Who has actually blown up the IRS??

[ChadS98GT]

Everyone always talks bad about the IRS being weak for drag racing and whatnot....but I havn't really seen much talk of people blowing up halfshafts and other IRS parts....

So those of you that have could you post up what/how it happened....and maybe what MOD's you have or how much HP your pushing....

:beer:

 

[99cbra]

i personally haven't seen it done but have heard across the three boards that I am members of a ton of people doing it.....If you actually stop for a second and think about wheelhop you'll realize how much force is being exerted on those half shafts. Just think about one letting go mid track or 80 mph on the freeway and you'll realize the severity of the problem

 

[ChadS98GT]

i personally haven't seen it done but have heard across the three boards that I am members of a ton of people doing it.....If you actually stop for a second and think about wheelhop you'll realize how much force is being exerted on those half shafts. Just think about one letting go mid track or 80 mph on the freeway and you'll realize the severity of the problem

yeah I realize the whole thinking/knowing there is an issue...I am just curious as to those that have actually blown their IRS up....just want to know how they did it...etc...

I am trying to weigh my options with keeping the IRS rather than going to the solid.....

 

[99cbra]

there is no f vcking option buddy....if you are going to do performance oriented mods to your car then it's virtually a must unless you spend the money to upgrade it with aftermarket halfshafts, diff bushing, torque forward brace, subframe bushing and all the other stuff. The 99 IRS is notoriously week with it's smaller spline shafts compared to the 03. Don't even think about putting drag radials and gears until you do. You know how much my swap cost me??? 500 for a magnaflow catback and uppers/lowers. My car sticks 8000x's better than with the IRS. You know how shiitty our cars handle in the rain....with the solid axle the car doesn't have the tendancy to want to do 360's as it did with the IRS.....the rear just slides out and you compensate for it. I say it is the best mod that I have done to date....lost about 100 pounds with it also something mustangs respond well to. Don't question it just do it. ;-)

 

[stock svt]

Holy crap...

Talk about not liking the IRS. I will give a somewhat positive note but before I do learn this.. the IRS is not for drag racing, period. But now if you take it out every now and then and have a spirited day with it I would just keep it. Coming from F-body's before my cobra I can say it rides sooo much better than a solid axle car. And for the daily driving it handles alot better. Even in the rain I have never had any problems until I run my tires down to slicks. But I also have bushings and a forward torque brace. On a side note I will say my car became alot more stable with the SFC's installed. I noticed alot more rear end stiffness for what it is. But even with my motor, I will suffer at the track but thats ok.... I am keeping my IRS because I want it to stay a cobra. Now when I buy me a nice new 05 then I might be setting the cobra up for track use.

 

[99cobrablack]

I'm with stock, just keep the IRS, its part of the cobra. It can be upgraded and will need to be done same as the solid rear, RioRed4V just tossed an axle in his stock GT rear. You can build it up so it will take some more abuse, granted its not near as much as a built solid axle. I have put a fair amount of miles on my bro's 02 GT and after getting out of my cobra the solid rear GT almost feels unstable, especially in the rain. I can see why the younger crowd piles up the earlier cobras with solid rear axles compared to our IRS cobras.

 

[NJCOBRA10thA]

Everyone always talks bad about the IRS being weak for drag racing and whatnot....but I havn't really seen much talk of people blowing up halfshafts and other IRS parts....

So those of you that have could you post up what/how it happened....and maybe what MOD's you have or how much HP your pushing....

:beer:

See sig for mods, blew 1/2 shaft at track got it replaced, all is well.

 

[99cobrajms]

Blew a 99 stock 1/2 shaft at the track, with DRs and only 295 RWHP when N/A. Added GKN stage III perf 1/2 shafts and never broken another one. Even with 548RWHP and D-1SC with IRS.

Eventually blew the rear, she totally Lockup pulling from a red light. I was on a steep hill and the car would not even roll backwards in neutral. The tow guy had to pull her on the the tow truck dragging the locked rear tires for a few feet. Never knew what blew, got the IRS pulled, and then add my built up Solid Rear. Sold the pile of IRS heap (minus GKNs and Paul's Brace) to a local guy.

The IRS rear at the time of failure had : 1) Paul's Brace 2) GKNs, 3) IRS bushings, 4) KB Alum Diff Bushings, 5) Koni Yellow SA Shocks with MM Coil Overs. I was running Goodyear F1 GS-D3 285s on the rear.

Most impressed with the GKN 1/2 shafts for 99 cobra (ie..28 spline). Least impressed that Wheel Hop did not go away that much with all this stuff added. Especially on the sticky track.

JOhn

 

[ChadS98GT]

Blew a 99 stock 1/2 shaft at the track, with DRs and only 295 RWHP when N/A. Added GKN stage III perf 1/2 shafts and never broken another one. Even with 548RWHP and D-1SC with IRS.

Eventually blew the rear, she totally Lockup pulling from a red light. I was on a steep hill and the car would not even roll backwards in neutral. The tow guy had to pull her on the the tow truck dragging the locked rear tires for a few feet. Never knew what blew, got the IRS pulled, and then add my built up Solid Rear. Sold the pile of IRS heap (minus GKNs and Paul's Brace) to a local guy.

The IRS rear at the time of failure had : 1) Paul's Brace 2) GKNs, 3) IRS bushings, 4) KB Alum Diff Bushings, 5) Koni Yellow SA Shocks with MM Coil Overs. I was running Goodyear F1 GS-D3 285s on the rear.

Most impressed with the GKN 1/2 shafts for 99 cobra (ie..28 spline). Least impressed that Wheel Hop did not go away that much with all this stuff added. Especially on the sticky track.

JOhn

good info...this is what I am looking for....

just out of curiosity what did you pay for the halfshafts?

 

[99cobrablack]

Blew a 99 stock 1/2 shaft at the track, with DRs and only 295 RWHP when N/A. Added GKN stage III perf 1/2 shafts and never broken another one. Even with 548RWHP and D-1SC with IRS.

Eventually blew the rear, she totally Lockup pulling from a red light. I was on a steep hill and the car would not even roll backwards in neutral. The tow guy had to pull her on the the tow truck dragging the locked rear tires for a few feet. Never knew what blew, got the IRS pulled, and then add my built up Solid Rear. Sold the pile of IRS heap (minus GKNs and Paul's Brace) to a local guy.

The IRS rear at the time of failure had : 1) Paul's Brace 2) GKNs, 3) IRS bushings, 4) KB Alum Diff Bushings, 5) Koni Yellow SA Shocks with MM Coil Overs. I was running Goodyear F1 GS-D3 285s on the rear.

Most impressed with the GKN 1/2 shafts for 99 cobra (ie..28 spline). Least impressed that Wheel Hop did not go away that much with all this stuff added. Especially on the sticky track.

JOhn

so it was an internal pumpkin failure?? So it would have most likely failed on a GT axle??

 

[99cobrablack]

i personally haven't seen it done but have heard across the three boards that I am members of a ton of people doing it.....If you actually stop for a second and think about wheelhop you'll realize how much force is being exerted on those half shafts. Just think about one letting go mid track or 80 mph on the freeway and you'll realize the severity of the problem

Ive never seen, or even heard of a half-shaft failing at half-track, or highway speeds. It has all been at the line.

 

[99cobrajms]

GKN Stage III were $820 new. I sold them recently. You can not get GKNs anymore. I think Raxles is one option if you stay 28 spline. JOhn

 

[99cobrajms]

[/QUOTE]so it was an internal pumpkin failure?? So it would have most likely failed on a GT axle??

I never had it checked out, just sold it as is. I quickly found a 2000 GT in the junk yard so I focused on that instead. Never heard back from the guy who took the IRS.


John

 

[cobraracer46]

GKN Stage III were $820 new. I sold them recently. You can not get GKNs anymore. I think Raxles is one option if you stay 28 spline. JOhn

I spoke with some GKN personell at the SEMA show and they stated that need for speed has the GKN stage III's in stock. :smmon:

 

[ChadS98GT]

GKN Stage III were $820 new. I sold them recently. You can not get GKNs anymore. I think Raxles is one option if you stay 28 spline. JOhn

wow them things are expensive! :coolman:

 

[99COBRA2881]

Eventually blew the rear, she totally Lockup pulling from a red light. I was on a steep hill and the car would not even roll backwards in neutral. The tow guy had to pull her on the the tow truck dragging the locked rear tires for a few feet. Never knew what blew, got the IRS pulled, and then add my built up Solid Rear. Sold the pile of IRS heap (minus GKNs and Paul's Brace) to a local guy.
JOhn

Guess, you forgot to mention that about the rear end when you were trying to sell me those halfshafts. Glad I didnt buy them.

The Internet is the equivalant of a fastfood drive thru. Why? Because, they f*ck you at the drive thru.

 

[99COBRA2881]

there is no f vcking option buddy....if you are going to do performance oriented mods to your car then it's virtually a must unless you spend the money to upgrade it with aftermarket halfshafts, diff bushing, torque forward brace, subframe bushing and all the other stuff. The 99 IRS is notoriously week with it's smaller spline shafts compared to the 03. Don't even think about putting drag radials and gears until you do. You know how much my swap cost me??? 500 for a magnaflow catback and uppers/lowers. My car sticks 8000x's better than with the IRS. You know how shiitty our cars handle in the rain....with the solid axle the car doesn't have the tendancy to want to do 360's as it did with the IRS.....the rear just slides out and you compensate for it. I say it is the best mod that I have done to date....lost about 100 pounds with it also something mustangs respond well to. Don't question it just do it. ;-)

"there is no f vcking option buddy....if you are going to do performance oriented mods to your car then it's virtually a must unless you spend the money to upgrade it with aftermarket halfshafts, diff bushing, torque forward brace, subframe bushing and all the other stuff"

We upgrade everything else on our cars why is the IRS any different? People will upgrade a solid axle all day and brag about it, when poeple have to upgrade the IRS which is rare that they actually do 'cause most of the time they just b!tch about it.

"The 99 IRS is notoriously week with it's smaller spline shafts compared to the 03. Don't even think about putting drag radials and gears until you do."

Yeah the 28 splines suck, but how in the hell are gears going to break a halfshaft. Wheel hop breaks halfshafts, not gears.

"You know how shiitty our cars handle in the rain....with the solid axle the car doesn't have the tendancy to want to do 360's as it did with the IRS.....the rear just slides out and you compensate for it."

Actually, no I dont... I leave traction control on and not once has the rear end come around on me or has the car felt unstable. I do drive accordingly to the conditions. If the weather is bad, I keep my foot out of it. Mustangs in general are not good in bad road conditions, that's why the Kansas Highway Patrol got rid of them. These were fox body 5.0s with solid axles not IRS cars.

"I say it is the best mod that I have done to date....lost about 100 pounds with it also something mustangs respond well to. Don't question it just do it."

It all depends on what you do with the car. Might have lost 100 lbs due to the solid swap but you took weight off the wrong end. Relocating the battery to the pass side of the trunk would help offset this and make the car more stable.

JMHO

 

[99cbra]

We upgrade everything else on our cars why is the IRS any different? People will upgrade a solid axle all day and brag about it, when poeple have to upgrade the IRS which is rare that they actually do 'cause most of the time they just b!tch about it.

there is a reason that something is rare...IRS even built still isn't up to the task.....wheelhop is a killer man

Yeah the 28 splines suck, but how in the hell are gears going to break a halfshaft. Wheel hop breaks halfshafts, not gears.

I said gears and sticky tires...if I have to explain myself on this one something is wrong

Actually, no I dont... I leave traction control on and not once has the rear end come around on me or has the car felt unstable. I do drive accordingly to the conditions. If the weather is bad, I keep my foot out of it. Mustangs in general are not good in bad road conditions, that's why the Kansas Highway Patrol got rid of them. These were fox body 5.0s with solid axles not IRS cars.

my car handled shiity in the rain...wheelhop like a mother just leaving a stoplight and the car spinning out on me in turns

It all depends on what you do with the car. Might have lost 100 lbs due to the solid swap but you took weight off the wrong end. Relocating the battery to the pass side of the trunk would help offset this and make the car more stable.

a 100 pounds is a hundred pounds no matter where you get it from....I can like you mentioned offset that weight with a trunkmount battery and my nitrous bottle. If the IRS is such a champ then why does pretty much everyone have a solid axle swap. 1000 for halfshafts eveytime they break plus the p.i.a. to install them isn't worth the little bit of handling the IRS offers....you can get the same performance with a panhard bar setup
JMHO

you know

 

[99COBRA2881]

Im not even going to get into a debate with which is better.... its pointless.
Everyone that drag races their car should swap to a solid axle. Thats not what the IRS was intended for and not everyone has done the swap. Like I said before, it all depends on what you want to do with the car. Wheel hop for me isnt an issue. I dont drag race my car, it handles the twisties like nothing Ive ever driven before and I still have some chassis mods left to do. Subframes being one of them.
Once the clutch gets a few more miles on it Ill post up with results of what the IRS mods have done for my car. I have MM 03 IRS brace, MM 3 pc. Aluminum diff bushings, and IRS subframe bushings. Car should have self built full length subframes here shortly.


Actually once you know what your doing IRS axles are very easy to replace, even easier than a solid axle. No need to even drop the diff cover to pull a halfshaft.

 

[cobraracer46]

I have no complaints with my IRS, because the Last time I went to the strip, my cobra had ZERO wheel hop. I'm I the only one here who likes the IRS and would never ever switch over to a solid rear?