Looking beyond mere calculus gives an indication of Corvette engineers’ priorities
Interesting article written by David Booth, he's an auto journalist and electrical engineer who writes for the National Post in Canada
https://driving.ca/chevrolet/corvett...-c8-tea-leaves
Well, the armchair engineers certainly seemed to be out in force this weekend, didn’t they, questioning pretty much everything about the new mid-engined Corvette, a few of their “How can theys” and “that’s impossibles” sounding like they came from skulking Porsche owners trying desperately not to come out of the closet. (And, lest I be subjected to the human rights crucible, by “not come out of the closet,” I am speaking of brand-concealing jealousy and not any closeting of sexual orientation).
Of particular concern, it seems, are the price — its incredible $69,998 projected Canadian MSRP — and the fact that it manages to accelerate to 100 kilometres an hour in around three seconds flat despite boasting only 495 horsepower. The first, as my original deep dive explained, is actually not all that surprising since the C8 really isn’t that new. Oh, to be sure, the engine is most definitely in a different place and, as a direct result, it sure as shooting looks different. The aeros all had to be redone and one surmises that an extraordinary amount of time was spent computer simulating the suspension calibration. But that’s up front costs and, while the costs of R & D are not to be discounted, they pale in comparison to the billions that it costs to actually build a typical, high-end, low production supercar.
And here the C8 is anything but revolutionary. Underneath that radically revised skin, the new car is so similar to the previous iteration that it could have been badged C7.5. Indeed, the major upgrade in chassis construction — again, not design — are some larger high-pressure castings, the kind of run-of-process improvement that General Motors would almost have incorporated even if the C8 had stayed resolutely front-engined. Other than a rear bumper beam that’s made of carbon fibre, there’s little new in the process of building a Corvette, hence why there’s been such a comparatively small increase — about 7.5 per cent — in suggested retail price.
'HOW IS THE C8 SO BLOODY FAST WHEN IT’S SO DARNED HEAVY?'
As for the much-deliberated subject of the C8’s acceleration abilities, the naysayers are picayuning the wrong Corvette deficiency. The issue they should be questioning isn’t horsepower, but weight. What they really should be asking is: “How is the C8 so bloody fast when it’s so darned heavy?”
The downside of the familiarity of construction is that new Vette is a bit of a lardy beast, its 1,530 kilograms really only outweighed, in the supercar spectrum, by the Acura NSX, which, you’ll remember has no less than three electric motors and two turbochargers to account for. Others, like the McLaren 600LT undercut its avoirdupois by some 230 kilos.
Nor, as those armchair Zora Arkus-Duntovs have proclaimed, is the Corvette’s monstrous acceleration simply the result of superior rear-engined rear weight distribution. Oh, that would account for why it’s quicker than the C7 although it’s some 70 kilograms heavier than that dinosaur, but it does not explain how the plainly heavier and significantly less powerful — 490 hp/465 lb.-ft. versus 710 hp/568 lb.-ft. — Corvette is but a tenth (and a smidge) second slower than Ferrari’s 488.
One hint may be Tadge Juechter’s contention that the new C8 has a monster low first cog, geared, as the chief engineer says, for “hard launches.” But torque multiplication alone can’t account for the C8’s unlikely turn of speed. Indeed, all that power needs to be controlled and therein, I suspect, lies the Corvette’s secret sauce — launch control.
Now there’s nothing special about the concept of launch control; it’s been a supercar staple for almost a decade now. What will be special, I believe, is GM’s application of it.
Chevrolet has, over the last few years, made something of a specialty of electronic traction nannies, its Performance Traction Management Systems (PTM) at the forefront of electronic chassis controls. At least part of the reason the C7 was so controllable on a racetrack was the incredibly judicious intervention — or non-intervention — of PTM into tail-wagging oversteer. The reason Camaro SS could be transformed from sow’s ear into the silk purse the Z/28 became — you don’t really think the Z/28 became 911-baiting as a result of suspension tweaking did you? — is thanks to PTM. Never mind that the reason that The General became so expert in electronic controls is because their basic chassis were so archaic, the reason we’re seeing such an unexpectedly quick C8 is because all that electronic traction nous is finally being applied to a modern frame design. These electronic controllers will also be easier to implement now that Corvette has abandoned both manual and automatic transmissions in favour of a dual-clutch DCT, it being much easier to electronically control a physical clutch than squidgy hydraulics.
And finally, it appears, as was much speculated, there is room to fit some (small) electric motors to the C8’s front end. That means, again as has been much speculated (with great encouragement from GM insiders, I might add), that a hybridized, all-wheel-drive variant of the Corvette is possible, if not probable. It almost certainly won’t be a Porsche 918-like plug-in, however, there being precious little space to fit a significant — i.e. 20 kilowatt-hour — battery into the current chassis. And, no folks, GM is not going to load 100 kilograms of lithium ion into either front or rear trunk, not when they went to such trouble to reduce weight — that aforementioned carbon-fibre bumper beam — at the polar extremes of the car.
In fact, I suspect that before we see a fully-electrified Vette, some form of mild hybrid — where an extra powerful alternator feeds a little power into the engine via an extra sturdy belt — will find its way into the C8’s engine bay. The General was once the leader in such systems — they called it their Belt-Alternator-Starter, or BAS system — and has much expertise that would benefit a gas hog like the C8. Wouldn’t it be interesting — and now this is me playing armchair engineer — if GM combined its BAS mild hybrid engine electrified support with real electric motor hybridization? More power, all-wheel-drive, as well as enhanced coasting and shut-off from the big, gas-guzzling V8.
And finally, there is perhaps the most ignored aspect of all the reports of Chevy’s new C8, namely Juechter’s contention that the centre of all that newly redistributed weight is concentrated right at the driver’s inside hip. That would be mighty impressive seeing as a significant portion of the feedback the driver receives from a supercar’s chassis is through their posterior. Having the car feel like it’s resting directly beneath your buttocks is always a whole bunch better than trying to pilot a car at its limit based on feedback from the trunk.
The 2020 Chevrolet Corvette C8 interior Chevrolet
It also gives us some glimpse into Chevrolet’s priorities in designing the C8. They were obviously not too worried about overall weight or high-rpm horsepower; hence their reliance on, for supercars, somewhat archaic aluminum frame construction and the ubiquitous small-block V8. They did, however, seem to care enough about weight distribution to take the time to design that aforementioned carbon-fibre bumper beam — which, by the way, is completely hidden, negating any potential “marketing” value — which would reduce the car’s polar moment of inertia. In other words, they didn’t spend their hard-to-come-by research dollars worrying about weight, but rather where it was to be placed.
So, here’s my last words to all you naysaying nabobs of negativism (more commonly known as Porsche 911 owners). It would seem that the C8’s handling could turn out to be even more impressive than its turn of speed. Be afraid. Very afraid.