Maximizing Chevrolet Corvette Z06/Z07 Track Pack Cornering

Most days, when the climate cooperates, you’ll find members of our testing group at one or one other of our take a look at amenities working all method of autos by way of our intensive take a look at routine. One of many assessments that we topic nearly all autos to is skidpad cornering efficiency, which ascertains most lateral acceleration—the utmost regular state cornering gs {that a} automobile can attain, a mean of a complete lap whereas turning each left and proper. Our testers do lots of of skidpad assessments annually, they’re specialists at it, they usually just about all the time match or exceed any claims supplied to us by producers about how laborious their autos will nook. Which is why we have been puzzled after we could not come near the Corvette engineering group’s max-lat claims for the Z06 with the Z07 observe package deal, which incorporates the newest gummy Michelin Pilot Sport Cup 2 R ZP tires.

The Corvette engineers informed us that the brand new Z07-equipped Z06 would maintain on to the tarmac as much as 1.22 g on a 300-foot-diameter skidpad like we sometimes use, and we had no cause to doubt their quantity as they’re, like us, meticulous testers. However we solely noticed 1.16 g—a major distinction and effectively beneath the corporate’s estimate. It was an excellent worse cornering quantity than we measured on the previous-generation front-engine C7 Z06/Z07, which held on for 1.19 g. What’s extra, we would simply additionally run a 2023 Z06 convertible with out the Z07 package deal on the skidpad, and its Michelin Pilot Sport 4S ZP tires had held on as much as 1.12 g, an enormous enchancment over the bottom C8 Stingray’s 1.03-g efficiency, one you possibly can really feel in your neck muscle mass. What was occurring right here?

Solely after the Z07 Vette left our possession did Chevy inform us the key sauce that unlocks its full cornering functionality. For all of our efficiency testing, which incorporates skidpad runs, we alter tire strain in line with the producer’s suggestions which are printed on the placard situated on the door jamb or B-pillar, or within the proprietor’s guide. If there are a number of decisions, we’ll use the high-speed, low-load specification. Oddly, the Z07’s placard required the Cup 2s to be set at 35 psi chilly, some 5 psi greater than the bottom Z06’s tire strain. For the reason that tires on the 2 variations of the Z06 are the identical measurement, we puzzled if one thing was off.

That had us digging deep into the Z06 proprietor’s guide the place we found a well-hidden suggestion: homeowners ought to decrease the Cup 2 R’s tire strain all the best way all the way down to 24 psi cod for optimum cornering on the observe. Huh? It took discussions with each the Corvette engineers and engineers from tire-maker Michelin to totally clarify the state of affairs.

The explanation the Cup 2 tires are speculated to be run on the road at 35 psi as a substitute of the bottom tires’ 30 psi has nothing to do with dealing with, journey, or gas financial system however quite wet-weather traction. The Cup 2s have so little tread depth—the outboard half of their tread is basically slick, like a full-on racing tire—that they’ve bother shedding water. Pumping the tire up that further 5 psi crowns the tread sufficient to make a major enchancment of their grip when the highway is moist in line with the Vette engineers.

But it surely seems that, counterintuitively, these latest Cup 2 Rs ship most dry highway grip on the decrease 24-psi strain. These Cup 2 Rs are the newest iteration of Michelin’s hottest street-legal observe rubber. The Michelin man on website on the Z06 observe occasion confirmed us a cutaway Cup 2R carcass, which revealed a current discovery by the corporate. Beforehand, the radial belts that undergird the tread rubber have been laid-on flat and straight throughout from one of many tires’ shoulders to the opposite. However Michelin found that placing a slight wave into the belts acts just like the corrugations in cardboard, stiffening the tire’s tread space that contacts the highway and protecting it flatter in cornering. That change and a few revisions to the tread compound not solely permits the tire to probably present barely extra grip, but additionally ship dramatically completely different efficiency over the course of a observe session. The grip of earlier Cup 2s was well-known for dropping off from its lofty peak after solely a few laps; these new ones are mentioned to have the ability to keep their grip, and therefore fixed lap occasions, by way of session after session.

We are going to little question admire that functionality after we run the Z06 with the newest Cup 2 Rs at our annual Lightning Lap occasion. However we want we had been tipped off concerning the inflation-pressure info hidden within the Z06’s proprietor’s guide in order that we might have delivered consultant cornering take a look at outcomes for the Z07 track-pack model. In spite of everything, cornering grip numbers aren’t solely necessary on the observe; they seem to be a proof level for ultra-high-performance carmakers and fans alike.

We’ll simply must get one other Z07 again within the workplace as quickly as doable to rerun our skidpad take a look at. We might consider a lot worse methods to spend a day.