Zdaddy

I like everybody else has distroyed my fair share of 10 bolt differentials! So like everybody else, I optioned to purchase a 12 bolt Moser in place of the weaker 10 bolt. There are a couple of minor issues with room for the 12 bolt not to mention it's larger parts do tend to create more inertia and recipicating mass with the ill effet of lost horse power. After living with it for a year, I bought a used differential out of an early model 1LE and began the R&D to create a bullet proof 10 bolt. Not possible you say? I don't blame you because I was equally as sceptical!

I did a lot of research on axles and found that a full competition axle will not live on the street due to the brittle forging process so I ordered up a set of Moser Street/Strip axles. Then came the center section. Found that there are two different carrier sections for the 10 bolt 7.5 and the stronger of the two is the 2.32 carrier section and also requires a thinker ring gear (more durability!) I optioned for the Richmond gears (ratio of you choice), Richmond Powertracs locker, and Richmond master bearing kit. I installed the Moroso bolt in stud kit. Make sure your tolerences are perfect! Now comes the VooDoo!

The weak point on the 10 bolt isn't just the carrier, it's the axle shaft tubes. They are small and under extreme acceleration pull forward push the ring gear away from the pinion gear causing catastrophic failure. If the ring and pinion gear can maintain perfect contact, then the failure horse power is MUCH HIGHER! So we purchased a Summit Racing Cast aluminum differential cover with the main cap supports. This helps keep the main cap bearings from walking some but not entirely! We sent the diff cover to have supports welded to both end and then welded equal supports to the ends of the axle tubes. This with the main cap support almost eliminates ring gear walk!

I can tell you I've been giving mine hell for a year now lanching the car at 4000 rpm on Mickey Thompson ET Streets and I'm make just under 500 hp at the wheels.

'Shifter

iTrader: (2)

Excellent job...I'm in the process of doing the same thing...but mine is for a
daily driver, so I'll be happy if it holds up to 350 horse...

its scot

lonching at 4000 with 500 hp and it lives for over a year ?
I have seen the pinion shaft twisted in half on an axedental nutral to drive shift @ about 2500rpm and 400hp with street tires!

formul8!!

The problem with 10 bolts is not the axle tubes, it is the ring and pinion do not have enough "meat" to absorb the forces of launching a high powered car on slicks.

You can really only band-aid a 7.5" 10 bolt to make it last.

AlkyIROC

As mentioned above, it's only a band aid solution.

You can beef it up all you want. It may help some but it's still a tiny ring and pinion and that's the weakest link in the whole diff.

My beefed up 10 bolt got me into the low 11's. I then installed a transbrake and knew the diff wouldn't handle the shock so I upgraded to a 9" at the same time.

EvilCartman

iTrader: (1)

For all the money you've spent on that 10 bolt, and the rest of the car, you still use a scissor jack?

86t/a owner

very nice setup you have there, It should last you a long time. But one where did you find this research on competition axles being more brittle?? There is no difference in the axle "blanks" from stock to 35 spline, some of the 40 spline stuff is a larger diameter, or has less taper of the shaft. Generally, spline count is looked at from the point of view that more splines=stronger/more "brittle", but it really has little to do with metallurgy. You could get 28 spl axles that have much less elasticity than 35 spl. It's all about the metal and how it's treated, not the spline count. But you cant say a competition axles that gets beat on from 1000hp and coming off a trans brake at 5500+rpms and lasts for god knows how long is going to brake on the street. Thats just my 2cents not that you asked for it or really cared just figured I would throw it out there. and once again looks like you have a very nice clean setup going for you that is working well. =]

Sonix

iTrader: (1)

the axles he's talking about are probably heat treated to have less ductility, and more strength - but are more brittle. I don't think he's talking about spline count x vs spline count y and the ductility differences between that, because that's not really related.

The main part I noticed (that I haven't seen before), is the addition of the braces on the summit girdle, and the bars going towards the tube. Got a picture of what was done to the tubes, such that those bars are connected to it?

Moroso main cap studs? I'll be damned, I couldn't find those, got a part # by chance?

Thanks

Zdaddy

The car is jacked at the sub frame connector and trailing arm point. Used the sissor jack to level the diff. I feel your concern....

Zdaddy

Contact Moser for that data, their engineers are who educated me. They did state that the Street/Strip axles are indeed different in how they treat the metal on the Street/Strip. Something to the extent that they absorb more lateral and vertical abuse in how they alow some of the torisional properties to remain to take up the impacts of pot holes and such on the street (and for road racing), where the full competition axle are fully treated to withstand primarily horizontal loads only and are in fact more brittle to vertial conditions. Like I said, call the engineers for a better explantion on this....

86t/a owner

my fault zman i thought you where talking spline counts. me sorry long time hehe. Have a good weekend.

chevymec

iTrader: (5)

I am on my 3rd set of gears in my 7.5" . Busted the ring and pinion everytime.
28 spline axles
LPW aluminum cover and brace kit. Helps brace the axles from flexing.
Eaton posi
4.10 gears.
I never had a problem with mine as long as my 60' time was 1.7 or higher.Once I started launching 3000-3500 rpms my 60' dropped to 1.6's and boom off the line it breaks. Ive run MT Sportsman pro's, Nitto's and now ET Streets. All had the same 60' times. It sucks cause it can pick the LF tire up a bit if it leaves hard but there is the price of a ring and pinion . I solved my problem by getting a 9" but just havent been motivated to put it all together yet. I think the only way to make a 10 bolt live is to run an automatic. Not saying you cant break one with an automatic but its alot less stress off the line.

Dels383TA

The stock 7.5 lasted about 20 feet at the track behind my engine,went kinda like this,pull into water box,burn out,pull to line,stage,rev to 4000RPM,pro light drops,side step clutch move 20-30 feet,get towed off,check rear,see lots of broken parts(center from posi,through cover,bent lower control arms,bent panhard bar,broken axle,dent in floor where posi unit hit),spend 2500+ dollars on new Moser 9: with 31 spline axle,detroit locker and a set of 4:11 gears.Oh and this was on a set of street tires.
My opinion of the stock 7.5 rear is "You can polish a Turd but in the end all you have is a nice shiny TURD"

5678TA

same thing happened to me.. got to the track, happy to finally race.. have my stock 7.5 with lightly used posi and 3.73s.. roll into burnout box, small smoke show, pull to the line, staged, 3000 ease out.. smooth launch, then i give it to the floor about 20ft out.. wheel hop and bang.. revs like crazy.. on KUMHO 711 Ectsa Street tires.. only 245/45-17's.. the hardest tires i have ever seen.. i end up shattering the differential.. i dont even think i made it to half track.. and i only dyno'd at 316rwhp and 359rwtq.. good stuff..
then on to the Currie 9", G-force T-5, Spohn Adjustable TA and Extreme duty driveshaft.. haha

YenkoST

iTrader: (5)

Did you also weld all the way around the axle tubes to the carrier case(pumpkin)....or did you just weld supports?

MrDude_1

let me take it to the track with a "mild" street/strip drivetrain, and i will explode it before the night is over.

Zdaddy

The last couple posts have mentioned their ability to destroy OE 10 bolts rather well as have I as mentioned in the 1st sentence of my original thread. There is nothing OE about my redeveloped differential. The only valid argument I've heard is from the guy that sheared his pinion gear... BTW, was that a Richmond gear set or a GM / Sawginaw part (need it for research)? It is easy to destroy an OE unit in more ways than one.

I have my own list:

Broken axles
fraged ring and pinions
fraged spider gears
fraged posi center

ALL OF THIS IS PRIMARILY ATRIBUTED TO AXLE SHAFT TUBE FLEX! With drag slicks, the tires try to propel themselves ahead of the rest of the diff and the direct effect is the ring gear pulling away from the pinion. Now these mods are not for a 1000hp car but for a purpose built street car with up to say 600hp.

Look, all I can tell you is I have been running the same differential now for a full year. I street the car, I drap race the car on ET Streets with a pretty violent launch! The differential still has a great bill of health. If you don't want to move to a 12-bolt or 9 inch and spend 2 grand, then this is for you.

YenkoST

iTrader: (5)

So, did you fully weld around the axle tubes and pumpkin together? I'm planning on the diff. cover from TA and welding the tubes around.

I have the 8.5" 10 bolt under my truck with 30 spline. Parish8(Jim) is running a G80(10 bolt 8.5" rear with an Eaton locker pushing 1055rwhp through his on DRs.

chevymec

iTrader: (5)

Zdaddy, what 60' times are you pulling ?

Dels383TA

You say with slicks,my car had street tires,radials,440 treadwear,rather hard,still left the rear in a pile of mush.Have alot less than 600HP,torque is allright but HP is not near 600(I WISH).
Some food for thought,if the 7.5 could be made strong,why did GM use an 8.5 in the Grand Nationl,Regal T-Type,Blazer ZR2,and a few others I cant remember.If it could be made to last then why did GM abandon it in favor of something that is stronger and can be built up to take the abuse.
Just some food for thouht,I do belive that what you are trying to do is a good thing ,but if you car was a stick car it may be a different story,hope it all works out for you thought.Good luck.

Zdaddy

I've seen some weld arould the tubes to the cast primary...helps some if not using a tube support setup. I opted to not weld the tubes. I've heard the 8.5's are worthy unit, but it gets back to the swap thing again...Just trying to show a possiblilty for using whatcha got.

Sonix

iTrader: (1)

eh?

Zdaddy

My car is a stick car. And once again I ask, was your 10-bolt purpose built as this or bone stock????? Nothing in life is impossible if you think through the solutions! Who would have thought I could make reliably 500hp at the wheels from a stock 305HO? I just stuck with it to solve the weak links. I don't need to be convinced or luck, I've been running the proof for some time now...

PS- 60ft time 1.70 and 1.68
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Sorry, I'll try to get you some better picture this weekend and the Moroso p/n.

Dels383TA

Not trying to convince anyone,just putting it out there,not saying that the way you are going at it is wrong,or that everone shoule rush out and buy 12 bolt or a 9".Just asking afew questions so that all angle are covered as not everyone knows everything about these rears and the weak points that they have.As for luck,I didnt mean it as an insult ,rather a justure of respect as it seems that you have a plan and are going to take it as far is it will go.

Sonix

iTrader: (1)

I'll save anyone their breath of calling his BS - he supercharged it.

WillSpeedy

Zdaddy, What spline axels are you running? And are you using c-clip eliminators?

Zdaddy

Hey it's all good!!! Still want to know what gear set that one guy was running that sheared the pinion...LATER

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28 spline and still running the c-clips. The Richmond PowerTrax has a really nice way of locking in the c-clips more reliably.

chevymec

iTrader: (5)

You sure GM put an 8.5 in aan S-10 blazer?? Have yet to see one of those.

jwfirebird

iTrader: (2)

i would like to know more about the tube brace too. is there an angle from the tube to the girdle or is it strait? if it is strait do you think it would control forward movement better at an angle?where did you get those adjusters?

im sure they used 7.5's cause they held up fine under stock conditions and thats all they care about. less metal to make, less rotating mass=more efficiency.

MrDude_1

so what are you going to do about the case flex by the pinion?

Zdaddy

There is a good amount of angle to increase effectiveness. The Adjusters are SPC toe adjusters p/n 69450 converted to a peice of mild steel tubing w/ the rod end adjusters.

The 10-bolt 7.5 outlasted the Borg Warner "Austrailian" and the 10-bolt 8.5. It was the differential in the F-body right up to 2002, right?

MrDude_1

yea.
but it was also the achilles heal of the Fbody since 82... with the stronger LT1 cars, or a stock LS1 car that hooks, you would break them. no question about it.

89gta383

iTrader: (5)

What kind of suspension mods do you have to be cutting a 1.70 and 1.68 60ft with 500 to the wheels? You should be cutting way lower 60 's than that. Once you get into the 1.4X range and lower you will know if your rear end can handle it consistently.

My 9-bolt with lca brackets and 335 rwhp has gone 1.65 and 1.68 60 ft's on motor but I know better to think it will hold up for a full season when I get to the low 1.6's-high 1.5's consistently.

I'm not knocking your mods, I just don't think you have the 60 ft's to confirm that your 10-bolt is 'bulletproof'. Bulletproof means you can throw anything and everything at it all season long.

Tony89GTA

iTrader: (7)

Thought you were making 459 at the wheels

I don't think you will be able to make it 'bulletproof' since it's still a 10 bolt so let's be realistic but it's sure hella stronger then what it was stock if what he is saying is true. Much better alternative for most then say slapping in one of these stupid Ford 9" that's never a bolt in and cost a **** load.

Orr89RocZ

iTrader: (20)

true, i have only 4 passes on the 10 bolt ls1 rear i put in my full exhaust only L98. i cut 1.74-1.75 so far. 3.42 gears, 2800 stall. i hope it continues to hold up. i have a good feeling with a few minor mods, i'll crack near 1.6x. its all in the tune and suspension and maybe alittle weight reduction. on my 1.754, i spun abit since my LCA's are no longer at the right angle.


Zdaddy...nice car you got there. lots of fine work in there, but i love your ground clearance! lol that exhaust is ridiculously low!

Dels383TA

Actually in 1993 the Fbody came with a 7 5/8 rear,a bit wider and has 28 spline axles,although the ceaner section is basically the same and interchangable with the right axles(87-92),I do belive that some of the 4th gens came with a Zexel Torsen carrier(worm gear posi) which was supposed to be stronger than the gov lock that most came with.

bowtiedude

Bullet proof nah. You aren't a very good shot is all. Take careful aim and BANG you'll get it .

chevymec

iTrader: (5)

Here is where I got mine from. http://www.lpwracing.com/p_axletubebrace.asp

Dels383TA

Not 100% sure but I do belive that is what came in the ZR2 Package.

Zdaddy

Ugh, that was 89gta that said he was making mid 300's, I'm making 459...You've got the point though, it is a good alternative to throwing 2000-3000 dollars at a differential if you don't intead on 1000hp motor or going to the drag strip every weekend and commit to 5000 rpm dump launches in hopes of getting that 1.50 sixty foot time. I'm more impressed with the 1/4 mile times than the sixty foot times though! I had the 12 bolt and took it back out....

PS- Beautiful car! I almost opted for the GTA....

Zdaddy

It only scrapes ounce in blue moon!
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Great source!!!

Zdaddy

Damn that's funny! And so informative too...

Orr89RocZ

iTrader: (20)

1/4 mile traps or ET's? lol ET's are in the 60 foots

chevymec

iTrader: (5)

Nah, they got the good ol' 7 5/8. The ZR2 package was a suspension/appearance package. You can take the guts from an s-10 rear and run in a camaro rear.
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Only thing that sucked was that you had to cut and weld all the tubes. The 3rd gen camaro kit was the only one like that at the time....

Zdaddy

Found the pictures of the diff just before installing it last year....

92 RSS

zdaddy, whats the pn for the diff cover? and where did you get the supports?

Zdaddy

Summit Cover- SME-8510400
SPC toe adjusters- 69450

The bracket to tie it all together have to be fabricated.

urbanhunter44

iTrader: (3)

Pretty cool man. How many passes do you have on it? What was your total cost in building it?

I've seen bone stock LT1 M6 cars shatter the rear end, if something can really be done to beef them up to survival your level of punishment, then it's quite an accomplishment.

92 RSS

yeah, but the cover from summit doesn't show the tabs for the rod ends.

Sonix

iTrader: (1)

He said in his first post that he had those welded on.
Not sure why this thread has gotten so much arguement, he's not exactly the first person on here to beef up a 10bolt...?
I'm still wanting to see where it's tied onto the tubes. Also, where the tubes preloaded.... in tension? ie, preloaded to pull the tubes backwards?