The Mid-Engined Corvette is not only back on the front burner - it looks to be a cert
Autoextremist by Peter M. De Lorenzo
Detroit. It was already supposed to be a done deal that the seventh generation of the Corvette would arrive in its current, front-engined, rear-wheel-drive configuration - albeit slightly smaller, lighter and with two engine choices. There was serious talk of an extremely limited production mid-engined "super" Corvette (fewer than 500 units), which would be built as an adjunct program to the traditional car, but that had not been decided. That's the way we reported it many weeks ago, and that was the assumption by many in the business as to how it was going to go down - until now. But after my conversations late last week with executives at the top of the company (who shall remain nameless for obvious reasons), I can tell you that the "idea" of a mid-engined "C7" Corvette has not only progressed far beyond the initial planning stages, the engineering on the car is well underway.
What brought on this monumental philosophical shift? Read on...
1. Cost. Up until this point, the argument that the Corvette's fundamental high-performance-for-the-money equation - one that has been a hallmark of the car since Zora Arkus-Duntov took over the program in the mid-50s - would be compromised with a mid-engined car has held sway over every future Corvette product discussion/decision. That's no longer the case, apparently. The two key stumbling blocks for a mid-engined Corvette that have always put a damper on previous discussions were the sophisticated, complex and highly expensive transaxle required, and the extremely difficult cooling challenges. The transaxle in particular has a heavy cost-per-piece price that cannot be subjected to shortcuts due to the engineering requirements necessary to accommodate the high horsepower output of a proper Corvette.
GM has found a way to solve these issues while still maintaining the Corvette's fundamental value proposition and while still delivering the kind of high performance expected of a car that wears the famed Corvette name. I have it on impeccable authority that as a result of the intensive engineering push on the C7 in the last five weeks, the new car will have a target base price that's very close to a loaded Corvette convertible of today, a number that will keep the future mid-engined Corvette well within reach of its core buyers at current volume levels. This would also obviously allow the Corvette to remain true to its raison d'etre - and continue to outperform cars costing thousands upon thousands more.
Judging by the digital images I have seen, the new mid-engined Corvette is sensational looking, which, given GM Design's roll of late, certainly shouldn't be a surprise. Futuristic, purposeful and bristling with exquisite "signature" Corvette design elements - with no "blades" and no bullshit gimmicks - the new Corvette is everything the Corvette faithful could hope for. But an interesting sidebar? Judging by the reactions of people I have spoken to who have seen it, the Cadillac XLR variant of the mid-engined car is drop-dead gorgeous too.
2. The Technological Imperative. There has always been a passionate group of True Believers within General Motors, Chevrolet and GM Racing that wanted to push the Corvette envelope further and aggressively present and promote the sports car as a technological showcase for the entire corporation. This group has always believed that GM has squandered the success of the Corvette - not only failing to use the power of the Corvette brand in corporate image advertising but failing to let the car's significant achievements in racing in recent years speak forcefully on behalf of the corporation in terms of technical ability. This is a belief I share, by the way, because in an era when GM - and the rest of Detroit - is literally and figuratively on the ropes and has become the favorite punching bag of the anti-car, anti-Detroit "intelligentsia" (and I use that term derisively) in the media and in Washington, here is a car that not only humbles cars costing thousands more on the street, it regularly competes and wins against the best that the competition has to offer on racetracks around the world. And its success goes largely unnoticed and unappreciated both within and outside the corporation.
The mid-engined configuration will not only propel the Corvette to the next level in terms of performance - giving cars such as the new Audi A8 and any future Porsche 911 fits, by the way (not to mention making Ferrari and Lamborghini very uncomfortable) - it will finally be able to assume the role as a global technological showcase for the corporation, something that it couldn't quite accomplish as long as it was hamstrung with its traditional front-engined configuration, even though the current Z06 already humbles some of the world's most expensive exotic sports cars.
Rick Wagoner got up in front of the media at the L.A. Auto Show last November and touted that GM was going to become a technological leader. But being a technological leader is about much more than producing plug-in electric cars - it's about demonstrating passion for the product and in your products - and the willingness to put your technological stake in the ground on all fronts. A mid-engined Corvette will help deliver Wagoner's positioning in spades.
3. The Competitive Imperative. Right now, GM's Corvette Racing program exists for one simple reason: to win the premier GT1 class in the 24 Hours of Le Mans - the world's greatest sports car race - every year. Everything else Corvette Racing does revolves around that single quest, which is why they find themselves running without competition in the American Le Mans Series this year. The ALMS' connection to the world's most prestigious sports car race requires that Corvette Racing wins over here in the GT1 class first, even though no worthy competitor (other than the occasional Prodrive Aston Martin effort) runs consistently against the Corvette in the series, which makes for some less-than-ideal "We beat ourselves - again" headlines.
But a mid-engined production Corvette changes everything.
Remember the first scenario that I mentioned? That the next-generation Corvette would be in its current front-engined configuration with the possibility of a ultra-limited-production mid-engined "super" variant? The decision to go with a mid-engined configuration for the Corvette alters the landscape significantly. First of all, it eliminates the expense of developing (and paying for) two separate cars, which was something that the GM brass was not jumping up and down with joy about, understandably.
Secondly, it allows GM and Corvette Racing to do something that is long, long overdue, and that is to become the second American automobile manufacturer to go for the overall victory at the 24 Hours of Le Mans - something that hasn't been achieved since the glory days of Ford's four-year winning onslaught in the 60s - some 40 years ago.
As you read this, GM's senior brain trust is contemplating every facet of this mid-engined scenario down to the last detail for the seventh-generation Corvette. The facts of the matter are hard to deny: The technical issues are on the way to being solved, the classic Corvette high-performance value proposition would remain intact, and GM's drive to establish itself as a global technological leader would be enhanced and embellished, especially with a mid-engined Corvette Racing prototype going for the overall victory at Le Mans.
I strongly believe that Corvette's True Believers out there - some of whom have been wishing and hoping for a mid-engined Corvette since the early 70s - are finally going to have their prayers answered - and very, very soon.
The word from inside sources intimately familiar with the next-generation Corvette is that a final "go" decision for the mid-engined C7 will be made by the first week in September, and given everything I've learned and everything I've pieced together on the timing, I'll bet the farm right now that the next-generation mid-engined Corvette will make its debut - on the street and at Le Mans - in 2010.
Re: The Mid-Engined Corvette is not only back on the front burner - it looks to be a
Good read! Thanks for posting it up Kingpin! Whatever GM decides to do, at least they are still going to make the Corvette! I have driven a few mid-engined cars, and frankly, I liked the way they felt! If they can keep the car within a realistic price point, I might even consider buying one when the time comes!
Jimbo
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Re: The Mid-Engined Corvette is not only back on the front burner - it looks to be a
Behind the front axle or in front of the rear axle, 50/50 is 50/50, it doesn't matter where the engine's located. Either way, you still have the same weight on each axle and the same moment of inertia halfway between the front and rear.
What don't I get about this?
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Re: The Mid-Engined Corvette is not only back on the front burner - it looks to be a
So the Corvette will no longer be the "daily driver" supercar - since "mid engined supercar" and usable all round vision and storage space ar emutually exclusive.
I wonder exactly what that will accomplish? Making the Corvette more European? Whats next? A Turbo V6? A diesel option? Hopefully GM just bought the rights to the Mosler, are refining that design and selling them with warranties.
And what would winning LeMans Protoype class prove or help? The rules are different to the 1960's.
Re: The Mid-Engined Corvette is not only back on the front burner - it looks to be a
[quote=Z16#670;1189755]Sounds great if your only focus is winning races.
Enjoyed the article and find it interesting. However, I will still want to put my golf clubs and a weekend bag in the Z in addition to having the outstanding performance. If all I have is a fast trip to the golf course or a weekend destination in a mid engined car and have to rent clubs and buy clothes when I get there, I think the Katech Z06 Street Attack Package becomes a reality for me. If that's too narrow minded blue collar, so be it. I write the checks.
Re: The Mid-Engined Corvette is not only back on the front burner - it looks to be a
I offer this explanation, in a simple Physics sense, for those who question the rationale for why, in a handling and performance standpoint one might, or might not, want a mid-engine car.
If the center of mass is closer to the center of rotation (vertical axis) the handling can potentially be improved, as its polar moment of inertia will be less. Polar moment of inertia means an objects ability to resist torsion. In this case, it simply translates into a cars ability to turn.
Think of a teeter-totter. A heavy person must be closer to the fulcrum (center of mass or CG) whereas a light person must be further away in order to balance one another. A balanced teeter-totter has a perfect 50/50 weight distribution, regardless of the weights of each individual or their distances from the fulcrum. In a Physics sense, we would say the system was in equilibrium.
However, which individual has the greater moment of inertia? The lighter one does. Even though they are lighter, their greater distance from the fulcrum results in a greater moment of inertia. Why is that?
Since they are further from the fulcrum, they are said to have a longer 'arm'. "Arm" being an objects distance from the CG. When you take the weight of an object and multiply it by its arm, in this case the teeter-totters fulcrum, you obtain its 'moment arm', or simply moment.
Now, think of a car. Take the engine and move it close to the CG, but forward of it. Place the differential and transmission aft of the CG but at a greater distance from the CG than the engine is. What do you have? You have a C5 or C6 Corvette of course!
If done carefully the result is a perfect 50/50 weight distribution. That’s good, right? Well maybe yes, maybe no. Let's take a closer look.
If you placed the engine, transmission and differential in approximately the same place, close to the CG, what would you have? Well, besides a Fiat X1/9 you'd also have a car with a low polar moment of inertia! Since the center of mass surrounds the axis of rotation, the car is said to have a low polar moment of inertia. There is simply not as much mass on either end of the arms and thus the car will rotate or turn around its vertical axis faster. Therefore, the car itself turns faster. Sometimes too fast, as cars with low polar moments of inertia can be tricky, as in little to no warning of when they are about to let go. And, since the majority of the cars mass is near the CG the weight distribution is easily kept close to 50/50.
On the other hand, a car with a high polar moment of inertia resists turning. It is rotationally more stable. Simply put, since the moments are greater the ends resist turning. (I can go on and explain the Physics of this, but think of a figure skater: when they bring their arms in they spin much faster.) This car can also have a perfect 50/50 weight distribution. Again, as with the C5 or C6 Corvette, but handle much differently.
Note: I have owned many mid-engine cars, including the Fiat X1/9 mentioned above. When I say mid-engine here, I am referring to mid-engine cars in the classical sense of the term: that being the engine aft of the driver but forward of the rear axle.
I still feel GM will not build a mid-engine Corvette, at least not for the 7th generation platform. The reasons for this I stated in a post about a month or so ago. Much of it was similar to what has been said here: not traditional Corvette design, potential lack of cargo volume, development cost, handling quirks common to mid-engine cars and on and on.
Re: The Mid-Engined Corvette is not only back on the front burner - it looks to be a
Quote:
Originally Posted by RocketSled
Behind the front axle or in front of the rear axle, 50/50 is 50/50, it doesn't matter where the engine's located. Either way, you still have the same weight on each axle and the same moment of inertia halfway between the front and rear.
What don't I get about this?
Another thing I wonder is, why is it super mega important to have 50/50 weight distribution when only the front wheels are steering?
My understanding is that a real 50/50 would mean the car's weight is distributed evenly between the front and rear wheels (not sure the same applies to left and right wheels, but let's pretend it does for the sake of argument).
I would think that when you steer, having a pure 50/50 is no better than, say, a Porsche 911-like 40/60, no?
Obviously, as you move further back, you'll reach a point where things are way too twitchy as No Doubt mentioned in his post, but essentially what's the big deal with 50/50?...
Re: The Mid-Engined Corvette is not only back on the front burner - it looks to be a
It isn't the be all, end all, to have 50/50 static weight distribution and in fact, many high performance sports and racing cars do not have 50/50 weight distribution, e.g.: most formula cars, LMP1, LMP2 prototypes, C.A.R.T. and Indy cars, Daytona Prototypes and some road cars too such as the Lotus Elise and Exige. 50/50 static weight distribution meaning when at rest as measured on scales. Although it has its advantages, like almost everything to do with cars, or aircraft for that matter, it also has drawbacks.
The advantage of static 50/50 weight distribution lies primarily in predictability and lateral grip, which, by the way, the C5 and C6 Corvettes have. 50/50 static weight distribution was a taunted aspect of the Porsche 944. The same can be said of the C5 and C6 Corvette. After all, if you can't have the weight rear biased it's better to have as much as possible in the rear. The result: 50/50 static weight distribution. The 911 series on the other hand, with their inherent static rear weight bias take advantage of another factor: dynamic weight distribution.
For example, as the 911 brakes, the rear weight bias transfers forward resulting in something closer to 50/50 weight distribution. This in turn aids stopping ability because all four tires contribute to braking more effectively.
A car with static 50/50 weight distribution will, dynamically speaking, end up with a front weight bias under braking. This results in two things: less weight over the rear tires and thus less traction and less rear brake effectiveness. The front tires are now being asked to perform the majority of both braking and turning. If you're familiar with the concept of the 'traction circle’, you can see where this is not beneficial. Hence, we brake in a straight line for the most part, in any car.
Another advantage of rear weight bias, or at least for a car where the engine is over the driven wheels, is traction when putting power down such as during corner exit.
Quote:
Obviously, as you move further back, you'll reach a point where things are way too twitchy...
Yes and some 911's were known for being "tail happy". That is the inherent disadvantage of having a lot of mass far back: an increased moment of inertia.
Mid-engine cars do not have their mass either far forward or far back but instead, centered closer to the axis of rotation and is one of the reasons they can turn quickly. As I said above, this is known as a low polar moment of inertia. However, they are also inherently less stable and that is one of their drawbacks. There is a learning curve when going from a front engine car to a rear engine car and even moreso when going from a front engine car to a mid-engine car. Again, mid-engine in this case refers to a car where the engine is behind the driver but ahead of the rear axle. Mid-engine cars, although very quick in transient response, can also be rather thrilling at times. Unlike a front engine car one can't hang the tail out and apply power and hold it there as easily. You may very well find yourself eating a telephone pole or Armco barrier. They can be like an on/off switch in that respect. Ever watch a F1 car slide? You don't see too many "saves". Once they go, they are gone and you are along for the ride and I can personally atest to that.
In reality however, even mid-engine cars are more rear weight biased, for the same reason the 911 is.
Finally, will GM design and manufacture a mid-engine Corvette? Will they abandon 54 years of tradition? Will they spend the money necessary to design, develop, test and produce a car with what amounts to a radically different design philosophy? I wouldn't hold your breath.
What advantage would a mid-engine Corvette offer? Well, it's not likely Dodge will come out with a mid-engine Viper so that's one possibility.
I'll say this to the person who wrote the latest article on GM's plan for a mid-engine C7 Corvette: Would it afford a better chance at winning the 24 Hours of Lemans, overall, while competing with an entirely new car design that's based on a production car against prototypes that have had years of refinement? YOU MUST BE JOKING!
Whatever GM decides to do, at least they are still going to make the Corvette! I have driven a few mid-engined cars, and frankly, I liked the way they felt! If they can keep the car within a realistic price point, I might even consider buying one when the time comes! 
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you'd also have a car with a low polar moment of inertia! Since the center of mass surrounds the axis of rotation, the car is said to have a low polar moment of inertia. There is simply not as much mass on either end of the arms and thus the car will rotate or turn around its vertical axis faster. Therefore, the car itself turns faster. Sometimes too fast, as cars with low polar moments of inertia can be tricky, as in little to no warning of when they are about to let go. And, since the majority of the cars mass is near the CG the weight distribution is easily kept close to 50/50.
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