana 44s on ebay can i use the coil spring mounts, torque arm, and weld in the brackets for the control arms?

SR-71

Simple answer: No.

More detailed answer: Depends on what you're wanting to do.

There's a basic principle at work here:

• Rear ends break on launch.
• Transmissions break on upper gear shifts.

The reason for this is because those are the times when the components of those units are under the greatest stress.

So.... If you make 500 horsepower, but use it only for high speed runs, and don't go to the drag strip, then you might get away with a 10-bolt.
If you bolt on a pair of slicks, clean'em up real good in the pit, then do a good, hard launch with great hook up.... Well.... Picture your 10-bolt becoming a 100-pound grenade. The 10-bolt can handle occasional abuse of up to 400 horses. For regular abuse, I'd limit it to 350 horses.

My 10-bolt is taking my engine's 420 horses/530 ft-lbs. only because I don't take it to the drag strip, and it never gets slicks bolted on. I built it to effortlessly eat miles on the highway, so I don't care if it will launch like a slingshot.

As for the Dana 44: Yes, you can swap it in. You can adapt anything if you take the time and money to do it right. Is it a simple swap? No.

big gear head

The only Dana 44 that will work is the one that was designed for it. You can't easily weld on brackets and put the torque arm on it. The amount of fabrication required to make the torque arem work is huge and above the skill level of the average car person. You can't weld to the center casting because it is cast iron, not steel.

A 7.6 10 bolt will not hold up to 500 HP and abuse. If you treat it real nice and your transmission shifts smooth and soft then it will probably be all right on street tires.

SR-71

I shoulda said

K2000

Thanks to all who replied to my questions, i still have more though. Can any other rear ends be swapped, say for example the GM 8.5 10, 12 Bolt, or even a Dana 60? My project is all about swapping and modifying instead of buying a brand new one so i appreciate any advice

JamesC

iTrader: (5)

Since this thread really concerns the 10-Bolt, you would probably be well advised to start a new thread. I think you'd see more replies.

JamesC

SR-71

There are lots of possibilities. 12-bolt comes to mind. Ford 9-inch, too. Search the forums, and you'll find lots of different things guys have done.

And as has been said, start a new thread. You'll get more responses.

big gear head

None of them are easy swaps. They will require much fabrication work to make them work. There are after market housings that are made to fit. Nothing else fits except the 7.5 10 bolt, Borg Warner 9 bolt and the rare Dana 44.

Cerridius

Ok so right now i have a 305tbi with a T5 and a 7.5 rearend with 3.08 gears I believe its Posi.
Im going to upgrade to a 400 with a T56, first question- Can i just change the gears in my 7.5 rear end to 4.10? If so how would my rear end hold up at the drag strip with say 400+HP, would it explode on a launch, or would i have to get it going then step on it?

big gear head

You would probably bust it with a manual transmission and sticky tires.

Cerridius

Ok, well am I even able to just change the gears from 3.08 to 4.10? I would just use normal street tires for the occasional drag strip

big gear head

Yes, you can change the gears. You will need to get the special thick gears for your 2 series differential, or get the standard gears and a 3 series differential. Have you read this? https://www.thirdgen.org/forums/tran...axle-gear.html

Cerridius

Yea I acually had that thread minimized while reading this thread and the one you said at the same time. Ya I just got done talking to my dad about it and he said that i would need to get the thicker gears, thanks for the info!

Hunter0075

Have a few Questions. I have a 91 RS, which i removed and installed a 350. Will the stock rear handle 390 ft lbs of torque? Or can I get a used posi from a junk yard out of a Z-28 or chevy truck? Do yo u have to replaced anything in the posi unit? I know I have a 3.23 gear acording to the stamp on the axle. Should I replaced the axle's or keep the originals? I know I have to replace the bearings. Do you have to press the pion gear into the housing? I'm new in rebuilding just don't want to do it twice. Thank you.

big gear head

https://www.thirdgen.org/forums/tran...axle-gear.html Read this.

larry mclean

iTrader: (1)

I just purchased a 91Z from the salvage yard. I discovered it has a dana 44 with pbr calipers and baer rotors.

ownor

iTrader: (5)

.. or make that say 'this post..'

Flightoficarus

Ok, I think I've posted a topic before, but I've been curious about rear-end stuff again.

I'm curious if a mildly upgraded 10-bolt will hold up for the setup I'm after? My car is really more of a long-term resto-mod project, and will not be used for drag racing or heavy abuse situations. If anything, it will mostly be a fair weather cruiser, with some occasional bouts of fun. I'm planning to replace the T-5 and 305 with a T56 and a 350 TPI, probably just built to the range of 300-350 crank HP or so. I'm looking at a gear ratio of 3.42 or 3.73.

I already have a 28-spline axle, so I'm hoping installing a posi in it, and some mild upgrades will suffice. If it means anything, I'm planning on adding subframe connectors and other suspension/chassis goodies to the car.

supr_fly03

iTrader: (2)

No one can really say that your rear axle will hold up under that kind of power and that drivetrain setup. You will find people on both sides of the arguement on here. Really depends on how you drive it. If you drive it like you stole it, then no, it will most likley break. If you drive like Miss Daisy, then it will probably live. If you are somewhere in the middle, well then I guess it really depends.

Good traction and a T56 will make short work of a 10 bolt if you drive it hard.

Flightoficarus

That's what I'm afraid of, lol. There seems to be two very different schools of thought on that power level with the 10 bolt. But based on the idea that even 350 crank HP is too much for a 10 bolt, it sounds as though it was an inadequate rear end, even for stock LS1 4th gen cars (unless there was something different in 4th gen cars to help aid the rear end).

My main concern with upgrading to something nice like a Moser 12-bolt, other than cost, is the work involved. I've been told that it's not a fun job to convert these cars to utilize a real rear end, and that it's expensive to have someone else do it. Though at the same time, I feel as though by the time I install a good posi differential, make some minor strength upgrades, and convert my rear axle to disc brakes, that I may already hit half the cost of just sucking it up and buying a nice rear end w/everything I want already there anyway.

I would consider the 9-bolt, but the general consensus seems to be that part availability sucks for them, and is only getting worse.

Do the Moser 12-bolt or 9'' axles fit like stock, even though I expect fabrication/welding work to be required? And can they make use of 1LE/LT1, or LS1 brakes? Another concern of mine would be that they use lots of other exclusive components that I can't just go buy at a local parts shop.

SR-71

See my post above, #76, for an explanation.
Basic answer-- Get it going then step on it. But that means the guy in the other lane will be long gone....

But then, if you're going to the trouble of swapping to a T56 (another swap that isn't a simple bolt-in), you might as well upgrade the rear end.

SR-71

For what you say you want, your goal is very similar to mine. 300-350 crank horsepower from a 350 will have about the same numbers for torque. That's a mild build that will give you a lot of fun on the street. 3.42 or 3.73 gears, with street tires, should break loose before you can do any damage to the rear end.

As I said above, rear ends break on launch. In my opinion, if you're running street tires, then a properly set up 10-bolt is up to the job. All disclaimers apply, 'cuz I can't control how you drive. Your results may vary.

I have full confidence in my 10-bolt's ability to take what I give it, and my 406 is putting out a lot more torque than you are talking about. I've built it for speed and cruising. The street tires break loose really quick if I get on it, even rolling in third gear. I never bolt on slicks, and I don't go to the strip (anymore). All my test & tune is done with an accelerometer and rolling starts. After having gone through my 10-bolt, and re-machining the posi's cones, the only upgrade I have planned for it is a girdle cover.

nitrq

how do i know how many splines my car has? looking at putting a posi-trac into my 88camaro just need to know the specs thanks

ownor

iTrader: (5)

@nitrq typically an 88 would have 26 splines as i think they changed in 89 iirc?
dunno if you could pull the cover to count them splines on the half shafts for cheap insurance before buying wrong stuff..

JamesC

iTrader: (5)

Since spline count is covered on the first page of the FAQ, I urge you to reread that info.

JamesC

Copperhead

This what I have, G92 with the 3.45:1 ratio. Currently I have it filled with Redline Extreme Pressure synthetic 75W90 and GM FM. Roadrace car. Should I replace it with dino oil? What's the latest consensus?