The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

The potential IRS for the 2015 Mustang.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Interesting, but the guy comes across as an ass.

I'm most interested in whether this rear end will fit into my Boss without serious modification and geometry compromise.

Shawn
 
6,394
8,275
Interesting, but the guy comes across as an ass.


I love the guys comment about the 03 Cobras being such problem children, the 03-04 Cobras were called Terminators for a reason, with a set of long tubes, a chip, intake and pulleys they would pull down over 500hp at the rear wheels without even breathing hard, witnessed it myself on 2 different occasions..ergo writer is a clown.
 
CPTMac689 said:
Interesting, but the guy comes across as an ass.

I'm most interested in whether this rear end will fit into my Boss without serious modification and geometry compromise.

Shawn

I am hoping it will even though the S550 chassis is supposed to be different. When they took prototype shoots a year or so ago it was on what looked like an S197, so it may just fit. Whether it will be a bolt up or a true IRS is a different story.
 

pufferfish

Supporting Vendor
1,094
66
Maryland
blacksheep-1 said:
I love the guys comment about the 03 Cobras being such problem children, the 03-04 Cobras were called Terminators for a reason, with a set of long tubes, a chip, intake and pulleys they would pull down over 500hp at the rear wheels without even breathing hard, witnessed it myself on 2 different occasions..ergo writer is a clown.
sure, they could easily make great power, but they were plagued with major warranty issues. I remember when I was shopping for a used cobra, I had to make sure that the 03 cobras had the TSB done to replace one of the cylinder heads. A CYLINDER HEAD! that's a major flaw!

I am intrigued by the bolt-in IRS for the S197 chassis. it is definitely a compromise setup, which I doubt saves any weight with its hulking cast aluminum skeleton, has a crappy sway bar location and the split spring/damper arrangement, but it looks vastly better than the sn95 irs bastard. if ford would release the drawings to a company who could manufacture them, it would make a lot of road racers very happy.
 

jr

Race tracks have turns!
24
0
CPTMac689 said:
Interesting, but the guy comes across as an ass.

Except he is right... looking around his site he obviously has a lot of experience with Mustangs and as he witnessed, just one of many people who had serious problems with the 'Terminator". Which, BTW, given the problem of with Ford Service, and the problems with the Ford GT, might just have been the reason for Coletti's abrupt departure. He has a point, that was a sequential process. Millions lost on Terminator service, millions lost on Ford GT recalls, and then he departs. No coincidence.
 
6,394
8,275
FWIW the TSB on the head was for 03 cobras with engines built BEFORE 11/02/02 a month's worth, if that, then production was halted, the problem fixed and the car re-entered production. The issue with the GTs, while Ford's problem and completely unacceptable, were with the contractor, (Citation Corporation in Alabama) and affected 283 cars, that one, probably did lead to Coletti's exit more than anything else
 

jr

Race tracks have turns!
24
0
And that cylinder head problem also affected the Lincoln Aviator. The Terminator also had issues with it's T-56, and a startup tuning issue that went on for a year. SVT had serious engineering and testing problems, where as the car diverged from the GT more and more, the issues became more and more serious. And that IRS was excellent on a road course, it made the car entirely different (I had three with that IRS), but it had it's issues too at first. The 99s had balance and vibration issues, and the bushings were also soft and deteriorated over time. The 2000 R had the best bushings, the rates changed almost entirely, and the 2003/4 were the best overall - it took them that long to get their act together.
So hopefully this legacy of testing issues, of delivering cars that were not ready for prime time (which means very hard driving by enthusiasts), won't affect the S550. We have already seen the IRS being testing in an S197 on a road course (there is a video), and that was last year. So hopefully the IRS has been and is still being thoroughly endurance tested. I want one of these for my Boss, it'll fit one way or the other since the S550 is mostly just an S197 underneath. But I'll probably just switch to the S550 to get the weight loss and the newer engine.
 
6,394
8,275
I'm not going to hijack this thread, but IMO clearly the 03-04 (and the "R" in 200) were watershed vehicles that may have had teething problems , mostly because of their cutting edge tech, but history has shown them to be reliable and horsepower monsters. go to any Chevy/Mopar forums and they give the blower cars a wide, wide birth. The "fox4" platform was about 25 years old at the time. IMO, without them, there would be no s197.
OK so I'm done with that.
So the new s550 platform is the same as the s197? is that what I understand?
 
blacksheep-1 said:
I'm not going to hijack this thread, but IMO clearly the 03-04 (and the "R" in 200) were watershed vehicles that may have had teething problems , mostly because of their cutting edge tech, but history has shown them to be reliable and horsepower monsters. go to any Chevy/Mopar forums and they give the blower cars a wide, wide birth. The "fox4" platform was about 25 years old at the time. IMO, without them, there would be no s197.
OK so I'm done with that.
So the new s550 platform is the same as the s197? is that what I understand?

That's what it appears. The S550 is an evolution/derivation of the S197 platform (also called D2C), which was loosely derived from the DEW98 platform originally developed for the Jag S-type and Lincoln LS.
 
6,394
8,275
dabossinne said:
That's what it appears. The S550 is an evolution/derivation of the S197 platform (also called D2C), which was derived from the DEW98 platform originally developed for the Jag S-type and Lincoln LS.

Some of this gets confusing, I was talking to an SVT engineer about the "new edge" cars (99-04) and he was ..what? that's what we called the sn95, ...still. (and the slang name was "fox 4" for the 4th conjuring of the old Fox platform) Apparently there's a chassis designation..and possibly another for the design studio that sometimes shows up. So how old is this platform? and is it international like the Camaro, Cadillac, Holden?
 

jr

Race tracks have turns!
24
0
"New Edge" is the design language the designers used for the 1999-2004 Mustangs. It's Ford's terms, not invented by "us".
But underneath the SN95 was very much an evolution of the Fox cars. In fact, when they were introduced at the press briefing, a cutaway body was shown that showed the differences. And of course the Foxes can be easily updated with SN95 suspension parts, the IRS, the dashboard, even the ABS.

The S550 is in that same vein, from the S197. Maybe going a bit further, because it has to pass crash standards worldwide - which vary, and also because it has to accommodate both right- and left-hand drive for the first time.

And while this goes back to the DEW98, dumbed down considerably, dropping the world-class front and rear suspensions (the DEW98 is still the most sophisticated platform Ford has ever produced), all that is left of it is the hard points, the middle of the floorpan, and the gas tank. A shame, because the plan was to base the Mustang on the full platform, but it was deemed too expensive.
 
Yeah, there are some good Wikipedia pages on these various platforms and how they relate. It does get somewhat confusing, and when they say, for example, that the S197 platform is derived from the DEW98 platform, this can be a pretty "loose" derivation with only a few pieces and/or hard points shared between them.

Since the S550 introduces (or re-introduces) IRS to Mustang, and assuming it's a further derivation of the S197, maybe it gets closer to the original DEW98 architecture. Or maybe not... most reports say the S550 Mustang will be slightly narrower and on the order of 200 lbs lighter than the S917. And supposedly the GT500's Trinity 5.8L motor does't fit in the S550 engine bay, so this new Mustang looks to be somewhat more compact dimensionally than the current generation. Dunno, but guess we'll find out soon enough.
 

jr

Race tracks have turns!
24
0
The S550 IRS is totally unrelated to the DEW98. And it's not the one that was designed and tested and ready to go for the original S197 either. This is a totally new design, unique to the S550, not sharing any parts. The web is full of pictures of it, since it was first spotted last year and has been seen many times since.

And, yes, the trinity engine does fit in the S550 engine compartment because it's all but the same as the S197. The tops of the strut towers are very slightly different, 3 bolts instead of 4. But the distance between the strut towers is identical because they are otherwise the same. Same for the distance between the frame rails. The only change is ahead of the engine, where because of the swept-back headlamps, the fuse box on one side had to be redesigned, and the intake box on the other had to be totally redesigned. And then Trinity will require a taller hood, but that is certainly easy.

So the Trinity will fit, for whatever that is worth. The rumors that started that idea were uninformed, and they didn't take a close look at the reworked engine compartment. But that doesn't mean they will actually offer it. Despite being only two years old, and economically it would make sense to continue it for a year or two (since new engines are coming longer down the pipeline). Car & Driver (new issue, just came out), claims it will be offered in the first year. And that the existing 5.0 (GT) and 3.7 will be identical in config. and output :(
 
pufferfish said:
sure, they could easily make great power, but they were plagued with major warranty issues. I remember when I was shopping for a used cobra, I had to make sure that the 03 cobras had the TSB done to replace one of the cylinder heads. A CYLINDER HEAD! that's a major flaw!

I am intrigued by the bolt-in IRS for the S197 chassis. it is definitely a compromise setup, which I doubt saves any weight with its hulking cast aluminum skeleton, has a crappy sway bar location and the split spring/damper arrangement, but it looks vastly better than the sn95 irs bastard. if ford would release the drawings to a company who could manufacture them, it would make a lot of road racers very happy.

Your Cobra info is highly inaccurate.


Sent from my iPhone using Tapatalk 2
 

jr

Race tracks have turns!
24
0
No, it's right on. The 2003-2004 Cobras had major issues, and the cylinder head was just one of them. It was part of the same crappy Ford lack of quality engineering and testing that made the Ford GT a disaster: Car & Driver Magazine - Ford a Supercar that Delivers a Super Headache. Coletti called this a "pace car for the entire company" - and apparently this and the Terminator may well have set the pace for his departure.
And according to the most recent quality survey this quarter, Ford is well down towards the bottom of the list.

The giant cast aluminum "skeleton" is the design they prepared for the S197. It has zero relationship to the S550 IRS, which uses a conventional steel subframe.
 

TMO Supporting Vendors

Latest posts

Buy TMO Apparel

Buy TMO Apparel
Top