It shoud it is the same IRS that is in the CTS and I would assume CTS-V.

 

Exactly...no need to re-invent the wheel here....

 

So the Kappa (CTS), IRS could work, in theory.

 

You are misreading my cues.

When I said you can always add stuff after you actually get the thing in production, I wasn't talking about YOU going in and adding stuff.

If Pontiac went to GM's board with a proposal for a Pontiac high performance sports car in the late 70s, they would have been slapped down so hard thier parents would feel it. However, when they came up with a low investment, high profit 2 passenger commuter car, it nearly sold itself.

The Fiero was sold to management as a 4 cylinder commuter car. Yet from the start, it was engineered to accept a V8, and had a unibody structure far stronger and capable than even the Corvette of the day.

In the time after the Fiero came out Pontiac added a sports version and revised suspension pieces that dramatically improved handling. Pontiac then added a V6. Then Pontiac added a swoopy body that looked nothing like a commuter car. Then Pontiac added electric steering. If Fiero had continued a few more years, it would have had a V8. An LT1 V8!

GM is in a cash crunch. Nothing is likely to be approved unless it's a truck or "core" vehicle (where CEO Rick Wagoner's now going to focus the cash) unless it's an overpowering business case that can't be ignored.

Again, once you clear the big hurdle get something produced & on the streets, if you make engineering allowences, you can always go back and add on things.

You think Team Mustang didn't the D2C to accept IRS later?

 

Wouldn't a gapping hole in Chevys line up be "an overpowering business case that can't be ignored."

 

I remember reading somewhere waaaaay back when the 4th gens debuted that allowances and room were left under the car for a future introduction of IRS.

Never happened did it? The money obviously went somewhere else and the car died. The 5th gen needs to be top of the class right out of the gate or it will be dismissed as yet another half hearted GM failure.

Does anybody else remember this 4th gen IRS story?

 

oooh. my bad. ya that is a little different.

alright but what are the advantages of putting LRA in a chassis originally planned for IRS? wouldnt that cost more for development/testing, etc.

 

Is the Kappa (Solstice/Sky) IRS the same one used in the CTS / Sigma?!?

 

The point about cost involved in reverse engineering a double a-arm front susp into a strut front is valid.

The point about the cost to dumb down an IRS chassis to a live axle is not.

Do you guys realize how simple the mounting is for a live axle in an F-body? There are literally four mounting points. The panhard bar, the 2 LCAs and the tq arm. That's it. You re-use the same shock mounting points and probably the same spring perches. All you're talking about are some small additional stampings that can be welded on.

 

I thought that they were similar, but it may have been the concept.

 

To all the people adamantly opposed to this "cheapened" Sigma:

If what you're looking for is a quiet, refined, vehicle with IRS and a sophisticated handling setup, than the car you seek is already on the market. It's called the CTS-V. Its got an LS6 V8, Quiet Steel in abundance, IRS, and an awesome handling setup tuned at Nurenbering. Oh, btw it costs about $50,000.
Seriously people, how do you think GM could produce the car you all are asking for at a price we will be willing to pay? A lot of people here say that the GTO is too expensive at $35,000, well you can't lower the price on a car with out giving something up. If you think Ford didn't have to compromise on the Mustang your kidding yourselves. Just sitting in it, one can certainly tell that the interior uses materials a step below those found in luxury vehicles. It uses the live axle setup. I'm sure people in the know with the Ford can relate many more cost cuts. I'm not bashing the Mustang - this is the way it needs to be done. The essence of a pony car is that it provides performance at a low cost for those who don't care about extras.
Finally, does anyone doubt that a vehicle produced on sigma, no matter how cheapened, would not be extremely refined and athletic? Even without its quiet steel, and with a mcpherson strut setup, sigma is an incredibly rigid, well engineered platform. Interestingly, no one had a problem when an economical alternative to sigma was given a fancy name like "zeta."

 

I was never a fan of the Zeta Camaro idea. I don't want a Sigma based Camaro either.

 

Evok put that business case together I believe in oh about a day or two to say the least. There's no reason why he should not be hired by GM. He has a knack for the business and more importantly knows how it works. Far and away better then the "suits" at GM does.

What Guy is trying to say is. Get the case there. Let them build it. THEN add the performance line to it.

It really is that simple folks.

 

It's not that we're opposed to the idea (well we are to certian elements)....it's just that no-one has explained how adapting (yes, it would require major re-engineering) not only a live axle, but Macpherson struts to a platform that was not designed to use these archaic parts.

Think about the differences in un-sprung weight between a live axle and an IRS.....then take into account NVH and chassis flex differences in the two different suspension desgins. GM doesn't just weld on a few brackets and calls it done.

Same with the front suspension. LSA uses entirely different attachment points and structural reinforcement points than a Macpherson strut design does......apples and oranges.

Then add in all the validation and durability testing, crash testing, sub contracting, etc............ suddenly we're stepping over a quarter to pickup a nickel.

Bottom line here is that it's not as easy or as cheap as it sounds......

 

I beg to differ......like someone already said, if it isn't part of the initial program it'll never get done....before some suit kills it all over again because of poor sales. Use the Fiero example again......by the time they got it close to being right (as they initially intended), they killed it off due to poor sales.

In today's market, you only get one chance to get it right........before the competition does it right and kills you.