Then, as the needle on the tach swung past 2,500, the beast awakened. Centrifugal superchargers build boost progressively; they freewheel when there's no load, and "spool up" like a turbo when under load and being revved. In other words, the more you rev it, the more boost it makes. And the boost doesn't hit all at once, which makes it a lot more controllable. Anyway...around 2,500 rpm, I could feel the extra power coming on and, as the needle swung past 3,000, I was getting pushed harder into the seat. The real fun started as it approached 3,500 and full, i.e.5.5 psi, boost. The black Vette lunged ahead as the back tires broke loose and I cranked in a little opposite lock. I kept my foot planted as the needle arced quickly towards the 6,000 rpm redline and slapped the shifter into second. Another tremendous surge forward while the overworked Goodyear run-flats fought a losing battle to grip the pavement, and once again, the needle swept across the face of the tach way faster than it could on a stock C5. Slap it into third for a second, then gradually back out of the throttle. I was already nudging 90! Of course, strictly in the interest of journalistic integrity, I had to do the same thing three or four more times. What fun!
This Corvette's manners are just as impressive as its prodigious power. It didn't get hot from multiple wide-open-throttle runs, and it didn't act up at all, in any way. We jumped onto a local freeway and cruised for a few minutes. After reaching a fairly open and straight stretch, Roger suggested I slow it down to about 60, shift back into fourth (that's about 2,700 rpm), and punch it. A stock C5 will respond to this routine quite respectably-a nice solid push forward, more than adequate for almost any passing situation. Do the same thing in SVI's blown C5 and it's once again blow-the-tires-loose time, not severely but enough to require some correction on the wheel. And once again, an incredible thrust ahead. From 60 to 100 mph takes maybe 5 seconds in fourth; 10 seconds is probably more like it in a stock six-speed. This thing is FAST!
Like I said, I've got enough wheel time with six-speed LS1s to know what they do. My Firebird has run a 13.15 at 108 mph at Pomona, on street tires. Because of our very limited time right now, we couldn't track test the blown and intercooled C5 but, based on experience and seat of the pants feel for the cars, I'm confidant that SVI's Vette will run the quarter well into the 11s at 120-plus. Their dyno testing indicates this soon-to-be 50-state-legal setup is making a hair over 500 horsepower at around 5,500 rpm and about 560 lb-ft of torque at about 4,300 rpm (425-plus hp and over 475 lb-ft of torque at the wheels).
Within the next couple months we'll take a C5, both dyno and drag test it in stock form, document the entire installation of an SVI supercharger and intercooler system, and retest it on the dyno and at the track. By then the system should have an E.O. number from the California Air Resources Board, which grants it full 50-state legality. Then it'll be time to go put the bite on the not-so big bad Vipers.