c-4 corvette rear differential/and suspension width

grumpyvette

Administrator
Staff member
Vette specs book says rear treadwidth is:
84-90 = 60.4"
91-96 = 59.1"
ZR1 = 60.6"
http://dazed.home.bresnan.net/narrowinga9.html

http://www.crankshaftcoalition.com/wiki ... _a_rearend

http://www.bhjproducts.com/bhj_content/ ... ng/dnk.php


http://www.currieenterprises.com/cestor ... px?id=3497

It's not specific on how the measurement is taken, but those numbers look narrow. It also doesn't make sense that it changes when the body style changed because there was no suspension change from 90 to 91.

would probably help if you told us/everyone, exactly where your measuring the length FROM & too,
the outside to outside edge of the disc brake rotors?
the wheel mounting pads,?
the tip of the wheel studs?
wheels on? or OFF?

please give some detailed referance and Ill go put the 1985 vette I have up on a lift and measure it

no that turned out to be slightly more complicated to answer than it at first appeared to be



OK ,I put my 1985 vette up,and measured it,with the car on a lift ,the wheel mount pads are almost exactly 61" wide...

but remember thats with the suspension not under load, hanging lower than it will while driving the car.
.with the car supported on the jackstands under the rotors like it normally sits, the suspension widens a bit as it squats, with the wheels on its going to measure 62-63",wide at the wheel mount pads,depending on load and ride height, if youve got the adapter plates too run the later 93-96 17" wheels on the early suspension youll add 3/4" to each side for the adapter thickness to either length (thats an extra 1.5" to the total length) keep in mind thats to the wheel mount pad, the wheel extends out and in from that dimension depending on the off set of its design, theses more offset to the inside as the rotors on the disc brakes are roughtly centered on the wheel but each wheel design can vary

bits of info you might need


http://www.carnut.com/specs/rear.html

http://www.teufert.net/other/rear end dimensions.htm

http://www.kevinstang.com/Ninecase.htm

http://www.currieenterprises.com/cestore/default_9track9.aspx

http://www.ford-trucks.com/article/idx/9/065/article/Ford_9_Inch_RebuildGear_Setup.html
the FORD 9" has advantages and lots of aftermarket support, but Ive used a DANA 60 rear with its heavier axles and bearings and 9 3/4" gears in all my race cars , they are slightly heavier (about 60 lbs) but basically indestructable compared to the 8 7/8" 12 bolt chevy or 9" fords


http://www.digitalcorvettes.com/forums/showthread.php?t=53882&highlight=dana

http://www.mopar1.us/dana.html

http://ford.off-road.com/ford/article/articleDetail.jsp?id=198404

http://www.ford-trucks.com/article/idx/9/200/article/Dana_60_Rebuild.html

http://www.currieenterprises.com/cestore/dana60.aspx

http://www.dutchmanms.com/pricesheet.html#Anchor-65123
so theres your answer

DANA 36 vs DANA 44

The C-4 Dana 36 was the only axle available in 1984 Corvettes. In 1985, Chevrolet brought out the Dana 44 which was similar to the 80-82 Corvette axle, but not interchangeable. The Dana 44 axle is considerably stronger, but not indestructible. The Dana 36 and the Dana 44 (44's in some autos and all manuals) axles were used through 1996.

The Dana 44 is much larger than the D36. The 44 has a larger, "beefier" carrier/components to handle larger (lower) ring and pinions, and increased torque. NOTICE THE LOCATION OF THE TOP CENTER BOLT HOLE ON THE DANA 36 THATS NOT ON THE DANA 44 REAR, thats a QUICK WAY TO TELL THEM APART

603967 GM 44 REAR 1980 CORVETTE
605172 GM 36 REAR 1984 CORVETTE
605180 GM 36 REAR 1984 CORVETTE
605220 GM 44 REAR 1985-87 CORVETTE
605239 GM 36 REAR 1984-86 CORVETTE
605260 GM 36 REAR 1985-87 CORVETTE
605321 GM 36 REAR 1988-90 CORVETTE
605322 GM 44 REAR 1989 1/2-90 CORVETTE
605365 GM 44 REAR 1988-89 CORVETTE
605417 GM 44 REAR 1990-90 1/2 CORVETTE
605490 GM 36 REAR 1990 1/2-96 1/2 CORVETTE
605491 GM 44 REAR 1990-96 1/2 CORVETTE
605492 GM 44 REAR 1990 1/2 CORVETTE


Look at the size difference, especially at the case above the yokes:

dana36.jpg

Dana 36

dana44.jpg

Dana 44

And visit

ikerds.com

Who were kind enough to supply the pics...



viewtopic.php?f=39&t=7

viewtopic.php?f=39&t=1317
 
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DAVE POSTED THIS

If you have a question as just how much power your rear end can handle here is a calculator that will tell you just how much stress you are putting upon the axles and differential.

http://www.moserengineering.com/Pages/axletech.html

Knowing how much torque you are applying (this assumes you have perfect traction with only a 10% slippage at your slick) to the axle here is a chart of aftermarket axles listing their failure points (on average).

28 spline axle________1.200" diam. ________ 4,571 lbs.-ft. stock (GM test data)
28 spline axle stub ___1.250" diam. ________ 3,787 lbs.-ft. stock Corvette (Dana 44)
30 spline axle________1.250" diam. ________ 6,473 lbs.-ft. stock (GM test data)
31 spline axle________1.315" diam. ________ 7,000 lbs.-ft. (Ford 8.8" rear)
33 spline axle________1.370" diam. ________ 8,200 lbs.-ft. (GM 14 bolt truck)
35 spline axle________1.500" diam. _______ 9,600 lbs.-ft. (Dana 60)
40 spline axle________1.710" diam. _______ 12,000 lbs.-ft.

Here is a web site with a great graphic that shows why spline count is so important.

http://performanceunlimited.com/documen ... guide.html
there ARE several suppliers of adapter tail housings for the conversion of a much stronger 4l80E transmission to the C4 corvettes C-beam support
4l80etail.jpg


Now bear in mind you must further reduce these figures by an additional 10% because that factory uses a cheaper steel alloy and then relies upon on an induction hardening for case strength at only the bearings. Additionally the total torque load is split by half (you have two axles carrying the load). Because of this my 12 bolt rear end is still together with it's 30 spline axles even though I am routinely hammering it with 7,063 lbs-ft of peak torque (582 cid BBC with 697 peak torque, 2.48:1 first gear in my 4L80E transmission, and 4.56:1 rear axle ratio.) But because I have broken rear axles before (among about every other part in the drive train) I am looking at replacing the rear with a Dana 60 that I recommend to everyone. With it's 35 spline axles stock and 40 spline with the use of a spool; it is virtually unbreakable.
 
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