I think you took my quote out of context. W/in the realm of stock and stockISH cars...cars that you can actually use on the street, on a road trip, etc....it's a monster. I could take it to Miller and drive by any stock or stockish car there...and past many modified ones too; all w/no issues w/brakes, temps, tires, nothing. That makes it a "monster",,,w/in the context of stock cars.

I could take it to our strip, which is at 4200' elevation and w/a DA of 7000'+, run 12's at over 110. W/in the context of stock, or stockish cars, that you can actually drive/own/trip with, getting 30ish mpg...that is a "monster".

However, it was not that fun. I bought a stock '92, which is no where near the "monster" on the track that the '06 was, and I never drove the '06 again. Sat in my garage for 4 months, then I sold it.

Anyone can find some car that is more "outrageous" than someone elses car. You happen to own one. Done any 2000 mile road trips in that car? or 800 mile days? Probably not. This thread is in the context of the OP's car, and I'd wager to say that w/in that context, the C6 w/Z51 package and nothing else...is a formidable "monster" on a track. But yes, it is also a cushy, soft, boring car.

 

The thread is quite informative. To lock it would be an injustice to 1MeanZ's efforts, so please keep on track.

JamesC

 

I wish I knew what you have forgotten about fabricating. Bravo! This thread needs to be a sticky!

 

I was thinking of doing this swap to another car I have big plans for and Im wondering since we have the advantage over a corvette of a longer rear 1/4 why you couldnt swap the left and right side spindles and control arms around L to R ?

it would allow the mounting to be at the rear of the car. and would save the rear seat.

 

I won't say it's impossible, but you would run into these issues:
*Spring
*Shock
*Tie Rods

When you flip the Corvette rear knuckles around, the connecting points for the above, move. The shock, you could deal with since you're making custom mounts in the car anyway. Spring is manageble too, if you're going to coil-overs. The Tie Rods, though...not sure how you'd get around that issue. I guess you could fabricate your own mount on the knuckle? Then there is the issue of the car bodies strength in the area behind the rear wheel wells.

 

The idea of using the front suspension as a template for the rear is great.

The spindle would need to be modified so that the axle could turn the proper parts, a CV housing would need to be made for each spindle, halfshafts for each side would need to be made, CV housings for the pumpkin, and a pumpkin would be needed. With some good scrounging, I imagine the only thing that you would absolutely need made is the halfshafts.

Attach a homemade toe rod from the RLAC chassis point to the steering ear on the spindle, run a coil over setup to caster/camber plates in place of the rear shock mounts, replace the ball joint with a Del-Sphere joint, and modify the spindle to accept the halfshaft and you should be good to go.

 

For what you're talking about, c4 diff with c5/c6 control arms/knuckles/suspension would be the best combo, if at all possible. Then all the design/geometry stuff is already made. C5/C6 stuff is the same front and rear so there is already room for a halfshaft to go through.

 

I have to say, well done, I was a little sceptical when I saw this first a while back, but now I'm really interested in doing it to my car once funding allows. This is really impressive.
I've been reading over this thread for the past few days. Maybe I missed it, but did you re-use the stock rear shocks for this? It looks like it, but I can't be sure from the pics.
Also, are the door bars neccesary? I have no need for my rear seats once the ar reaches the point I can do this, but it's not enought of a track car to need them unless it's required for structual reasons with the front diff mount.

 

I did re-use my Koni Yellows on the rear. They seem to be valved plenty firm to control the 84 non-Z51 spring I'm using.

Door bars are not a must, I did them for structural rigidity of the car, not the diff mount. I could have made a saddle or modified the driveshaft tunnel in a way that would accomodate the diff mount that would have been much less intrusive, but since the car had a roll bar anyway, I went for the ultimate in strength and rigidity. When I pounding this car on a road course with slicks I don't want to worry about anything moving.

 

You did an awesome job I bet you're Z kills Bimmers and Porches all day I was wondering though, do you think this set-up is any heavier than the original solid axle set-up and did you use quarter-inch plate the whole time or did you use thinner gauge in certain areas?

 

The corvette parts are all aluminum, so I'm sure it's lighter than the solid axle. I haven't had the chance to weigh the car yet, but I'd like to corner weight it this spring after I get my front suspension done.

I did not use 1/4 plate on anything, it wasn't needed. The thickest plate I used was 3/16 and that was for the trailing arm mounts which were also reinforced into the roll bar.

 

I think I just saw this car in GM High Tech, looks great. I was wondering, what size tire you have in the back? It might say in this thread but I did not see it. I am very interested in doing this swap and I want to make sure my rear tires will fit. I am running 335/30R18 on the street and 305/35R18 on the road course. Thanks for your help. I would love to get a close up look at this car, I live just NW of Indy. If you are at any car shows or anything this year let me know and I will drive up and look at it, thanks.

 

Yes that was my car in GMHTP in the IRS article.

The rims are 17x11, tires are 315/35/17. As you can see in the pix, I did minitub the car about an inch. With no spacers on the rear the 11" rims tuck in pretty nicely, about as far as the stock rims. I could easily pack a 12" rim and 335 or even 345 on the car without too much trouble, I just don't have the money for a set of custom rims right now.

 

1MeanZ
I have been fallowing this thread closely, I have always wanted to do this, just before Christmas I purchased a 1990 Dana 44 for $300.
when you said that you could run up 335 or 345 with custom wheels, what would have to be done to make that work? my wife is getting me new wheels for fathers day and I have been looking at 18's what would your suggesting for wheel tire size for the rear? I do not want to spend big $$$ on wheels.
I have mixed felling in a roll bar / cage one day I want on other days I dont.
what is the angel of the control arms and mounting brackets? this is one thing that is holding me from pulling the trigger on this mod.
thanks

 

Someone alse asked arlier in the thread but I didnt see an answer, How does the IRS compare in width, rotor to rotor to a stock 10 bolt?

 

i "think" this is accurate, it is an earlier year though

 

That was a steal of it is a real Dana 44. I've never seen one go for less than $1k

I cut the inside of the wheel wells out and moved them in flush with the "frame". Basically I minitubbed the car 1".

If you're going to run 18s, I'd just run some 18x10.5" Z06 replicas at all 4 corners. I'm saving for a set of CCWs....

If you're going to abuse the car on-track with slicks I wouldn't do the swap without attaching it to the roll bar. For street use only I think you could copy what Jay Cutshaw did on his 4th gen Formula and be OK. I've spoken with him on the phone about his setup(he is a great guy) and he says he has no issues changing the geometry the way he did.

I think I posted a diagram displaying that info on the first page. If not I'll post a link to it again.

I never measured mine. I think the later units (89?-96) are slightly wider but I'm not sure. There are a lot of subtle differences between the "early" and "late" setups. What I can say is that I had my 11s on the rear with 1.5" spacers on the stock rear axle and the tires were flush with the outside of the fender lips. Now with the IRS and no spacers they are about .5-.75" inside the fender lip.

 

That certainly is a steal. Dana 36's are that cheap, but I got my Dana 44 for about $1500, and that seemed to be the market price for them.


If it really is a 44, you might wonder what's wrong with it.

 

One more question I may have missed, did you need to change your DS length at all?

 

it had been for sale for about 6 months, just before Christmas, & needed the money. with cost of shipping no one wanted to spend the $600. to get it to the mainland. mostly just timing, he was also selling a ZF 6 speed from the same car for $500. he works for the state and HI is in a bad debt, state salaries have been cut by 10-15% & two days off a month unpaid, that's tough but better than getting a layoff.

 

This too

I just realized you said you would re-post this info

 

Is the ZF still for sale?

 

Amazingly I am running a stock aluminum driveshaft LOL..

 

How much stick out or slack do you have on the DS into the trans? If I were to do this I would probably move the whole thing forward as you said you made a mistake and have it a half inch too far rear-ward. I am just hoping that I would still be able to use the DS I have now.

Thanks for your replies too! I just started reading your thread on FRRAX a little while ago.

 

Thanks, 1meanZ!
This information is priceless!!
I'm going to start my own thread and show my progress.
and yes it is a true 44,

 

and the deal of the decade.

 

Have any more pics of it?

 

To interface with my TKO600, I have a C6 yoke on a stock AL driveshaft. The driveshaft is really close to being too long. I'm not sure if moving the diff 1/2 forward would break the deal or not but it will be close. I also have a lakewood bellhousing and I don't remember how long my TKO600 is. In other words, I don't have a GM part from the back of the block to the driveshaft, and my diff is in the wrong spot so I'm not really a guy to make driveshaft recommendations LOL... If you've got the dough and talent to to do the swap, shortening a driveshaft should be the least of the concerns...

 

2 bolts on top, easiest way to identify a D44. The 36 has only 1

 

Not when its Carbon fiber..... got one used/new for a REALLY good price. I am hoping to be able to use it in the swap, if I cant I will just get an aluminum or chomemoly the proper length at the end. Car is down for the count right now anyway so I have plenty of time.

Thanks for answering all my questions though! Now I just have to find an IRS to put under the car, its going to get an LS at the same time.

 

Yes, I know I have one I just wanted to see more pics of the $300 find.

 

a stock 3rd gen driveshaft or a 4th gen one? FWIW, the 98-02 aluminum shafts are about 1" shorter than the 3rd gen ones, so that may help with yoke clearance if needed.

 

I'm running a stock 3rd gen AL shaft.

 

Sorry, one more question. When you spoke of your driveline angles, what part of the body do you reference them from? My car is already apart and I wont be able to measure anything before hand.

OR are you simply referencing the angles against each other? so your pinion angle is 2 degrees down and the tailshaft is simply 4 degrees opposite the pinion angle?

 

driveline angle is measured as the angle between the driveshaft itself and the output shaft of the trans, and also at the rear pinion yoke. It is the angle that the U joint has to manage between the driveshaft and the device it is attached to. The angles need to be equal and opposite eachother. my trans is 2* tilted down, so i made sure the pinion was 2* tilted up.

 

Wow......great ****ing job.

 

extremely impressive, very very cool. You just put on paper what is wasted on my generation, very few really have the talent to fabricate like that anymore (the aftermarket really has hindered technicians) No one makes or rebuilds things any more with all the aftermarket parts available, it's just to bad, more power to you.

 

with all the bolt one customizing, my father in law is rolling over in his grave and dropping the F-bomb.

 

Thought I'd check back in and let people know how the car does on the road course now that i've actually been out and raced it.

I participated in the Motor State Challenge at Gingerman raceway recently and had a blast with the car. My best lap on the new larger course was a 1:48.5. I placed 5th out of 84 cars, some had slicks, some did not. I was running an old hard set of Hoosier Grand Am Cup scuffs, so I did have an advantage over some of the guys there.

The car really did a nice job for being an essentially unsorted combination. The car was slightly loose. I need to add an adjustable proportioning valve to dial back the rear brake bias, and I lowered my rear tire pressure too far which caused the car to feel greasy in the back. I also could probably use a tiny bit less rear roll stiffness from my custom rear sway bar. Otherwise the car did very well and I had a good time.

My oil temps were over 300* so it's time for an oil cooler, then back to the track this fall possibly.

Once I get pictures around I'll post them.

 

I'm quite impressed with your independent rear suspension swap! I've gained a lot of ideas even though I have a 2nd generation firebird. I recently decided that I will be going the t56 route assuming I can find one at a reasonable price.
What you did on the trans tunnel was a great idea, I plan to do the same. I may even attempt the c4 IRS swap into my second generation bird, who knows.

Thank you for all the great information!
And if anyone has a handle on a cheap used t56 let me know!

 

sweet build man. this was something I was thinking about doing before I even read about people doing it (although I thought about taking it from a wrecked 5th gen).

Anyways, I'm curious. you haven't said much about results. have you noticed a difference? but more importantly, to eliminate bias have you noticed a difference in the lap times or something like slalom speeds? what about everyday driving? how does it feel.

 

I never seriously tracked the car before the swap, and I have not autocrossed it since the swap so I don't have any apples to apples comparison.

On the street and track, the difference is very noticable. The car stays composed over bumps MUCH better than ever before. The car was especially jittery when entering a corner hard on the brakes, especially if there were any bumps or pavement imperfections. For general street driving the car is simply more comfortable. It absorbs bumps so much better than before. If it wasn't so much work to swap in, this is the setup everyone would run. GM obvioulsy thought so too since they built a test mule with a C4 setup.

 

This is a very kick azz build sir. good job! I'm thinking the only things I would change or try to change are..
1. move it 1/2" to the front. J/K had too
2. I may have tried somthing diff with the center mount. Mine is waaaay more of a street car..
Maaaybe a trans from a LT1, cut the vet "C" channel and lengthn it or whatever. Would that work? ooor not??
3. I would have made you put it in my car instead of yours!!!

 

absoloutely amazing job man. i wish i had the time skills and money to do that to mine.
all i have is a driveway, a jack, and jackstands. hey u kno what? i might do it though. thanks for the thread

 

cant wait to see this done... DAMN!

 

It has been done for like 8 months now..... https://www.thirdgen.org/forums/post...0-post139.html

Instead of just jumping to the end & posting, you really shoulda actually read everything.

 

cant wait to ~*SEE*~ this done...

def post some pics when you can!!!

 

Dude, the car is done. It has been in a magazine and everything.

 

http://www.gmhightechperformance.com...ion/index.html

 

I want to do this some day.