CadVetteStang

What are the torque and horsepower limits of the Dana 36 and Dana 44? Are we talking Gross flywheel power, or net?

vader86

There is no concrete limit to the torque either can take. They can each blow when they feel like, if you hook well enough. HP doesnt break things.

In practice I'd say D44 is good til youre in the low 10s, D36s the low/mid 12s, but some will have gotten 1000 passes at times lower than that, and some wont get 2 passes.

Mr. Magoo

Hmmm looks like I should grenade my D36 this spring.

Overboost

I am in the same boat as you. I will run it with what I put on it, until it goes BOOM in a big way, then upgrade.

I have towing insurance.

bobmic93

I think the best measurement to use would be the 60' times that members have taken there 33 or 44 to befor the bust. What are the best 60' times you have seen befor the bust. My 33 has seen best of 1.76 and I put down 365hp to wheels

MTVette

My D36 took hundreds of passes in the 13's with no problem. Sixty foot times in the 1.9's and occasionally into the 1.8's. Finally I upgraded to a HotCam, 1.6RR's, LT headers, a 2600 stall torque convertor, and 3.54 gears in the D36. I had a few dozen passes in the low 1.7's, and the gears grenaded.

bobmic93

Did you buy a new or used 44? What did it cost? Curious why you went with 3.33 gears unless it came with it. Looks like those MTs work good for you.

0ski_dwn_it

It is all hit or miss.

I ran my MODIFIED D44 with a spool to 1.37 60' times, but everything else was breaking besides the actual differential.

The first MAJOR problem are the spider gears in the carrier, then is the carrier itself, followed by the perimeter equipment like 1/2 shafts and stub axles.

There are just TOO many angles and components that are too small to handle abuse. Its like trying to balance a 10lb weight ontop of a toothpick. You might be able to do it if you can load the toothpick perfectly in the vertical direction, but as soon as you get an angle involved (which the IRS has plenty) then you snap it like a twig.

I have been there and tried it all for MANY years. There are things you can do, but I never got more than a few good days out before getting another broken component. In my case I was LUCKY to never break anything major - however I am one of the few to push it as far as I did and not get the center broken. Others I race with and know have all broken the centers making MUCH less power and 60'ing much less than I was/did.

In my honest opinion, once you start to break stuff - whether its your power level or way your drivetrain is setup - you will be plagued from then on out. Furthermore if you are a stick car, your likely-hood of breaking something major (case) is 50x better.

There are other options out there now like the solid rear conversion where you would be 100x better off and be able to put as much power as you want at the car and be safe and free of breakage. I went for years and though an engine build that I limited the power on due to the IRS. Now I wish I had put -15 or -11 heads on it and be running mid to low 9s!

lt4obsesses

Just to throw this out there. These rear ends were not really designed for the drag strip. The IRS was designed for the handling aspect of the Corvette. There are alot of intricate moving parts back there. The whole set up is designed to reduce roll while allowing for acceleration out of a corner. Remember that Corvette was and is designed to be a lower cost alternative to Porsche and whatever else the Europeans want to throw at us.

That being said, we still can have alot of fun at the strip. But if you want to hit the drive train with 350-450 ft-lb of torque like a sledge hammer, it's going to break eventually. There are only two ways I can think of to prevent this. One, if you really want to drag race, invest in a solid rear designed for it. Or, two, learn to drive around the IRS and build your car for top end trap speed. Just my .02

neat

I've broken as much rear end parts as anyone, and I can vouch that it is definitely not power or 60 time related. The biggest thing, is how that power is applied to the rear end, if you are a stick or an auto, and controlling wheel hop.

On motor, my car is making 270 RWHP and 360 RWTQ. I broke spindles and half shafts cutting 1.9's on street tires. The reason is because of the clutch I was using, and the way I was launching the car. The clutch I had hit like a Mack truck, and just dropping it from 2500, 3500, or 4500 was a death sentence on the rear. I don't know exactly why, but I have some theories on it:

1 is the obvious, a stick car doesn't load the drive train at the line like an auto. There is slack in the clutch, transmission gear lash, U-joints, rear end gear lash, some more U-joints, and finally the spindle to hub lash. I don't know what the max amount of slack could all add up to, but I know it's pretty much impossible to have all that stuff be tight when you leave the line with a 6 speed car.

Look at the rear end of your car when it's sitting at normal ride height. The rear differential sits above the hubs, so the half shafts point down. This puts a crazy load on the U-joints if you try to apply power suddenly. It's like a swivel that you would use on a ratchet in your garage. If the angle is slight, the swivel works pretty good. The steeper the angle, the worse the swivel works. On steeper angles, the swivel will work OK for 30 degrees or so, then kind of bind up. When it binds up like that you can usually muscle through it and force the swivel to turn. I think sort of the same thing is happening in our rear ends. With the differential up high, the angle is pretty steep for the U-joints. When the engine muscles them past the point where they are binding up, everything deflects causing a failure.

The best way to solve this is to allow the rear end to act the way it was designed to. The differential will drop lower as the car squats and leaves the line, which helps align the half shafts with the rear hubs, which takes the bind out of the U-joints. With a clutch that hits really hard, the rear doesn't have time to sit down before power is applied. Couple that U-joint binding with the sudden smack of power associated with the slack in the drive train and you're almost guaranteed to have a failure. There are a couple ways to solve this. You can slip the clutch, allow the car to roll a few inches before coming off it completely. You can use a clutch that doesn't hit like a mule, I have had great luck with the dual friction centerforce. There are some alignment changes you can make to help. Or you can go solid axle. In my opinion, if you're looking to cut 1.6's or even high 1.5's at the drag strip, the stock D44 should handle it pretty much forever, as long as you are willing to accept that the car must be squatted down before you really hit the rear with power. The easiest way to do that is to use a stock-ish clutch set up that uses a dual mass, uses a sprung disc, or a sprung hub of some kind. Any clutch with some give to it will help tremendously. The give in the clutch allows all the slack to be taken out of the drive train smoothly, with no sudden hit. It also allows the car to start to squat down without 100% engine power being immediately applied to the rear.

Before everyone thinks that the only way to make it work is with a horrible, slipping, clutch; just realize that your stock set up slips - a lot. Most people don't realize that the stock clutch has so much give to it. The dual mass turns a great deal while the clutch is engaging, really cushioning the hit to everything. So, laying 20 feet of rubber when you rip second, barking the tires on the way into third, all that is being done with a clutch that has considerable give to it. A clutch that slips slightly is not the worst thing in the world. I can vouch that difference between one that has some give and one that has no give is night and day. Find someone with a McLeod twin disk in a C4 and go for a ride. The brutality and violence with which it engages is impossible to describe in words, you literally have to feel it to believe it. I know I thought my stock clutch was hitting pretty hard, then I thought my stock set-up with a hardened clutch disk was pretty stout, then I bought a McLeod and my entire opinion of clutches changed. I eventually sold it and went back to a slipper style clutch like the Center Force and I'm much happier, and breaking far less parts.

88BlackZ-51

Good post Neat.

I have been in Mos 90's car with the McLeod twin disc and in my opinion it's overkill. It's grips so hard! He is running a solid roller 396 in the area of 490rwhp (not too mention the 200 shot of NOS).

I have a friend that just installed the same clutch that you had in his 89 coupe with a 383/superram etc.....I am curious to see what parts he breaks if any. Here is a post by Jerry.

http://forums.corvetteforum.com/show....php?t=1941967

In his case, I dont know if its the D44 he should be concerned about as much as that clutch that he purchased. Time will tell I guess.

I have been in 415 ZR-1's, TT C5's making 700rwhp, TT Vipers's making 850rwhp. I have never felt anything like Mos90's McLeod twin disc. I will never put that clutch in my car if I go with a ZF6. It was a feeling like no other that I have felt in a car, and I have been in ALOT of cars during my life.

MTVette

I bought the D44used, with about 10K miles on it. That's why it has the 3.33 gears. I'd rather have used 3.54 or 3.73 gears, but I'll go with what was cheap and available. I've got those MT's down to 1.68 on a good day, and I can drive them to the track if the weather is good.

MikeyT84

I have 340/350 to the wheels, Stage 1 clutch ROD 6, 3.73's and BFG G-Force 315 D/R's I have had about 20 or so 1/4 mile passes best 60' being a 1.72 the D36 is holding fine for now but when more mods come and it breaks a 44 will be on its way.

CadVetteStang

Anyone have a Dana 44 with 3.07 gears that they don’t want because of the ratio? It sounds like I could make a Dana 36 survive if I don’t play with it too much, but I don’t want to break it, because the car will be a daily driver and about the time I get it finished, my son will start college. I could start out with a 36 if I knew I’d be able to find a 44 with 3.07 gears for an affordable price and do an upgrade. Am I correct that you can change the carrier only without changing drive shafts or axle shafts? Is it a direct bolt-in, or does it require cutting and welding? My engine in stock trim was rated at 400 HP @ 4400 RPM and 550 lbs. or torque @ 3600 RPM. The upgrades should add 15% - 20%, so with the deduction to figure rear wheel HP, it should put the 400/550 to the wheels. (maybe a little less) but still, I’m not convinced that a Dana 36, though cheaper to buy, is a good choice for my combo.
Thank you all for the great information, it tells me that if I have to go with a 36 I can make it live until I can buy an upgrade.
Cody

bobmic93

6 speeds came with D44. Just call me Santa Clause!

scooter18155

judging my mikeys sn he might have an 84 which didnt come with dana 44s in standard cars 85 and up did.

MikeyT84

I wish the 84's did, the car did have a 4+3 stock, we swaped it out with the ROD 6 when the stock unit failed.

hgh pwr

I can tell you my dana 36 a4 didn't last long after i did the lt4 heads and hot cam,the next day after i drove my car home i decided to get on it coming out of my condo,I beleive it was the down shift to 1st gear that did it but i was living on borrowed time anyway,went with a toms differential that was on sale so i went for it ,a little expensive but there was no solid rear that was close to what i spent or else i would go that way.
What vader says is true when its time it will break.

turbotim23

well I have a 93 w/automatic would like to install a nitrous kit and race it once in awhile[and soild axle is not in the budget].I bought a dana 44 but haven't put it in yet.You make it sound like how you launch it makes all the difference in how it lasts. Any tips on how to best do this? Or if the rear end is high at ride height before launch couldn't different springs or shocks help the rear end squat down faster so that driveline would be straighter much quicker? Thanks Tim

neat

The auto will help tremendously. Just hold the brake and come up on the converter pretty hard to load the drive train, then let her rip.

With the D44 and an automatic, I don't think you'll have any problems at the power levels we're discussing.