hypothetical: would you retrofit your S197 with 2015+ IRS (if it would fit?)
Cobra R Member
Joined: September 22, 2012
Posts: 1,690
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From: Ontario, California
I like the live rear axel. I was very hesitant at first. I am a lifelong mustang fan. My second car was a 1967. My father and grandfathers favorite car was the mustang.
Even with this I was concerned coming from mostly European cars in the last 10 years. Then I read an article that compared the Porsche 911 and the Mustang. It stated how the Porsche worked with a rear engine layout that most engineers would say it poor. The live rear axel functions under that same stigma. The engineering it takes to over come this trait is what makes it special.
I drove a friends 07 and starred to be convicted. I test drive a 12 and I couldn't think of owning anything else. I think the old school axel makes it special.
Even with this I was concerned coming from mostly European cars in the last 10 years. Then I read an article that compared the Porsche 911 and the Mustang. It stated how the Porsche worked with a rear engine layout that most engineers would say it poor. The live rear axel functions under that same stigma. The engineering it takes to over come this trait is what makes it special.
I drove a friends 07 and starred to be convicted. I test drive a 12 and I couldn't think of owning anything else. I think the old school axel makes it special.
Bullitt Member
Joined: December 28, 2011
Posts: 284
Likes: 17
Any woes you might have with a SRA can be addressed with better shocks, lighter wheels and control arms. Cheap and easy compared to solving woes with IRS.
I don't expect Ford to get the IRS right. They've tried several times and missed the high five each time. Even when they get one from someone else it ends up being iffy.
I don't expect Ford to get the IRS right. They've tried several times and missed the high five each time. Even when they get one from someone else it ends up being iffy.
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Shelby GT350 Member
Joined: May 18, 2010
Posts: 2,318
Likes: 15
From: CT
It seems the fastest street cars in the world have irs. Porsches, Ferraris, corvettes, and etc operate very effectively with irs. Because of this, i have a healthy respect for well designed irs systems. So, yes assuming good quality design i would consider the modification.
Any woes you might have with a SRA can be addressed with better shocks, lighter wheels and control arms. Cheap and easy compared to solving woes with IRS.
I don't expect Ford to get the IRS right. They've tried several times and missed the high five each time. Even when they get one from someone else it ends up being iffy.
I don't expect Ford to get the IRS right. They've tried several times and missed the high five each time. Even when they get one from someone else it ends up being iffy.
I took my car out of storage and cruised around the block while the roads were dry this weekend...the frost heaves in the pavement played total havoc with the composure of the car in a way that my IRS cars never felt.
Last edited by MRGTX; Mar 10, 2014 at 08:45 AM.
Legacy TMS Member
Joined: January 1, 2010
Posts: 3,033
Likes: 66
From: White Plains, NY
It seems the fastest street cars in the world have irs. Porsches, Ferraris, corvettes, and etc operate very effectively with irs. Because of this, i have a healthy respect for well designed irs systems. So, yes assuming good quality design i would consider the modification.
Thread Starter
Shelby GT350 Member
Joined: May 18, 2010
Posts: 2,318
Likes: 15
From: CT
Corvettes use a transverse leaf spring not an IRS but I understand where you are coming from. Honestly I like my log and they can be made to work EXTREMELY well!! So, no I wouldn't swap them, even thought the S550 IRS is supposed to out handle the Boss right out of the gate.
V6 Member
Joined: January 7, 2011
Posts: 65
Likes: 0
From: Pittsburgh
I read where the IRS on the new 2015 will be 1.25 to 1.5 inches wider, so it wouldn't be an easy modification.
2011 GT 400A, GT500 AB, BMR Panhard Bar, Airaird CAI, JLT Oil Separator, Whiteline Tranny Insert.
2011 GT 400A, GT500 AB, BMR Panhard Bar, Airaird CAI, JLT Oil Separator, Whiteline Tranny Insert.
Bullitt Member
Joined: February 25, 2013
Posts: 394
Likes: 2
Only after someone figured out the right spring rates and sway bar stiffness to make the front and rear suspensions work together, and even then, only for a certain price.
I'd sooner try to make the telescoping steering wheel from the S550 work. That has more impact on my daily life.
I'd sooner try to make the telescoping steering wheel from the S550 work. That has more impact on my daily life.
Legacy TMS Member
Joined: February 8, 2004
Posts: 3,399
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From: Cincinnati, OH
Having heard how the platform was revamped and the front suspension redesigned because the rear suspension was much better, and given the new car is wider in the rear, I would say "no way, man". It seems you'd have to sink too much $$ so it might as well be put toward the new car.
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Shelby GT350 Member
Joined: May 18, 2010
Posts: 2,318
Likes: 15
From: CT
Reviving an old discussion now that the S550 has been kicking around for a while and has proven itself to be a very good driving/handling machine.
^this has proven to be true. Ford is offering stronger axles already.
Interesting post.
The thing is that the s197 is really designed for IRS, the SRA was put in after an idiot bean counter. The s197 platform traces its roots to jag, if I'm not mistaken.
With this being said, yes if the price is reasonable. In the real world tuning an IRS or an SRA is not so different. Its all about maintaining geometry. For years tuners have made cars handle "Better" by limiting suspension travel. Same applies to SRA cars. But the fact of the matter is that you want as much suspension travel as possible while being able to control such travel. I have said it before, I don't care how much the body leans as long as my contact patch is maximized. You limit travel and your in a world of hurt when things go south and you cant recover it. If my mustang was a track only car, well probably the SRA would stay just to reduce the cost and R&D on developing it. But IRS's have been around for so long that yes you can have one handle massive power. Ask the Charger guys who invest in 1K+ axles and are set for 1000+hp. The freaking truck axle needs to go.
So count me in if the cost of it is less than 3k. You have no idea how much time I have spent underneath my old mustang examining the tub and looking at the dimensions. A real IRS would fit in there with room to spare. They will probably put in the same pumpkin that is in the old explorer. That is a 8.8 unit, throw some good axles on it with cast control arms and a center cage made of the same, it would not weigh anymore than the SRA and be just as strong.
With this being said, yes if the price is reasonable. In the real world tuning an IRS or an SRA is not so different. Its all about maintaining geometry. For years tuners have made cars handle "Better" by limiting suspension travel. Same applies to SRA cars. But the fact of the matter is that you want as much suspension travel as possible while being able to control such travel. I have said it before, I don't care how much the body leans as long as my contact patch is maximized. You limit travel and your in a world of hurt when things go south and you cant recover it. If my mustang was a track only car, well probably the SRA would stay just to reduce the cost and R&D on developing it. But IRS's have been around for so long that yes you can have one handle massive power. Ask the Charger guys who invest in 1K+ axles and are set for 1000+hp. The freaking truck axle needs to go.
So count me in if the cost of it is less than 3k. You have no idea how much time I have spent underneath my old mustang examining the tub and looking at the dimensions. A real IRS would fit in there with room to spare. They will probably put in the same pumpkin that is in the old explorer. That is a 8.8 unit, throw some good axles on it with cast control arms and a center cage made of the same, it would not weigh anymore than the SRA and be just as strong.
Super Boss Lawman Member
Joined: February 5, 2015
Posts: 4,247
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From: Yukon, OK
I wouldn't attempt it simply because it wasn't designed for my '13. I'm not anti-IRS though. Every car I have ever owned had an IRS prior to my Mustang. Ford did a great job with the SRA in the S197's.
SUPERCHARGED RED ROCKET ------------------Master-Moderator
Joined: May 11, 2006
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From: Carnegie, PA
I don't know if anyone remembers this or not, but the S197 was originally designed to house an upgraded version of the control blade IRS from the 03-04 SVT Cobra.. However the bean counters over at Ford decided to scrap it at the last minute, claiming that it was considered as too costly..
Afterwards the engineering dept were instructed to come up with an upgraded/improved design for the existing SRA instead, that was considered as less costly
Afterwards the engineering dept were instructed to come up with an upgraded/improved design for the existing SRA instead, that was considered as less costly
FR500 Member
Joined: May 22, 2014
Posts: 3,574
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From: Rockaway, NJ
One of the downsides I've been seeing lately on S550's at shows and cruise nites is that many of the younger owners are turning them into Honda tuners. The IRS allows for some really goofy looking negative camber.
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Shelby GT350 Member
Joined: May 18, 2010
Posts: 2,318
Likes: 15
From: CT
I don't know if anyone remembers this or not, but the S197 was originally designed to house an upgraded version of the control blade IRS from the 03-04 SVT Cobra.. However the bean counters over at Ford decided to scrap it at the last minute, claiming that it was considered as too costly..
Afterwards the engineering dept were instructed to come up with an upgraded/improved design for the existing SRA instead, that was considered as less costly
Afterwards the engineering dept were instructed to come up with an upgraded/improved design for the existing SRA instead, that was considered as less costly
If only we could get our hands on these parts.
I suspect that something like -2* would do a lot for the cornering of a Mustang.