I've got a 80 and am having one heck of a time trying to find a good stable rear end for it. My stock rear won't stand a chance. I hear the C4's d44 are much better. So how much HP has lived through these? Are there spline upgrades available?

Any info will be helpful.

 

HP does not break anything, torque does.

The answer is reasonably well-explained on my website.

 

It will basically go out when it damn well pleases! Isn't that right vader86?? LOL

 

The D44s are not all that strong once you start pushing around 500ftlbs and sticky tires. They can generally handle 1.5x short times on a regular basis and with modiciation can go into the 1.4s. The spider gears are weak point so to reliably go into the 1.4s, many have installed spools. I've seen D44s handle more and go into the 1.3s, but i wouldn't recommend trying on a regular basis. Smaller gear ratios seem to be a little stronger too (less TQ multiplication in the rear). If you're going to modify the car to fit a D44, why not just install a solid axle?

If you're bust'n you C3 rear, i'm assuming your application is drag racing.

 

This video from C4 Forced induction section has got me rethinking this:

http://www.speedwaycorvettes.com/vids/840sKingVette.wmv

 

Weight has alot to do with how much these things will handle too... there are some people with 425+ft/lbs running 1.6's all day on a D36. I think thier cars weight is ~2800lbs though.

 

They're quite strong with the proper modifications. In conjunction with another member on here we're building some D44's that are easily 8 second capable, and we'll see if 7's are possible with my car. The secrets are removement of driveline slack, setting up the differential very tightly (if you're using a posi-unit), cryogenic treatment of the assembly. This will take you to around 650-700 lb/ft. After that you'll be looking at a spool, chromoly halfshafts, and 300m spindles. I've got two complete units about to go out to their respective new owners and I wouldn't hesitate for a minute to say they'll take anything 99% of Vette owners could ever throw at them.
-Jeb

 

Jeb, i think yo're being a little aggressive (unless your including all the TQ multiplication factors)......but i DO hope you're right. That unit you cryo'd for me is still working fine after two seasons of abuse......but i'm not into the 1.4s yet. I'm afraid to put more converter in it.

btw, i will be calling you later today.................whoops nevermind. Just read your PM; you must have read my mind

 

What is your website?

 

Click his profile. It should show the link to his website.

 

I agree with both Ralph and Jeb here. Jeb and I worked on getting the spool in one of these rears after I experienced a little trouble with the stock carrier. I looked at it for the first time and said, NO way am I putting this thing back in the car. Therefore in went the spool. It took some trial and error, but I was successful on the second attempt with locking the stub axles in place.

Since then, knock on wood the only things I have had trouble with are the u-joints, and 1/2 shafts.

Broke two 1/2 shafts, mind you they were stock on the car from the factory in 89, with literally HUNDREDS of runs on them (not bad if you ask me).

On the u-joints this past year the car was eating them up like candy. Sometimes as little as 1 launch would crush the needle bearing up like sand.

Finally I came across a guy on the superstock forum and he suggested that I use some mobil 1 synthetic grease, I did it as a last ditch effort, and also cryoed the entire rear at my fathers place.

At this point in the game I was getting 1.3 60' times nearly ever pass.

After doing the last two things I was trouble free for nearly 1/2 the season. No problems at all. (knock on wood). There is no "babying" it when I get up to the line. Its ALL out every pass - and it sees MANY.

I was in a discussion before on a "making things seem easy" so I am not trying to make it seem that these things will work for everyone. I have spent a considerable amount of time working with my suspension to get it to launch like it does. There are a LOT of dynamic angles involved when you hit the gas in one of these things.

But I see no reason people can't go mid 1.4s pretty reliably with the D44 and these mods. Or even high 1.3s. With the stock carrier in there and spider gears, I would not give it pass 1.5s for long. You will break one of the spiders, they will start to sphal and then break, and where that broken piece lands, its anyone guess. If its in the wrong place you will break out the case. With the spool you eliminate this possibility.

Lastly as mentioned there are also some other obvious things you can do that I think many mess up with, and that is properly setting up the ring and pinion, and installation of the C-Beam.

One last point, if you have a manual transmission, and are making any amount of power at all, FORGET all the above, you will eventually break it from the shock. Its just TOO MUCH of a snap when you dump the clutch for the C-beam and other mounts to absorb. This should not be taken as a dig against manual transmissions - just making a point.

 

Thanks for the food for thought.
As far as what I am trying to accomplish is, I have a Twin Turbo 406, in the car now. It's been about 3 years of work to get to the point I am now. However for the last 6 months I have been at a stand still trying to figure out what to do with the rear. I do not intend on using this as a drag car. I plan on mainly using it as a show car, weekend driver. But I would be lying if I said I wouldn't want to make a couple passes on the strip. I want everything in the car to be capiable parts. I planed on installing the guildstrands 5 link rear suspension conversion along with a
78 center center section with a BOE kit from Toms rear end. However After talking with him he maintains that he would not be confidant in the rear holding up, Aside from that, he also cannot tell me how long it would take for him to get the parts together. I am initally hesitant on the the C4 rear ends because they are aluminum. However like some have shown here, they look to be more promising than what I am currently working with. Aside from that, the suspension is already 5 link, so that would save me the 2.5k in buying guildstrands kit. I believe the fabrication requirments to install the control arms would be about the same for both anyways.

I have thought about a solid rear, but... it's a corvette. it's meant to have IRS. I know I am probabily making life much harder for my self by deciding this, but I must persist in sticking with a IRS.

I have found that the batwing differance between the c4's and c3's is only about 3/4 of an inch, dimensionally this looks like the best direction to take.

I thank your all for your input so far.

 

I would suggest calling Tom at Tom's Differential and looking into one of his IRS setups for the C2/3 Vettes... Good to 7.50's but not cheap.
-Jeb

 

Hi guys, just to give you a little information of the Dana 44 rear end. I've had a 3300 Lbs C4 Corvette and was 60 footing 1.31 this was my nitrous car. I had a 4800 Stall converter and left on a transbrake with a 200 shot right out of the box at the track, it gave it another 200 progressive second and third gear ETs were 9.20s @ over 149 MPH Street trim.

Here are some things that I've learned about the Dana 44 Rear end. First thing is find a '93 and newer Dana 44 Rear end from a 6 speed C4, because the case is ribbed more and stronger, also find 93 and newer C4 halfshaft, it has to be aluminum; they are much stronger and thicker than the earlier models. For U-joints, use brute force u-joints they're heavy duty. The Aluminum halfshafts tend to absorb some of the shock, in my past racing history with C4 Corvettes I have never broke one of these halfshafts. The brute force u-joints hold up very well and never broke one. Another point is to find complete rear spindles from a '84 Corvette with no ABS, they're very strong as well never had a problem. Keep in mind, all my passes were on 28/10/1/2 slicks.

In my best knowledge; I find the IRS Suspension that I noted above had no problems and was driven on a daily basis on drag radials. In my past history I found it very reliable and works great! for low 9 second cars. Also I have tried and succeeded of going 8.40s at @176 MPH (this was a turbo car) on this suspension noted above. Problems I found were: couldn't keep U-joints in the halfshafts more than 5 passes, it would crush the needle barrings into powder so I didn't find it after these times and speeds to be reliable at all for an everyday car. The turbo car made 1200 RW HP and weighed 3500 lbs. with driver. www.speedwaycorvettes.com

Hope this helps the questions.