IRS...

[Rampant]

Now that Ford has brought out the GT-R racing concept and it has the solid rear axle, any thoughts on what Ford is thinking with the IRS? They have said they plan to bring it back in the Cobra, so why not show it in the GT-R--supposedly the ultimate racing version? Granted, it is a pretty sophisticated solid axle, but I can't imagine it could compete competitively with IRS setups in a racing environment.

Since the platform is partially shared with the T-Bird and LS, why not just use that IRS system? Seems the be the logical solution. They have the parts, so design shouldn't be an issue, and it certainly would be the cheapest option. My only thought would be its ability to handle the added torque.

The other option I guess would be to use the IRS from the current Cobra, but that setup isn't exactly ideal.

Could this be why it is going to take until '07 to get the next Cobra--so they have enough time to design a new IRS system?

Anyone have any thoughts?

 

[SVTdriver]

I think it is them taking the time to develope the new IRS. Because while it may share dome desing with the LS. It has been stated that it is no tthe same. So maybe that IRS wouldn't work. And since it is a new chassis I don't think the old IRS would work either. And since the Cobra seems to have been delayed a year. It makes sense that the IRS isn't on the GTR.
It is my understanding that they did upgrade the suspension. They have apparently made it out of lightweight chrome-moly tubing. Which while not giving it IRS. Makes for a lighter suspension.

 

[Rootus]

For a dedicated race car, I can't see why they would want to go with an IRS anyway. The live axle is simpler, stronger, cheaper, etc. I can't think of any advantage of the IRS in performance on the racetrack .

Dave

 

[ThRippeR]

I would think an IRS would have quite an advantage on the racetrack. We are not talking 1/4 mi here. I was surprised that the GT-R is not IRS.

 

[rhumbline]

Depends on the track. On very smooth, level tracks, where a suspension doesn't do much anyways, an IRS's advantages are probably minimal. In these easy situations, cheap, simple and rugged live axles would likely suffice just fine.

Now, should the track be a bit more challenging, with lumps and bumps and complex transitions all mixed in together, a live axle with its horrendous unsprung mass handicap will quickly be brought staggering to its knees -- just no getting around the physics here when the suspension is actually tasked to, well, actively suspend rather than just sit still as on a smooth race course or drag strip.

I'm not sure just what class of racing Ford foresees for the GTR-40, but my guess would be the former, smooth-track style venues. My guess, too, is that Ford is still in the process of developing the IRS system for upmarket Mustangs and that it's not yet ready for prime time.

 

[Mach460]

Depends on the track. On very smooth, level tracks, where a suspension doesn't do much anyways, an IRS's advantages are probably minimal. In these easy situations, cheap, simple and rugged live axles would likely suffice just fine.

Now, should the track be a bit more challenging, with lumps and bumps and complex transitions all mixed in together, a live axle with its horrendous unsprung mass handicap will quickly be brought staggering to its knees -- just no getting around the physics here when the suspension is actually tasked to, well, actively suspend rather than just sit still as on a smooth race course or drag strip.

I'm not sure just what class of racing Ford foresees for the GTR-40, but my guess would be the former, smooth-track style venues. My guess, too, is that Ford is still in the process of developing the IRS system for upmarket Mustangs and that it's not yet ready for prime time.

That would be fine if Ford plans on shipping the GT-R to Europe to run on FIA licensed and F-1 billiard smooth tracks. None of which exist in the U.S. except for the road course at IMS. Most tracks in the U.S. are woefully underdevelopment and have reputation for being bumpy, uneven, and brutal on tires and suspensions.

But even on smooth tracks. The advantage of an IRS systems over live axle for road racing would justify the cost. Things such as individual control of each wheel, camber adjustments, etc. There are things you can do with IRS on a road course that you can't do with a live axle..simply because with a live axle both wheels are tied together...what you do to one immediately affect the other.

You ask any road racer...and chances are they will tell you they prefer IRS over solid any day of the week.

 

[Mach460]

I think it is them taking the time to develope the new IRS. Because while it may share dome desing with the LS. It has been stated that it is no tthe same. So maybe that IRS wouldn't work. And since it is a new chassis I don't think the old IRS would work either. And since the Cobra seems to have been delayed a year. It makes sense that the IRS isn't on the GTR.
It is my understanding that they did upgrade the suspension. They have apparently made it out of lightweight chrome-moly tubing. Which while not giving it IRS. Makes for a lighter suspension.

I don't think that may be the case. I think Ford is overstating the differences between the Lincoln LS chassis and the Mustang chassis. It's also been stated that the IRS was developed alongside the live axle (though I'm more inclined to believed that the IRS was developed primarily, then the solid axle came into it late from on high). To be honest...it's my firm belief as an engineer and student of vehicle mechanics, that there would be no real difficulty in developing the IRS to fit the new Mustang chassis. It's a matter of choosing materials and refining production methods.

Personally...my feeling is Ford is doing the Mustang on the cheap...at least in terms of the suspension. That's good in terms of car cost, means that the final product will cost less and more people can afford it. Long term though, it hurts because when they do try to invest the money into car, you find yourself running into difficulties (a la Cobra IRS). Also, I believe ultimately, Ford is just kowtowing to the drag racers....because even if the GT-R is meant for road racing...most people will just want the engine anyways. Happened with the Cobra R where it's not unheard off people ditching the IRS and going drag racing.

 

[Rampant]

...Happened with the Cobra R where it's not unheard off people ditching the IRS and going drag racing.

Good point. But, if the Mustang was more competitive on a road course (double wishbone or multi-link IRS, more aerodynamic, lighter/smaller, etc.) then perhaps it wouldn't be the case. In the instance of the '00 Cobra R, no one in their right mind would choose that over a (cheaper) Vette and go road racing.

So, this tells me that the Mustang is FIRMLY planted as a drag racing only car. It got this way by selling mid-70s technoogy all the way through 2004, and doing well enough to be the only survivor. It looks like Ford is sticking to its guns and not trying to change that. Which is fine for me, I am not looking to get that extra half second on the track. But, trying to say the GT-R is ultimate road racing version of the Mustang (which Ford is aparently trying to say) without an IRS is ridiculous.

Personally, I don't mind Ford selling the solid axle on the GT--I think it is the right move for their core audience. But I would like the option of paying a little (not a lot as the case with the Cobra) for a nice riding car for the horrible streets I drive. I was just saying it would make sense to me that since Ford has the parts already in the bin for the IRS with the LS/T-bird, wouldn't it be cheap and easy for them to drop them in the Mustang?

This wasn't meant to be an IRS v. solid axle debate, but a "use the IRS from the LS/T-Bird since its cheap" v. "design a new IRS system" debate.

It will be interesting to see how this all plays out.

 

[shatner saves]

Trans-Am and some SCCA sedan classes would probably require a live axle because that's what the producstion GT comes with.

 

[SVTdriver]

I realize I don't get out to see that all the drag races. But I find it hard to believe that any dignificant amount of people are using the Cobra R for drag racing.

I do think it should be an option. But I seriously question it's availability. And I don't think the LS parts would work. Otherwise why such a long delay on the SVT?

I don't think the mustang being more drag race oriented has as much to do with the car. But more with the decline in road racing in america itself. I live in a state where we get very little road racing. Now in california it's seems to be different.

 

[Mach460]

I realize I don't get out to see that all the drag races. But I find it hard to believe that any dignificant amount of people are using the Cobra R for drag racing.

I do think it should be an option. But I seriously question it's availability. And I don't think the LS parts would work. Otherwise why such a long delay on the SVT?

I don't think the mustang being more drag race oriented has as much to do with the car. But more with the decline in road racing in america itself. I live in a state where we get very little road racing. Now in california it's seems to be different.

Well...I disagree with your contention that road racing is in decline here in the States. Of course if you were to believe the hacks who follow NASCAR and consider anything coming out of Daytona as sacrosanct, then yeah, you'd think road racing was in a death spiral.

The facts point otherwise.

1. In a recently released report, the CART ChampCar World Series was second to NASCAR Nextel Cup in average attendance and overall attendance in the world with over 150,000/race and over 2.5 million for the year. F-1 was third and ALMS was 4th. The IRL (an all oval series) was 6th.

2. In the past 5 years, there have been more road courses built in the U.S. than ovals. This article on Speed shows the growing popularity of grass roots level road racing:

They Built Them...so Go Already

It only seems like road racing is in decline because NASCAR simply dominates the media air waves generally, and specifically, because for the most part it is shunned by the Mustang community (i.e. the magazines, the aftermarket, etc.). The Mustang media seems more content on Mustangers beating each other up on the drag strips than actually take the competition to the road course, which is the domain of BMW's, Porsche, etc., where they know the Mustang is woefully inadequate, unless you have a Cobra R

As for the delay by SVT....who knows. But I doubt it has anything to do with availability. Remember, SVT is deeply involved with the production of the Ford GT, plus probably more focused on making sure the Lightning blows the Ram SRT-10 into the weeds (God I hate that Ryan Newman commercial), so right now, the next gen Cobra is probably down the list of priorities.

 

[Rootus]

Has anybody here driven a car with the same setup the 05 Mustang GT is going to have? This sounds like a lot of conjecture, I haven't heard anything backed up by reality. And no offense to anyone involved, but I think Ford knows how to make a race car. I doubt very much they would have used a live axle in the GTR if it was not an appropriate choice. It's not like they spared any other expense.

 

[SVTdriver]

I think you missed the point where it said so go already. Which would seem to indicate that more people should be going. But not necessarily are.
http://www.pacificraceways.com/road.html
Not many of these are races that will ever air on tv. Or be part of any national championship. And as the article pointed out. They are building them in california and the east coast mainly. While a dragstrip can be planted nearly everywhere or at least so it seems. I don't care much for nascar or drag racing. F1 has 1 countem 1 race in america. And ALMS which is something I really enjoy watching has 9 races on the schedule. And CART has 16 races with 7 so far being in the U.S. While nascar has how many races in the U.S. But NHRA has 19 events scheduled for TV alone. And that is only NHRA. I'm not going to bring up the import racing or any other type of darg racing.

As for the SVT. Yeah they are building the GT. But they have dropped all other things. I don't think all of it's assets are needed to build 1500 cars. And the lightning is being delayed a year as well. If all the parts as you contend were avaible then why delay the introduction. This is something comletely new for Ford to do.

 

[jasonlee0704]

This debate, as far as it goes for real-world implications, is moot.

If you're a serious road-racer and can already afford a GTR, it'll be pocket change to get either an aftermarket or the '06 Cobra IRS and swap it out.

The only ones who'll be putting the GTR through its paces in stock form are the car magazines.

 

[SWortham]

Yes, a live rear axle will hurt your performance when driving through the twisties. The fact is that no track is completely smooth. And the large amount of unsprung weight you get with a solid rear axle will really hurt the car's damping abilities. And the smallest hops you get with your rear tires will cause it to lose traction in the turns sooner (reducing it's lateral G capabilities). That, and the way the camber is effected during compression and rebound with an IRS would be so much better.

The GTR seems that it could be great for autocross or club racing. And I agree that IRS would've helped a lot. Maybe they'll redesign it with IRS in the upcoming years when they have perfected the new IRS system as SVTdriver stated.

 

[Rampant]

I have a sneaking suspicion the GTR was a testbed to see how far they could take the solid rear axle design and whether or not it could be competitive. With good results, that probably influenced their decision to keep it in the GT.

I also feel the GTR is to the GT as the Cobra R is the to Cobra. That being said, it would be very interesting to see a similarly powered cobra against a GTR in a race.

They have already told us they plan to offer the IRS in future variants, I just wonder what sort of IRS they are going to employ and whether or not they are going to carry over the LS/T-bird IRS system.

 

[new22003]

Solid axles can be made to work well. They hold nascars on the track at 200 mph or on road courses at 120.

But as far as putting a IRS in the new stang, yes it would be easily done. Heck it was easily done in the old fox platform. The T-Birds had it and of course the later cobras.

Since the new mustang is based off the tbird/ls/jaguar platfrom im sure some form of irs would fit it quite easily. I wouldnt pay extra for it but some would.

 

[SWortham]

Solid axles can be made to work well. They hold nascars on the track at 200 mph or on road courses at 120.

I can believe it. But there are a lot of things about NASCAR that aren't optimal. The reason they use a solid rear axle is not because that's best for racing, it's because it's required. But take a look at INDY cars, they have an IRS and they are known for their world class handling characteristics. And the same goes for the new Ford GT -- if Ford had used a solid rear axle in it I'm sure it would not have done so well against the Ferrari and Porsche in the Road & Track comparison test.

EDIT -- But you could be right, I know the solid rear axle isn't optimal, but it may be decent in the GTR. If anyone at Ford wants to hire me, I'll be glad to do some comparison tests.

 

[351CJ]

This debate, as far as it goes for real-world implications, is moot.

If you're a serious road-racer and can already afford a GTR, it'll be pocket change to get either an aftermarket or the '06 Cobra IRS and swap it out.

Except that in many of the road racing classes you are NOT allowed to add IRS in. Although suspension mods are allowed in most classes (springs, shocks, sway bars, bushings, etc) you are not allowed to change the type of suspension. (solid rear to IRS, front strut to double A etc. would not be allowed).

The only other thing I can say, is that in EVERY road racing class that allows IRS, IRS cars dominate the class.

 

[SadbutTrue]

IRS is not simpler, and while I can't comment on weight, its definitely not stronger either. Cobra owners wouldn't be switching to 8.8 inch solids if the IRSs were stronger (same with the Fbody guys using live Ford rears... wouldn't use them if they weren't stronger). I imagine for some reason, the 03 Cobra IRS wasn't going to fit in. I also imagine the Jag/LS/Tbird versions weren't strong enough, though fit could have been an issue there too, since the S197 platform is only loosely based off the DEW98 of those three aforementioned cars.