Are you referring to the rear axle housing? Are you implying that it has no mass? Sure sounds like it me.

 

I think he's saying it doesn't need a heavy *** cradle to bolt to like an irs.

 

My "race car" is also a daily driver. I'm simply willing to put up with different compromises than you and others. I use the phrase "different compromises" intentionally, as we are ALL compromising something to get what we want, not matter if we get a 3400lb, 3700 lb, or 4000 lb Camaro.

And if a car is lighter, it will likely have better balance/ride/handling and precision.

Might not have those heated seats and 20 airbags though. Darnit.

Bob

 

Explain, then, how these factors apply to the Corvette and not to the 5th-gen Camaro.

 

I thought I had?

 

Um, no. Everything you mentioned also applies to the Zeta-based Camaro.

 

What? Are you Guy's attorney? j/k

Like I said in a post 5 or 10 pages back, a cradle is not required (heavy *** or not) for an IRS. But it's preferred for NVH reasons.


Now, getting back to that 'mass-less' cast metal rear axle housing....

 

Why would you ask so many suits to rat out their fellow suits?

 

Is it made of iron? I thought the last generation of BMW I6's used an aluminum block with a magnesium skeleton intergally cast so that they could offset the weight of the VANOS system.

Another point of interest, and unrelated to BMW, but Ford's WAP 4.6 block weighs a skimpy 80 lbs bare and the prefered TEKSID block weighs a suspension crushing 85 lbs bare.

 

So does the 25 pounds assume no cradle? What if you add a cradle?
Does the 25 pounds assume both made of aluminum?

 

Dunno. But I was attempting to directly answer the question you posed to me regarding Corvette.

I'm over the charades. What's your point re Camaro? Camaro is not a pure sports car like the Corvette which implies there are some design 'compromises' along the way. Camaro is a car derived from a sedan platform... and it will be cheaper to make than Corvette.

Is that a good enough answer?

 

No, with a cradle. Without a cradle, the weight difference may even be negliible.

And there are no assumptions about one being light weight materials intensive and the other not.

 

With the Mustang GT weiging in at around 3500 pounds and the GT500 weighing nearly 300 pounds more, you can atribute the entire weight gain to the supercharger package, fortified engine & drivetrain parts, and braking componets needed to produce a reliable and warranty safe 500-600 horsepower.

We can likely expect the same weight gain with a blown "Super Camaro", unless GM sells the car as a "Stripper".... not likely.





Actually, unless we're talking about a version of Body On Frame construction (ie: Corvette, Kappa, most race cars) or we're talking about a version of trailing or semi-trailing arm suspension (ie: the last Commodores and GTOs, early decade BMWs, etc..) then actually, you do need a suspension cradle for the lower control arms of the type of IRS setup that seems to have the advanced handling qualities of the most modern IRS.


I believe this is the type of IRS I believe you're thinking of that doesn't need a cradle, is only a little heavier than a live axle (roughly 25-50 pounds) and/or can be bolted directly to the body. It's the type of trailing arm IRS that I mentioned.



Modern IRS systems attached to unibodies have subframes. True, they help with NVH, but it's also provides a point to mount the lower control arm (can't mount it to the differential), and can me made as a modular unit.















Point is, a subframe is a requirement with modern IRS. That subframe adds substantial weight, and why every modern rear drive car with IRS is substantially heavier than a live axle car with all else the same (I'm going to save the increased expense part for another thread).

If you're going to pump 500 plus horsepower through these things along with the same torque, things are going to need to be pretty tough.

 

One minor point of clarification.....the GT500 weighs 3920 lbs. The GT weighs 3480. That is well OVER 400 lbs more than the GT, not "nearly 300" lbs more.

The single biggest hunk of that weight is the 5.4L iron block (vs aluminum 4.6). Add the larger 4V, 4 cam heads (vs 3 Valve with 2 cams), the blower stuff, and the 6 speed, and that is the vast majority of the weight increase - the engine and (to a much lesser extent) the transmission. GM doesn't have those engine issues when comparing their base LS1/2/3 with their top-of-the-line LS7.

The increased braking components are needed, in part, because of the extra weight of the car.

Bob

 

Okay, so the 25 pounds is with a cradle, with both being made of the same material. I would assume that to be aluminum, and that if both were made of steel, that both would be about the same percentage heavier than aluminum counterparts.

I just wanted to make sure I understood the context.