Project "IRS Typhoon"

[CheshireC]

A bit of history
Around about 30 manual 1988 corvettes with the RPO Z5 1 packaage were shipped direct from the manufacturer to Lotus engineering in the Uk for them to start work on the ZR1 project. When the cars arrive, at least half of them were stripped ,parts labled and put in heated storage for spares. All had Dana 44 8.5",code 5YX 3.07:1 ratio.As a new suspension system was used on the ZR1, all the Danas never saw the light of day. Until Lotus bosses decided in 2002 to junk them as they werent needed and were taking up valuable place. So a scrap merchant was called and paid to remove them. Thankfully he had a bit of savvy and made some calls and the owner of the UK leading Corvette specialist Tom Falconer, purchased them for Claremont Corvette. As they had been kept in heated storage, they were as good as the day they had been taken off the cars, But he had them all stripped and seals replaced anyway.
I have just bought one of those Dana 44 to start work on project IRS Typhoon

Now the bad news. What i have is the bare "T bone" , so to start with im gonna need some help making a list of parts required to complete the rear end set up, before I even think about actually fitting it to the Ty.
Im looking around th web for a microfiche of part#s but im not having much luck at the moment.
I figure i need hubs, tie rods and shaft, spring, lower control arms, steering knuckles, half shafts and new gearing ratio to match the Tys 3.42s
If any of you have a vette in the garage and you could drag yourselves away from the SyTy to spare the time, could you crawl under the vette and help please.
And / Or If any of you have some spare Vette suspension parts taking up space and you'd like to turn them into $$$s to spend on your trucks, again please let me know.
Im also planning to use a PST carbon shaft and was wondering if i should go carbon for the rest of the suspension parts??
Also any input/suggestions or drawings scrawled on the back of a cigarette packet would be appreciated.

Thanks
Adam

 

[turbosonoma]

well i have three vettes in the garage i could look at if you need, or if you are not in a hurrey i can take pics of my chassis when it comes out of the shop :lol:

 

[CheshireC]

Thanks, Im not in too much of a hurry....(as its christmas :lol: ) pics would be great if you could take some, thanks for the offer :tup:

 

[TYTILIDIE]

Sounds like a fun project. Ive thought about doing this myself. If you want part#s go to the Ecklers website and order yourself a catolog. I just sold my Vette. But for the last 6 years Ive learned a lot about them. Ill help ya out with whatever I can. I know that that is a complicated mod as you have to rebuil the frame in the rear. The control arms will probably be the hardest part for you I would imagine. Im curiouse as to how it turns out. Especially since the track will be so much wider. Keep me posted if you dont mind.

Mike

 

[Christian Dionne]

If you goto the Hybrid section of TurboBuicks.com you'll find Scottie-GNZ and a few others who've swapped Vette rears into their cars. One is a 240Z and another is an RX7 which came with IRS of course, but both cars required alot of new parts and engineering. I'm sure you can email Scottie and ask for some direction, he's a real nice guy and is an engineer as well. It's hard for IRS to go 9s, but he's done it alot and doesn't ever see a trailer like some Supras that perform the same.

HTH, Christian

 

[vette40509]

On ebay under "Thunderbird" someone is selling a complete independent rear from a new bird, complete with mounting frame. Maybe its worth a look. They were asking for $300.

 

[turbodog]

There are also a few sites with detailed pics and info regarding putting the Vette IRS in 55-57 Chevy's, including narrowing, etc. Pretty good info. My issue with the Vette IRS is that the trailing links are occupying some very valuable real-estate... namely, the area next to the frame rail needed in order to run those beautiful 11 inch rims and 315 tires. Near as I can tell, you'd be limited to 9 inch wide rims (or have the rear tires hanging out from under the cladding). Bummer.

 

[CheshireC]

Thanks for your help / ideas and suggestions guys :tup:

I found this and it seems usefull

www.rodandcustommagazine.com/techarticles/86279/

 

[turbosonoma]

There are also a few sites with detailed pics and info regarding putting the Vette IRS in 55-57 Chevy's, including narrowing, etc. Pretty good info. My issue with the Vette IRS is that the trailing links are occupying some very valuable real-estate... namely, the area next to the frame rail needed in order to run those beautiful 11 inch rims and 315 tires. Near as I can tell, you'd be limited to 9 inch wide rims (or have the rear tires hanging out from under the cladding). Bummer.

does not matter, just have to shorten the bat wing to the needed legnth then its good to go.

 

[canadian]

Found this one a while ago:

http://www.heidts.com/images/art7.pdf

 

[turbodog]

There are also a few sites with detailed pics and info regarding putting the Vette IRS in 55-57 Chevy's, including narrowing, etc. Pretty good info. My issue with the Vette IRS is that the trailing links are occupying some very valuable real-estate... namely, the area next to the frame rail needed in order to run those beautiful 11 inch rims and 315 tires. Near as I can tell, you'd be limited to 9 inch wide rims (or have the rear tires hanging out from under the cladding). Bummer.

does not matter, just have to shorten the bat wing to the needed legnth then its good to go.

Don't think you understood my concern. Go here:
http://www.progressiveautomotive.com/55CJ.htm
and look at the top right black and white pic. See how much hardware there is outboard of the frame rail but inboard of the rear tire. See how they narrowed the frame rails in that area to get even a moderately wide tire/wheel combo in there. Now think about how much clearance there is between a properly-spaced 11 inch wheel/315 tire package and our frame rail. No room for the trailing arms. So, you would have to go with narrower wheels/tires, or do surgery on the frame. Here's another site with good pics showing the problem. This guy also narrowed the frame rails:
http://www.picturetrail.com/gallery/view?p=999&gid=676692&uid=465705

The Heidt's IRS avoids that problem by using the beefy lower control arm to position the hub fore-and-aft. No trailing links needed.

 

[turbosonoma]

to bad i already ordered my michelin 335/30/20's, if theres a will theres a way, ill make it work, ill keep ya posted to.

 

[CheshireC]

Its looking more like im gonna be taking a route "similar" :wink: to the Heidts setup, but using the Dana instead of the Ford 9" they use.(cuz i'm damn well gonna have 11"ers on the back)

Unless of course any of you suspension wizards have some funky ideas about how to replace the "dogbones"

If im gonna have to make up so many new parts, think i might just aswell go Carbon Fibre as I have a CF shop near me. I'll get some drawings done over the christmas / new year period and any parts i get made for this project i'll get pics and post them.



Whose mad idea was it, to do this anyway?????

 

[HighPerformanceTrucks]

I've done a ton of research in the past and considered using the following company to build the conversion kit:

Flat Out Engineering
Rancho Cucamonga, CA
909/608-7432

This kit is the most likely candidate to fit our trucks and can be either a complete bolt in or weld in kit. The only tough fabrication part would be to set up the pinion support bracket which needs to be welded onto the cross support.

Here's a link to a similar build, but is an older Ford truck with slightly wider straight frame rails.

http://www.customclassictrucks.com/howto/58799/

I've been trying to pursuade the owner of Flat Out Engineering, Don McNeil to build me a kit for over a year now, but he needs someone to bring a truck down when he can find the time to do some measurments.

The kit would most likely work with some creativity, but the question is will the eyes for the double ear brackets fit outside the frame rails or will the end up directly underneath the frame rails requiring some serious frame notching and reinforcing of the frame rails.

I would discard the stock Vette trailing arms that look like "dog bones" as well as the stock camber rods and upgrade to some much stiffer pieces from Doug Rippie Motorsport.

Here is the link:

http://www.dougrippie.com/drm/new_products.htm

Other things to consider are matching the 3:42 gears and posi, shortening the driveshaft, possibly shortening the half shafts and developing a sway bar mounting kit.

Flat Out sells brackets that eliminate the transverse leaf spring so you can covert to coil over shock setup.

 

[canadian]

Check out the latest Hot Rod magazine (the one with Leno's Toronado). They have a C5 rear in that with a composite leaf spring setup. If it'll hold up to that, it should do fine in a Sy or a Ty, although coil-overs would be cool.

In that issue (or maybe Car Craft's latest), there's an article on making a Vette IRS live in a high HP car. They show some custom half shafts in there that are built to handle more power along with a 12 bolt center section.

The parts are out there to make the rear survive in a high HP application, it's just a matter of $$$$.

 

[dgoodhue]

Other things to consider are matching the 3:42 gears and posi, shortening the driveshaft, possibly shortening the half shafts and developing a sway bar mounting kit.

A majority of C4 Dana 44 rear ends came with 3.45:1 gears, C5's came with 3.42, but they rear end is part of the transxle (ie Tranny and Rear in on unit) The 3.45's is probably close enough for our 3.42's. Unfortunately they cost around $1200-1500 for a good used rear end (not including the suspension) The Dana 44 only came in 85-96 standards with most all 91-96 6 speeds coming with the 3.45 ratio. The Dana 44 is pretty beefy with C4 doing 10's on the stock IRS, with AWD taking 35% of the power up front, they would hold any SyTy. I would upgrade the half shafts on higher HP truck (9's and 10's) as I have seen a few Vette twist them on regular racers with sticky tires.

 

[HighPerformanceTrucks]

Check out the latest Hot Rod magazine (the one with Leno's Toronado). They have a C5 rear in that with a composite leaf spring setup. If it'll hold up to that, it should do fine in a Sy or a Ty, although coil-overs would be cool.

In that issue (or maybe Car Craft's latest), there's an article on making a Vette IRS live in a high HP car. They show some custom half shafts in there that are built to handle more power along with a 12 bolt center section.

The parts are out there to make the rear survive in a high HP application, it's just a matter of $$$$.

I don't see how the C-5 rear IRS would work on our trucks considering it's a transaxle setup.

 

[HighPerformanceTrucks]

Other things to consider are matching the 3:42 gears and posi, shortening the driveshaft, possibly shortening the half shafts and developing a sway bar mounting kit.

A majority of C4 Dana 44 rear ends came with 3.45:1 gears, C5's came with 3.42, but they rear end is part of the transxle (ie Tranny and Rear in on unit) The 3.45's is probably close enough for our 3.42's. Unfortunately they cost around $1200-1500 for a good used rear end (not including the suspension) The Dana 44 only came in 85-96 standards with most all 91-96 6 speeds coming with the 3.45 ratio. The Dana 44 is pretty beefy with C4 doing 10's on the stock IRS, with AWD taking 35% of the power up front, they would hold any SyTy. I would upgrade the half shafts on higher HP truck (9's and 10's) as I have seen a few Vette twist them on regular racers with sticky tires.

I think the C-4 rear end from the manual transmission vette would more than suffice especially since the torque is split between the fromt and rear wheels anyway.

 

[canadian]

I don't see how the C-5 rear IRS would work on our trucks considering it's a transaxle setup.

wasn't considering it for installing in a sy or ty, just that it looks like a vette rear would be able to put up with the abuse a syty could give it.

 

[CheshireC]

I've done a ton of research in the past and considered using the following company to build the conversion kit:

Flat Out Engineering
Rancho Cucamonga, CA
909/608-7432

This kit is the most likely candidate to fit our trucks and can be either a complete bolt in or weld in kit. The only tough fabrication part would be to set up the pinion support bracket which needs to be welded onto the cross support.

Here's a link to a similar build, but is an older Ford truck with slightly wider straight frame rails.

http://www.customclassictrucks.com/howto/58799/

I've been trying to pursuade the owner of Flat Out Engineering, Don McNeil to build me a kit for over a year now, but he needs someone to bring a truck down when he can find the time to do some measurments.

The kit would most likely work with some creativity, but the question is will the eyes for the double ear brackets fit outside the frame rails or will the end up directly underneath the frame rails requiring some serious frame notching and reinforcing of the frame rails.

I would discard the stock Vette trailing arms that look like "dog bones" as well as the stock camber rods and upgrade to some much stiffer pieces from Doug Rippie Motorsport.

Here is the link:

http://www.dougrippie.com/drm/new_products.htm

Other things to consider are matching the 3:42 gears and posi, shortening the driveshaft, possibly shortening the half shafts and developing a sway bar mounting kit.

Flat Out sells brackets that eliminate the transverse leaf spring so you can covert to coil over shock setup.

Looks like we're on the same wavelength :tup: I spent alot of the holiday period doing research and came to several similar results. If i was living in the USA, my truck would be at there doorstep this afternoon !, sadly I'm in the UK, which hinders that slightly.
The meaurement for the dana frame is 40.5"
The Ty frame (at the bumpstops) is ~about the same....meaning framework alteration is needed to either the Ty :tdown: or the dana frame :tup:
I looked at one of the links someone previously posted about Scottie putting the dana in a mazda....very usefull (they narrowed the dana frame too) so that would seem to be the route to take
MY thoughts were to lose the stock "Dogbones"....and the camber rods will have to be custom made about 2 " shorter....(prolly go Carbon Fibre) and the transverse leaf spring..swaping it for coilovers.
The guys at Doug Rippie seemed quite helpful when i asked questions.....(well they might have laughed at me :wink: )
The half shafts will need to be shortened, which im not too concerned about. I bought a pair from ebay and they are currently sitting in a box at Todds (Tydriver) house, while a few more bits arrive, then they get shipped to the UK. After ive worked out the size of the halfshafts, I plan on getting a local shop make me a set of HD carbonfibre ones :tup: (also a drive shaft at a later date)
The 3.45 and 3.42 problem..
I figured this might be solved with a different wheel / tire size (???) to bring it as close as possible, but i need a wheel wizard to help with that

Thanks again for all input and suggestions,
At the moment im doing a lot of research on 'vette parts and measurements and variations etc(I only wanna do this once, but i want it done right) so im not particularly doing much wrench time yet