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destroyertta
11-15-2015, 09:52 PM
So what's the difference between the viper and the corvette Dana44 I believe the viper one is stronger is it the same case and the internals are stronger or the bat wing and everything different if so later if I want to change my corvette Dana44 for a viper one will it bolt in the same place

chevynut
11-16-2015, 06:01 AM
They are not a bolt-in. The internals are the same Dana 44 HD parts and they should be the same strength. In fact, you can put Mopar (Viper) gears into the Corvette case as I'm doing now ;). The Viper batwing is shorter by quite a bit. Also, there is no provision for a toe adjuster mount or lower strut rod mounts. I would not consider replacing the C4 Dana 44 with a Viper part as you don't gain anything and would have to do a lot of custom fab work.

markm
11-16-2015, 06:03 AM
I really doubt there is much difference a Dana 44 has an 8.5 ring gear the same as the later corporate 10 bolt. I believe serious Viper racers have a Dana 60 center section.

chevynut
11-16-2015, 06:17 AM
The C4 Dana 44 is called a "Dana 44 HD ICA"

"The C4 Dana 44HD is a modified Dana 44 using the Dana 60 pinion with larger bearings and of course a different housing, cover etc. I don't believe the term "Super 44" came around until the Viper.

In Dana terms they're all just D44/216 ICA rear axles. The 216 is the metric dimension of the ring gear diameter. It's traditionally known as an 8.5" Later D44/226 ICA rear axles found in the Viper and later Jeeps are essentially the same with 2 exceptions, ring gear diameter (226mm) and the ring gear bolts are 7/16 diameter vs the 3/8 diameter of the earlier 216mm packages. A 226mm ring gear can be packaged with either 3/8 or 7/16 bolts and can be used in the Corvette housing but may require some "clearancing" for the ring gear. You don't want the 226mm with the 7/16 bolts though.

There's very little from the C3 D44 that resembles the later C4 D44 packages. The C4 D44 housing from '85 - '87MY's is somewhat different in appearance than the '88MY + housings but they'll interchange with no problems. Internals are the same."

Read more: http://www.corvetteforum.com/forums/c4-tech-performance/1964263-how-to-tell-the-difference-between-a-dana-36-and-44-a.html#ixzz3rfDyelJH

destroyertta
11-16-2015, 02:43 PM
I just heard the viper ones are stronger how much torq can the d44 take with mine i plan on atleast changing the gears but maybe just replace everything when the time comes mine is a stock 87 d44 with I believe 3.08 gears in it want maybe 3.73 or the something close

chevynut
11-16-2015, 02:58 PM
I just finished installing the ring gear on my rebuilt carrier. I measured it and it's about 8.9" in diameter (OD), which is the 226mm 4.10 Viper gear. It just barely fits in the case.

After doing this rebuild on mine I don't think I'd recommend just "replacing everything" because the cost can really add up. I replaced my posi clutches but the ones I took out are barely worn. hey must have been replaced when the 4.11 gears got installed. A couple of the bearings had some dark spots on them from sitting around so long as somehow water got into the differential and came out when I removed the batwing. I think the vent was broken off. It didn't really hurt anything. You can get a master rebuild kit from Tom's Differentials pretty cheap, or you can just replace what's bad. I had some new bearings already and bought two new Timken carrier side bearings off of eBay for $20 shipped with cones and races. They are usually around $48 for the set.

According the a writeup I have this is what the D36 and 44 can take:

Output Torque Ratings-
Max Continuous-
D36=850 lbs-ft
D44=1,100 lbs-ft

Max Short Duration-
D36=2,800 lbs-ft
D44=3,460 lbs-ft





When will they fail?

There is no concrete limit to the amount of power that a rear axle will hold, they will blow when they damn well please. Remember, its not the HP that breaks anything, its your TQ number. The transmission is the same way.

The important specs here are the output torque ratings. It's really all about traction. If the tires let go before the axle reaches it's terminal max short duration load, nothing breaks. Output torque is subject to about a 10 percent safety factor. Remember that engine torque is multiplied by the drivetrain. If you have 330 lbs-ft x a 3.0:1 first gear and a 3.07:1 axle ratio, that's 3,039.3 lbs-ft of potential torque. (Multiply by ~2.0 for a torque converter) If the tires could hold that much, you can see which axle will break first. Fortunately, most tires can't hold that much torque. You can calculate available traction torque using the following formula. You need to have the weight on the rear tires, plus the amount added from weight transfer.

weight on rear tires X COF X tire radius
Traction Torque= __________________________________
12

COF= Coefficient of Friction. For "normal" tires and pavement, use .7 as a "worst-case." For really sticky tires on normal pavement, use .9. For slicks and sticky dragstrip pavement, use 1.0 to 1.5.

Radius= Measure from center of wheel to ground with tire aired up as it will be driven and the car loaded normally.

Sample: 1993 C4 Conv. 3383 lbs, 50-50 weight Dist + 10 percent rear weight transfer (kinda on the high side), 285/40-17 tires (10.7 radius)

1860 X .7 X 10.7
TT= _______________ = 1160.9 lbs-ft
12

So, with that '93, it's engine can generate 340 lbs-ft, first gear of the automatic is 3.06 and the axle ratio is 2.59. That combo generates 2694.6 lbs-ft of potential torque. Because there is some loss of efficiency for various reasons, multiply that by .9 to get 2425 lbs-ft.
The Dana 36 in that car can handle a peak of 2800 lbs-ft and on the street, you can generate 1160.7 lbs-ft of traction torque, so your are very safe. Start plugging higher COF numbers, adding deeper gears, taller tires or more torque to see just how safe you are with all your mods. Ideally, your traction torque must stay well below output torque. Remember that the dynamics of all this is not necessarily linear like the equations. You may be lower or higher because of changes in pavement, etc. You may momentarily exceed the output torque rating of the axle.

Finally, Don't forget those universal joints back there. A 1350 size u-joint is rated for a maximum of 2,260 lbs-ft (ultimate strength), 1240 lbs-ft max short term and just 206 lbs-ft continuous.

However, a D36 should handle a fair amount under street duty, 400-500crank Tq will eventually kill it, but it may last 50,000mi that way. (it could also go after 10K, you cant say) But, if you put race slicks on it to go drag racing, its gonna blow, and probably that day. Drag Radials like Nitto might let it last 10 passes, or it might last 1000 passes, depends on the hookup of the launch.

The Dana 44 with its 8.5" ring gear is essentially equal in strength to the much touted GM 12 bolt. A D44 is usually bulletproof under street duty, and can usually go into the 10 second range in the 1/4 before it goes. The biggest weak spot in them is the drive spindles and the posi-unit. At this point you may want to either cut back your power, or go to a straight axle. IRS is a great thing, but its not made for that kind of power. I know Speed Demon motorsports builds some billet drive spindles that are essentially bulletproof but do come at a substantial price, but are probably worth it to those running serious ET's with their IRS.

Cryo treating the cover and the ring & pinion gears will make the unit much stronger, on both. The ENTIRE diff and drive spindles might also need it.

markm
11-16-2015, 05:32 PM
The Dana 44 with its 8.5" ring gear is essentially equal in strength to the much touted GM 12 bolt. A D44 is usually bulletproof under street duty, and can usually go into the 10 second range in the 1/4 before it goes. The biggest weak spot in them is the drive spindles and the posi-unit. At this point you may want to either cut back your power, or go to a straight axle. IRS is a great thing, but its not made for that kind of power. I know Speed Demon motorsports builds some billet drive spindles that are essentially bulletproof but do come at a substantial price, but are probably worth it to those running serious ET's with their IRS.

8.5 is the 71 newer corporate 10 bolt ring gear size, the 65-72 12 bolt was a 8 7/8 ring gear. The only OEM factory diff ever good enough to go to the 10s in the 1/4 is the Dana 60 with 35 spline axles and 9 3/4 ring gear.

chevynut
01-29-2016, 06:00 AM
Here's some real-life experience feedback with the Dana 36 and 44....

http://www.corvetteforum.com/forums/c4-tech-performance/2221642-dana-36-and-dana-44-horsepower-limits.html

CameoVette
07-08-2019, 11:26 AM
They are not a bolt-in. The internals are the same Dana 44 HD parts and they should be the same strength. In fact, you can put Mopar (Viper) gears into the Corvette case as I'm doing now ;). The Viper batwing is shorter by quite a bit. Also, there is no provision for a toe adjuster mount or lower strut rod mounts. I would not consider replacing the C4 Dana 44 with a Viper part as you don't gain anything and would have to do a lot of custom fab work.
Hi, I see you installed Viper ring and pinion in a corvette Dana 44 years ago. Did you have to grind out some of the housing to allow for the larger ring and pinion? If so can you tell me where to find information on where to grind and how much? Bradley

CameoVette
07-08-2019, 11:41 AM
Does anyone know information on where to grind the housing for a Corvette C4 Dana 44 housing to allow for the larger 8.9" Viper ring and pinion to fit?

chevynut
07-08-2019, 12:18 PM
Does anyone know information on where to grind the housing for a Corvette C4 Dana 44 housing to allow for the larger 8.9" Viper ring and pinion to fit?

I installed a Viper (Dana) 4.10 gearset into my stock Dana 44 case with no grinding or other problems. It's a late 89-96 housing.

BamaNomad
07-08-2019, 07:02 PM
I put 4.10 Dana gears in a 1990 ZR1 (replacing the 3.45 gears), but I didn't like it... 4.10 is too much for the street - it made me feel like 'Joe Hot Rod' and I drove that way. After a few months I put the original gears back in. After that experience, I think the 3.70- or 3.73 gears would be the best compromise on the street (if you're running a 6-speed manual)...

chevynut
07-08-2019, 07:45 PM
I put 4.10 Dana gears in a 1990 ZR1 (replacing the 3.45 gears), but I didn't like it... 4.10 is too much for the street - it made me feel like 'Joe Hot Rod' and I drove that way. After a few months I put the original gears back in. After that experience, I think the 3.70- or 3.73 gears would be the best compromise on the street (if you're running a 6-speed manual)...

Most guys I've read about on Corvetteforum.com say they love the change to 4.10s. Of course that all depends on what your transmission gearing is as not all transmissions have the same gear ratios, not even 6-speed manuals...not even all Tremec T56s. One reason I went with the 4.10s is to be able to better use the 0.5 OD sixth gear on the highway. And I think a 10.91 overall ratio in first is going to be great in town. It would be like a later Muncie M20 with a 4.26 rear gear or an M21/22 with 4.96 rear gears...nothing wrong with that. My Porsche has a 13.15 overall first gear ratio and it's a blast. :)

markm
07-09-2019, 10:50 AM
I cannot imagine running less than 4.10 if 6th is .5-1 that makes final drive 2.05-1.