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<< 2008 Corvette Tech Center

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Interview with Sam Winegarden, GM's Engine Guru: Page 3 of 4

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© 2008 by Hib Halverson
No use without permission, All Rights Reserved

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CAC: Of other manufacturers overseas, which do you think has the same ability? Toyota? Do you think it does as much analysis as GM Powertrain?

SW: I don't have data to back up my suspicions so I probably shouldn't speculate.

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The "pinnacle of Corvette performance"? Mr. Winegarden says "Yes."...but only for now.
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CAC: Oh, let's.

SW: They probably don't. Some benchmarking studies I've seen suggest that I probably burn more CPU time than Toyota, but it's a little different development process and cycle that we go though and they, obviously, do very well with theirs. I just depends on how you choose to set up to run your business.

CAC: What about BMW?

SW: They're good. BMW, Mercedes, Toyota, Honda...all very capable. All I have great respect for and I worry about, but I'll stack my guys up against anybody and I think I'll win.

CAC: Do you think the LS9 is the pinnacle of performance of Corvette engines?

SW: Up to today.

CAC: With respect to 620 horsepower Corvettes, some have said that CAFE is a problem you can work with, but CO2 regulations may not be.

SW: Clearly, the CAFE legislation is out there. We know we have to do that. We've been working on it for quite a while and continue to work on it.

They're really both a CAFE question in terms of the Corvette. You can take the CO2 and back-calculate that into an equivalent fuel economy number. The C02 standards that have been talked about would be even more aggressive than the recently-passed CAFE numbers, so that, obviously, is what leads to your question.

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Winegarden believes, in-spite of high gas prices and stringent new emissions regulation, there still is a market for very, high-performance V8 engines like the LS9. We figure...he oughta know.
Image:  Author
The answer is: No. We think there's still a market for enthusiasts who want a ultimate performance vehicle and as we work through advanced technologies, I'm not quite ready to give-up on five or six-hundred horsepower Vettes, yet. Someday, you may get me to the point, but it's a pretty talented group of engineers at GM and we're not quite saying it's the end, yet. We're going work this one for a while before we get to that conclusion.

CAC: I look at your face and listen to the tone of voice...obviously CO2 regulation will be a difficult challenge and you may not be exactly sure how you can...

SW: That's fair. I'll be honest with you, if the CO2, the way it was proposed to be legislated in AB1493, came true that would be a tough technical challenge. I'm just not quite ready to give up without working on it some more, but I will also tell you that I don't have a 620 horsepower answer in my back pocket this afternoon.

CAC: Suffice to say that there's a lot of research going on to deal with the possibility of CO2 regulation in California.

SW: Absolutely.

CAC: The only way to meet the standard is to burn less fuel. Is that right?

SW: Yes. Which is, in effect moving the fuel economy number up higher.

CAC: But, it's not like other pollutants where you could change the calibration or add a secondary air pump or something. It's much more basic.

SW: Yes. Run your chemistry model for complete combustion. What do you get? CO2 and water vapor. There's no after-treatment system that would significantly reduce CO2 emissions.

CAC: Let's say we have our 620 horse LS9 Corvette and in 2010 the law comes in effect for CO2 emissions have to be reduced 15%. If that happened, what could you do?

SW: Ah...if we had to do that, it gets pretty complex, because, from a company perspective, frankly, the problem will be much bigger than the Corvette.

CAC: A falling tide beaches all boats.

SW: Oh, yeah. And it gets to be a much more complex answer.

Trucks...even most of the car fleet would be in jeopardy. So how would we somehow find a way to meet that in the short term? It would be really tough. We obviously wouldn't want to do it by not selling stuff. One way to meet that reg-don't sell trucks? Probably not a good plan. Or, some cars we couldn't sell? Stephens would be a better guy to ask from whole-portfolio perspective.

The other problem you have is our ability to react quickly to something that aggressive is limited. You're not giving me much time to develop the alternative propulsion strategy because some of it, frankly, is not ready.

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Winegarden believes, in-spite of high gas prices and stringent new emissions regulation, there still is a market for very, high-performance V8 engines like the LS9. We figure...he oughta know.
Image:  Author
CAC: You think the 2012 could still have a base six-two?

SW: Ah...It's a long way off. The only reason I'm dancing on you a little bit is where the CO2 thing goes. Clearly, I would like it to have but I can't answer that question for you.

CAC: You're going to be putting in a lot of O.T. if CO2 gets regulated.

SW: A lot of people in General Motors are going spend a lot of sleepless nights if EPA granted that waiver tomorrow.

CAC: Are you talking about the waiver the State of California was seeking which would have allowed it to set its own CO2 standards?

SW: Yeah.

CAC: I was under the impression it was denied and that the State Attorney General was going to sue in Federal court in an attempt to overturn EPA's decision.

SW: Actually, I believe that's the situation at the moment.

CAC: California has a huge budget problem. Filing suit...talk about a waste of taxpayers money. Sheesh.

Ok. I've opined. At this point, there's no predicting what's going to happen in the courts, but, currently, on the Federal front, what's happening?

SW: EPA and NHTSA have gone down the CAFE route as far as passing new legislation. They have not, yet, written a CO2 regulation. I'm not sure whether they will or whether they'll let CAFE lower CO2 by itself. If you burn less fuel, by definition you make less CO2. But, it's better to ask our legal guys to get the latest on that one.

CAC: If California prevails in that lawsuit then puts a more stringent standard in place, would it be a case, as has happened before, of not selling certain products in California?

SW: That certainly could be a possibility, especially, if it happened really quick.

CAC: I would think it couldn't happen quick, if it's tied up in the courts. It could go all the way to the Supreme Court.

SW: Ah...I wouldn't discount that as a possibility.

CAC: What the California A.G. is trying to do is make this a big State's Rights issue.

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Regardless of which way future CAFE or CO2 regulations may go, Sam Winegarden has a number of specific technical strategies which could be used in an attempt to comply with the requirements, but still bring us Corvette engines with segment-leading performance.
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SW: Exactly. Sam's personal opinion: I think that's what you're watching take place. Besides the environmental question, a Federal Government vs. States Rights is at the heart of the debate.

CAC: Let's say reality ends-up not as grim and there is only the revised CAFE. Going forward into '10, '11 and '12, features not on the LS9 now, say AFM, is that possible?

SW: I can't give you specifics of future product.

CAC: When we talked in Bowling Green last April, you said AFM was a problem with Corvette...harmonics.

SW: The engine is more than capable. The controls are there. You basically take the truck software algorithms and adapt them, but with most of the trans mass in the back, the torque tube in the middle, the engine in front and the structure in the Vette; we had harmonics in four-cylinder mode we could never tune out to an acceptable level without putting a lot of mass in the vehicle. Dave and I just said, "Wait a minute, we're not going to put that much mass in the back to fix this problem."

We still have to find a way to get those harmonics tuned down so when we're in four-cylinder mode, you don't object to it. The first solution we had was not mass efficient and not very elegant. That much extra mass was diametrically opposed to what we're trying to do as far as performance and fuel economy, so we never used it.

CAC: What about a cam phaser?

SW: We are doing cam phasing on a lot of our engines. As we move into the future, almost all of them will have it. The ability to control that overlap both helps you shape the torque curve and it helps with fuel economy, too.

CAC: No Corvette has a cam phaser, yet.

SW: It's one of those packaging opportunities Tadge and I are still trying to work through.

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The L92 V8, a slightly detuned version of the Corvette's LS3 used in premium SUVs, has a "cam phaser", the device on the front of this Gen 4 camshaft. It's controlled by the engine computer and changes the phasing of the valve events to the movement of the piston. Changing the valve opening and closing in relation to piston movement can improve fuel economy at light loads.
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The cam phaser is located inside the front cover, ahead of the timing chain and increases the overall length of the engine. That extra length is the packaging "problem" to which Mr. Winegarden refers.
Image:  GM Powertrain
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