I've got everything except the billetflow brackets and mine still does it. Super annoying.
I like everything about my car EXCEPT....
- Thread starter dezracer
- Start date
mine has done this since I got my car with 30k, after I installed the IRS brace and irs subframe bushings it went away for 7 to 10k. So now I am going to replace and the diff bushings and I bet it goes away for good. we shall see. IRS=03/04 cobra going to solid is just another mustang with a blower. imo
Your argument hold no merit. The S197 cars (with proper suspension components) are able to compete with the M3 at autoX events, and they have a solid rear axle.
Sorry to continue this "stray off topic"
It happens when shifting gears right? Mine "clunks" too. I'm adding FTBR front and rear diff bushings along with there 9/16 subframe bolts. Also a LPW cover and H&R race springs. Will any of this help? I know if not it should help the cars overall performance.
But they are not cursed with quadra-bind 4 link rear suspension and they have a way better front suspension also.
These cars are what they are, they are not even close to perfect.
They are however quite capable with a few mods that are proven to work.
The clunk can be nearly eliminated with Bushings and subframe bolts.
But if someone has no finesse while shifting and they go from coasting in 6th to a hard hit on the gas it will still clunk.
After only two weeks of driving mine BONE STOCK I was able to completely drive around the clunk, that's right it completely stopped happening.
Now with the IRS rebushed I have to try in order to get any clunk out of it.
If you are drag racing go ahead swap for a SRA, there are plenty of guys bailing out of their quadra-binds that want an IRS to go tracking with.
Lets be clear, there is no comparison between a SRA in a 79-04 Mustang and the 05-12 S197 cars... none at all. They are night and day different.
Even the SN95 torque arm set up is inferior for handling to a well set up IRS.
An S197 Mustang driving around cones competes with an M3
........if you say "so"
I actually think Ive figured out were this cluck is coming from, I was under the car yesterday checking my diff leak and if you push front to back on the vibration damp under there you can see the diff jump up and down the bracket for the dampner actually pushes it up then lets it drop, im sure its coming from there cuz one when I installed my LPW cover I put the bushings wrong and I had a cluck from hell Im mean really bad. So anyway there needs to be a way to get those two bolts and bushings tighter with no play so the diff and DS dosent jump up and down. Im have to post a small vid of this.
:dw:
So the IRS is what makes a cobra a cobra?
No, it just makes it less of a Cobra and more like a GT.
Most people who are looking to buy a Cobra are likely to take a pass on one seeing the IRS swapped out for a live axle and will also hurt it's re-sale value. That and the fact the car is very likely to have been abused under the shock loads of drag racing.
The IRS is a better set-up for handling which makes it more fun to drive. Why swap a superior suspension for an inferior suspension?
The clunk is the play in the rear-end. Every 8.8 I have ever seen has that clunk between teeth.
God I get so sick of hearing that! :bash:
The IRS in the cobras aren't superior to much of anything, Is it better for road racing? Yup I'll give it that, but IMO thats about it!
:rollseyes
I bet you do :-D
Spoken like a true drag racer.
Perhaps Porsche, BMW, Ferrari and just about every car company building performance cars didn't get your memo :dw:
An IRS is just as relevant on the street as it is on a road course and maybe more.
Yea well maybe if Porsche, BMW, or Ferrari made the IRS thats in the Cobra this conversation would be going in a different direction but they didn't. Ford built it and did a shitty job. So enjoy your IRS, I'm fine with that. You like yours, I didnt like mine! Dunno what your getting at but it wont change my opinion? :shrug:
Perhaps this will:
Here is an article from Maxiumum Motorsports concerning the IRS vs. a solid rear axle you may find interesting:
IRS Questions: Answered by MM test driver Dave Royce.
MM test driver Dave Royce answered these questions after he won the first American Iron event we entered after swapping an IRS into the MM race car.
Dave’s answers may be quoted, or just use them for background information when talking to customers.
Compare driving the car with the IRS to driving it with the Solid Axle with Torque-Arm & Panhard Bar (SATAPB).
1. Were there any differences during corner entry between the SATAPB and the IRS?
A - Corner entry is changed in a way I didn't expect. Like the SATAPB, the car has great initial turn-in. However, once the car is set, it seems more stable from turn-in to mid-corner or Apex. This allowed for harder corner entry and earlier throttle application.
2. How does the IRS compare to the SATAPB during mid-turn, steady-state cornering: In long, sweeping turns? In shorter, tighter turns?
A - Mid corner with the SATAPB is good, but the IRS feels very stable and ultimately allows the driver to use either the throttle, brake or steering wheel to make micro corrections to maintain perfect balance. Long, high-speed turns are always a challenge in a Mustang, and the entry and exit play a huge role in how well the middle of the turn works. However, sticking to the question - Mid-turn is quite good. With the SATAPB, I would have to wait just a little through the middle, and then use the incredible launching capability of the Torque Arm to get great straight-away speed. With the IRS, I was able to apply the throttle just after turn-in and maintain some throttle application throughout the middle of the corner. Specifically speaking about the Talladega/Riverside corner, in the counter-clockwise direction, I could come off Magic Mountain with full throttle, make the right hand turn, stay drivers right, and maintain at least a quarter throttle at turn in. After turn-in, I could start to slowly roll into full throttle all the way to the braking zone for the Bus-Stop turn.
3. At corner exit when can you put the power down? What are the differences between the IRS and the SATAPB?
A - Corner exit changed the most. The SATAPB required a relatively straight car attitude to apply all the power, or risk a sloppy, slower exit. The IRS, with increased mid corner grip, allowed for earlier as well as a consistent throttle application (always desirable). Some corners I would be applying throttle just after turn-in.
4. Compare the two suspension types in transitions- especially quick right-left-right changes such as S-curves or slaloms.
A - The key to a great handling chassis is how it transitions, or handles the weight transfer. The SATAPB would transition well, much better then the OE Mustang suspension, but would have understeer and then oversteer - not much transition between the two, requiring at times, requiring the "Good Driver Award" to keep it out of the dirt. The IRS maintained composure throughout the S's. I was able to run full throttle through the S's, and would often touch the curbs without having to apply corrective inputs.
5. Was there any wheel hop during the standing start?
A - The launch was probably the most surprising to me. I have done zero launches with the IRS, so I was ready for one of two things; either a mild to severe wheel hop, or a hazing of the tires. I was sure it wouldn't just free-spin, as it had decent grip out of the low speed corners, so I put that possibility out of my mind. With this mind-set, I readied the car to launch at about 2500RPM, while rolling on the throttle and letting the clutch out in a rapid, controlled release. Much to my surprise, the car hooked up with absolutely no wheel hop. I believe the tires were hazing, or slightly spinning, but I was able to keep rolling on the throttle until it was time to pull second gear, and so on.
6. Compare the SATAPB and the IRS in how the car reacts to hitting berms, and other variations in the track surface, such as large bumps or dips.
A - I touched on this a couple of questions ago. When hitting "berms" the SATAPB, or more specifically straight axle, as I don't think the TAPB is a major contributor to this change, would usually set the back of the car over or upset the balance to the point where the driver would have to induce correction, obviously slowing the car. The IRS does what you would expect. It leaves the outside tire with full contact, while the inside tire rides over the berm. This was very noticeable in high speed corners where there is a small steep berm that usually must be avoided. I was able to allow the inside rear tire to be on the berms, and not have to lift off the throttle. This provided that extra few inches sometimes needed to keep from sliding off the track at corner exit, as well. On some berms the rear felt a lot like the front, almost a non-issue.
7. Which would you rather drive, a Mustang with IRS, or a Mustang with a solid axle and a torque-arm?
A - IRS, hands down!
8. How was the braking with the IRS, compared to the SATAPB? Was there any rear brake hop?
A - Braking was a little better. The biggest advantage was the ability to do more trail-braking, deeper into the corner No detectable wheel hop under braking was experienced.
9. What were the worst features of the car with the IRS? With the SATAPB?
A - IRS, not enough horsepower. Too much body roll.
A - SATAPB, not enough horsepower. Seemingly difficult to tune in consistent and predictable corner grip. You can tune it for better entrance, better mid-corner, and decent exit grip, but getting all three seems to be a challenge.
10. What were the best features of the car with the IRS? With the SATAPB?
A – IRS, Terrific transition and mid corner grip. Able to roll onto the throttle earlier. The ability to negotiate berms and curbing without upsetting the car.
A – SATAPB, Great acceleration, no wheel hop, substantial improvement over the OE 4-Link.
11. People often complain about wheel hop during acceleration with IRS cars. Was this a problem you saw with the MM race car?
A – With the setup from MM I completely forget that IRS has a wheel-hop issue. In fact I can say there is no longer a need to associate wheel-hop with IRS, at least with the set-up I drove from MM.
12. You have driven the MM race car with both our complete solid axle torque arm system, and our complete IRS system. What would you say to people that are considering either switching to the IRS or to a solid axle, in cars that came with the opposite rear suspension? Assume they were looking at it from a performance standpoint, were technically able to do the work or have it done, and wanted to make their car handle the best they could? Is there a clear winner between the two?
A – The SATAPB is a lot better the OE, but requires the driver to mechanically balance the car during corner exits. The IRS has a more natural balance tendency, and therefore is easier to keep balanced on the edge with the throttle and brake. So the clear winner is the IRS.
13. How would you compare the modified IRS in the MM race car to other IRS-equipped cars you have driven on the track?
A – I would say it’s comparable to any IRS car I’ve driven. It’s better than most stock IRS, including the Cobra.
14. How did the entire MM road race car, in its current IRS form, compare to other road race cars you have driven?
A – The MM road race Mustang was comparable to the GT3 Porsche in a lot of ways. This may be due to the fact that I set cars up similar for my driving style, but it usually is the fast way around the track. The high-speed stability is good, trail braking is much improved, and steering response at turn-in is great.
15. Did the MM products on our IRS cure any issues or complaints you observed when testing any other IRS-equipped cars?
A – Some IRS cars do not allow for enough camber adjustment, and have undesirable bump-steer.
Did the MM products on our IRS cure any issues or complaints you observed when testing any other IRS-equipped Mustangs? (i.e.: Did you notice any benefits from the MM IRS products we added to the OEM Ford IRS?)
A - As compared to the stock Cobra – street set up – it’s night and day. The OEM car seemed to float around in the middle of the corner, and exhibited unpredictable traction or wheel spin. The MM race car, even with “R” compound tires, felt positive in most driving situations. Mid-corner predictability seemed vastly improved.
16. How is the overall balance of the car with the IRS, compared to the SATAPB?
A – The SATAPB had good balance as compared to OE 4-link and the OE Cobra. After two days of testing the IRS with MM upgrades, I think there is no going back. The balance is what one would expect from a well-sorted performance car.
17. Are there any differences in the tune-ability of the two systems?
A – The ability to tune the rear alignment and static camber is substantially beneficial. If we can get the car to launch off the corner as good as the SATAPB does, you definitely have a better package. However, if I was drag racing, I think I might stay with the SATAPB.
Regarding the actual design of the Ford IRS I have another technical publication you may find enlightening. I will post after you get a chance to digest this.
:beer:
Last edited:
Here is an article about the guy who actually developed the "shitty" Mustang IRS.
In you case I guess I'm too late but I'm sure anyone who was contemplating making this swap is now thinking differently.......more IRS's saved for future generations!
:banana:
I hope Bruce gets a hold of this thread (more iceing on the cake)
Although The T-56 AND the 8.8 CAN and DO accumulate quite a bit of play in them, this play is not always manifested as the proverbial "Cobra Clunk". The "Cobra Clunk" is most often worn rubber OEM differential bushings (front and rear) or aftermarket poly bushings that have met an early demise. Also loose undersize (factory issue 12mm) front subframe bolts. And anyone that sells you poly differential mounting bushings is DOING YOU A DISSERVICE!!!
There is a reason that every single high performance sports car manufactured for the last 20 or so years, is delivered from the factory with an IRS under it. Can you guess that reason?
There is also a reason that economy cars, mid-sized cars, full sized cars, pony cars, mini-vans, sport utility vehicles etc, etc, are also coming from the factory with independent rear suspensions under them. Can you guess that reason?
Name me ONE single high performance sports car that comes from the factory today with an SRA under it??? (A Shelby is a pony car BTW)
:thumbsup::coolman::beer:
i only noticed the end of the article when Klaus says it was a piece of crap? :shrug:Here is an article about the guy who actually developed the "shitty" Mustang IRS.
In you case I guess I'm too late but I'm sure anyone who was contemplating making this swap is now thinking differently.......more IRS's saved for future generations!
:banana:
I hope Bruce gets a hold of this thread (more iceing on the cake)
On the subject.
I like everything about my car, except theres no motor in it now.
I like everything about my car, except theres no motor in it now.
You make great points man. These arguments can go on forever, but the truth is that ALOT of people swap out their IRS for some reason that i do not know. I'm doing a swap because my friends who also own Whipple and Kennebell High hp Cobras all broke their IRS's at the track. They all have SRA now and have not broken anything yet. Not saying SRA is better but i guess it depends on what you plan to do with your car.
IMO, if i wanted a track car i would not even consider a 2003-04 Cobra or even Shelby GT 500's. I would go for C5 Z06's-C6 Z51's, etc. that would easily dominate any Cobra with an IRS.
And another thing, i would've rather bought a car that has a strong rear end setup even if it was dragged, at least then i would know its safe to get on it all the time. In my case, i bought probably one of the nicest Cobras around, but needed more parts to beef up the IRS.
Users who are viewing this thread
