Automagically

These things are mutually exclusive. I can get a Jeep Grand Cherokee to pull 1g on a Skid pad. Besides, Roush doesn't equal factory. They have nothing to do with each other. rhumb has pretty much pointed out the reasons for an IRS and that's pretty much it.

For those very serious about drag racing the car, call your aftermarket industry and get Currie to start building SRA kits. Because they will be a somewhat hot commodity. For everyone else, the IRS will do the chores of straight line performance, cornering and road manner. IRS keeps the car just a bit more planted and tire surface area to pavement is a bit higher due to the movement of each section of the IRS, camber really. Where the IRS tilts like a see saw. It's not that it isn't possibly the best SRA in the business, it is. But there are a great many advantages to refining the Mustang.

It's just called progress. If it ain't broke don't fix it attitude means we'd all still be driving Model-A's maybe not even that, probably OX carts.

gtcs07

Most people will never drive these cars hard enough to pull 1g, that was my point. More drag race them than anything. That's why the solid axle is so popular. They had IRS in the Cobras, why do you think they dropped it? I think IRS would make a nice option for some people or models but I'm not a fan myself. I've owned plenty of cars with it and it def. has it's place, just not everyplace.

Automagically

As I'm sure you're right. The IRS in the early Cobra just wasn't up to snuff. But what was back then? It was great for basically a bolt in kit that worked with the car. Kenny Brown has done some extensive work on the IRS and you need to put a few dollars in it to get it right. I think this was the demise of the IRS. Plus, not many people noticed as you are basically getting at the fact that many of the drivers have no idea what's going on out back anyway.

You'd be surprised what talk will do though. No matter what Ford does with the SRA, unless the hand of God comes down and writes the definitive answer about the SRA vs. IRS debate, magazines and internet blogs are going to keep criticizing the SRA until it's gone. Then they will criticize the IRS when it gets put in. Those words keep a bug in the ear of Ford that possibly they should put the IRS in. Maybe I'm wrong though.

2 Go Snake

If Ford puts an IRS in the rearend, they had better make it robust enough to be bounced off curbs without the alignment knocked out of kilter. We dont want no flimsy halfshafts that break easily and need to be upgraded right away. Problem I forsee is the rearend will end up being too heavy to meet my expectations for durability.

rhumb

Which would also be a valid argument for nothing more than a four cylinder, drum brakes and bias ply tires.


Perhaps that putting the cart before the horse in that a lively axle has limited the Stang's proficiency and thus appeal to the narrow realm of drag racing, something that perhaps 1% of Mustang owners overall indulge in anyways.


Various reasons, probably mostly related to a rather contorted and ill handled S197 development program that killed the IRS originally intended for it late in the game to save a few pennies yet ending up with the SRA that ended up costing about $100/car than the IRS would have anyways. The SN95 IRS effort was a valiant one given what SVT had to work with -- not much -- but ultimately was a rather cobbled together piece that hardly represents the apex of IRS capabilities. One should not extrapolate very broadly from that one experience.

I think IRS would make a perfect option, too, for some people or models, specifically, 21st century sport coupes/pony cars striving for class leading chassis dynamics. I've owned plenty of IRS and lively axle cars and have found IRS to be markedly superior overall, even if not appropriate everyplace (tractors and trucks still can benefit from a log axle).

Undoubtedly, Ford, as with every other manufacture, would design and build a Mustang chassis to the same level of durability, even to survive curb-bouncing lummoxes (look at the beating IRS rally cars take) without significantly increasing overall weight (while hugely decreasing the much more important unsprung weight). While perhaps they could come up with interchangeable rear suspension designs that are both great, I see that as unlikely. I think the whole argument that IRSs are somehow inherently fragile a bit of a red herring as there are ample examples to the contrary.

Given Ford's current drive to rationalize platforms across multiple models and global markets, I see little chance for an archaic live axle to survive into the NextStang as the same platform will likely underpin other RWD models in markets that would find a live axle laughable. Rather, we will have to suffer through an excellent IRS -- and is rugged as the various Aussie IRS cars are -- and put up with the increased handling and ride quality that comes with it.

rhumb

Probably not.

What it would do though is make that 1G far more widely available across a far wider range of driving and road conditions beyond a billiards smooth skidpad/race track, and without nearly as much compromise to ride quality either.

Again, IRS is not about peak numbers -- a go-cart can readily pull 1G -- but rather, much broader real world, off-track useability and driveability.

Boomer

Not a bumpy skidpad it wouldn't

RandyW

I guess the Mustang must be a better car than those lousy Ferraris, Aston-Martins, Porsches, and McLarens with their clearly inferior fully independent suspensions. By the way, does anybody know where I can get an aftermarket kit to convert my disc brakes to drums?

Automagically

Yeah...when you pry them from my cold..dead..El Camino.

bob

Oh good another IRS vs. SRA arguement with the wishy-washy hope they have both camp.

Well, the wishy-washy camp needs to pick a side becuase a plug-in rear suspension would bone both an IRS and SRA (if Mustang goes IRS just see what you'll have to hack up in order to get an SRA in there)

The current Camaro and CTS-V are very valid arguments for IRS equipped cars that can put the power down in a drag race (there are 9 second IRS Camaros - not to mention Terminators)

However, I'll side with SRA camp, just because I've really learned to love K.I.S.S (no not Knights In Satans Service - Keep It Simple Stupid) from a maintenece standpoint (I've never had to get an alignment on any Mustang I've owned) it also pleases me to have something a bit different when it comes to my car. Sure it may not be as confidence inspiring as an IRS car but its still hella fun and its also fun to watch IRS guys get all shook up and talk about how they almost died while trying to drive a Mustang.

That said, whatever, if IRS is in the future, my only request is for it to be as rugged and dependable as the current SRA - especially since tires can be **** expensive and the thought of having to rush down to the alignment shop every time I hit an expansion joint or face spending 400 to 600 bucks to replace the rear tires isn't appealing.

gtcs07

There are plenty of examples of modern cars that have IRS that can do all kinds of things well, my points were that a Mustang can do most of those same things with a SRA now. A guy I work with has a Honda Civic that runs 9's with it's 4 banger, maybe that means that we should give up on archaic V8 engines too. Mustangs have always been more about keeping to the essence of the original '64 1/2 design, not trying to turn it into a Ford Probe. Half the content that comes in these new cars I could do without personally. Black boxes, Sync, traction control, TPMS, etc., I don't want or need. Same with IRS. If you do, keep dreaming. Maybe in the next redesign you'll see it.

Wolfsburg

Yeah, I don't think anyone is arguing that IRS is inferior to SRA. The question is simply: Is IRS necessary for the Mustang?

Personally I don't care either way though the Mustang does seem to do just fine with the ol' SRA.

jsaylor

IRS is a virtual certainty, I just hope that Ford thinks it through and goes with a simple, rugged, and inexpensive design like the Control Blade setup. Upper and lower control arms sound great on paper, but the reality is that a double A-Arm suspension is larger, heavier, and more expensive to design, develop, and produce than the Control Blade setup.

In this instance I think the Mustang's cross town rival, the Camaro, is very much an example of how not to do it. Zeta sounds great on paper, but cars in the price range of the Camaro don't garner high enough transaction prices to pay off the development costs of a chassis as complicated and large as Zeta without some help, and the serious pruning GM gave Zeta made sure that help never came.

All too often scenarios like that leave the market with cars that are, literally, 80% finished including the suspension setup. In this case I find it rather ironic that the Camaro's suspension setup feels bout 80% finished when you drive it.

Given a choice, I would rather stay with ridiculously simple and very well sorted rather than go to a setup that looks good on paper but that the funds don't exist to properly finish. Fortunately for us, Ford doesn't seem to be into 80% finished cars. Just my two cents.

2 Go Snake

If Ford does put the IRS in the Mustang, will they have a lightweight version for the base Mustang and a heavy duty version for the high performance Mustangs ? Will Ford Motorsports have a good selection of rear gears for the rearend center section ??

Moosetang

I certainly wouldn't expect them to half-**** it. Control blade, or an evolution of it, seems a safe bet considering how much experience they have using it in multiple vehicles already.

Automagically

I'm just going to leave this here.

http://jalopnik.com/#!5794951/watch-...n-second--mile

rhumb

I would imagine a situation quite analogous to what you have now with the SRA suspension across the base V6 up to the stonking GT500. My guess is that the basic structure/componentry would be basically the same as it is now, but with specific uprated parts sufficient for the duty-level of the particular model.

As for rear-end gears, there's certainly no reason why there wouldn't be just as many for an IRS differential as for a live axle rear -- the actual differential internals are just the same either way, its what hangs off the differential that differs.

In any discussion about live axle vs. IRS, I must presume that Ford will design either system to sufficient strength and durability for the Mustang. Sure, one can point out substandard and weak examples of either, but too, there are just as many examples of either type be very well designed, rugged and durable.

Weight discussions have several angles: quantitative, i.e., overall system weight, and qualitative, i.e., unsprung weight. The former is probably more important for simple straight line acceleration on smooth surfaces, the latter more important on every other performance criteria. Even for the former, I would be surprised if the actual system weight is more than 50lbs greater for a properly designed IRS.

Sabre

I had a very good 20 minute conversation with Steve Ling, Ford Marketing Manager at the Barrett-Jackson auction in West Palm Beach this month. One of the things I asked him about, was if he was familiar with the SRA VS IRS debates on the various Mustangs forums. He said, "Oh yes, we are watching them very closely!" He asked which camp I was in. What I took away from the conversation, was to not expect to see an IRS in a Mustang anytime soon. The weight of an IRS VS SRA seemed to be a really big issue....as they are trying to reduce weight not only for power/weight ratio for performance, but for MPG as as well. Coming CAFE standards play a big part in this, as Ford is working hard across their complete vehicle line up, to decrease vehicle weight through new materials, design and innovation to meet future CAFE requirements.

rhumb

With unsprung weight being by far the biggest negative of a lively axle, I wonder if that could be addressed by using a lot more lightweight materials in the driveshaft and axle assemblies to bring that down from steam-age mass levels. Yes, of course costs would go up, but that might be a way to strike a balance between a live axle and IRS.

I wonder how much more liberal use of high-strength steel alloys, aluminum, magnesium, or even titanium or carbon fiber could trim off a live axles prodigious bulk without totally busting the budget or blowing past an IRS's costs.

As for Ling's inferences, while I can certainly sympathize with the need and desire to reduce weight, an admirable focus and goal that's long overdue industry-wide, I would hope they would do so in other areas that would not compromise the Stang's overall performance (as distinct from simple straight line performance) and also potentially losing credibility with a broader market segment. While the Mustang could get away with scrimping on a live axle in '05 when it was essentially the only game in town and thus could thrive on the more "muscle car" customer base, which really didn't care much beyond straight-line performance and thus a live axle was sufficient, there are now two strong competitors in that arena already divvying up that market and expanding the Mustangs sales base beyond the simple 1/4-mile crowd would demand an IRS as a basic ante in requirement.

The current Stang, even though at an impressive peak of capability, is still getting outsold by the Camaro and the Challenger is holding tough in its third slot, even though these two cars are on the portly side and not as well tuned and developed as the Stang. Bottom line is that the Stang will never have the muscle car market to itself like it did and get away with the good enough attitude that marked the 2005-'10 years, even though "good enough" was quite good.

A potential wild card in all this is the Hyundai Genesis Coupe. Should Hyundai finally decide to grow a pair and do the obvious by sticking their own excellent 5.0, with a stout 429hp IIRC, that would really shake up the muscle/pony car market. While Hyundai has up until now been quite timid and reticent about doing this, their current market successes and desire not to be seen simply as a cheap second-tier manufacturer may well embolden them. Dropping their 5.0 into the G Coupe would drop an atom bomb into the enthusiasts market/world and REALLY put them on the map as a serious first tier builder well beyond the impact of even the excellent Genesis and Equus sedans.

Sure, the Mustang could retain a lively axle to differentiate itself from its IRS competitors, but I think that would be far more contrarian than canny, regardless of how the marketing department might try to spin it and certainly wouldn't be a credible approach beyond the current cadre of live axle fans anyway -- it would basically be a case of preaching to the choir, not to the potential new converts Ford will need to bring into the Mustang temple.

Hopefully, Ford in contemplating this will look beyond, though not forsake, the core Mustang fans which for various reasons do currently tend to be more of a muscle car attitude than a broader pony-car / sport-coupe mindset, to make those distinctions. So while a live axle might be acceptable, or even in some instances, desirable to the existing fan base, it approaches a laughable DSQ (disqualified) for many/most buyers outside that current realm.

To solely cater to the current crowd will, IMHO, merely a sales base reflecting past but not future conditions and sales and runs the high risk of choking off the future sales outside the current muscle car market segment that would be necessary to remain viable. Again, not that the current owners thoughts should be foresaken, but neither should they be a veto that overly constricts what a Mustang is/could/should be. The Mustang has cast off many other "traditional" technologies over the years -- leaf springs, push rods, carbs, drum brakes, etc. -- and likewise, the future Mustang should be tied to of defined by yesterdays technologies. Rather, it should adopt and integrate tomorrow's technologies into the Mustang persona as it has so often in the past (coil springs, DOHC, FI, disk brakes, etc.).

The 2005 Mustang, for better or(and) worse, was in many ways a very backward looking car, being delightfully retro in the best sense but also simply retrograde in others. The next Mustang will have to be much more forward and broader in its conception, yet still maintaining its most basic DNA and essence (no FWD or no-V8 stupidity).

2 Go Snake

If Ford is interested in reducing weight in the Mustang, you would think they would at least offer an option of getting a one piece aluminum driveshaft in the Boss 302 and GT500. I do not think the purchasers would be concerned about possible higher NVH.