I’m still tingling from this morning’s 300 mile cross country-blast in the Corvette ZR1. I didn’t go over 140 mph, but Lordy, what a car! Punch the gas and the LS9 bellows like a lion kicked in the balls, delivering a surge of pure, weapons-grade thrust. The short-throw Tremec TR6060 six-speed is slicker than any gearbox handling such massive torque loads has a right to be. The massive Michelin Pilot Sport tires grip like leeches, the steering is accurate and nicely weighted, and the huge carbon brakes are simply bulletproof, hauling the ZR1 down from unfeasibly fast velocities time and again without a hint of fuss and fade.
This ZR1 is without doubt the most accomplished Corvette ever; the first that could be considered a true Ferrari rival. I adore it, so much so I can forgive its cheap-looking, made-by-Mattel interior and the faint whiff of Dogtown surf shop when I open the rear hatch. So why on earth did I suggest GM build a V-6 Corvette in my story on how we’d remake GM’s product range earlier this week?
Back in 2007 we pulled together a number of scenarios for the C7 Corvette, which at the time was scheduled for a 2012 debut. In it we outlined three different scenarios for the C7’s development. Our preferred option was a careful evolution of the C6, with a three model line up — base, Z06, and ZR1 (though at the time we didn’t know what the super-Vette was going to be called) — all powered by V-8 engines.
A couple of things have changed since then, though. First, timing: The C7 program has been on hold indefinitely since last year, and the sudden retirement last November of Tom Wallace, only the fourth Corvette chief engineer in the car’s history — he was barely three years into the ultimate gig for any GM engineer with an ounce of gasoline in his veins — suggests it’s not likely to be started again in a hurry. That pushes the potential launch of a next generation Corvette to 2014 or 2015 at the earliest.
The other big change since our 2007 story, of course, is that we now know exactly what the new CAFE regulations look like. We based our preferred scenario on a CAFE mandate of 35 mpg by 2020. As we now know, it’s 35.5 mpg by 2016, and because SUVs still get a break, that translates to a 39 mpg target for cars. Bottom line: If Chevy green lights the C7, it now has to meet a tougher fuel economy target from the get-go.
The 6.2-liter LS3 V-8 that currently powers the base C6 Corvette is an impressive engine. It’s relatively light and compact and quite fuel efficient for its capacity. A base C6 manual returns an impressive 16 mpg city and 26 mpg highway, though GM is a master at gaming the EPA numbers: you get 26 mpg courtesy of a mountain of torque and a moonshot sixth gear, and 16 mpg only if you’re prepared to live with the klutzy first-to-fourth skip-shift and drive like a granny.
Could the LS3 be made fuel efficient enough to survive beyond 2016 in a Corvette that’s going to have to be smaller and lighter than the C6? Cylinder deactivation is difficult, because the system sets up all sorts of weird harmonics through the Corvette’s torque tube and rear-mounted transmission layout. Direct injection is a more promising alternative, as you could reduce the LS3’s capacity to further improve fuel economy while still delivering good power. Variable valve timing offers potential for further efficiency gains. Both add cost and complexity, however.
So it would be foolish not look at the direct injection 3.6-liter V-6 as option. The hardware’s shared with a large number of GM products, helping keep a lid on costs. Would performance suffer compared with and LS3 powered C6? Sure, but not by as much as you might think. And if the alternative is no Corvette at all, why not consider it?
My other point is this: A V-8 under the hood is nice, but it doesn’t automatically make a Corvette a great sports car. Exhibit A: The 1975 C3, which boasted a pathetic 165 hp, and could barely get out of its own way. And unless we want to turn Corvette into a kind of four wheeled Harley-Davidson — an amusingly pointless anachronism — we should be prepared to accept the fact that sports cars must change and evolve with the times.
Porsche’s 911 started out as a flat-four before it became a flat-six, and the company is looking to going back to a four again for an entry-level Cayman. Ferrari’s first road car was a four-banger, then came a long line of V-12s before it built its first V-6 road car in the 60s and first V-8 road car in the 70s. Lotus sports cars have been powered by fours, sixes and eights; Jaguars by sixes, eights and twelves. Cylinder count does not define a great sports car.
Besides, if you re-read my story carefully, you’ll see I didn’t say all C7 Corvettes should be V-6. If I ran the New GM I’d make sure I’d keep that mighty LS9 alive, powering a C7 ZR1. It’s a 2000-3000 unit a year car at most, low enough volume to keep it flying under the CAFE radar. America should continue to build at least one true, no-holds-barred Ferrari fighter.
Source : blogs.motortrend.com/6520948/editorial/the-v-6-corvette-and-other-heresies/index.html