I hope I can swallow the pill you've taken within the next few years but what is wrong keeping a sra? Have you raced a camaro? Bro, it's a no contest. The sra is underrated in my opinion. Yea its old technology but so was the 7.3 diesel that should still be powering our trucks.

 

Engines are comparitively easy but providing a plug in IRS or SRA and doing them right is a different matter entirely. In order to get a great IRS and a great SRA in the same car would essentially require two different back halves compounded by the need to make a rear structure that could support the loads of both. This is adding un-needed weight and complexity.

 

^^^^^^ Bob's totally right.

 

I cannot complain about the SRA in the newer Mustangs... Only on very bad roads which I rarely ever drive. However, I did have a 1989 Thunderbird with IRS and I really liked it. I feel confident Ford is going to give us a great IRS that will handle all the torque required to move the next Mustang along.

 

Exactly. I don't ever want to read about a half shaft breaking at the drag strip. Otherwise the Mustang has devolved into the same weak rear end of the Camaro and Chally.

I'm always puzzled when I read these. After decades of snow & ice driving (incl commercial) with an SRA on a variety of vehicles, my reflexes are automatic and don't even raise my heart rate.
I've been in a few hard turns that skipped a bit but I was under hard acceleration (one 2nd, one 3rd). I didn't correct a bit. With the track-lock it just hooked and finished the curve.
The other day I was passing with TC off in 3rd under hard acceleration. When I crossed the bridge gap there was a bit of a skip (as you say) but again, I didn't correct at all. It just felt like I hit a bump and I zoomed past the other car.
Are you letting off the accelerator and having worse consequences?

 

I'm with you on this. It just doesn't unsettle me as a driver like it does others. I've had a great IRS and I didn't really feel any more planted or confidence inspiring. I guess I just haven't pushed either hard enough. All I know is that they both have advantages and are keen to different driving styles as well.

 

Unfortunately we don't have the luxury of driving on near perfect roads over here, as a matter a fact, city streets are crappy as hell.
So count me in for a good IRS, or make it an option for us up here.

 

IRS can have it's own issues over bumpy surfaces. It all depends on design. The 370Z can get just as skittish over bumps as the Mustang does, but compare it to a Cayman S and the S is far more composed over the rough stuff. Given the choice I'd rather have a good IRS over a good SRA. You get more adjustment, overall more dynamic control, and typically you get better tire wear and more efficient use of the contact patch with a proper setup.

But then again I don't give a **** about drag racing. I know a lot of people do so I can see why there is some outcry against going 100% IRS. But it's just time to move on. IRS with beefy half-shafts will withstand some pretty hard launches.

FWIW, I do agree with those who commented that driving over unsettling bumps mid-corner is not scary. I think the natural reaction for most people is to jump out of the throttle when that happens but it's really the last thing you want to do. It's just the rear end moving in an arc relative to the body... 9 times out of 10 the car will settle right away if you stay in it.

In my experience, a Watts Linkage has made the car very, very stable over rough surfaces. But it always could be better!

 

Man I am a red [censored] hair away from getting the fays2 watts link. Not only to fix the issue with panhard rod (I'm used to it, but better is better) but the ability to adjust instant center without the LCA relocators would be nice as well if only for being lazy and taking my car through the tunnel car wash again. After installing the LCA relocators it killed the ground clearence enough that going through the car wash would lift the back of the car right off the ground.

Anyways, I've no dig either way, I like the SRA for its simplicity and ruggedness but won't begrudge Ford if they can bring an IRS to the table that is every bit as rugged as the 8.8 log axle that underpins my car now.

Testing for this should be easy; put on some seriously sticky rubber on the car, go to a seriously sticky track, make sure its a cobra jet mule with another 250 to 300 horsepower on top of what is already there then launch the thing like your trying to rip the bumper off the car doing a wheel stand.

When something breaks fix it, rinse and repeat until you can't break it anymore

 

I welcome the prospect of a Mustang with a properly engineered IRS. Tired of the SRA hula when driving my Mustang on the lousy roads around here.

 

Agreed, simply having an IRS is not a guaruntee of suspension greatness. However, properly engineered, it has a greater potential for a more broadband (ride AND handling) vs. the more limited capabilities of a live axle (ride OR handling). Sure, if you live in a realm of generally smooth roads, you can slow down your live axle car around lumpy bends. But isn't that antithetical to a performance car -- having to slow down to compensate for a lack of capability? Many more of us, I would submit, do suffer less than ideal roads for the most part and thus, the greater handling capabilities of an IRS would be a great handling and safety benefit, not to mention a ride benefit too for some icing on the cake.

As for the drag racing sub group, don't forget that your live axle basically have half shafts too -- hidden inside the axle tubes -- that need to be just as strong as IRS half shafts to transmit X amount of torque. IRS do have two joints per side, generally of CV design, but those can be designed sufficiently strong for X amount of torque too, nothing inherently weak about them.

Watts linkages can certainly help a live axle, but they can't do away with their more basic Achilles heel, their huge unsprung mass, which is pretty much inherent in the design regardless of how firmly located they are.

 

Agreed. Getting rid of unsprung weight will be a huge plus. And what I'd give to run -1.5* camber out back right now!

You do make a great point about ride AND handling with IRS vs. ride OR handling with the SRA.

 

So FoMoCo, their you have it, all the pros and cons. Choice is pretty clear in my book.

BUILT IT FORD STRONG.

 

That. And I'd love it if my Boss had a lower stance.

 

You should have seen old HWY 66 I drove yesterday up and over where the Siskiyou's meet the Cascade's. Very narrow with no pullouts and you're too busy staying away from the edge to take any pics. It's a twisty, rough, uneven s.o.b., with a series of tight curves that climbed about 3000' in 15 miles. A number of curves had sunken grades from winter that had been quick filled, rough paved, uneven, so there was a line/bump where it matched the old pavement. A couple of pretty hard bumps. Really uneven with about 6" of shoulder, not enough guard rails, plenty of bumps, and the steep drop off was giving me vertigo. lol The curves are so tight that its a series of of l/r snakes one after another with hardly any straights in between. Did I mention the pavement was really uneven with lots of bumps?

I was following a motorcycle with a big fat tire about 5 car lengths behind so I wasn't crowding him. But stayed even all the way up. The curves were tight enough that I was mostly all in 2nd gear in the 4k - 6k range on/off, on/off. So in addition to great handling and great torque in the power band, I was getting the full effect of Bullitt's tone matching the GT40 movie dub. Only had a couple of brief straights to shift into 3rd a few times. The rear end was firmly planted and didn't 'skip' once! (TC off) It was awesome!

The motorcycle guy must have been thinking "that's a Mustang. How can a SRA be handling so well on this rough road??" lol

Just fine thank you!


Just sayin...

 

I know it does pretty well... but it really could do so much better!

 

The rear is clearly an IRS test mule. Personally I prefer my solid rear and I love my 5.0 motor. I find the cover over the fuel cap more intriguing than anything else.

 

I'm thinking they have a fuel cell in the trunk due to inability to retain the existing fuel fill, hence the cover.

 

How can you prefer your solid axle to a IRS that we know basically nothing about and haven't driven yet?

 

While I have a 2013 on order, I would really like it to have an IRS over the current LRA. I know it would be an improvement across the board!