Cobra IRS vs. Corvette IRS

[terrydf]

I'm wondering why the Cobra IRS has such a problem with wheel hop... The Corvette doesn't have this reputation, so why hasn't Ford figured this out? Can someone explain this?

I'm on my second Cobra with IRS. I had heard the problem had been worked by Ford (since the 99 model), but after several more years, it persists. What are the issues?

 

[JWC]

I drove a friends Z06 and it wheel hopped a little. My Cobra stopped hopping with the MM coil overs. We traded cars for a few runs making black lines the Cobra won.

 

[terrydf]

Some years back I had a 1970 Corvette roadster, 4 speed with 350/350. Old technology for sure. But I can't remember once experiencing wheel hop. Still wondering...

I'm not too sure where this line of thought will get me. My car still hops. I rarely load it up that hard, because it seems and feels so destructive. It probably is destructive. I don't race the car, but occasionally like to wind it out flat, till my internal governor says to lift... I hate the hop.

I'd mod the rearend if it would fix the hop without loosing IRS and without becoming so firm that the ride sucks... Guess I'm getting old enough to like the luxury and the air conditioning. I like what muscle cars have become!:lol:

 

[JKD COBRA]

The corvette's still have wheel hop. Even the 2003 Srt 10 viper has wheel hop. I drove one. If you drop the clutch in first gear it will hop pretty easily.

But the difference is, you could tell by how sturdy the car felt that their IRS was not going to break even if you were getting hop.

I don't know a lot about the differences in our IRS and theirs, but basically, our IRS is a "bolt on" IRS. Meaning, it can be swapped into a GT or whatever. But the viper/corvette's IRS is actually part of the car. Therefore its much stronger and probably doesn't have weak rubber bushings. But I really don't know for sure.

 

[E. Green Cobra]

Ford compromised the design of the irs so that they could get it into the mustangs- using the same or similar mounting points as the solid axle, and not slowing the factory down. So this irs (99-04) is a combo of convenience/cost than actual performance- supposedly its right in the 06 cobra.

 

[terrydf]

supposedly its right in the 06 cobra

I thought I heard about this concerning the 03... It was one reason I began considering the swap to an 03 from my 99.

 

[03CobraBro]

Originally posted by terrydf
I'm wondering why the Cobra IRS has such a problem with wheel hop... The Corvette doesn't have this reputation, so why hasn't Ford figured this out? Can someone explain this?

I'm on my second Cobra with IRS. I had heard the problem had been worked by Ford (since the 99 model), but after several more years, it persists. What are the issues?

I cant give you any techinical opinions, but im going to say it has to do with the Fairmont platform not originally being designed with independant rear suspension in mind, where the Vette was built esspecially for it.

I wouldnt worry about it though once Ford gets the car on the purpose built Mustang platform, the S197, in 05 a future Cobra with IRS should run as smooth as a C6. Atleast I would think.

Kevin: Do the C5 and Viper boys suffer from the same half shaft problems we do?

 

[cito]

Just thought I'd add that the new CTS with the Z06 engine is supposed to have some pretty bad wheelhop as well. It was designed with an IRS, but probably not for the type of power it now has.

On my 1999 Cobra, I changed over to the '03 brace, steeda bushings, and bilsteins and the hop was pretty much fixed, but I only had about 310 rwhp in that car.

 

[JKD COBRA]

03cobrabro - As far as I know, they dont. I haven't really been able to talk to many corvette owners about it. But I was talking to one guy with a corvette making about 550-600rwhp and he said not too many people buy halfshafts. Its not really a big deal for them like it is for us.

They do have some aftermarket ones availible though. Some are titanium! They are really expensive. But like I mentioned before, for them, it sounds like they don't really have to worry about their halfshafts. Also, GKN supposedly makes halfshafts for the vipers/corvettes making 900rwhp or more. GKN is coming out with halfshafts for us very soon. They are not rated for any type of HP, but they are supposed to be just as strong as the ones the vipers use.

 

[grnenvy]

I had a 2000 hard top vette that hoped also. I could not launch that car hard it would either bog or spin/hop all over.

 

[03CobraBro]

Originally posted by KevinJKD
03cobrabro - As far as I know, they dont. I haven't really been able to talk to many corvette owners about it. But I was talking to one guy with a corvette making about 550-600rwhp and he said not too many people buy halfshafts. Its not really a big deal for them like it is for us.

They do have some aftermarket ones availible though. Some are titanium! They are really expensive. But like I mentioned before, for them, it sounds like they don't really have to worry about their halfshafts. Also, GKN supposedly makes halfshafts for the vipers/corvettes making 900rwhp or more. GKN is coming out with halfshafts for us very soon. They are not rated for any type of HP, but they are supposed to be just as strong as the ones the vipers use.

Good deal. Hopefully I wont ever have to worry about replacing a halfshaft myself... but If I do, hopefully by that time this GKN halfshaft will be available for our cars, and ill make sure to look into one. I doubt ill ever have upwards of 900hp, then again I might, if you would have told me 5 years ago I'd be driving around in a car with upwards of 500hp I would have laughed, but it would be peice of mind knowing I have something super heavy duty back there that I wont have to think twice about.

 

[03DOHC]

Originally posted by KevinJKD
But I was talking to one guy with a corvette making about 550-600rwhp and he said not too many people buy halfshafts. Its not really a big deal for them like it is for us.

I think the vette "half-shafts" are like little driveshafts. Where we have CV joints they have U-joints.

 

[terrydf]

I think the vette "half-shafts" are like little driveshafts. Where we have CV joints they have U-joints.

Would you please explain the diffference to me?

 

[03InThe11s]

we have weak halfshafts. they have weak (550 hp or so) bottom ends. i think we got the better deal. :beer: and every vette i have been in has some wheel hop. it doesnt feel like the car is going to come out from under you, like in miy cobra, but it is still there.

 

[03DOHC]

Originally posted by terrydf
Would you please explain the diffference to me?

A CV joint is what front wheel drive cars use. A u-joint is built different and works different.

 

[YELL03]

I also have a 2001 Vette Vert 6 speed that I let my 65 year old father drive to keep him young.

Let me tell you, that Vette hops just like the 03 Cobra does.:uh oh:

I added a cold air induction to the Vette which really woke it up powerwise and I remember nailing it in 1st at like 3000rpm and was like "What the heck is going on!!!"

Needless to say I had my 1st experience with wheelhop in the 2001 Vette.

I had a 2000 Vette coupe automatic before that, it didn't hop nearly as bad, but it was not the same powerwise, only ran a 13.7 @ 101mph with 1000 miles on the clock with a conservative 2.1 60' time.

I think the hop in the Cobra is more pronounced due to all the low end torque, it is just to easy to break them loose at any speed. :burnout:

Howard

 

[blacksnake04]

Vettes hop too

I owned a 99 vette 6 spd coupe. It had pretty bad wheel hop with a high rpm launch in 1st.

I'm still breaking in my new cobra and taking it easy. I'd be suprised if wheel hop is any worse in the cobra.

 

[JKD COBRA]

I think the vette "half-shafts" are like little driveshafts. Where we have CV joints they have U-joints.

Thanks for the clarifacation 03DOHC. I didn't know any details why the corvette IRS is stronger, I just knew that it was 'built' into the car more, unlike our bolt on IRS. But I didn't know why. You brought up a good point.

 

[03DOHC]

Here's a pic I found of a vette irs.

 

[03DOHC]

And this is a pic of half shafts w/ CV joints.