Carroll Shelby explains why there won't be IRS
The extra weight of the iron block motor certainly won't help either handling or acceleration.
The Vette has some pretty basic performance advantages over the GT500, namely much less weight (probably on the order of a 1/4 TON less), better weight distribution, lower CG, more centralized mass, better aerodynamics and a better suspension. Of course, it only carries two folks and costs, base, twice as much, though the GT500 and non-Z06 Vette prices will be much closer. The Vette is, basically, a pure, purpose built high performance sports car and its design clearly reflects this.
In the Stang's corner will be more peak power and torque and a broader spread of power over the powerband. Whether this will be enough to counteract that extra 1/4 ton of deadweight will await the dragstrip. The Stang is also somewhat larger, capable of carrying 4 in a pinch and perhaps a bit more luggage for hitting the high road. The SC 5.4 will be more easily modded to make significantly more power, with pulley change, modded chip and some intake/exhaust enhancement likely to yield at least a full bodied 100+ extra horses. Its chassis, as much of an improvement over the ancient SN95s as it is, is simply not on par with the more sophisticated -- and expensive -- Vettes. The Mustang design is, of neccessity, not nearly as focused as the Vettes, for better and worse, and has obvious compromises, for better and worse, in terms of ultimate performance capabilities.
How the GT500 will fare against the upcoming Z06 is another matter, and perhaps a bit more apples and oranges as the latter is likely to cost well north of $60K. On the other hand, you get a hugely thorough and aggessive upgrading of the Vette, from an all AL chassis to a semi-race 7L motor. While the GT500s motor might be able to be modded enough to make up the weight difference, and thus acceleration in the straights, its chassis simply is not nearly as performance oriented nor as sophisticated as the Vette's. While it may be possible to create Vette level numbers in some isolated test scenarios such as a smooth, constant-rate skidpad, it is unlikely to be able to match the full spectrum performance capability of the pricier Vette.
The Vette has some pretty basic performance advantages over the GT500, namely much less weight (probably on the order of a 1/4 TON less), better weight distribution, lower CG, more centralized mass, better aerodynamics and a better suspension. Of course, it only carries two folks and costs, base, twice as much, though the GT500 and non-Z06 Vette prices will be much closer. The Vette is, basically, a pure, purpose built high performance sports car and its design clearly reflects this.
In the Stang's corner will be more peak power and torque and a broader spread of power over the powerband. Whether this will be enough to counteract that extra 1/4 ton of deadweight will await the dragstrip. The Stang is also somewhat larger, capable of carrying 4 in a pinch and perhaps a bit more luggage for hitting the high road. The SC 5.4 will be more easily modded to make significantly more power, with pulley change, modded chip and some intake/exhaust enhancement likely to yield at least a full bodied 100+ extra horses. Its chassis, as much of an improvement over the ancient SN95s as it is, is simply not on par with the more sophisticated -- and expensive -- Vettes. The Mustang design is, of neccessity, not nearly as focused as the Vettes, for better and worse, and has obvious compromises, for better and worse, in terms of ultimate performance capabilities.
How the GT500 will fare against the upcoming Z06 is another matter, and perhaps a bit more apples and oranges as the latter is likely to cost well north of $60K. On the other hand, you get a hugely thorough and aggessive upgrading of the Vette, from an all AL chassis to a semi-race 7L motor. While the GT500s motor might be able to be modded enough to make up the weight difference, and thus acceleration in the straights, its chassis simply is not nearly as performance oriented nor as sophisticated as the Vette's. While it may be possible to create Vette level numbers in some isolated test scenarios such as a smooth, constant-rate skidpad, it is unlikely to be able to match the full spectrum performance capability of the pricier Vette.
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Unfortunately I know that the upcoming Z06 is going to walk all over the Shelby. I am just hoping that by some miracle, the shelby out handles the base c6. Highly unlikely, but even if it comes close, I will be happy. The weight will play a huge part in the handling, this I know. I guess we will have to wait and see.
V6 Member
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Originally posted by Joes66Pony+March 23, 2005, 9:01 PM--><div class='quotetop'>QUOTE(Joes66Pony @ March 23, 2005, 9:01 PM)</div><div class='quotemain'>Counterpoints:
According to Ford and Hau Thai Tang, who was in charge of Mustang development, the new gen Mustang was designed right from the offset to readily accept IRS, and that IRS was developed in parallel with the SRA. According to some stories I've read, the Mustang was designed right from the outset for IRS and was well along in development until the beancounters intervened.
As far as spreading the cost, it goes back to my original argument (made wayyyy back in the Fall) of making the IRS at least optional, if not standard, in the GT.
So how is it that Ford can build a truck (let's call the Adrenalin for what it is) with IRS that can handle 390 hp? I mean by all logic, that's a tremendous load you're asking the IRS to put up with. But ask Ford to put it in a Mustang (which should hopefully be a lot lighter), and all of a sudden their panties get into a bunch over strength and cost.
It's not a question of using exotic materials or big huge beefy parts. It's a question of actually putting the commitment to quality engineering and thought into a design, rather than throwing big hp. Take a look at the F-Series trucks. The engineering and thought that goes into those things is amazing. If Ford put that much thought into their cars, then "Year of the Car" would be more than just a catchy slogan.
So it comes down to this. How is it that everybody else (especially cross town rivals GM/Dodge), can build IRS systems that can withstand big hp/torque, but Ford can't.
<!--QuoteBegin-Josh69@March 23, 2005, 12:22 PM
PS, I would also suspect that Ford has already learned a lot from the IRS they installed on the previous Cobra, which has not been entirely reliable, so my guess is they know firsthand more than any of us could postulate, what it would take to make a suitable IRS for the new Cobra, that won't shatter, and won't weigh a ton, etc. They've already tried it...my guess is they know better than any of us could pretend to what they are doing.
Originally posted by Josh69@March 23, 2005, 12:22 PM
I think the two most obvious reasons were already stated, but apparently completely missed by those who are still whining.
1) $5K extra to build an IRS for THIS car, not any other car...for this car...which is perfectly logical in economics as well as engineering. For one, they don't make an IRS for any other Mustang to distribute the R&D costs over time, so for economy to scale, it'd be prohibitively expensive to build IRS for a limited production car. The BMW 3-series all share the same chassis, albeit with slight differences, but they make 450,000 of them a year worldwide...which allows them to R&D and share the load. Simple economics.
I think the two most obvious reasons were already stated, but apparently completely missed by those who are still whining.
1) $5K extra to build an IRS for THIS car, not any other car...for this car...which is perfectly logical in economics as well as engineering. For one, they don't make an IRS for any other Mustang to distribute the R&D costs over time, so for economy to scale, it'd be prohibitively expensive to build IRS for a limited production car. The BMW 3-series all share the same chassis, albeit with slight differences, but they make 450,000 of them a year worldwide...which allows them to R&D and share the load. Simple economics.
As far as spreading the cost, it goes back to my original argument (made wayyyy back in the Fall) of making the IRS at least optional, if not standard, in the GT.
Originally posted by Josh69@March 23, 2005, 12:22 PM
2) Power, building any IRS that is capable of withstanding the kind of power output this car has would take a lot of R&D, some pretty seriously heavy parts, big hardened gear sets, beefy links, beefy axles and bearings, beefy CV and/or universal joints, etc. All of that stuff would need to be very heavy duty, and that costs lots of money, weighs a lot, and takes a lot of R&D, and if you want it to weigh less, you need increasingly more exotic materials and even more R&D...which all leads us back to point #1, see above.
Obviously Ford has made a very competitive rear end with what they are using, and the fact that it competes well against IRS cars is enough to satisfy even the raggedy old automotive journalists, why not some of you?
End of story, so everyone who is b1tchin up a storm, get a grip, be happy with what you're (if you are even planning on buying one) getting for the money, that's a LOT of horsepower for the dough. And after all, this is a Pony/Muscle Car right? Or did I miss something....
2) Power, building any IRS that is capable of withstanding the kind of power output this car has would take a lot of R&D, some pretty seriously heavy parts, big hardened gear sets, beefy links, beefy axles and bearings, beefy CV and/or universal joints, etc. All of that stuff would need to be very heavy duty, and that costs lots of money, weighs a lot, and takes a lot of R&D, and if you want it to weigh less, you need increasingly more exotic materials and even more R&D...which all leads us back to point #1, see above.
Obviously Ford has made a very competitive rear end with what they are using, and the fact that it competes well against IRS cars is enough to satisfy even the raggedy old automotive journalists, why not some of you?
End of story, so everyone who is b1tchin up a storm, get a grip, be happy with what you're (if you are even planning on buying one) getting for the money, that's a LOT of horsepower for the dough. And after all, this is a Pony/Muscle Car right? Or did I miss something....
It's not a question of using exotic materials or big huge beefy parts. It's a question of actually putting the commitment to quality engineering and thought into a design, rather than throwing big hp. Take a look at the F-Series trucks. The engineering and thought that goes into those things is amazing. If Ford put that much thought into their cars, then "Year of the Car" would be more than just a catchy slogan.
So it comes down to this. How is it that everybody else (especially cross town rivals GM/Dodge), can build IRS systems that can withstand big hp/torque, but Ford can't.
<!--QuoteBegin-Josh69@March 23, 2005, 12:22 PM
PS, I would also suspect that Ford has already learned a lot from the IRS they installed on the previous Cobra, which has not been entirely reliable, so my guess is they know firsthand more than any of us could postulate, what it would take to make a suitable IRS for the new Cobra, that won't shatter, and won't weigh a ton, etc. They've already tried it...my guess is they know better than any of us could pretend to what they are doing.
The problem with this last piece is that the IRS in the 99-04 Cobra was a severely compromised set-up, shoehorned into a car that was never designed to accept it in the first place. Supposedly , the new gen Mustang was designed for the IRS from the outset, so of the problems with the IRS Cobra would have been eliminated. So to say they tried it and they know better simply doesn't apply, becaused they tried it on a car that was never meant for it. My fear is that Thai-Tang was feeding us a bunch a bull about the car accepting IRS from the outset, and any IRS that may be fitted in the future will again be a compromised set-up.
[/b][/quote]
To your counterpoint, your points are well taken, however, even though they originally designed the chassis to ACCEPT and IRS, may not have much to do with building and designing the IRS itself, the R&D I'm discussing is that of the actual differential and it's ancillary components, not the chassis. With that said, since the previous Cobra had a shoe-horned IRS, also doesn't necessarily bear directly on the longevity of the internals of the differential and the strength of the axles/hubs, etc. Not only that, building an IRS for the GT isn't going to require the same torque handling capabilities that the Cobra needs.
Since they aren't offering it on a GT, it doesn't share costs, and if it was an option, it still may not be economical, since many GT buyers may not want to spend an extra couple of grand for it based on it's demographic and price points. I'm sure Ford has done it's share of evaluating the cost/benefit of building it, or the car would have the IRS.
To your counterpoint, I'm not aware that anyone is building an IRS for this level of horsepower output for a car in this price range. The GTO shares it's platform with the Monaro and Vauxhall, so worldwide they are selling many of those cars and they've been around for a few years, so they can afford to put it in the GTO for it's price. The Vette doesn't compare pricewise. Even still, none of these cars produce this much torque. There is a difference between 350lb ft of torque and over 500lb ft of torque, and consequently, Ford has to engineer the heck out of it to stay together for a production car with a warranty. I'm sure plenty of guys have run that much power into a stock set-up that wasn't designed for it, but Ford has to be more vigilant due to warranty concerns. If you had to shell out $5K+ to replace a differential for a customer each time one blew, you'd want to make sure that possibility was as small as possible.
To your last point, I can see your point, but still believe that they learned a valuable lesson in building the IRS for the previous Cobra, just because the mounting points etc, may not have been ideal, should not affect the longevity of it's internals, etc.
Bottom line is the car doesn't have IRS, and I'm sure there is a reason, and I'm positive that reason is money. Just think of the horsepower you are getting for your money with this car. For $38K or whatever the base price is, you have to expect that cost is a major factor in building a factory car for this price, with this much power. That means you aren't going to get everything you want in it. It's Economics.
For the record, I am an Economist, not an Engineer...so I don't pretend to know all the intricacies of what it takes to engineer and produce this car with IRS, but with some common sense and practical mechanical knowledge, I can infer that Economics is the major limiting factor in this case.
Also, a couple of years ago I rebuilt a Lotus Esprit with a transaxle, and those are rated at exactly 350lb ft of torque, you go past that, and they start shredding gears and pinions, so the power handling is a real factor in building a diff. That is in a $90K car, and Lotus deemed it too expensive and costly to re-design the unit, so they lived with it and kept the power at 350lb ft of torque. My point with this tidbit is that it's not a new story, Ford didn't invent an excuse.
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Joined: February 26, 2004
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Haven't posted here in a long time...
Anyway, I'll side with the IRS guys, however, that doesn't mean SRA is bad. The biggest disadvantage SRA has is a bumpy corner, plain and simple. It's the only time it's faults are really brought to light.
I've had a number of cars, almost all IRS except for the '97 Mustang GT. Whenever I was in a turn that wasn't smooth, the rear end felt like it wanted to do a "two-step", it was very unsettling and not very confidence inspiring. In contrast, my WRX (and my Audi A4 before that) handled these same turns with much better ease. heck, even my old '90 Cougar XR-7 did as well.
While I think the new Cobra looks fantastic and I'm loving the specs, I think it should have gone with the IRS for it's price point. I'd still buy one, but the SRA will probably hinder it in real world comparisons. On the track I don't see a problem as they are usually smooth.
It appears Ford wanted to move the Cobra up-level with the interior treatments. I'd have forgone them for the IRS to keep the costs the same. It's a huge jump in price from the GT to the Cobra, compared to say, the jump from a WRX to a STi. Yet the STi manages to have an upgraded interior, upgraded motor, upgraded wheels, tires, suspension, brakes, tranny, AWD system, etc... for under $10k more.
In any case, I look forward to seeing what the Cobra will do and I think it's safe to say we will see a Mustang with IRS again sometime in the future.
Just my $.02
Anyway, I'll side with the IRS guys, however, that doesn't mean SRA is bad. The biggest disadvantage SRA has is a bumpy corner, plain and simple. It's the only time it's faults are really brought to light.
I've had a number of cars, almost all IRS except for the '97 Mustang GT. Whenever I was in a turn that wasn't smooth, the rear end felt like it wanted to do a "two-step", it was very unsettling and not very confidence inspiring. In contrast, my WRX (and my Audi A4 before that) handled these same turns with much better ease. heck, even my old '90 Cougar XR-7 did as well.
While I think the new Cobra looks fantastic and I'm loving the specs, I think it should have gone with the IRS for it's price point. I'd still buy one, but the SRA will probably hinder it in real world comparisons. On the track I don't see a problem as they are usually smooth.
It appears Ford wanted to move the Cobra up-level with the interior treatments. I'd have forgone them for the IRS to keep the costs the same. It's a huge jump in price from the GT to the Cobra, compared to say, the jump from a WRX to a STi. Yet the STi manages to have an upgraded interior, upgraded motor, upgraded wheels, tires, suspension, brakes, tranny, AWD system, etc... for under $10k more.
In any case, I look forward to seeing what the Cobra will do and I think it's safe to say we will see a Mustang with IRS again sometime in the future.
Just my $.02
Shelby GT500 Member
Joined: September 2, 2004
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From: Chicago
Man this is REALLY disappointing. I really love the look of this car, but wouldn't probably buy it without an IRS rear. This car might smoke various higher end cars at the drag strip, but I have a feeling that us Mustang owners will be admiring C6 Z06 rear end on the track. I am skeptical of the 5K cost, seems REAL high. At least make it an option.
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The new GM Zeta platform has an IRS. Unfortunately they realized that they can't sell any at the price required to make any profits from the added cost so they pulled the plug.
People crying about the lack of an IRS just don't have any business sense. Ford will sell probably 5K-7K Cobras a year for about 3 years before the next model change over. They will have to price it at least +$5K to recoup the tooling investment for all the new control arms, differential, rear subframe, halfshafts, bushings, springs, shocks, mounts, etc... That's before you add in the cost to engineer the parts, to do the incremental testing and proveout, and change AAI over to install and assembly IRS for 5K Cobras. Add in the lost production of launching the IRS, and impact on cycle time on the assembly line and it's not unrealistic to see that it will end up raising the price $5K.
Instead of asking why Ford can't build a Mustang with an IRS... you should ask why NO ONE has been able to build a 300HP car at $25K and a 450HP car at $40K!
You may want to try going to business school after you complete your Statics & Dynamics class and graduate with your BS in Mechanical Engineering before you start telling Ford how to run their business.
People crying about the lack of an IRS just don't have any business sense. Ford will sell probably 5K-7K Cobras a year for about 3 years before the next model change over. They will have to price it at least +$5K to recoup the tooling investment for all the new control arms, differential, rear subframe, halfshafts, bushings, springs, shocks, mounts, etc... That's before you add in the cost to engineer the parts, to do the incremental testing and proveout, and change AAI over to install and assembly IRS for 5K Cobras. Add in the lost production of launching the IRS, and impact on cycle time on the assembly line and it's not unrealistic to see that it will end up raising the price $5K.
Instead of asking why Ford can't build a Mustang with an IRS... you should ask why NO ONE has been able to build a 300HP car at $25K and a 450HP car at $40K!
You may want to try going to business school after you complete your Statics & Dynamics class and graduate with your BS in Mechanical Engineering before you start telling Ford how to run their business.
GT Member
Joined: April 6, 2004
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Pretty much sums it up..."stupid".
The only reason it doesn't make business sense is because doesn't want to make an investment in it.
Shelby GT350 Member
Joined: March 11, 2004
Posts: 2,146
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TOTAL BS, and you guys belive it.
1. IRS does NOT add 180 lb.
2. IRS does NOT add $5,000 to the cost of a car.
Ford must be plain incompetant. Somehow the Vette makes do with 500 HP IRS and 12 sec quarters.
1. IRS does NOT add 180 lb.
2. IRS does NOT add $5,000 to the cost of a car.
Ford must be plain incompetant. Somehow the Vette makes do with 500 HP IRS and 12 sec quarters.
Tasca Super Boss 429 Member
Joined: May 18, 2004
Posts: 3,657
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From: San Antonio, TX
Originally posted by V10@March 25, 2005, 6:30 PM
Somehow the Vette makes do with 500 HP IRS and 12 sec quarters.
Somehow the Vette makes do with 500 HP IRS and 12 sec quarters.
Mach 1 Member
Joined: January 31, 2004
Posts: 852
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Originally posted by V10@March 25, 2005, 6:30 PM
TOTAL BS, and you guys belive it.
1. IRS does NOT add 180 lb.
2. IRS does NOT add $5,000 to the cost of a car.
Ford must be plain incompetant. Somehow the Vette makes do with 500 HP IRS and 12 sec quarters.
TOTAL BS, and you guys belive it.
1. IRS does NOT add 180 lb.
2. IRS does NOT add $5,000 to the cost of a car.
Ford must be plain incompetant. Somehow the Vette makes do with 500 HP IRS and 12 sec quarters.
Bullitt Member
Joined: January 29, 2004
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Originally posted by BlackRiderX+March 25, 2005, 9:51 PM--><div class='quotetop'>QUOTE(BlackRiderX @ March 25, 2005, 9:51 PM)</div><div class='quotemain'><!--QuoteBegin-V10@March 25, 2005, 6:30 PM
TOTAL BS, and you guys belive it.
1. IRS does NOT add 180 lb.
2. IRS does NOT add $5,000 to the cost of a car.
Ford must be plain incompetant. Somehow the Vette makes do with 500 HP IRS and 12 sec quarters.
TOTAL BS, and you guys belive it.
1. IRS does NOT add 180 lb.
2. IRS does NOT add $5,000 to the cost of a car.
Ford must be plain incompetant. Somehow the Vette makes do with 500 HP IRS and 12 sec quarters.
[/b][/quote]
And the 300C has a 5.7Hemi and IRS for 34K
Ford is BS ing us, again... either they are too lazy or incompetent to do the job, if it wasn't for their truck division they would have gone belly up a long time ago.
GT Member
Joined: February 24, 2004
Posts: 158
Likes: 1
I think we should wait and see the inevitble press comparisons of cars with IRS against the GT500. Only driving the car will determine its success or failure, but in real world standards, it won't matter at all. The vast majority of owners will never need the benifits (so called) of IRS, no more than Hummer2 owners will ever know its off road capabilities.
Administrator clevparts@aol.com
Joined: November 27, 2004
Posts: 12,560
Likes: 4,310
From: Visalia Ca.
It will be a Whole lot easier to Clone a Non IRS Car at least from the Outside with the Hood Down! And do not tell me that front fascia won't have brisk sales.
kc
kc
Cobra Member
Joined: March 6, 2004
Posts: 1,010
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From: Monroe, NC
Originally posted by Wolf@March 25, 2005, 9:26 PM
I think we should wait and see the inevitble press comparisons of cars with IRS against the GT500. Only driving the car will determine its success or failure, but in real world standards, it won't matter at all. The vast majority of owners will never need the benifits (so called) of IRS, no more than Hummer2 owners will ever know its off road capabilities.
I think we should wait and see the inevitble press comparisons of cars with IRS against the GT500. Only driving the car will determine its success or failure, but in real world standards, it won't matter at all. The vast majority of owners will never need the benifits (so called) of IRS, no more than Hummer2 owners will ever know its off road capabilities.
Which is why I'm really getting sick of people complaining about the car not having an IRS when most of the complainers won't notice a difference in the way they use the car anyways. :bang: When I traded in my 2000 GT for my 2001 Cobra, the ONLY time I noticed the difference in the two suspensions was the first couple times I went over older railroad tracks. Other than that, I never gained any benefit from the IRS because I'm not racing the car on a race track. So, I don't care what rear suspension the new Shelby Cobra has in it. I'm buying it either way. And if the people who keep complaining about the lack of IRS aren't going to be racing their cars either, than they should stop whining about it.
If it helps keep the car more affordable, I'm all for it. :yes:
Cobra Member
Joined: March 6, 2004
Posts: 1,010
Likes: 3
From: Monroe, NC
Ford is BS ing us, again... either they are too lazy or incompetent to do the job, if it wasn't for their truck division they would have gone belly up a long time ago.
That's like saying if it wasn't for Honda's car division, they would have gone belly up a long time ago. Of course each company is going to have it's stronger parts and it's weaker parts. No company is perfect. 
Cobra Member
Joined: January 31, 2004
Posts: 1,261
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I was thinking the same thing, John!
If it wasn't for Windows, Microsoft would have gone belly up a long time ago.
I'm surprised nobody's started complaining about the Shelby not having the transmission placed in the rear of the car like in the Vette. Sheesh.
And yes, the 300C has IRS and a 5.7L Semi-Hemi with 340hp base priced at $34k. But, do you realize that car weighs nearly 4,000 lbs.? Chrysler's new Semi-Hemi is a mass-produced engine with a relatively low cost. The 5.4L 32-valve supercharged Ford motor is only used in the Ford GT supercar and the Shelby itself. Thus, it has a much higher cost.
I can sum it all up here. Some of you guys are naming all these cars that have a strong engine and IRS, but when it comes down to it, you're still on a Mustang forum and you still love the car. You keep coming back because you know you love the Mustang more than any of those cars.
If it wasn't for Windows, Microsoft would have gone belly up a long time ago.
I'm surprised nobody's started complaining about the Shelby not having the transmission placed in the rear of the car like in the Vette. Sheesh.
And yes, the 300C has IRS and a 5.7L Semi-Hemi with 340hp base priced at $34k. But, do you realize that car weighs nearly 4,000 lbs.? Chrysler's new Semi-Hemi is a mass-produced engine with a relatively low cost. The 5.4L 32-valve supercharged Ford motor is only used in the Ford GT supercar and the Shelby itself. Thus, it has a much higher cost.
I can sum it all up here. Some of you guys are naming all these cars that have a strong engine and IRS, but when it comes down to it, you're still on a Mustang forum and you still love the car. You keep coming back because you know you love the Mustang more than any of those cars.