Interesting. So does this mean that Sigma (might as well lump in Zeta too) will have a short lifespan? I guess it's more likely that Sigma/Zeta will essentially morph into Alpha while (hopefully) ditching some heft while getting more flexible? I can't see Alpha being a completely from scratch development - the timetable's too short for that. Hopefully this all sorts out and is a win-win for everyone - GM and RWD fans.

 

Lighter and more flexible. Hmm. Something sounds too good to be true.
We shall see....

 

Well, Sigma had been due for replacement around 2015 all along. This 'stretched' Alpha as a Sigma replacement is news though.

As far as I know, Alpha is all new. Keep in mind that work on Alpha has been going on for a couple of years already.

We'll see how flexible it ultimately turns out to be. Remember all the 'Zeta is sooo flexible' hype? Well, it turned out to be not so flexible at all. Let's keep our fingers crossed on Alpha.

 

I hear ya. Let's call it guarded optimism...

 

Well Charlie, it is flexible...just not in the range the industry is looking for right now.

 

Sure, there's some flex. As long as your range is a large sedan, large coupe, or large Ute.
I think we've been exposed to incredible and exaggerated hyperbole on this topic.
I mean, we still have people on this very site, claiming that Alpha is actually a cut down Zeta. Now that's ridiculous.

 

No, not a cut down Zeta. A lighter, scaled down arcitecture that doesn't need to handle 500 horsepower and uses Zeta as the step off point.

Love to hear how you think that's ridiculous.

Actually, Zeta is highly flexible and quite inexpensive while having handling dynamics that put it on par with BMW. Modifications to the basic structure are far and away cheaper than it is to a traditional unibody car because it's front and rear sections are very much like a traditional BOF vehicle, and it isn't restricted by a fixed "firewall" (which can influence beltline height) or crash standards (the tubular extentions "frames" adsorb impact).

Zeta's drawback is that it was created to handle monster horsepowered vehicles. Therefore, it's an extremely robust structure. Great for handling large sedans and 500+ horsepower V8 coupes, but not the 1st choice if you want to develop lightweight, economical cars that center on 4 cylinder engines, with V6s as the upper power source.... which until recently, GM saw FWD as the vehicle of choice for cars like that.


The items that made Zeta flexable will end up on the Alpha because the Alpha is intended to be the architecture that will cover vehicles from small sport coupes to what we today view as mid-sized sedans (Espilon 2s will likely fill the need for future full sized cars for the rest of next decade in FWD and AWD form). It's likely to even serve as the basis of a 2 passenger sports car.

Like the original North American Zeta, all cars will have the capability to be made on the same line.

Zeta doesn't make much sense for vehicles smaller than Camaro outside of Camaro. The chassis is almost overengineered, and would be a waste on a V6 coupe. Sort of like putting a NASCAR grade roll cage in a Prius.

Alpha will be a lighter version of Zeta, but don't expect any 426 horsepower LS3s or it's successors to be under the hoods of them.

 

That! That's what's ridiculous. Alpha has nothing to do with Zeta. It's a completely different architecture.

 

How will it differ from a scaled down Zeta? Will it have a different suspension design, for example? I would think it would not be cast in stone yet, but that GM would have a pretty good idea what the components would be. I'd hope they'd keep what they could use from Zeta.

 

At this point, Alpha is pretty much locked in. I'm not privy to it's details, but it's safe to say that it is completely unrelated to Zeta.

 

Then what set of components is it based on, if not Zeta (at least loosely anyway)? Sigma's just as big or bigger than Zeta. Y would be too expensive and is meant only for two seat coupes as is Kappa which borrowed heavily from Y, IIRC.

I'm still not completely sold on the idea that GM is going to turf Zeta completely after such a short run, relatively speaking.

Despite this uncertainty, I am anxious to see what Alpha has in store for us........ curiosity is piqued for sure.

 

You can't get to where Alpha needs to go by basing it on Zeta, Sigma or Y car. It's from scratch. I mean what would make anyone even think that it is somehow based or even evolved from Zeta?

With that said, I'm sure you'll see some parts sharing from the global parts bin. That only makes sense.
But the architecture itself is all new.

As far as Zeta goes, Holden may continue it for awhile longer, (maybe even well into next decade), - but I think you can put a fork in it for North America.

 

Its still a car, correct? Not meant to belittle or dismiss what you're saying, however its very likely that same engineering concepts that are used in the Zeta or Sigma architectures could very easily be "scaled-down" for Alpha. While it may not use the Zeta/Sigma platform as a starting point; it can still be influenced by Zeta/Sigma conceptually and be a new architecture.

 

In that regard, I think that most modern architectures have influenced what Alpha is or isn't. Certainly GM programs like Sigma, Zeta, Epsilon, Delta, Kappa, etc. have created data and experiences which will go into the gene pool. I'm sure BMW's 1/3 series have as well, MB C-class and even Nissan's FM.

But Jeff, I think there is a BIG difference between being "influenced" by other programs or products and being based off them.

 

So Alpha could very well have a new suspension design, rather than one based on Sigma or Zeta?
I wonder if they'd use a simpler, lighter IRS, as in the previous Commodore, to save weight, or if they'd go with a heavier but also more capable design like Sigma or Zeta use.
More generally, in the inevitable tradeoffs between weight and functionality, which way are they going with Alpha?

It'll be interesting to see.