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View Full Version : IRS Swap: still deciding


Mystic_Cobra
10-11-2002, 03:09 PM
Even though I still haven't had a chance to talk to this guy who wants to trade his IRS for a solid rear. I'm still researching. I was hoping to get some more feedback about the IRS on track.

Is anyone running IRS in NASA or SCCA (other than the guy Tom mentioned)?

Is it safe to conclude that a MM TA/PB solid rear would be better than a stock IRS, and that a beefed up IRS (from KB or others) would be better on track than the beefed up solid rear?

I'm still undecided on whether I want to go through with this.
This would NOT be a dedicated track car, but continue to be my daily driver and a weekend driving school car.

thanks,

sn8kbit
10-11-2002, 04:13 PM
best place to drop race/track questions on the IRS would be www.v8venom.com both guys ran IRS for a while before going to a solid axle, and can probably explain that mess a ton better.

i'm going to stick it out with the IRS. i honestly believe it can be made to work, for a daily/weekend driver....

98banana
10-11-2002, 04:21 PM
My opinion, and I stress MY OPINION because I've never even driven an IRS, is to go for the IRS for street use and occasional track duty.

If you're looking for a serious track-only car, go with the beefed up solid axle. When and if I ever start building my next car, I'm going with a solid hybrid axle with my own home-grown frame mounted Watts link. (I think there's another techy name for it.) I seriously doubt any IRS could outperform it, KB or not.

And I stress again, this is my opinion from the limited research I have done.

Cobra-R
10-11-2002, 04:45 PM
Originally posted by Mystic_Cobra
Even though I still haven't had a chance to talk to this guy who wants to trade his IRS for a solid rear. I'm still researching. I was hoping to get some more feedback about the IRS on track.

Is anyone running IRS in NASA or SCCA (other than the guy Tom mentioned)?

Is it safe to conclude that a MM TA/PB solid rear would be better than a stock IRS, and that a beefed up IRS (from KB or others) would be better on track than the beefed up solid rear?

I'm still undecided on whether I want to go through with this.
This would NOT be a dedicated track car, but continue to be my daily driver and a weekend driving school car.

thanks,

I am going to give my opinion here, but realize that is all it is, based on having both setups you are talking about. I am also talking in regards to track and street driving, obviously the solid axle is better for the drag strip.

First, the solid axle car I am using for reference is a 95R with MM torque arm, panard bar, and lower control arms. I have added Koni's with coil overs, Griggs front end, and some misc parts lately, but what I am going to say is based on the car before the Griggs was added.

The IRS car I am referencing is a 01 Cobra originally run stock with Bilstiens and H&R springs. I have since added delrin bushings in the rear arms, coil overs with Koni's, and a griggs front end.

Stock to stock, I would give the edge to the IRS both street and track. Add solid bushings and ecspecially Koni with coilovers and the IRS is a pretty good setup for on track and still good for the street. You will get a little more noise thru the chassis, but that is to be expected.

The stock solid axle is junk on the track, no way around it. Add a torque arm, panard bar, springs, and control arms and the solid axle is top notch. A major downside to adding all that, is you car will push like a pig on the track until you give the front end some attention (Griggs in my case) Once you have upgraded the solid axle, it is deffinately more noisy and harsh on the street although adding coil-overs helps that alot.

Bottom line, if you want a decent track car, I would go with the IRS. You can make it pretty good for both track and street use without dumping in alot of $$. If a all out track car is in your future, the solid axle is a good setup to upgrade with the torque arm, panard bar, ect but you are spending quite a few dollars to get to that

Cobra-R
10-11-2002, 04:49 PM
Originally posted by 98banana
My opinion, and I stress MY OPINION because I've never even driven an IRS, is to go for the IRS for street use and occasional track duty.

If you're looking for a serious track-only car, go with the beefed up solid axle. When and if I ever start building my next car, I'm going with a solid hybrid axle with my own home-grown frame mounted Watts link. (I think there's another techy name for it.) I seriously doubt any IRS could outperform it, KB or not.

And I stress again, this is my opinion from the limited research I have done.

lmao, you slipped in while I was typing my reply. :thumbsup: :thumbsup:

98banana
10-11-2002, 05:08 PM
Originally posted by Cobra-R
lmao, you slipped in while I was typing my reply. :thumbsup: :thumbsup:

And I think we agree!!! :rotf:

98banana
10-11-2002, 05:12 PM
And Brian is right about the "quite a few dollars" part.

A hybrid axle with TA and watts link or panhard bar is around $3500 not including brakes, shocks and springs. If you wanted to go all out, you could add another $2000 for koni DA and springs + another $1800 for Sierra/Griggs rear brakes. That puts the rear at $7300 + another $800 for a diff cooler!!! Ouch!:eek: :eek:

Cobra-R
10-11-2002, 05:53 PM
Originally posted by 98banana
I seriously doubt any IRS could outperform it, KB or not.



I do believe it is only a matter of time untill Griggs or Maximum Mortorsports comes out with a new rear subframe for the Cobra with all new geometry that makes the IRS into a great setup.
Maybe If Jack Hidley see's this, he will chime in and either give us hope or kill our dreams. ;) ;)

Brian

Cobra-R
10-11-2002, 06:04 PM
Of course all my comments are based on the fact that I drive half the speed that everyone else does. ;)

Thought I would say it before Kevin did. :D :D :D

kevin
10-11-2002, 06:11 PM
Originally posted by Cobra-R
lmao, you slipped in while I was typing my reply. :thumbsup: :thumbsup:

brian, think banana :D

kevin
10-11-2002, 06:15 PM
Originally posted by Cobra-R
Of course all my comments are based on the fact that I drive half the speed that everyone else does. ;)

Thought I would say it before Kevin did. :D :D :D hehehehe

butt it doo depend on which car your driving.

i think brain's done enough to his 95 to make it work real well.

but i agree it's only a matter of time before some one comes up with some irs goodies that make it far better than it is now or any solid axle. i know my other race car is not a fair comparison - but, i wouldn't want a solid on it cause the irs makes it work so damn great