by Robert Loszewski
© February 2013
No use without permission, All Rights Reserved
Corvette Action Center: With all the technology that went into this Gen V engine, did you have specific output levels in mind for it?
Jordan Lee: Yes. We worked with Tadge very carefully on what he was trying to achieve with this car. Obviously the easy ones are acceleration, and it's a pretty simple formula to calculate how much power you need based upon the mass of the car, and how fast you want it to go 0-60. We [also] look at things like response; when you dip into the throttle, you want that instantaneous torque. I think that we're famous for having ground-pounding, thunderous torque. That's the heritage of the small block and we never want to let that go.
So there was the responsiveness, the acceleration, top speed, track performance — all of those variables went into defining how much horsepower and how much torque we needed and also the characteristic of the torque.
We have a tremendous amount of low-speed torque that's enabled by that DI fuel system. The DI fuel system and combustion efficiencies have allowed us to raise the compression ratio to 11.5:1 which is a pretty lofty number. If your combustion system is very knock-insensitive, and we are, you can use that power and torque all day long. Even if the engine gets hot, or the air temperature gets hot, you're not detonating and taking out spark which is hurting efficiency.
Because we were allowed to raise that compression ratio, and all the other things that we've done, our 6.2L LT1 Gen V has the same torque as the LS7 seven liter all the way up to 4,000 RPM. So in you're normal driving experience, you're going to feel like you're driving a seven liter.
We have the same specific output; horsepower per liter as the LS7; actually a fraction of a horsepower per liter more. Overall, you're getting LS7 type performance in an engine that's a standard engine in that car. That's something we're really proud of.
When you drive it, I think that instantaneous throttle response, power and torque under your right foot is there at your beck and call the second you dip into it. You can't get that with a small, down-sized turbo engine. You can always get the high-speed horsepower, but there's always going to be turbo lag no matter how good of a job you do and you don't have that instantaneous response. The BMW is good, but go drive it and then drive an LT1 back to back and you'll see a huge difference in just the responsiveness and the throttle input with your foot.
So all those things went into why we chose the architecture, the configuration, the torque curves — all those characteristics we were aiming for in the LT1.
Jake Drennon: As you mentioned earlier, several components are different for the Z51 performance package engine vs. the standard engine?
Jordan Lee: Yes. Tadge is always pressing us harder to make his cars more track-capable. The all new Corvette Stingray is a monster on the racetrack. It is a very track-capable car. As a result of the very high g-levels the car can achieve and sustain, we had to redesign parts of the lubrication system and offer the dry sump system for anyone that wants to compete with their car. So now the Z51 [will come] standard with a dry sump if you want to compete. If you aren't going to compete, the wet sump is still available for some of the other base configurations. Very capable — autocross, track days, you name it...it's a great, hot street car, and an excellent competitor car on the track. For the serious competitor, the ones that want to race all day, we wanted to make sure we offered a lube system that was capable of the task at hand. Hence, the two different lube systems.
Jake Drennon: I understand that we'll have an automatic with the Z51 and a dry sump application?
Jordan Lee: Yes, we will.
For more details on this extraordinary powerplant, check out 2014 Corvette Powertrain - Preliminary Specifications here on the CAC.
Moving on from the powertrain, we wanted to take a look at the quality of this new Corvette. For that, we had a chat with Alicia Boler-Davis, GM's Vice President of Global Quality and U.S. Customer Experience. Prior to her current role, Alicia had been plant manager of the Orion Assembly and Pontiac Stamping plants in Michigan, as well as vehicle line director/vehicle chief engineer, small car; plant manager for Lansing’s Consolidated Operations and Arlington Assembly.
Alicia Boler-Davis: [The C7 is] an exciting product, and we're really focused on getting the new product into the market at quality levels that exceed the previous product. We know that the enthusiasts expect that from us, and that's what we're focused on delivering. So all of the neat features and things that are a part of the vehicle, we want it to be fully functional, and operational for the life cycle.
We have a lot of pride in the vehicle, and [it has] a lot of rich history and we want to continue to grow that. So this is a very important vehicle for the company, and quality is very important.
Dan Adovasio: And they are continuing with the continuous improvement on the line as the product goes through? It's not just a one year change?
Alicia Boler-Davis: Absolutely. I grew up in the plant. I used to be a Plant Manager for General Motors, so continuous improvement is a big part of what we do. Our team members are very experienced, and they can find a better way, and they always find a better way. Even part of the vehicle development process - as soon as we can get these vehicles in the plant, it takes a life of its own. The team members live and breathe this every day, and they will find a way to continuously improve it.
Corvette Action Center: Are there any particular aspects when it comes to the quality of the car, and developing the C7 that you said to yourselves: "we need to do this or that, much better than we did with the previous generation"?
Alicia Boler-Davis: If you talk with the engineering team, or the program team, we wanted to build upon the performance, because Corvette customers expect a certain level of performance. We also wanted to improve on the refinement. We wanted to make it quieter. We wanted to improve the door closing efforts and how it sounds. We wanted to improve just the overall integration in the vehicle, so there were specific things that were done as far as where things are placed, and how they feel with the materials that were selected. The lighting that's in the vehicle — all of those are things that the team wanted to focus on and those are the little things that create the "wow" moments for our customers.
Dan Adovasio: We talked about how your job is to make cars, but your job is really to make smiles. There is no other car that I know of that brings a smile to your face when you sit in it. That car produces smiles, and that's what you make. You make smiles for people.
Alicia Boler-Davis: And that's our goal really with every vehicle that we make. These vehicles are big purchases for our customers, and they spend a lot of time in them. They mean a lot to them. We want to make sure that we're delivering on the promise [of] quality and excitement so they can have a high level of satisfaction.
Jake Drennon: It seems like quality starts off good; your vendors are giving you the best quality product they can give you and then through the build, they start slacking off. We [would often hear at the plant] that quality isn't where we want it to be. What have you put in place to make sure that your vendors are giving you what they showed you at the beginning and [will provide] for you the whole way?
Alicia Boler-Davis: Within General Motors, we have a very robust global manufacturing system. Obviously, quality and this idea of quality improvement is very key. We work with the supplier to make sure that they clearly understand the requirements, what the part should meet, and make sure that they have good process control plans in place.
We also expect them to have a robust manufacturing system the same as we have in our plants. We hold them to the same standards. We have a high amount of new content on this product, and every part that goes through has to be properly validated. Then the supplier has to prove that they can build that part with quality as they're accelerating.
We send people into the suppliers and they review the process and review the output of the process. Then they have to earn their way out of a process where we monitor them. They have to demonstrate that they can build the part with quality at the quantities that we need, and they have to do that consistently.
We're putting more boots on the ground in our supplier quality, because we don't just want it to be sending a report and it's ok. We want to go on and partner with our suppliers. At the end of the day, the customers want great parts, and it's a General Motors car.
Ideally, we want to get better with every car we build. With every car that we build, we want it to be better than the last.