Should i go IRS with my 1990 Mustang fox

gottabeford · 02-01-2009

im getting a 99-01 irs out of a cobra with 3.73s for $400. should i throw it in my fox? i will have the motor in my sig and do plan on running some at the drags. iv herd wheel hop is the problum with these and that my mickey et streets will help. but not sure if it would be worth the work (not a lot but still). the cool factor is deff. there. and i hear they hook better than a solid axle on the street, were most the battle if fought anyways. what do you guys and gals think?

oneFASTmustang · 02-01-2009

IRS in a fox is very cool!

**RLG34750** · 02-02-2009

as we speak i know someone who is doing that swap.....

i you are doing for the handling and aesthetic value i say go for it

but if the car will be primarily a drag car stick with the solid axle

BIG G · 02-02-2009

i agree with rlg34750. big G

**EagleAutosports** · 02-02-2009

Definitely... for a strictly drag only car, keep the solid axle. If you intend to try some curves with it, then go with the IRS.
Wheel hop is really bad with an IRS on a drag strip. What you could do is check Steeda for their 'Stop The Hop' kit, and I would also say check The Driveshaft Shop for their axle kits. Stock axles aren't that strong, this kit has axles that can handle up to 1000 hp, you can't ever have too much strength.

THE DRIVESHAFT SHOP

302Feen · 02-02-2009

IRS is good for road course racing. Not straight line racing.
If you don't intend on doing A LOT of road course racing then save yourself A LOT of money and stick with your solid axle.
A solid axle can even be made to run with IRS cars on road courses even.

The only reason you should need an IRS is if you plan on REALLY getting into road courses.

gottabeford · 02-03-2009

The guy I got the irs from has a 03 cobra irs in his 99 gt with a twin turbo DOHC 4.6 pushin 600+ to the wheels. And his irs hooks like no other. And has ran 10.60 in the quarter. He does have the leve 5 axles and the sperical pushings soooo. Idk I am not going to speend that kinda money on it though. So maybe the solid is the better way to go. But on the street, damn that irs hooks HARD.

302Feen · 02-03-2009

Quote:

Originally Posted by gottabeford

The guy I got the irs from has a 03 cobra irs in his 99 gt with a twin turbo DOHC 4.6 pushin 600+ to the wheels. And his irs hooks like no other. And has ran 10.60 in the quarter. He does have the leve 5 axles and the sperical pushings soooo. Idk I am not going to speend that kinda money on it though. So maybe the solid is the better way to go. But on the street, damn that irs hooks HARD.

Like I said, if you just mainly doing straight line racing, then stick with your solid axel. The IRS won't help and maybe won't hurt you either with drag racing but you would be throwing yoru money away.
If you just looking for better handling on the STREET then your solid axel will still work well if you modify the suspension for it.
The only reason you would want to spend the extra money on the IRS is if you REALLY going to get into road courses. In that case your money would be very well spent!

**EagleAutosports** · 02-03-2009

Here's something else. I believe the Super Coupe Thunderbirds aren't hard to find... grab the IRS out of that and it'll go right in with only drilling a couple of extra bolt holes. It might be less expensive than the popular Cobra IRS that everyone wants. It's just no one thinks of the Bird IRS so it's less expensive but it's the same thing.

gottabeford · 02-03-2009

is 4 bills for an irs considerd expensinve? eagle i too would have never thought of the turbo coups heck i didnt even know they had an irs suspension. interesting. is it based off of the 8.8 or the 7.5?

**EagleAutosports** · 02-04-2009

Not meaning to split hairs, but there's both the turbo coupe and the Super Coupe. It's the Super Coupe that had it.
It's an 8.8 rear. The Super Coupe replaced the Turbo Coupe in 1989 and is on the MN12 platform (hence why some extra bolt holes are needed). Kinda odd a 3.8 V6 with 12 psi of boost could put out 210 hp and 315 ft lbs of torque which later went to 230 hp and 330 ft lbs.
I would say $400 isn't excessive for the swap. You're including all the A arms, bushings, brackets, among other things so that wouldn't be bad.
Anyway, if you were to look for it, look for 1989-1995 Thunderbirds that have "SC" on their front and rear bumper covers, much like the "Mustang" is molded in ours.