You did already.

The 1999 IRS Mustang Cobra (before the supercharged versions in '03) weighed about 3400 pounds. The same year a Mustang GT weighed just about 3270 pounds (V6s weighed 3115). About an extra 125-135 pounds.

No official cost estimates. One can easily imagine IRS costing almost twice what a live axle would cost in labor, assembly, and the need for a subchassis/suspension cradle to hold it all and attach it to the underside of a body as opposed to simply bolting an glorified steel pipe to a couple of springs and a pair of control arms attached to the body.


Very accurate post in all regards.

An extra $5,000 charge isn't going to get alot of lightweight goodies. First, GM (or any other company on the planet) isn't going to take that extra 5 grand and buy 5 grand worth of stuff. Taking 5 grand and buying 2 grand worth of new stuff is optimistic, but lets use that anyway.

For 2 grand, you'd probably get a carbon fiber hood. If you're lucky, you might get a few scattered usage of titanium in a couple of structural areas. But that's it (Titanium is very expensive). If you're licky and the guys doing this are absolute wizards, you might lose 25 to 50 pounds..... and be $5,000 poorer.

If you want to make cars lighter, the only way to do it is to give up horsepower and/or top speed. A car engineered for a maximum of 300 horsepower is going to be much lighter than a car engineered for 500.

The new Camaro and it's Zeta platform is fully capable of 500 plus horses and running to at least 200 mph. The Dodge Challenger's LX chassis is also extremely capable of remaining rock stable at ultra high speed. However, even though the current Mustang has a 500 horse engine, that engine's still governed to 155 mph.

Camaro could have easily came with a solid axle (if Ford can convert a DEW98 to carry a live axle, GM could have done the same on a Zeta even easier). However, do a search in the archives and look at the screaming, ranting, and threats that were posted here even at the mere sugestion that the next Camaro come with a live axle. Even when it was pointed out that IRS would add weight and expense, I guess there were those who felt the laws of physics and economics didn't apply and that IRS would be no heavier and no more expensive than a live axle.

So.... here we are.


BTW: Nissan's 370Z is 95 pounds lighter. Aluminum is new to the doors, hood, & hatch (which were steel before... the old aluminum hood had a steel inner support stamping, it's all aluminum now), carbon fiber radiator housing, and the sum of a few onces here and there. Nissan went over everything with a fine tooth comb and rejected any weight savings that compromised structural rigidity (which would have compromised handling and stability) and powertrain durability.

 

I really don't expect the Mustang to gain much weight when going from the 4.6 to 5.0.

729 mm diameter wheel/tire is the same for all Camaros, whether they come with 18's, 19's or 20's , I think even the performance parts 21's.

As far how much extra weight an IRS would add to a Mustang, I guess that all depends on it's design. Some, but certainly not as much as some seem to think around here.

 

I do and I have described why before, but we will just have to wait and see on this one.

I was talking in terms of weight. The diameter may be the same, but the wheel/tire combo is usually heavier for the larger diameter wheel.

I rounded to 150lbs. It could be less, it could be more. Depends on the components used.

 

Can you expound upon that? You're saying that the wheels and tires on the new Camaro are 160 pounds heavier than the old 16"ers?

Where did you get that from?

I believe that one of the reasons the uplevel V6 is lighter than the base V6 Camaro is due to replacing steel with aluminum wheels. Is your number comparing like with like?

 

You'd think that, but I couldn't tell you for sure.



I'm not even sure if the current architecture is even getting IRS anymore. But if it did, it wouldn't add anywhere near that - more than likely, less than half. Maybe even much less.

 

Actually I can't really expound on that. I don't know much more on that than what was stated, and I'd doubt my source would appreciate being named.

 

How about what you mean by 160 pounds then?

A set of 16" wheels and tires might weigh 40 pounds each, where a set of 20" wheels and tires might be 70 pounds each (quick check on tire rack). A 40 pound delta per wheel sounds high.

But the whole industry is moving to giant wheels and tires, whether they need them or not.

I like the 16" wheels on my '02 just fine.

 

Like I mentioned, I'm not sure what that's compared to.

 

Read this article from Top Gear. They claim that a twin turbo V6 will be available in the future claiming 415 bhp.

http://www.topgear.com/us/blog/more/...stang-is-here/

 

The 729mm wheel/tire combo supposedly adds 160 pounds. That seems a bit high. You'd have to be comparing lightweight and relatively narrow 16" wheels/tires with heavy 20". From reading your other posts, I'm inferring you just heard a number and not how that number was arrived at.

You could put 17" 60 series tires on an SS and save quite a bit of weight with lightweight wheels.

 

Okay. But the Mustang is within a few inches in all dimensions, and there really aren't any 4 seat 400ft lb V8 4 seat coupes that are significantly smaller. I know you think that it's just a matter of shoehorning an LS V8 into an Alpha, and you may be right. If so, GM may be the 1st to market with a car of that type (we can always hope!). But there may be factors you and I don't know about that make that sort of car difficult to build (and pass worldwide regulatory requirements).

At least you're not blaming it on Zeta any more. Now that we have the 370Z (built on same platform as M45) and Genesis Coupe (built on same platform as Genesis Sedan), we have proof that it's possible to build a 4000+ pound V8 sedan and a much-lighter coupe on the same platform. But of course, the more re-engineering, the more $$$.

 

That 160 pounds was one small point in a much larger exchange. I too was wondering "compared to what"? but didn't bother to follow up. 17" wheels would save some weight, but as you'll see when you spend some time looking at the production car, they would look as ridiculous as space savers within the car's bulky haunches.

Actually, Nissan and Hyundai have proven it. If anything, Zeta disproves it.

 

Of course, you know I'd like to see a smaller, tidy, relative lightweight Camaro with an available V8. But forget about me. What I want is neither here nor there - other than the 1 or 2 of them I'd buy.

What matters is what GM needs. And what GM needs is a Camaro which can be sold in base form with an I4 or turbo I4.

 

Logically speaking, Zeta doesn't disprove it. It just doesn't prove it. Nissan and Hyundai have proven it. But how much heavier would those both be with their respective company's V8s? There are rumors of a V8 Nissan Z (500Z?), though I've not seen anything lately. I suspect the project is on ice. But I'd be very surprised if the V8 Z-car was not at least 300 pounds heavier, based on the weight gain from G35 to M45. The M is only minimally larger than the G, especially inside. Most of the extra size is up front -- presumably for the V8.

And it'd still be a two-seater.

The car you want may be impossible to build without a luxury-car price tag for all the weight saving components that'd be necessary.

 

It could be that we're comparing apples to oranges. I think it's safe to say that Zeta has the ability to make larger cars than Hyundai's Genesis and Nissan's FM. By the same token, Genesis and FM have the capability to make smaller cars than Zeta can.

How much weight would incorporating a V8 add to these cars? I can only guess. But both Mustang and Camaro gain almost exactly 100 pounds when going from V6 to V8. So, I see that as a good reference point.

As far as the car I want, who's to say what's possible. We're at the dawn of an age where reduced mass will take on enhanced importance. Where what was exotic tech and materials previously, will be mainstreamed to even entry level cars. And GM will be developing it's first small RWD car in what - 40 years - except now it wants it to have topnotch, worldbeating, dynamics.

Yes, I'm hopeful.