Z28Wilson

I'm no suspension expert by any means. The last time Ford tried to dabble in "IRS for some" Mustangs, people ended up just canning the IRS in their Cobras because they were a patchwork design, full of flaws.

I was under the impression that one car generally can't contain both a live axle and then a great IRS option in the lineup because of all the differences between the two. If that IRS is going to be a cobbled-together design again, I think they'd be wise to just forget about it until they can take the plunge across the board.

guionM

Actually, it depends on how the car was engineered from the start.

In the current Mustang's case, the IRS DEW-98 chassis was modified to create the live axle D2C chassis. In other words, the IRS capability is still there and baked into the car.


Jumping back to the Cobra, the issue with it's IRS is strictly related to the dragstrip, and the only time you hear about IRS being an issue with the Cobra is with regards to the supercharged 2003-2004 models, not the 1999/2001 Cobras which also had IRS, but had a N/A 4 cam V8.


IRS Cobras were made to handle, not be dragstrip wonders. The SN95 chassis was a revision of the Fox chassis Mustangs & it's reputation of it's rear end's tendancy to hop around like a rabbit on curves that aren't smooth is legendary. I had a few. I can tell you stories. The SN95 chassis removed a good portion of that, but it was still a Fox chassis prone to the Fox's shortcomings when the road got a bit bumpy. Cobra's rear end eliminated that, and was actually very good in handling.


The downside is exactly the same in ALL IRS cars when you take them to the dragstrip, bolt on sticky tires, and go to town in the burn out box: you either get massive axle hop and/or it tends to adsorb power. Eventually, with enough power & stick you'll tend to grenade them. Not just the diff as in live axle cars, but pretty much the whole setup.

There are evidently more Mustang Cobra owners who drag race their car than take it to a race course... and with VERY good reason.

A bone stock supercharged Cobra engine packs a Kellogg high strength forged steel crankshaft; specially machined expensive "off the shelf" drag strip quality Manley connecting rods, unique gaskets and sealing, a supercharger that has more displacement than many 4 cylinder engines (it was the biggest car supercharger on the market at the time), and the whole contraption (after breaking a dynometer at Rouch when 1st tested) was tested at full supercharged boost for 300 hours (everyone else test blowers only part of a test, and the typical endurence test is only 100 to 150 hours at WOT).

In laymans language, the supercharged Cobra engine.... in stock form... is essentially drag race engine that can dish out some horendous punishment if you change the pulley which cranks up the boost from the stock engine's relatively meager 8 pounds of boost.

So, yes, serious drag racers lose the Cobra's IRS because in this instance, IRS... any IRS... is not the best tool for the job.



Trivia: The 500+ horsepower engine in the new GT500 is fully capable of handling over 700 horsepower. Yet, it still wasn't built to the same durability standards of the 2003-2004 supercharged Cobra engine, which though smaller, is fully capable of producing just as much (or even more) in stock form or with minor modifications.

Also, the Cobra engine shares very little with the 5.4 Lightning engine. Internals or otherwise. Lightning makes it's horsepower at a modest 4,700rpm. Cobra reaches it's peak at 6,000 rpm. While both Cobra and Lightning share throttle bodies (twin bore 57mm), the Cobra has the bigger mass air sensor (90mm vs 80 in the Lightning)

Yea, been reading up.... almost bought one 2 weeks ago.

JakeRobb

You didn't say it wasn't a variable, true. You did, however, say:

"Almost irrelevant" is as close to "not" as you can get without being "not". My argument is that R-compound tires are almost exclusively responsible for the Mustang's exceptional handling performance in that article.

99SilverSS

Hmm It’s going to be an interesting comparison next year. Ford doesn’t really need an IRS if the track pack is working with well. The extra HP should be all that's needed to bring up the Stangs only real shortcoming. That is if they can keep the weight from going up too much from the new engine and I would assume/hope 6-speed addition.

Chevy could give the SS a shot in the arm if they looked at the suspension settings and refined them a bit more. Maybe even offer a track pack type option too. Mate 3.73's with the LS3 would make more use of the engines higher HP peak and help even out the gear chewing tall tires.

None of this would really add to the cost or weight of the car especially if 3.73's were an M6 option but it would tighten up the SS and keep things close to a much improved Mustang 5.0.

bossco

I'm not saying that, that engineering mule could have been so glued to the track it could climb walls like spiderman, but if it did so with an SRA, the IRS set would just come up with --->insert snide remark here<--- and simply dismiss the car as a fluke (or whatever strokes their egos at the moment).

Hell there are guys on this site that will tell you with a straight face that you'd be safer frying eggs off the elephant's foot at Chernobyl than crawling down the street with an SRA equipped car.

Zigroid

0-60 mph is a pointless stat any more, that comes down to traction, not power. of course its gonna be easier to hook 315 hp than 420 hp.

we should look at 40-80 mph passing. that is where the camaro will hand the new mustang it's ***.

or put a set of drag radials on both cars THEN take them to the track with no other mods. test them with street tires and with DRs. look at trap speeds. 111 mph vs 105 mph. thats power youre gonna feel at any point.

91_z28_4me

But if you put a supercharger on an LS1...oh wait are we arguing a different pointless point?

jcamere94z28

that's the thing... with the big weight advantage the mustang has over the Camaro... closing in that gap in performance won't take much. That's why I was hoping the mustang got an IRS quick... so the weight went up a little...

oh well.. all that means is that I am gonna have to mod my car a little. lol

guionM

Jake... what's going on with you? I leave the site for about a week or two, and come back and you become a word splitting, cranky old hag?.... or even worse, the site's prosecuting attorney? You are a moderator for christ sakes. I would expect this type of hair splitting, meaning twisting, convulsive translating, definition gymnastics from some newby Mustang-hater over in the lounge, not someone I respect over here.

I explained it the exact same way to a female friend of mine from work just in case I was missing something. She understood what I was saying in the 1st take, and she knows less about cars than the average person here.


My exact words were exactly the same as my exact meaning:

The Mustang GT is getting 400 horsepower next year.
It's also getting roughly a 50 lbs/ft torque boost.
The current car almost tail grabs the BMW M3 already.
The power increase alone will be more than enough to equal the M3.
With the power increase the GT is getting, adding stickier tires are almost irrelvent.

That is about as clear as I can make my point without resorting to crayons and construction paper.

Thank you.

For a moment I thought I was in the Twilight Zone here.

guionM

0-60 mph IS an important stat. The only time I ever hear it isn't is when the result is unfavorable to a car a person is enthusiastic about. You never heard this back in the 4th gen days.

0-60 is what most "Stoplight Grand Prixs" run. A quick 5-7 seconds, then slow down before the next light, an obstacle or risk of an accident, or unwelcome notice from local law enforcement.

0-60 is also relevent merging on freeways into open slots.

The real point of 0-30, 0-60, 0-80, and 0-100 is to demonstrate a car's acceleration. Very much a point,

If anything, being that no one is likely to do a 40-80 blast on a city street, and no one is going to start a freeway run at only 40 mph, it's the 40-80 statistic that's pointless IMHO.


FWIW:
Car & Driver (the only car mag that does any test like that) does 30-50 and 50-70 mph. It's worth noting that in the 30-50mph acceleration test, Camaro SS needed 12.7 seconds while the GT needed only 9.4. In the 50-70 test, the result was 8.7 Mustang, 12.2 Camaro.

Although in real life, this never happens, they do this test in manual transmission cars without downshifting. What the test does demonstrate is that:
1. Weight can be a disadvantage when accelerating at any speed (not just at standstill).

2. Gearing is extremely important (SS has a 3.45 axle and a .57 top gear ratio... GT has a 3.73 with a .68)

3. Even dismissing the fact that they didn't downshift (and in reality, both would downshift), it's obvious that the Mustang GT wouldn't exactly get "smoked" by the Camaro SS in either 30-50, 50-70, or perhaps even your hypothetical 40-80 run.

In fact, it would be a very interesting, very good, and perhaps even surprising race.

JakeRobb

Or, *gasp*, we could look at quarter mile ET and trap speed.

Bob Cosby

Put me into the "0-60" time being useless crowd.

Sorry Guy....though I do agree with most of your thoughts in this post.

Plague

I would think this is much more about gearing instead of weight. Once the car is moving and you have a decent amount of traction, weight means much less than gearing. Kind of odd to use proof of this being a top gear acceleration vs actual acceleration to those speeds.

Z28Wilson

Spoken like a true 1320' drag racer.

Seriously, 0-60 stop light grand prixs can be fun, but are much more predicated on traction and driver skill than the capabilities of the car. Zero-to-60 times are lumped so close together (0.5 sec or so comparing Camaro SS and Mustang GT) that it's anyone's ballgame. Heck, with a less-than-perfect launch in an LS3 Camaro you can be surprised by a whole host of vehicles out there. It's not a reflection on the car though.

Z284ever

Imaginary direction? All I did was push the "quote" button....