Looking for a ‘03-04 Cobra IRS for my ‘93 Cobra project. Serious buyer PM me if you have one.
IRS is SO much better for a true street cars.
-J
IRS is SO much better for a true street cars.
-J
Do you guys ever though about going for SRA ?
- Thread starter BADBOYSVT
- Start date
And my 90 coupe has a cobra IRS...
Sent from my Moto E (4) Plus using the svtperformance.com mobile app
Sent from my Moto E (4) Plus using the svtperformance.com mobile app
But wouldn’t you rather have the built rear ended out of a ‘93 Cobra in exchange?
Sorry, had to try
-J
I had never bought a new car before the Cobra. It got me because it had everything desirable in one package: V8 with forged internals, supercharger, 6-speed manual, IRS, AC and in my case a convertible that was a few bolt-ons from the 11s. I think it is one thing to improve that package, but an injustice to subtract from it!
Built IRS is a nice thought until you get over 700RWHP. If you want safety and traction.... applying ALL of it at once in a straight line then go SRA.
I have a built SRA now and wouldn’t go back at that power level. I had a built IRS and it was flat out dangerous and squirrelly at times at the drag strip.
Lots of misinformation on an IRS comes out in these types of threads based on reservations from 03/04 cobra owners to swap to a SRA. I respect the “purist” idea of keeping to the original intention of supercharged with a IRS. Now that I have taken the original intended use to almost 2x the original power level I had to make the switch.
Unfortunately, I listened to these types of threads initially and built my IRS. I could never get the cobra to perform the way that it should. This lead to all types of failures, frustration and disappointment.
I made a decision to make it a straight line performance cobra. It all comes down to what the intended use is for your friends cobra.
Here’s some perspective from our friends at Cortex Racing: “We often see solid-axle cars keeping up with or even outrunning their IRS-equipped competitors. Why? The reason is simple: An independent rear suspension doesn’t necessarily perform better than a well-designed solid-axle setup. This is especially true for vehicles with a lot of front weight bias, like a Mustang.
It all comes down to how a car shifts its weight backward when it accelerates. That weight needs to transfer to the rear tires so they can grip the road during power-down, but it takes time to travel through the springs and shocks–especially on a front-heavy vehicle. On a high-horsepower car, that time delay shows up as lost traction.
(IRS does work well on mid- and rear-engine supercars, since their back tires don’t need as much additional weight to put down the power. Even a Corvette gets pretty squirrelly when it has a 52- to 58-percent rear bias.)
The way to speed up the process is to increase the anti-squat geometry. This allows the weight to transfer directly, without waiting for the springs to load up.
However, an IRS with significant anti-squat generally has bad rollsteer characteristics, making this an impractical solution.
The same is not necessarily true for a solid axle. A torque arm design is good for both power-down and cornering because it allows for a relatively high anti-squat value without compromising other geometry. It’s also very tolerant of rear ride-height changes (IRSis extremely sensitive in comparison) due to the stable foreaft instant center location.
If you drive on bumpy surfaces, it’s usually better to reduce anti-squat since it will let the suspension move more, allowing for more tuning and engagement of the shocks and springs. This can be accomplished by changing the angle of the rear lower control arms.”
I have a built SRA now and wouldn’t go back at that power level. I had a built IRS and it was flat out dangerous and squirrelly at times at the drag strip.
Lots of misinformation on an IRS comes out in these types of threads based on reservations from 03/04 cobra owners to swap to a SRA. I respect the “purist” idea of keeping to the original intention of supercharged with a IRS. Now that I have taken the original intended use to almost 2x the original power level I had to make the switch.
Unfortunately, I listened to these types of threads initially and built my IRS. I could never get the cobra to perform the way that it should. This lead to all types of failures, frustration and disappointment.
I made a decision to make it a straight line performance cobra. It all comes down to what the intended use is for your friends cobra.
Here’s some perspective from our friends at Cortex Racing: “We often see solid-axle cars keeping up with or even outrunning their IRS-equipped competitors. Why? The reason is simple: An independent rear suspension doesn’t necessarily perform better than a well-designed solid-axle setup. This is especially true for vehicles with a lot of front weight bias, like a Mustang.
It all comes down to how a car shifts its weight backward when it accelerates. That weight needs to transfer to the rear tires so they can grip the road during power-down, but it takes time to travel through the springs and shocks–especially on a front-heavy vehicle. On a high-horsepower car, that time delay shows up as lost traction.
(IRS does work well on mid- and rear-engine supercars, since their back tires don’t need as much additional weight to put down the power. Even a Corvette gets pretty squirrelly when it has a 52- to 58-percent rear bias.)
The way to speed up the process is to increase the anti-squat geometry. This allows the weight to transfer directly, without waiting for the springs to load up.
However, an IRS with significant anti-squat generally has bad rollsteer characteristics, making this an impractical solution.
The same is not necessarily true for a solid axle. A torque arm design is good for both power-down and cornering because it allows for a relatively high anti-squat value without compromising other geometry. It’s also very tolerant of rear ride-height changes (IRSis extremely sensitive in comparison) due to the stable foreaft instant center location.
If you drive on bumpy surfaces, it’s usually better to reduce anti-squat since it will let the suspension move more, allowing for more tuning and engagement of the shocks and springs. This can be accomplished by changing the angle of the rear lower control arms.”
After driving cobras and newer GT's, and not being much of a 1/4 mile guy but more of a spirited mountain road and road course guy, I am actually going the reverse and swapping out a soild rear for IRS in my 2002. High horsepower for straight line I can see the argument for a soild axle. But as far as comfort, cornering ability and predictability I definitely prefer IRS
and Jeffrey Epstein didn't kill himself.
and Jeffrey Epstein didn't kill himself.
SVTXTC:
You’re points are very true, as it’s all about intended use.
For a street car with our imperfect roads, I’ll take IRS all day long.
For a car that regularly sees the strip, definitely SRA.
-J
You’re points are very true, as it’s all about intended use.
For a street car with our imperfect roads, I’ll take IRS all day long.
For a car that regularly sees the strip, definitely SRA.
-J
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