Converting from Live Axel to IRS--Anyone done this?

[Clois Harlan]

What are the tricks to alignment. What are the pit falls? Advantages? Will a Cobra IRS hold up to the torque of a 450 hp engine? Will the body need to be completely removed to install this setup? Lots of questions. Anyones input would be greatly appreciated?


Clois

[Clois Harlan]

I can't believe no one in this group has not made this conversion! Most of us run some version of a Fox body suspension and I would think someone has at least thought about this conversion.


Clois

[mr bruce]

There's more to it than just finding an IRS assembly and sticking it in there. The rear has to work with the front suspension. A Jag settup seems to work farly well. Look under an ERA, Contemporary, Midstates,EM,etc. Pretty simple design. Another one might be the F5. But then again, what front suspension are you using?

[Jon Miller]

Hi Clois,
It may not help you much, but I did convert my E-M from leaf spring to Jag IRS. In my case I was able to go to E-M and get the drawings that they use for their Jag cars along with the parts that I needed for the conversion. Since their frame is/was available setup for the Jag it was very straight forward when it came to the conversion. Just cut out the old mount points and weld in the new parts. Alignment was easy by dropping a plumb bob from points on the frame and making marks on the garage floor, then shifting things around until it was just right. I did deviate from their design by using radius rods rather than the forward mounted control arms that they use. With the E-M you could do the conversion with the body on, but it would be alot less fun..........

My car is not done yet so I can't comment on the live vs IRS performance, but the Jag IRS does look alot better than the leaf spring .

Good luck!
Jon

[mylesdw]

I think the Jag IRS will take your 450hp ok, the Salisbury diff is quite strong but its weakness is in twisting of the lower wishbones under fierce acceleration so if drag racing is more your thing than track it may be better to stay with the live set-up.

The fitting of radius rods to the Jag IRS is a very contentious subject. Put simply, if the chassis pivot point of the radius rod is not on the projected inner pivot of the lower wishbone, the radius rod does more harm than good (assuming the diff is solid mounted)

[Clois Harlan]

Actually, I have a complete 98 Cobra Mustang complete IRS spotted at one of our local salvages. Complete with all the brackets, brakes and brake lines, shocks, all suspension parts etc. When the car was salvaged it only had about 23,000.00 miles on it. Price is very resonable. One of my concerns is that if I have to cut the axels down an inch on each side then how will that effect my braketry (sp)?

Clois

By the way I don't drag race very often if ever anymore. Most of my miles are on the race track.

[petek]

DV did a coversion to one of his CR Cobras. He had a few pictures in the thread that discussed the conversion. Commented that it cost mucho $$$.

[Jim Werth]

Give Bryan at B+B a call. I was told IRS was an option on their cars. Jim

[sharpe 1]

Try looking at the web site for slip angle racing. They did a ffr car and have some good pictures of the change over.

[Dusty Rhodes]

clois, I am going to call B&B tomorrow and ask the same question. I picked up a t-bird today with an IRS 5 lug in it. I pick my B&B up Oct 4.