Cobra IRS wheel hop

thomas91169 · Sep 13, 2007

WANNA_BE_GT said:
The majority of your high end imports like BMW are sporting IRS suspension.

i think ford is the last of the domestics to still utilize solid-rear on their RWD Car lineup.

the GTO is IRS
the Corvette is IRS
the new Camaro is IRS
the new Challenger is IRS

Ford Mustang is SRA. its also lacking in almost every other department, it takes a blower and a 75k+ price tag to do what almost every other one listed above does without boost and at a much lower price.

I wish ford would commit to IRS. they slapped it a SN95 chassis that wasnt designed for it, we got a somewhat decent IRS unit in an aged chassis. they then designed the S197 for IRS useage and ended up opting out for Solid Rear.

tomustang said:
when it comes to modifying them the Solid rear is cheaper

Mainly because its half a century old by design. id hope to hell its alot cheaper. how long has ford been using the 8.8" Rear end?

Give IRS the same time in modders hands, and see what happens.

tomustang said:
You only say that to a bumpy ride comparison daily driving, you take both of them to a road course and see the difference, which is not much,

Have you owned both? have you put in track time using both or is this just more hearsay from the solid rear camp?

tomustang said:
and when it comes to modifying them the Solid rear is cheaper

id hope to hell its cheaper. fords been using the same setup for how many years now?

give irs that much time in a chassis and holy ****.

EDIT: Whoops, wrong window to submit on........

tomustang · Sep 13, 2007

thomas91169 said:
Have you owned both? have you put in track time using both or is this just more hearsay from the solid rear camp?

No, actually all I buy is granatelli products.

thomas91169 · Sep 13, 2007

midlifecrisis99cobra said:
Everything I've read says the properly set-up SRA is superior to the POS IRS designed by Ford for this car.

lets see. lets compare a car with modded solid rear versus stock IRS. yeah. totally legitimate comparison there.

why not take a stock fusion and take on a nascar while youre at it. one is properly prepped, after all

how bout you compare IRS and SRA with equal modifications. run them on a stock 03/04 cobra, the same car, swap out the irs for the sra and see what happens. id imagine 1) slower track times with the SRA, 2) driver would probably feel less confident in the turns 3) driver would wonder why the first tests felt like his beamer in the corner while the second tests the car felt like a civic.

grey03cobravert said:
yes i weight all the parts swapped out and it was dead on 160lbs. lighter , i just did mine but still haven driven it yet to see if i like it or not i got about about 1)00 bucks on it all. after seeling some of my irs parts.

i hope i like it cause i sold my axles and center center already.

hahahaha.

sucks to be you.

the guy i sold my cobra to was going to do the whole solid rear swap (actually the first deal was for my payoff amount, he gets my solid rear from my GT, i get the IRS from the cobra). after driving it for a week, he declined the deal and gave me 1000$ extra, he couldnt stand the thought of going back. he actually stopped driving his Bullitt as well, and plans to make that IRS.

IMO if you drive on the street, IRS is far far far far superior to solid rear. like ive said before, track only vehicles would be all i would go back to solid rear for, just for ease of availability of parts, not necessarily cheapness or durability (hell, most other cars halfshafts can barely hold stock power levels, let alone 450+ that we put through on a Cobra)

Uncle Meat · Sep 13, 2007

tomustang said:
Oh Meat, it's only a difference of 70~ pounds, not 150

No Tom. When we're talking about the 03/04 IRS compared to a SRA it's actually closer to 150. At least that's what I'm told from the guys who have already performed this swap and compared the components and weighed both. I know the 03/04 IRS is a little more beefy than prior years and they may account for the additional weight savings.

Until Ford pulls their head out of their ass and actually designs an IRS that works as well as the others previously mentioned (GTO, Vette, BMW) I'll still praise the SRA for hard driving.

U.M.

Look at this monstrosity for Christs sake!

tomustang · Sep 13, 2007

Uncle Meat said:
No Tom. When we're talking about the 03/04 IRS compared to a SRA it's actually closer to 150. At least that's what I'm told from the guys who have already performed this swap and compared the components and weighed both. I know the 03/04 IRS is a little more beefy than prior years and they may account for the additional weight savings.

Until Ford pulls their head out of their ass and actually designs an IRS that works as well as the others previously mentioned (GTO, Vette, BMW) I'll still praise the SRA for hard driving.

U.M.

Look at this monstrosity for Christs sake!

Rotor weight, brake caliper/pads, and struts are added to the IRS weight (not judging by the pic, but I bet that's why)

Ever carry 2 boxes of rotors before?

Differences between 99/03 IRS

*
Half Shafts Stronger on 03
*
Inner Tierod Mounting Point about 5mm lower on 03 (99/01 vs 03/00R)
*
Front differential tie bar is not intergrated with the differential mounting bolts on the 99-01
*
Control arm bushings are of a higher durameter on the 03
*
Knuckles (uprights) are significantly weaker on the 99-01
*
03 Differential has weight damper (donkey balls) hanging off the diff casing
*
99 had 28 Spline half shafts while the 01+ had 31 spline half shafts

Not much of a weight increase from the two of them

MustangDanny · Sep 13, 2007

I'm about to change to 03 Bilsteins and H&R Race springs on my 99 from a 100% stock setup so I'll let you know how much of a difference that makes on my car. I'll be running 295 BFG Comp TAs for rubber.

Uncle Meat · Sep 13, 2007

tomustang said:
Rotor weight, brake caliper/pads, and struts are added to the IRS weight (not judging by the pic, but I bet that's why)

Ever carry 2 boxes of rotors before?

Differences between 99/03 IRS

*
Half Shafts Stronger on 03
*
Inner Tierod Mounting Point about 5mm lower on 03 (99/01 vs 03/00R)
*
Front differential tie bar is not intergrated with the differential mounting bolts on the 99-01
*
Control arm bushings are of a higher durameter on the 03
*
Knuckles (uprights) are significantly weaker on the 99-01
*
03 Differential has weight damper (donkey balls) hanging off the diff casing
*
99 had 28 Spline half shafts while the 01+ had 31 spline half shafts

Not much of a weight increase from the two of them

That picture does not represent what was weighed, it was merely added for visual impact to illustrate how many more components the IRS consists of. If I ever personally remove mine I'll make sure I remove the calipers, pads, struts, etc. before snapping a pic.

As for why the 03/04 gys report almost 150lb weight savings I can't say. It's just what most all of them report.

U.M.

grey03cobravert · Sep 13, 2007

i got a buddy wi th 95 rear end minus brakes with 4.10 for sale for 300 bucks pm me ,
o and no axles . i got some out
of 97 if theyll work ?

Kilgore Trout · Sep 13, 2007

grey03cobravert said:
i got a buddy wi th 95 rear end minus brakes with 4.10 for sale for 300 bucks pm me ,
o and no axles . i got some out
of 97 if theyll work ?

^^ Well there ya go stangsalwayswin throw them fine parts on yer 99 Cobra and sell the IRS that Ford installed

WANNA_BE_GT · Sep 14, 2007

So, for all you cobra IRS haters, why don't you actually come up with some engineering facts that show the cobra IRS is inferior to lets say the Corvette IRS. Oh, and a side note, it is the thunderbird IRS that ended up in the Cobra. So, those 2 are the same.

Uncle Meat · Sep 14, 2007

WANNA_BE_GT said:
So, for all you cobra IRS haters, why don't you actually come up with some engineering facts that show the cobra IRS is inferior to lets say the Corvette IRS. Oh, and a side note, it is the thunderbird IRS that ended up in the Cobra. So, those 2 are the same.

The proof is in the pudding.... you don't see Corvette owners installing SRA's in their cars and you don't hear them complaining about wheel hop either! What more proof do you need? It's only the IRS Cobra owners who seem to do this.

U.M.

stangsalwayswin · Sep 14, 2007

Kilgore Trout said:
^^ Well there ya go stangsalwayswin throw them fine parts on yer 99 Cobra and sell the IRS that Ford installed

Screw that my cobra is not a "race car" it is my daily driver that i get out and have fun with. I just hate the wheel hop and it will take a little money to stop. If this were a race car I would swap in the SRA.

grey03cobravert · Sep 14, 2007

mines not a race car . and a swapped , it looks better under the rear now . you can fool people to thinking you got a cobra clone , by looking at your exhast , them tell yes it is ,, then smoke them.

Kilgore Trout · Sep 14, 2007

Uncle Meat said:
The proof is in the pudding.... you don't see Corvette owners installing SRA's in their cars and you don't hear them complaining about wheel hop either! What more proof do you need? It's only the IRS Cobra owners who seem to do this.

Sounds like someone needs to get a Corvette already... :Zip2:

WANNA_BE_GT · Sep 14, 2007

Uncle Meat said:
The proof is in the pudding.... you don't see Corvette owners installing SRA's in their cars and you don't hear them complaining about wheel hop either! What more proof do you need? It's only the IRS Cobra owners who seem to do this.

U.M.

Actually, I know people who have blown up their corvette rear ends. It usually happens when they get that nice big launch. But, since the car wasn't designed for the drag strip, you don't see them out there all the time pushing their rear end's as far as they can go like the mustang crowd. PLUS, they are rocking on the race track. Other than the IRS being mounted in an aluminum chassis and mounted a little differently, that is really the difference. They put the IRS in for the same reasons ours have IRS, better wheel travel, more road control, better daily comfort.

It is possible to brace ours up to not hop. Even a solid axle will hop with out quad shocks.

Kilgore Trout · Sep 14, 2007

I get a lot less wheel hop with the new BFG KDWS tires that I got in the stock size. They grab like crazy so it launches and its not really about the massive brake stand. Its more about the launch and the twisties.

My GT would hop sideways on the slightest crack in the pavement every time on curves. The Cobra just powers through them.

But I suspect we are comparing apples to oranges because I am basing my assessment on a stock GT compared to a stock Cobra by an owner who prefers to keep his Mustangs largely stock.

But at the end of the day I will always recommend no SRA swap for Cobras unless the owner specifically states that he is building a straight line racer and will be hauling it around on a trailer.

tomustang · Sep 14, 2007

Uncle Meat said:
That picture does not represent what was weighed, it was merely added for visual impact to illustrate how many more components the IRS consists of. If I ever personally remove mine I'll make sure I remove the calipers, pads, struts, etc. before snapping a pic.U.M.

That is why I said

tomustang said:
(not judging by the pic, but I bet that's why)

tomustang · Sep 14, 2007

WANNA_BE_GT said:
So, for all you cobra IRS haters, why don't you actually come up with some engineering facts that show the cobra IRS is inferior to lets say the Corvette IRS. Oh, and a side note, it is the thunderbird IRS that ended up in the Cobra. So, those 2 are the same.

The corvette IRS was designed for the corvette, that is a good enough answer

Uncle Meat said:
The proof is in the pudding.... you don't see Corvette owners installing SRA's in their cars and you don't hear them complaining about wheel hop either! What more proof do you need? It's only the IRS Cobra owners who seem to do this.

U.M.

I would point more toward the cobra being a muscle car being that it will see more strip time than a corvette, since the vette is gear towards road racing, and road racing enthusiasts, and small penis men

oh and you will see more vette owners complaining about eatin up diffs due to wheel hop over just having wheelhop

thomas91169 · Sep 14, 2007

Kilgore Trout said:
My GT would hop sideways on the slightest crack in the pavement every time on curves. The Cobra just powers through them.

But I suspect we are comparing apples to oranges because I am basing my assessment on a stock GT compared to a stock Cobra by an owner who prefers to keep his Mustangs largely stock.

But at the end of the day I will always recommend no SRA swap for Cobras unless the owner specifically states that he is building a straight line racer and will be hauling it around on a trailer.

agreed 100% with the above.

BlackenedSVT · Sep 14, 2007

HOW TO FIX WHEEL HOP:

http://www.modularmisfits.com/forums/viewtopic.php?t=3691&sid=1526511d3494a3c988a7ff4af3f53ab0

Cobra IRS wheel hop

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