I recently purchased a 2007 Yukon and it's interesting to see how much of the Corvette technolgy, particularly the DIC system, has been moved into that vehicle. It is pretty much identicle along with tire pressure monitoring etc.

The stero in the Yukon is hands down better than my C6, mind you it is a much bigger environment and a little easier to engineer around.

The C6 is a heck of a lot more fun to drive though.

 

Yes it is Dan, of course CALF is a fun place to drive no matter you're in!

 

I've owned a '69 roadster, '72 Coup, '80 coup, '03 AE & now have a '06 and for (almost) as long as I can remember one of reasons I was told the Corvette survived at GM for 53 years is that so much "new" technology was first showcased in the Corvette, then trickled down to GM's other car lines.
It could be said Corvette's role at GM was as a "test mule", in that respect.

The then cutting edge 1984 C4 with all the digital jazz is a great example, & all that digital crap began showing up in the more upscale Cads, Buicks, Olds & Pontiacs the following year.

There might be a few exceptions, but what they might be number precious few.
One though was the infamous 4-6-8 on Cadillac in the early 80s.
Damned good thing GM tried it on Cad first & not Corvette too, it was a disaster.
Corvette lovers got real lucky missing that one.

 

The C6 may get displacement on demand for 2008. Thats when we get the new engine since the LS2 will be history.

 

 

I've heard the same thing (rumor?).
Only difference is I'd heard the DOD will incorporate VVT (Variable Valve Timing) in the design, also.
Supposedly our first look at this motor will be in the new C7, allegedly set to debut in 2009.
We shall see.

Yup, and the "new" 425HP motor will be derived from the Vortec V8.
An engine I associate more with Chevrolet's Silverado pickup truck line.

Makes me wonder.
GM spent a king's ransom -- GM claimed $2,000,000,000 (that's billion) -- developing the "new" LS series small block, first introduced in 1997 for the then new C5.
Now it'd appear GM's intent on obsoleting the LS series small block after only a 12 year run, assuming 2009's the year it goes bye-bye.
Consider, the previous interation of GM's small block lasted nearly 50 years?
Hmmmmm.

Wonder what GM's up to?

Perhaps the powers-that-be at GM have intentions of taking the [entire] company "PC", ultimately ceasing production of what we Corvetters know as a "performance V8 engine"?

 

GM calls it "deproliferation". They did the same thing for transmissions. The impetus for the A6 was not the Corvette, it was designed to be a truck transmission from day one. It allows trucks to retain pulling ability while also using a lower (numeric) differential for better highway MPG. The Corvette is light enough that it didn't need a 6 spd auto, but for deproliferation purposes, it got the A6 too (besides, marketing realized they could gimmick it up with paddles and charge extra for it in the Corvette). This way GM only needs to make one auto tranny for V8 powered vehicles, and the number of different rear axle ratios needed can be reduced too. Similarly, GM needed a new truck engine that could get good gas mileage. The LS series wouldn't work because, though the blocks have provisions for DoD, there's an unfortunate resonance that makes them unpleasant if run that way. So Powertrain got to work on a different engine. It turns out the new L93 not only is a good truck engine that gets good MPG, but it can also easily be setup to make lots of power. Since GM needed to close the St Catherine plant that makes the LS2 anyway, it makes sense to put the L93 (rebadged as LS3) in the Corvette so that GM will only need one engine plant and one engine to serve the V8 market. Then slap a supercharger on it, and you have the supercar LS9, eliminating the need to build the LS7 too.

 

"Deproliferation"??
Perhaps in the early 80s when all the division's sheet metal was/looked (essentially) the same, save for glass, that'd have been the same thing as what GM's going to do under the hood with engines & trannies, today.
If it were me I'd have called this, "Consolidation" but I'm not, so "deproliferation" it is.

Wow, I'd never have guessed.
As a F1A fan I assumed GM was attempting to catch-up to the European/Japanese with their paddle shifter automatic.
But GM were thinking trucks all along, you say.
Interesting, and for a variety of reasons beyond the obvious.

Makes sense from a design/engineering standpoint, nails the 2 main criteria dead-on.


Figures.
So the "paddle-shifter" is a marketing ploy, neglecting what the imports are up to with their versions.
Even more interesting.

Since a transmission's transparent to most people, the idea's a fairly good one so long as it performs well.

If I have an issue with this "deproliferation" concept it'd be how GM will over use their engine designs, eventually having maybe 3 designs for their powerplants...4, V6 & V8.

The 3800 Series II V6 is a great example of what I'm talking about, too.
Showed-up everwhere.
The Mitsubishi 4 cyclinder Chrysler put into virtually every car made for almost a decade & Ford's [tired] 302 another.
Extremely reliable while not exactly state-of-the-art, performance-wise.

Guess on the one hand the upside is making so many of the same thing quickly bullet-proofs a design, while on the other the downside has to be the customer is very limited in their choices.
That's "progress", I suppose.

You're really cutting-edge knowing that kind of a detail, SD.
Not any old Joe is privvy to such info, I'd think.

Best of both worlds for GM, obviously.
GM has to be counting heavily on their new "L93" engine to help shore-up their recently sagging fortunes if even half of what you've said is true.
If the L93 delivers the 425HP as rumored and decent fuel economy to boot, few [here] could argue it's a "bad move" for Chevrolet & Corvette.

As long as you mention it why is GM closing that plant, aside from consolida...errrr deproliferation?
I used to live in Champaign, IL. Just east on I-74 in a little pissant town called "Tilton" (I believe) GM used to have a large foundry, part of the drivetrain division. They closed it years ago (in the 90s) due to age we were told & I'd bet enviromental "issues" played a role in the closing, also.
I didn't think the St. Catherine plant -- where the former F-chassis Camaro/FBird used to be built? --was all that old, though.
Then again shortly after my organization completely rewired the old BOC Kalamazoo plant, GM closed it anyway thereby wasting millions of dollars.
GM's reason(s) for doing what they do are rarely visible to an outsider, but given their recent fortunes I'd bet GM wished they had some of those wasted millions back.
Be that as it may...

Makes sense to me.
Just (selfishly) hoping the L93 doesn't show-up in every car & truck GM builds, is all.
Still this engine-transmission arrangement's an excellent example of the Corvette being the beneficiary, not the innovator.

Wonder if GM isn't following Ford insofar as slapping airpumps -- be it turbo or superchargers -- on IC engines to attain their "high performance" need(s)?
Seems to me Ford relies too heavily on this old trick, while GM in the past has been able to meet & exceed Ford's airpumped performance through plain old good engineering design.
Hate to see GM become a follower, if you know what I mean?

In any event my sincere thanks for taking the time to attempt enlightening me as to what the upcoming changes really imply for the future at GM, SD.

 

I don't know about a C7 in 2009 but this new motor will be coming out sooner since the LS2 plant will be closed in the summer of 2007.

 

Let's see, I'd love to have a 4 speed auto with 3.92 gears to be able to run more quickly in the 1/4 mile. But that leaves me with too short of rearend gear in 4th gear on the highway so I won't get good gas mileage. So, I guess I need to switch to 2.45 rearend gears to get a nice highway gear that will give me great gas mileage. But then I won't have good 1/4 mile performance. How in the WORLD do I get the best of both worlds? It's called the A6. It's equivalent to the A4 with a 3.92 in the first 3 gears for the 1/4 mile, then it's equivalent to the A4 with a 2.45 rear end gear when you are cruising in 6th.

I just can imagine why anybody would not like this?????

 

At its heart, an internal combustion engine is an air pump, and nearly every engineer understands that a 2 stage pump can be made more efficient than a single stage pump. There can also be driveability advantages to forced induction. Cams needn't be so radical, ports don't have to be as large (causing loss of flow velocity at part throttle), etc. So you can have a nice docile daily driver with crisp part throttle response and good fuel economy that can also be a hard charging monster on the track when you bury the pedal. When egineered properly from the factory, what's not to like?

 

Please enlighten me. And remember, the Ford supercharged engines are not intercooled.

 

Aside from increased complexity, cost, size, weight, and increased reliability concerns, I agree, more gears can be better. The ideal would be a CVT, which provides an infinite number of "gears" so that the engine can always operate at either peak economy RPM (in NA IC engines, that's normally 80% of peak torque RPM), or peak power RPM (the choice being determined by the computers, depending on driver demand via the loud pedal). Nissan has just put a CVT in the Maxima.

But there are trade offs, and points of diminishing returns. Simpler, more robust, and less expensive systems have advantages too. Particularly in a light vehicle whose engine has a very broad flat torque curve, added transmission cost, complexity, size, and weight, may not be worth the modest benefits of having more gears.

It is interesting to note that of the few reports we've seen of A6 cars on the dyno, most have shown lower RWHP numbers than A4 cars. That extra complexity in the transmission doesn't come without a performance cost. It is also worth noting that the EPA mileage numbers for the A6 haven't been increased over cars with the A4 either. So the touted advantages in the Corvette of the A6 over the A4 may be more theoretical than real.

Powertrain's hook graphs show a theoretical 2% 0-60 advantage for the A6 over the A4, but the real world hasn't borne that out in better times on the drag strip (mainly, I think, because the stock rear tires have enough trouble handling the low gear torque of the A4, much less that of the A6). Powertrain's hook graph does show a 5% boost in MPG, but again, that hasn't been reflected in the EPA numbers, or in the MPG reports here on the forum, though the latter is probably because most Corvette owners can't resist putting their foot in the throttle long enough to accumulate good MPG numbers. I expect that in trucks the theoretical advantages of 6 speeds will deliver more in the real world than they do in the light torquey Corvette.

 

I'm not here to defend Ford. Poor design choices lead to poor results, no matter whose company name is on the front. But there are numerous examples where FI does improve both performance and efficiency. The piston engine aircraft industry was an early example. The current high outputs of factory turbocharged import cars is another. The long reign of the Offy at Indy offers another performance example. Then of course we can talk of the advantages of forced induction for the millions of diesel powered vehicles, or further afield, the phenomenal efficiency numbers of turbo-compounded stationary power plants. There's a reason good air compressors are two stage rather than single stage, and that reason is efficiency.

 

Considering how some of these technological wonders now work in vettes I can't wait to mash the gas hear the mighty road of my 8... errr.. 6.... errrr.. 4 cylinder roar. When a vette can now get 30 mpg cruising who the hell needs displacement on demand? If it’s needed to avoid the gas guzzler tax all well and good. If not save that stuff for GM’s SUV’s and sedans and leave the vette alone. I never bought my vette because of great gas mileage. I see displacement on demand as just something else to break….

 

WHERE DID YOU GET THIS INFORMATION? IS THIS FACT OR RUMOR?

 

I hope it's nothing but fiction.........

 

Its fact. If you followed last years announcements from GM it specified a number of plants in the US and Canada would be closing. This is part of the restructuring of GM. The St. Catherines plant that is the only source for the LS2 was identified for closure. This makes sense since GM has other engines available that could work in the C6.

 

You make some very good points.

I still think the A6 will prove out to be an excellent choice in a tranny. The reports on this board show that the A6 is quicker in the quarter mile and people are reporting better fuel mileage, so I believe the real world is proving it better. The quickest stock auto is an A6 by far. I've also haven't notice what you report that the A6 dyno's lower. I'm betting that when you see an A4 dyno higher it's because that they have software that allows them to lock the torque converter. This is a dyno trick and doesn't show real world horsepower since under WOT the converter is unlocked.

I've also cruised my A6 in 6th gear and gotten over 29 mpg on long trips. If you are on level ground in 6th, you'll show 31 on the DIC for fuel mileage. Drop it down to 5th (like the A4 would be) it will drop to 29, drop it into 4th and it goes down to 27. The tall 6th gear helps a lot, guess GM knew what they were doing.

You are right about the trade of complexity versus benefit, but the A6 only requires 1 more planetary set and clutch. As far as the CVT, it's also a very interesting choice. I've seen a video of a CVT built by PIV in Germany operating in a Williams F1 car. It's eery to hear that car accelerate and the engine pitch hardly changes. The CVT's biggest problem is transmitting enough torque through the belt. It may be a while before they get one small enough for a car to transmit over 400 foot pounds.

 

All good examples. I've always known that turbocharged engines are more efficient because it reclaims waste heat. However, my question is why is a 2 stage air compressor more efficient than a single stage unit? I know if you intercool a 2 stage compressor you can drop the temp and it will be more efficient, but what if there is no intercooling, is it still more efficient? I'm just trying to learn something here.