......... Who makes a kit to convert the C4 IRS rear to a live axle ? .................

 

This is the only current bolt-in kit that I am aware of. They have a good reputation and I know a few forum members put one in..... including MackeyRed96, so you might want to drop him a PM to see how he likes it, which I believe he does.

I have it on my long list of things to do.... just haven't gotten to it yet.

http://www.rodandracecraft.com/products_corvettec4.htm

 

Autofab in MD was advertising for a c4 to use as a donor to build a kit. Here is a link to the ad. http://www.racingjunk.com/Rear-Ends/...nversion-.html
I talked to them before they posted the price, but I got to tell you, that is waaaay to rich for my blood.

They offer this kit for a c3 and if they come out with something like this for the c4 and its in this price range I may do it. http://www.racingjunk.com/Suspension...nversion-.html

Good luck on your search. BTW have you changed your mind on the spool in the 44?

 

..... Oh Boy ! ... 10K ... for a rear axle ? ... that would be a lot even if it included the C4 ... not in my budget , ever ... I can buy a certified dragster chassis roller for less than that ... I'm still looking to do a spool , just weighing out the other options ...

 

... This one is a little closer to reality ... ONLY 5K for a 12 bolt ... that would be a good price if it included installation ... no pics of the kit .............. I see about 3 grand in parts retail if you did it ala-carte ..........

 

For what its worth, I am told its just a one day conversion.... so you could probably get them to do it for another $ 500 or maybe even thrown in... not sure, but its worth asking.

The man/owner who developed that kit used to be a member here at cf and the owner of a 7 to 8 second C4 corvette. I believe he was murdered a few years ago though.

But, the company still offers the C4 kit.

 

I'll also add, forum member MackeyRed96 was running one of those kits. (I don't remember which) in his 9 second C4, putting out 1.3x 60 fts and he was very happy with the kit.... worked well for him. That's all I remember on that though and not sure the exact details of the kit he had installed.

 

The cost of that stuff, even doing it myself is one of the driving factors in me keeping the IRS under my 84.

With good UJoints, a spool and the right TQ Converter it can be reliable.

I have run a best of 1.27 60ft this season. I just counted up mystery time slips and since I put the spool in the car, I have made 53 passes on the IRS without failure. Of those the worst 60ft is a 1.35....

I have made a lot of progress with the IRS in my car. It was reliable for a number of yrs even running 101k mile stock ujoints and other stuff, when the car was just on motor and only ran 1.42 60fts and mid 10s in the 1/4. This season we put the bottle on the car and that 101k mile stuff lasted 10 passes before a ujoint broke.... fixed them and the tranny broke a sprag.. found a broken cap on the D44 checking everything over while the tranny was out getting fixed.

Thats when I decided to build the D44 the best way I knew how... so far so good. Im only halfway thru our season but I think it'll do fine. I do still check ujoints every couple of passes and then really look close at them between races.

Im happy to share the parts I am using and little things that make it live and 60 so well if you decide to stay IRS on yours.
Will

 

Will,

How much $$ do you have in the parts to beef up the D44 ? I'm considering going in your direction.

 

Those are some crazy 60' times, Will. I couldn't make my 44 last under 1.5. What are you turning in the quarter?

 

$293 - Yukon 3.90 ring and pinion (PN YKD44HD-390)
$200 - Yukon D44 Spool (PN YP FSD44-3-30DN)
$245 - Yukon master install kit (PN YK D44HD-Vette)
$50 - ARP ring gear bolt kit

Those prices are right off of Randys Ring and Pinion web site but believe me, using the PN's I gave you - ebay is your friend for a price break....

I did not give you the PN for the ring gear bolts because it depends on which gear set you get from Yukon and what size bolts it uses.... some of the gears are factory Spicer Viper gears and only drilled for the 7/16 bolts, some are dual drilled for 3/8 and 7/16 and some are only 3/8.... ideally you'll want to use the 7/16 bolts and luckily the spools are dual drilled so you can do whatever you want/need depending on which gear set you get.

You will have to modify the spool or have a machinist mod it. Not a big deal and anybody competent with a lathe, having the orginal positraction in hand can measure and see how much to narrow it up and turn the brg ends down to the right size. Then you need to drill and tap 2 holes in it for the stub axle retaining bolts... I used 5/16 fine thread allen head cap screws. Grind or mill a couple of flat spots on the stub axles and your almost ready to go....

You need a small peice of alum, steel or brass to make a spacer for inbetween the stub axles.... this is so the stub axles push against it and in turn load each other instead of the retaining bolts doing all the work. This is VERY important IMO and where alot of previous efforts have had problems by not using a spacer.

Beyond that $150 in new Spicer ujoints and strap/bolt kit from Denny's drive shaft.

Thanks. I have a ton of time working on the suspension to get it that fast. Took alot of work with the rear shocks to get the car to stop porpoising in low gear.... finally figured out it was the extended suspension snubbers/bump stops.... when the car hits them the shock rebound valving was unable to control the extra "spring rate" . A set of Koni double adjustable shocks cured most of it but I still need to send them in and have some more work done on the valving as I'm maxed out on rebound adjustment....

I'd also like to get a stiffer rear spring... I have the 84 Z51 spring under it right now but I don't know if there is anything stiffer availiable.

Some of it is also in the TQ converter which PTC specially built for it. 8" 4500 stall with a special "soft hit" stator.

That said I know this stuff can break. I check it over really close every week and give it a quick look between passes.

I'd have to talk to the previous owner of the car for a exact pass count but he raced it for over 2yrs on the stock ujoints... I kid you not, 101K miles on that stuff. The car ran 10.50's@125mph and cut 1.40 60fts. Why he spent the time and $$$ to convert it to a D44 and didn't rebuild the half shafts while it was apart, I'll never know.... Like I said I killed those factory ujoints in about 10 passes with the bottle on it.

I don't run 1/4 mile. I have played around in the 1/4 testing earlier this year by either rolling into the throttle (and bottle) easy off the line or running to the 1000ft mark and shutting dow and coasting... both resulted in 9.50's and 145mph or so.... the car only has a 6pt roll bar so I can get in trouble pretty fast doing that at a sanctioned track. My class runs 1/8th mile and I've consistantly run 6.0's to 5.90's in the 1/8th.

Keep an eye out, I'll keep the forum posted about what I do next for season once this one is over in Sept.... I'm running my pump gas street engine (603hp) with only an 82 jet in the nitrous plate (about 200hp) right now.

This winter when I freshen it up, I'm not fooling around with keeping it a pump gas motor any more. 8.50 cage is on the way this winter as well so I'll be able to run it in the 1/4 mile for real.
Will

 

Very impressive Rklessdriver. I remember you had a prior thread about that car.

You can have VBP build you any spring rate want (I have a 411# spring that I am not using).

When my 92 is finished I will post a thread with photos of my 9" conversion. It is coming out nice. Most is complete-just working on a locator (not sure if it will be a watts linkage or wishbone).

Regards,
Steve

 

5G is for a 10bolt. I priced a 9 bolt setup and the kit alone would have been $6500 plus some more items so I figured around $7500 once you were done.
I now have Summers Bro's billet spindles, Denny's Nitrous half shafts, and true track. I check everything after each race. I'm on my second True Trac and think the gears are twisting again. If it goes out I may try a spool. I hope to tear it all apart to inspect over the winter but we are looking to build a new house/garage so I'm not sure if I will have time.

 

Thanks Will.... will strongly consider the spool. I've never really looked at the choice before.

 

I think at that link, the 10 bolt is $ 4000.... the only option I would probably take is the QA1's.... do not need the brake options.

For 5k, they have a 12bolt strange I believe.

None of this is a great deal, but the engineering portion is done and supposed to be just a bolt-in. Things like this rarely are though, so I imagine some level of fabrication would be necessary, but don't know.

 

You're putting out some horses.

 

Well if someone offered a kit like the autofab kit to use your own rearend of choice like they do for the C3, that would be nice. Their kit, http://www.racingjunk.com/Suspension...nversion-.html
includes the following.

Kit Includes:

* CAD designed, laser cut front 4-link brackets to mount on the frame
* Laser cut housing brackets with adjustable shock mounts
* Chromoly 4 link bars with weld in tubing adapters
* Chromoly Rod Ends
* QA1 Coil-Over shocks DR4855B (single adjustable)Upgrade to AFCO or Strange shocks for an additional fee.
* QA1 Springs 10-200 (most commonly used but other spring rate can be substituted for different spring rate)
* Upper shock mounting tabs
* Chrome-moly Track Locater (pre TIG welded)
* Template to use to notch factory cross member
* All necessary brackets and grade 8 hardware
* Detailed Installation Instructions

That is for $1150.00

For that price, I would do one, but just cant see 5-10 thousand dollars. Too rich for my blood.

 

I had the 9" kit for 5g, brake kit 400, locker upgrade 200, and crossmember for 500. + tax.. I would still have to modify the exhaust and I think have a driveshft made to be correct. Yes all the engineering is done for you but it all adds up for sure.

 

That would be nice..... and affordable.

 

Did you like it after the install ? Every good, tight and reliable ?