IRS on a 1000HP car?

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I'm sure Ac will disagree and the Irs gurus will come in and say all hail the Irs. Posi is right. When it comes to driving you barely can tell the difference. If it was an all out circuit car then Irs. But drag and street sra. Boogie just put a brace on a torn knee. It works but problem is still there
 

mach1033

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A few years back Difeo Ford had a track day at Englishtown. I believe it was April of 08. A guy with a red cobra ditched the IRS and went SRA. He was making a little over 550 to the wheels at the time. On his second pass at a 4k launch he grenaded his his rear. So would it be fair for me to say the SRA is not what its cracked up to be? No of course not. I went from an 03 Mach 1 to my Cobra and when I took it to the track I was not impressed with the IRS. I was hopping and I didnt like the way the IRS felt on top with it being swirly. I have since done all the required upgrades to my IRS along with other suspensions mods to get rid of any and all the BS associated with it. FTBR kit is not cheap but it works. I have a vert and you all know how bad verts are with the hop and his kit eliminated all of it. And I agree a SRA is the way to go when it comes to drag racing and it also saves you on weight compared to the IRS. The OP asked for our opinions if an IRS would be a worth while mod and I think it would be considering that you dont see many IRS on fox bodies.
 

Jefe

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If TurboFiveOh wanted opinions on SA's I think he would of asked that question. This IRS/ac427 bashing is getting old...

I ran a SA in my 01 GT, 02 GT and 03 Roush GT for 100k+ miles. As shitty as the Cobra IRS is, I never want a solid axle Mustang on the streets in my city again. The stock IRS is worlds better than the solid just cruising around town.

This thread is asking for reviews from high horsepower IRS owners. Can we leave it at that?
 

SlowSVT

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And this is coming from a firm believer in the irs.. with a completely built rear suspension including your kit. 485rwhp breaking halfshafts hopping all the way to the bank... 9in and call it a day, end thread.

:smmon:

Well folk ask yourself: Would you take suspension advice from a guy who's only interested in 60' times and 1/4 mile trap speeds.

......... or from a guy who actually tracks his car? :pop:

[nomedia="http://www.youtube.com/watch?v=ch5Dx2ftTwg"]2000 cobra r chasing down a porsche carrera gt - YouTube[/nomedia]
 

unit213

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Can you name me one single high performance sports car that comes from the factory with an SRA under it? Just one!! Start Googling, I've got all day! ;-)

Do you consider a GT500 a high performance car? Let me guess...It's not a sports car. It's a 'pony car' right? Where is that roll eyes smiley?
Should we compare the POS IRS to a real IRS? Maybe that is the problem.

I think you need to wake up to reality and understand that these cares are nothing special other than straight line performance. Given that, you might as well run a rear end that works in a straight line. There is very little difference in the way my car feels on the street with the SRA vs the IRS...and my rear end is good for low 9's at a minimum.
 
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Competition

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My IRS Cobra rides no different than my friends Mach 1. Even if the SRA felt worse I wouldn't cry about it, because I have a penis.
 

ac427cobra

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Do you consider a GT500 a high performance car? Let me guess...It's not a sports car. It's a 'pony car' right? Where is that roll eyes smiley?

The Shelby GT500 is NOT a sports car. Sports cars are two seaters, they are manufactured for basically one purpose, performance. They are not a practical car for everyday use because many of them can barely haul a few bags of groceries or a bag of golf clubs. They are meant to accellerate fast, go around corners with great speed, grip the road well and exhibit excellent handling characteristics. That is why these high performance sports cars built today ALL come equipped with an IRS. Because handling AND ride are both superior with an IRS.

Should we compare the POS IRS to a real IRS? Maybe that is the problem.

Almost every single person, with a Cobra IRS is disappointed with it. I was so disappointed with the IRS I took it out of a brand new 2000 Cobra R and fixed it. I could not stand having Corvette's passing me. Thankfully after fixing my IRS, Corvettes were not kicking my ass on the track any longer.

I would like every Cobra IRS owner to experience the transformation the IRS goes through by removing the all rubber in it.

I think you need to wake up to reality and understand that these cares are nothing special other than straight line performance. Given that, you might as well run a rear end that works in a straight line. There is very little difference in the way my car feels on the street with the SRA vs the IRS...and my rear end is good for low 9's at a minimum.

I've already woken up. There is absolutely NOTHING more entertaining than spanking Corvettes, Vipers, Porsche's and GTR's with a Mustang on a road course. If I would do that activity with a Ford GT I'd be bored to tears.

FWIW
 

xXSnakeBiteXx

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I do. Why does yours hop and this one doesnt?

I can dead hook my car as well, I have failed 3 carrier bearings doing so. I can also blow my tires off when I feel the need. But when that time comes where you launch just over that thin line of traction you know what happens. All I was stating in my previous post is I have dumped countless hours and a little over two grand into my IRS and can still snap a half shaft and/or wheel hop on command. I DD my cobra 95% of the time and don't plan to go SRA but on the weekends you can find me at our local spot ready to run anyone whos willing to throw down. Idk about you but I don't like to lose, and when moneys on the line theirs no "abort run" option... So its frustrating when you put everything in you can get, but instead get a ride home in a flatbed with a hole in your pocket. Im speaking purely from personal experience.. but what do I know my PPD is a .06
 

mach1033

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I can dead hook my car as well, I have failed 3 carrier bearings doing so. I can also blow my tires off when I feel the need. But when that time comes where you launch just over that thin line of traction you know what happens. All I was stating in my previous post is I have dumped countless hours and a little over two grand into my IRS and can still snap a half shaft and/or wheel hop on command. I DD my cobra 95% of the time and don't plan to go SRA but on the weekends you can find me at our local spot ready to run anyone whos willing to throw down. Idk about you but I don't like to lose, and when moneys on the line theirs no "abort run" option... So its frustrating when you put everything in you can get, but instead get a ride home in a flatbed with a hole in your pocket. Im speaking purely from personal experience.. but what do I know my PPD is a .06

It just went up to .07 so you have more cred now. ;-) :D
 

Jefe

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haters-gonna-hate.jpg
 

turbofiveoh

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I've been thinking this over for a while and I appreciate all of the responses, even thought the subject changed quite a bit. I'm leaning toward sticking with the SRA and doing the supporting mods. (TA, PHB, etc) I've been told by more than a few high horsepower IRS owners, most of whom has replaced every rubber bushing in the IRS, that a properly built SRA is the way to go.

My fox is a turbo car, Jefe knows the car very well, and I can turn the power down to ~600rwhp by dropping the boost to 8psig but I wouldn't want to do that all the time. The car is driven on the street 99% of the time and frankly the ride of the solid axle doesn't bother me at all. In fact, when my friend switched his cobra from an IRS to an SRA I couldn't even tell so the ride quality difference is non-issue for me. The point was not to start a full blown debate but to get a better sense of what challenges I'd be facing at my power level, especially by people who have walked the walk.

I did get a chance to talk to the guys at FTB and it sounds like they make a great product and really know their way around an IRS. If I had decided to follow through with the IRS I would have no doubt bought their products. At this point, I don't think the Cobra IRS is going to provide the kind of increase in performance that justifies the inherent risks that come with it at the kind of power I'm making. Not to mention, what another guy here said, a car like mine is going to have some serious oversteer on any road course.
 

SlowSVT

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Good call

If you want to maximize the cornering capability the IRS is the way to go. You don't install an IRS for an improved ride. On a 900 hp Fox the straight axle is the way to go. Your car must be a hoot. Next to my Terminator an 86 notch is my second favorite Mustang. Post pics!
 

turbofiveoh

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I'd like the car to corner as well as it can but I have to keep longevity in mind first and foremost. The fox will never be a true road race monster but with the TA/PHB I can still have a lot of fun with at the occasional track day.

The car is a blast. It's not too out of control with the traction control on, but as soon as it's turned off the car just kills the tires in any gear at any speed. I don't remember if Jefe has ridden in it, if he has he can tell you what it's like.

Here are some pictures of it:
NS001.jpg


Stang04.jpg


903rwhp/938rwtq
903_small.gif
 

Black*Death

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I was disappointed with my IRS until I installed the FTBR kit. Most of us use are Mustangs as DD.

Don't undersestimate the "fun" of driving around a car that corners amazingly...even around town.

For a purely drag car than SRA is the way to go, but OP does not appear to do a lot of drag racing.

If money is the issues than I think stay with your SRA, but if you want a more "fun" car as a DD that is still good at the drag strip than go with the IRS and FTBR kit.

If all the OP cares about is his 1/4 time at the track then SRA is the way to go.

OP..anyone near you have an IRS Cobra with a bushing swap? Maybe get a test ride in an IRS car? Guarantee you will note a large difference between the two..
 

Jefe

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Your car must be a hoot
It is. I havent been in it in boost but we lined up and he embarrassed me in just a few seconds. As that thing should...Ive never been left in the dust so hard :lol:

OP..anyone near you have an IRS Cobra with a bushing swap? Maybe get a test ride in an IRS car? Guarantee you will note a large difference between the two..
Not that I know of unless Kenny is still in town(white coupe). One of these days the FTB kit will go on mine. He has driven a high hp IRS Cobra many times before so...

The main reason I prefer the IRS over the SA is bumps in the road, especially through turns. Every SA Mustang I had would catch air time if I was going over 40 through a bumpy turn. The IRS stays much more planted on the same roads.

An IRS in a Fox with 1000HP is more of a "bling" mod IMO. Im seeing a handful of snapped axles lately so maybe its a good idea to stay as is. That Fox has seen enough down time!
 

turbofiveoh

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Jefe, I'll call you when it's all bolted back together. The heads had a thin deck and were contorting under boost. The new heads just showed up. I need to have the turbo headers rebuilt because of the higher port on the head and the new header bolt pattern. It'll probably wont be back on the road until sometime this summer. I'm thinking about selling the AEM and doing a Haltech while it's down so it could be even longer. I've got lots of time to mull this IRS vs SRA thing over.

Another IRS owner mentioned that snapped axles can a lot more damage when they flail around. If lower HP cars are snapping axles I'm going to do it for sure, and probably on a routine basis. I drove Mike's Cobra back from Tombstone when it had the IRS and it wasn't anything to write home about. Granted it probably had all the stock rubber junk in it. Jefe, if you get the FTBP done if yours you'll have to take me for a spin up the mountain.
 

SlowSVT

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It is. I havent been in it in boost but we lined up and he embarrassed me in just a few seconds. As that thing should...Ive never been left in the dust so hard :lol:

I've ridden in Juice46's car (single Hellion) and let me tell you a Turbo Mustang shows no mercy :eek: I prefer a PD blower for all around driving but a Turbo Mustang on the highway will mop the floor with a twin screw car :uh oh:
 

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