IRS rear swap in a fox?

[bditty50]

Well one thing I'm afraid of with an IRS is regretting doing the swap at all. That's why I'm going to keep the solid axle laying around if I happen to change my mind. I plan on beefing the factory IRS. I plan all the bushings,better subframe, 750 hp diff, better bearings, and maybe Kb parts if they ever open again. About a good launch at a drag strip there are Cobras breaking into the 9s with cobra irs rears. Another thing I'm worried about is heat in the diff. I might have to install a cobra r diff cooler. I like to run in the turns hard. Right now my car pulls turn very hard and I imagine it could out handle most vettes. I just want the IRS for highspeed stability,ride quality,better weight distribution, and camber adjustment. I think its a dumb mistake for cobra guys to swap the IRS for a solid axle. They should of waited for all the parts that are out now that have fixed all the problems.

 

[ryan218]

there is a guy on four eyed pride that has a 03 cobra IRS in his 83 hatchback...ill see if i can get you his email to talk to him about it.

 

[bstrd86]

I have one in my '86 coupe but it's not running yet, so I couldn't tell you how it rides.

 

[bditty50]

bstrd86, Did you install the IRS yourself? I worked on cars during highschool and on for like 5 years doing basic stuff. With friends I did like motor swaps, clutches,etc. on mustangs. I was wondering what the difficulty rating on this job, I always have doubts before doing a automotive job. Usually, with a good outcome in the end. I just want to make sure I'm not getting in over my head with my capabilities. I probably have to find someone to weld brackets for me right? Did you upgrade anything on your IRS unit?

 

[bstrd86]

I did the swap myself in my garage. It didn't take any trick tools or anything. The most "complicated" part was cutting the bumpstop brackets out and drilling the rear frame rail area for the additional holes needed for the IRS cradle mounts. The mouthbreather site is pretty informative, but when bolting in the rear frame mounts you should either weld in an insert between the trunk floor & the rail or cut out a small section of floor to gain access to the rail and run a shorter bolt. In the pics it shows the cradle bolted through the trunk floor, it just seems to me that the bolts could pull through the thin trunk sheetmetal. The job was pretty easy, I had the rear in the car in just an afternoon. There's not really any welding involved unless you want to weld the rear brackets in, but that's not really necessary.

As far as upgrades it's a stock '03 unit, it didn't have any brakes when I bought it so I made brackets to mount 4 piston Wilwoods. I already had them so I figured I would try to use them, and I have access to a complete CNC machine shop where I work. The rear is pretty dirty, I plan on taking it back out and replacing the bushings with aluminum and delrin ones that I'll be making (because I'm too cheap to buy them) and cleaning it up for final installation. I may buy the IRS brace because of time issues, and most of them are a reasonable price.

 

[bditty50]

I wan't to have both handling and hard hooking. I like my MM setup now I just want to handle alot better. The problem on hard turns with a solid axle is that you can feel the car lifting and that makes it very unstable especially if you oversteer just a bit. I think with all the parts available for a IRS its pretty much possible to have the best of both worlds to make it handle incredibly and also hook hard without breakage. If I could afford a CONTROLFREAK unit I would fork out the 10,000 grand and buy one.