The Corvette Performance Build Centre - as always seems to be the case with such places - is hidden away at the back of an industrial estate (writes CJ Hubbard
Established in Wixom, Michigan, in 2005, this state of the art facility is modelled after similar operations at AMG and Hendricks Motorsports, looks like an exclusive dealership but is in fact an engine plant. Combining pride of ownership with the latest computer controlled technology, the 'PBC' gives a select team of technicians the luxury of time to hand assemble every single 505hp LS7 (Z06) and 638hp LS9 (ZR1) Corvette motor, as well as the 430hp dry-sump LS3 variant that's fitted to manual gearbox Grand Sport coupés. That's currently around 4300 engines a year.
And, as of 10 months ago, North American Z06 and ZR1 buyers have been able to pay an extra $5800 (£3500) to come here and assemble the very engine that will be fitted into their Corvette. With the imminent introduction of the same option for European customers, it's this Corvette Engine Build Experience that PistonHeads has been invited along to try.
The difference is we're not actually buying a car. So the LS7 with our name on it - literally - will be going into an unsuspecting customer's Z06 in about two weeks' time. No pressure, then. Fortunately (given our almost total lack of mechanical engineering experience), all amateur engine builders are mollycoddled every step of the way by one of the PBC's top class technicians. In this instance, a lovely chap named Bruce Blomfield.
The LS7 is remarkable. At 7.0 litres it's the largest capacity 'small-block' Chevrolet has ever produced, giving 505hp yet revving to 7100rpm (peak power is at 6300rpm, with a 470lb ft max at 4800rpm). A direct result of the Le Mans Corvette race car program, it features forged titanium con rods, titanium intake valves and CNC ported cylinder heads. Yes, it is also just two valves per cylinder and an old-school cam-in-block design - but once you've experienced the noise and performance you quickly learn not to care. In the US the LS7 also comes with a 100,000-mile/5-year warranty - even if a PH reporter has built it.
This process begins with eight enormous pistons. Bruce explains there's a knack to almost everything, and shows us the easiest way to hold each part to perform the necessary pre-assembly inspections, marking them up with a bright orange paint pen as we go. These checks prove their worth when we spot a nick in the edge of a piston crown - Bruce frowns, and selects a replacement. "Not worth the risk," he says.
We move on to collect the block, and the build process begins in earnest - using one of the two regular assembly lines (paying customers have access to a dedicated spare, and all day if necessary). Torque is the most important element for consistency, and so this is set by computer controlled wrenches that log the correct (or incorrect) application of twist to every single bolt on the engine, permanently archived by the central computer for future reference.
The wrenches are a mix of individual handheld devices that require a firm grip, and big, cumbersome overhead multispindles made by Atlas Copco. Everything is activated by barcode scanners and buttons. There are four zone checkpoints along the way in the form of Jake, Corvette's skull mascot; if Jake goes green you're a-okay, but if Jake goes red something's awry...
Under Bruce's tutelage it's all fairly straightforward - despite the bewildering number of bits and bobs we still don't entirely understand. Fun and games, however, include a multispindle mis-torquing a cap bolt (it does up fine the second time, but puts us one torque over the usual number), someone (who, me?) failing to insert all of the side cap bolts (this is why the parts come in kits at every stage - Bruce spots the leftover bolt immediately), and the tricky art of 'stuffing' pistons. Then the versatility of the plant is highlighted when one of the multispindle machines stops working ahead of us; a moment of head scratching, then Bruce swaps us to the other production line, and we carry on without further incident.
We're happy to report that the LS7's trick heads come with the sodium valves already installed, but each of the lifters need to be bolted down individually, and it's a case of gloves well and truly on when it comes to handling the manifolds and the clutch pack.
Eventually, after many generous applications of $15 an ounce(!) lubricant, a grand total of 364 computer controlled torques (that's 17 over in the end thanks to the crashing multispindle), and one paint pen-scrawled signature (hidden from the customer by the Valley Cover, but there nonetheless) it's time for the moment of truth. The spark plugs are in, the leads connected, sensors attached, air and oil cavities checked for leaks - but it's the cold start test that will show whether the past few hours have been a huge waste of time and money for Corvette.
Gladly for us - and Bruce - our baby passes with flying colours. Last stage is a quick balance, which Bruce judges beautifully, and then the LS7 is crated up ready for shipping to the Corvette factory in Bowling Green, Kentucky, and its new Z06-shaped home. The satisfaction is incredible - even though we won't get to benefit from all that hard work. To be a customer and know that you personally built the engine under the bonnet of your brand new 505hp sports car is an intimacy that no other manufacturer can currently offer.
For us, the anticipated European price of €6000 - including flights, accommodation and more - makes the Corvette Engine Build Experience option an absolute no-brainer. As Corvette puts it: "there is no way of getting closer to your car".
This is all assuming you want to buy a Corvette in the first place. And in the UK that would put you into a serious minority (just 11 found homes last year). Being left-hand-drive only doesn't help, there's the leaf spring suspension that many find bothersome, the perceived build quality, and the brash image. But we're talking about a range where the entry-level model does 190mph, and the bang per buck is extraordinary. Where does Corvette go from here?
Corvette Chief Engineer Tadge Juechter seems the right person to ask and, like all Corvette Engine Build Experience customers, we get the opportunity to grill him over dinner in the evening. Corvette, he says, has "benefitted from bankruptcy", as external auditors of GM's recent financial difficulties examined it from a cold hard business perspective and found strong reasons for the marque to continue - it's innovative, aspirational, and sports cars can make big money. Just look at the Porsche 911.
As such, $131million is being invested in the factory at Bowling Green, to prepare the bespoke production facilities - which Corvette spokesman David Caldwell likes to joke are the closest Kentucky will ever come to Maranello - for the next generation C7 Corvette. Sadly, since this isn't due for at least two years, Juechter won't be drawn on many details. But he does say we should expect something "surprisingly different".
Juechter dismisses the speculation about a switch to a mid-engine layout by saying Corvettes have always been practical, and the switch away from a front-engine, rear-wheel-drive layout would significantly dent that; Caldwell, meanwhile, is happy to speculate that the engineers may be approaching the dynamic limits of this set-up.
What is clear, however, is that we can expect Corvette to make much more noise about how advanced its cars actually are from this point onwards. Everyone forgets that the Z06 - and subsequently the ZR1 - has single-piece, hydroformed frame rails made from aluminium instead of the regular car's steel, floor panels of carbon fibre wrapped round a balsa wood core, and magnesium for major structural components, including the engine cradle. We were struck by just how much the rolling chassis resembles that of the McLaren MP4-12C - like that car, the composite body panels merely keep the rain off; racing competitors complain Corvette is effectively using a tube-frame chassis, a significant advantage, but one that only occurs because that's effectively what underpins the road car.
Supporting those leaf springs these days is an adjustable magnetic ride control system - developed at GM, and now used by Audi and Ferrari. A five-setting race-spec traction control system is also available, including launch control. You can even have ceramic brakes. Okay, so the driving experience at low speeds doesn't seem all that sophisticated - both cars tramline and thump over poor surfaces. But step on the accelerator, and not only does a modern 'Vette deliver sensational performance, but it also settles down into itself to serve up a thrilling - yet dependable - driving experience as well.
The goal for the future is to become a global performance icon, rather than just an American dream. For most Europeans this will require a better quality interior as well as an exterior visual makeover; Corvette simply says it will continue to build 'the best car that it can'. We're struggling to think of a contemporary alternative that offers quite the same blend of value and power.
As for the front-engined/mid-engined approach, we're going to go ahead and call: both. If the current ZR1 isn't taken as seriously as its immense capability suggests it should be - 205mph and 0-60 in 3.6secs for £100k - then perhaps that's because it's not differentiated enough from the rest of the range.
A proper, no-holds barred mid-engined Corvette supercar could certainly fix that.