IRS vs SRA

[Tholomew Plague]

For handling, is the IRS that much better?
From what I hear a SRA can handle just as good as a stock IRS when it has the same shocks and a pan-hard bar.
Is there any truth to this, and would it be worth swapping out for an IRS?

 

[blacksheep-1]

If you put a panhard bar on the stock rear suspension of a mustang ( 4link) stick your finger in a meatgrinder, if you do it after you installed the latest, trickest, stiffest upper control arms, then pour alcohol on it when your done. The IRS was built for a reason, because it is superior to the the 4 link, which is almost constantly in a bind and induces snap oversteer on corner exit. The MM Truck arm is a great improvement, but the watts link will solve the problem almost completely. You still have to contend with the tires being on the same plane, unlike the IRS which can follow two seperate levels. I have 3 mustangs that I autocross extensively a Fox body, SN95 and a New edge, they all have Cobra IRS units in them. Now for drag racing, completely different story.

 

[zukman31]

^^^^ Very Well said. I replaced my IRS in my 03 Cobra but only because I was into drag racing.

 

[98 Saleen Cobra]

Griggs Racing/ Thread.. SRA.. Throw a Watts link/Torque arm/ and be done.. Coilovers if you want.. Sorry but a 04 Cobra IRS can't compare. You don't see AIX, AI, Mustangs running a IRS. It's for a reason.

 

[blacksheep-1]

Griggs Racing/ Thread.. SRA.. Throw a Watts link/Torque arm/ and be done.. Coilovers if you want.. Sorry but a 04 Cobra IRS can't compare. You don't see AIX, AI, Mustangs running a IRS. It's for a reason.

Mostly which is they've never taken the time to understand it and probably read too many advertisements telling them otherwise.

Many people who do not understand the IRS very well think an SRA is a cure all. The main reason for this is because the solid axle has been around for centuries and it’s not complicated. My opinion is if you want to put an archaic stick axle in a car the SVT engineers thought would be better served with an IRS, by all means it’s your right to do so. And as long as I don’t have to drive it, I’m ok with it. It’s your car, do with it what you want. But I would advise HIGHLY against it. There are several reasons a Cobra costs more than a Mustang GT and the upgraded suspension with the IRS is one of them. Many of the people that put an SRA in their Cobra could have easily used their IRS had they understood it better. Most people drive their cars on the street 99% of the time and the IRS will deliver superior ride and superior handling for that 99% of the time. The only way I would recommend a stick axle in a Cobra would be if you had a dedicated drag race car that you hauled to the strip on a trailer.

The IRS is a FAR superior suspension component than the archaic stick axle. Besides, a Terminator for example, already has a poor F/R weight distribution percentage of 57/43 and putting a SRA in the car makes this worse. There is a reason why every high performance sports car from every single manufacturer comes from the factory with an IRS today. How many true high performance sports cars have SRA's in them? Well none actually! Unfortunately for Cobra owners, they have a sour taste in their mouth regarding the IRS. The IRS was delivered from the factory in a very poor state. You really need to remove ALL of the rubber (and or any aftermarket poly) from the entire assembly including the subframe to raise the efficiency level of the IRS.

http://www.fulltiltboogieracing.com/mystery_of_irs.htm

 

[98 Saleen Cobra]

Mostly which is they've never taken the time to understand it and probably read too many advertisements telling them otherwise.




IRS Informational Article

I'm sure that companies that provide suspension for SRA have taken the time and done research on the 03/04 IRS.. This is what they do for a living you know.. You took a quote from FTBR which exclusively makes IRS bushings.. Which is why you get that answer..

Yes a IRS is better if they actually built a proper IRS like Ferrari, Corvette etc etc.. The issue is that they built a IRS around a frame and not the other way around.. A proper IRS like from the companies I listed is far superior.. BUT we aren't talking about those we are talking about a IRS from a 03/04 Cobra.. Which is just a shitty design IMO..

Again this is why you a SRA setup in Mustangs that run in any extreme racing conditions..

 

[blacksheep-1]

Again this is why you a SRA setup in Mustangs that run in any extreme racing conditions..

The real reason is that it's lighter by a considerable margin, and less maintenance, right now in Grand Am the Mustang guys are crying for an IRS, like the one that the Porsches, Subarus, BMWs, and Camaros have. and FTBR also runs a Boss 302 they don't just do IRS.
in 200 Ford built the Cobra "R" they used an IRS and they could have used anything they wanted.

 

[Blkkbgt]

I'm sure that companies that provide suspension for SRA have taken the time and done research on the 03/04 IRS.. This is what they do for a living you know.. You took a quote from FTBR which exclusively makes IRS bushings.. Which is why you get that answer..

Last I checked the Maximum Motorsports yellow fox body that has set records has an IRS. That right there is a company that sells parts from both. For me those two things remove a lot of bias.

 

[Tholomew Plague]

Thanks for the advice. Even if it's a bit biased on both sides.
And no need to get angry at each other. I know you weren't but I've seen these conversations go south really quick

 

[98 Saleen Cobra]

It's not Bias.. My personal philosophy is build what you have.. If you have a IRS want to handle build that.. If you have a SRA build that, The cost will be the same.. For all out racing though I would use a SRA.. For most Open tracks, time trials, auto X, etc etc Either or will be just fine.

As for the MM Fox, I'm pretty sure that has a SRA I could be wrong.. Even still I'm sure it's set records at somepoint, but there are still AIX, AI cars that have beaten it with a SRA.. Now the HP maybe different though..

 

[LilRoush]

The IRS in the Cobra has one MAJOR downfall. It was built to fit where a SRA was in the first place. On the street, if you want a smoother ride, by all means swap in the IRS.

If you want a good open track car, a 5 link is the way to go. Even with the bushings and what not on the IRS, you are going to have more money into it and equal or lesser results than a properly set up SRA.

I looked at doing the IRS swap on my old 2000 Roush track car for a LONG time. I looked at every angle I could, talked to racers on both sides about strengths/weaknesses and even drove both. When it all came down to it, the best match for my track car was SRA. I will be doing the same thing again if I take the '98 to that level.

I deal a little bit with the Grand Am Mustangs, and the driver's seem very happy with the SRA set up with them.

I think it really comes down to what fits your driving style/ability and not thinking that what works for someone els will work for you.

 

[blacksheep-1]

"Any suspension can be made to work reasonably well if you keep it from moving"
Colin Chapman

This only applies to billiard smooth race tracks however

 

[Blkkbgt]

It's not Bias.. My personal philosophy is build what you have.. If you have a IRS want to handle build that.. If you have a SRA build that, The cost will be the same.. For all out racing though I would use a SRA.. For most Open tracks, time trials, auto X, etc etc Either or will be just fine.

As for the MM Fox, I'm pretty sure that has a SRA I could be wrong.. Even still I'm sure it's set records at somepoint, but there are still AIX, AI cars that have beaten it with a SRA.. Now the HP maybe different though..

I am not saying you are bias. I was refering to what you said regarding companys that make products for the IRS. To me you were making them out to be bias because that is the business they are in.

Last time I called MM they told me the yellow fox runs an IRS.

 

[Tholomew Plague]

The IRS in the Cobra has one MAJOR downfall. It was built to fit where a SRA was in the first place. On the street, if you want a smoother ride, by all means swap in the IRS.

If you want a good open track car, a 5 link is the way to go. Even with the bushings and what not on the IRS, you are going to have more money into it and equal or lesser results than a properly set up SRA.

I looked at doing the IRS swap on my old 2000 Roush track car for a LONG time. I looked at every angle I could, talked to racers on both sides about strengths/weaknesses and even drove both. When it all came down to it, the best match for my track car was SRA. I will be doing the same thing again if I take the '98 to that level.

I deal a little bit with the Grand Am Mustangs, and the driver's seem very happy with the SRA set up with them.

I think it really comes down to what fits your driving style/ability and not thinking that what works for someone els will work for you.

So if I were to build my SRA would a Steeda 5-link and G-trak set up be the same/better/worse than something like the MM Max Grip Pack for a 04 GT?

 

[blacksheep-1]

`OK, I'm going to try and post this once more, look at the rear suspension of a mustang, it has 4 links, two lower trailing arms which are parallel, and two upper which are at angles to each other. If you want to stiffen the bottom arms go for it, no real problem there, the major issue with mustang suspension is the upper arms. Those arms are used to locate (center ) the rear end in the car along with controlling movement front to back. Whenever and engineer decides to use one piece to do two things, it usually turns out bad, thus the case herein. The upper arms oppose each other whenever the rearend moves up or down, they "fight" each other to keep the rear centered. they are designed to center the rear "AT THE STOCK RIDE HEIGHT AND WHILE THE SUSPENSION IS AT REST". So say if you've lowered the car, you've already screwed up what the engineers have tried to accomplish by forcing those two arms to bind against teach other. This will show up in a handling characteristic known a "snap oversteer" when exiting a corner, it may be mild to wild, depending on what else you have done the the car. It is created by those upper arms trying to force the rearend back to center on corner exit. If you put hard bushings, or God forbid heim joints in those upper arms you are just creating a bigger problem. If you locate some of the upper arms that fit these cars, that have the oblong bushings you will be better off. To use a panhard bar to try and help this situation out, just adds another, competing arc to those two, already opposing arcs and creates more suspension bind. I have seen guys do this and you can actually jack up one side of the car by cranking on the adjustable panhard bar...don't do it!
That leaves you with a truck arm which is what camaros have used from about 83- 0-whatever, it's simple and works like a champ, two trailing arms, a panhard bard bar and the truck arm, brilliantly simple, effective and you wonder why Ford didn't do this.
Aside from that there are Watts linkages and of course the IRS, but they are getting expensive these days. All of which work well, but the truck arm is probably the lest expensive way to go with the most results. I've seen guys add a panhard bar and remove one of the upper control arms, which actually works well, but to be done right the arm needs to be parallel with the lower arms and centered in the chassis.
Here is an example of a rear suspension that I would have built (but with coilovers, and a better designed swaybar..which he later does) but of course, you couldn't do this in a car with a back seat. leaf through this it's in there someplace, with pics. You should get the idea, bars are parallel and non binding.

Building a Open Track, Road Racing Car... - Ford Mustang Forums : Corral.net Mustang Forum

 

[STAMPEDE3]

`OK, I'm going to try and post this once more, look at the rear suspension of a mustang, it has 4 links, two lower trailing arms which are parallel, and two upper which are at angles to each other. If you want to stiffen the bottom arms go for it, no real problem there, the major issue with mustang suspension is the upper arms. Those arms are used to locate (center ) the rear end in the car along with controlling movement front to back. Whenever and engineer decides to use one piece to do two things, it usually turns out bad, thus the case herein. The upper arms oppose each other whenever the rearend moves up or down, they "fight" each other to keep the rear centered. they are designed to center the rear "AT THE STOCK RIDE HEIGHT AND WHILE THE SUSPENSION IS AT REST". So say if you've lowered the car, you've already screwed up what the engineers have tried to accomplish by forcing those two arms to bind against teach other. This will show up in a handling characteristic known a "snap oversteer" when exiting a corner, it may be mild to wild, depending on what else you have done the the car. It is created by those upper arms trying to force the rearend back to center on corner exit. If you put hard bushings, or God forbid heim joints in those upper arms you are just creating a bigger problem. If you locate some of the upper arms that fit these cars, that have the oblong bushings you will be better off. To use a panhard bar to try and help this situation out, just adds another, competing arc to those two, already opposing arcs and creates more suspension bind. I have seen guys do this and you can actually jack up one side of the car by cranking on the adjustable panhard bar...don't do it!
That leaves you with a truck arm which is what camaros have used from about 83- 0-whatever, it's simple and works like a champ, two trailing arms, a panhard bard bar and the truck arm, brilliantly simple, effective and you wonder why Ford didn't do this.
Aside from that there are Watts linkages and of course the IRS, but they are getting expensive these days. All of which work well, but the truck arm is probably the lest expensive way to go with the most results. I've seen guys add a panhard bar and remove one of the upper control arms, which actually works well, but to be done right the arm needs to be parallel with the lower arms and centered in the chassis.
Here is an example of a rear suspension that I would have built (but with coilovers, and a better designed swaybar..which he later does) but of course, you couldn't do this in a car with a back seat. leaf through this it's in there someplace, with pics. You should get the idea, bars are parallel and non binding.

Most of us understand this. The uppers at a crappy angle to do both and it is shitty.
It is also why I tell people NOT to remove quad shocks because the uppers alone do a shitty job at controlling axle roll.

However, The IRS is also a retro-fit afterthought as I call it and is no where near perfect.
I respect Bruce and what FTBR has done with it.
It can be made worlds above factory with his kit.

But a properly set up SRA can be a mean machine.
They now make 3 link convertion kits with P/H bar.

The Steeda 5 link is a great kit which changes the uppers from angled to parallel with the lowers and uses the P/H bar to control lateral motion.

Then there is one of my favorites which is great for drag or open track and that is the Torque arm set up. I believe you call it truck arm which I've never heard it called.

Personally I would take any of those over a retrofit IRS.
Maybe I'll change my mind when Bruce lets me drive the R

 

[98 Saleen Cobra]

Speaking off all this suspension talk. I just scored a brand new Griggs Watts link for 500 shipped. Reg 1200 plus tax, shipping etc.. My MM panhard will be for sale shortly

 

[JDUB348]

All I can say is I can't wait to drive my car very soon. I just converted to a built sra w MM torque arm, MM pan hard bar, MM lower control arms, and bilstien coil overs. Not to mention the rest of the MM suspension!

Sent from my DROID BIONIC using Tapatalk 2

 

[ROCKNROLLA562]

Irs ftw lol

 

[STAMPEDE3]

Irs ftw lol

That's your whole arguement?
OK