But the LS9’s superiority is about more than just numbers. In the old days, when big-blocks were bold, if Duntov wanted more power, all he had to do was add a little more of everything. That meant more cubic inches, extra compression, hotter spark, colder air, and/or additional carburetion. It was all a juggling act between maximum power, driveability, and durability. And we won’t even get into fuel economy.

ZR1 Corvette production is scheduled for only 2,000 units, beginning in July of 2008. All LS9 engines are hand-assembled at the GM Performance Built Center in Wixom, Michigan. This powerplant was three years in development and makes major advancements through the use of cutting-edge engine-management systems. These “black box” electronic wonders help balance out the radical hardware while ensuring emissions compliance and respectable fuel efficiency.

Those willing to pony up 100-plus grand will get prodigious output along with a relatively mild cam grind that makes for a very stout but tractable vehicle. After all, the ZR1’s stated goal was to be a docile pussycat around town and a track-day tiger. At 1,000 rpm the LS9 is already making 300 hp and 320 lb-ft of torque, with maximum readings of at least 620 hp and 595 lb-ft coming at 6,500 and 4,000 rpm, respectively. Incredibly, ninety percent of the LS9’s peak torque is available from 2,600 rpm to 6,000 rpm. For an EPA- and GM-durability-certified engine, that’s damn impressive!

Let’s go through the basics and see how this mouse roars from beginning to end. The LS9 displaces 6.2 liters, with bore/stroke measurements of 4.06 x 3.62 and a 9.1:1 compression ratio. The engine is a pushrod, 2-valve-per-cylinder design with a 12-quart dry-sump oiling system. The block and cylinder heads are aluminum, but the heads are spun-cast from A356-T6 alloy for higher heat tolerance.

The LS9’s block is essentially the same as the base LS3’s, but nearly all other components are either completely new, upgraded LS3, or LS7 parts. Reinforced bulkheads improve block stiffness by 20 percent. The LS9 uses six-bolt steel main caps with high-strength steel bearing caps, a new forged-steel micro-alloy crankshaft, and a new 9-bolt flywheel mount. The head-gasket design is unusual, too. The gaskets are cut to the same shape as the LS3 units but have four layers of steel instead of two. Also, the intake tract incorporates a “swirl ring” to improve the air/fuel mixture.

I know what you’re thinking: Why didn’t they just use the 427ci LS7 to start with? Designed for use in the naturally aspirated Z06, the LS7 block was rejected because its thinner cylinder walls prompted durability concerns with the added pressure from the supercharger. Maybe we’ll see that setup in the C7 Corvette.

When it comes to making power, it all begins with copious amounts of compressed, cooled air. That air enters the intake tract and travels straight into a new Eaton R1900 2-rotor supercharger nested between the cylinder banks. Each of the blower’s rotors has four lobes, making it both efficient and quiet. Using a 2.3:1 pulley ratio, the Eaton unit pumps out 2.3 liters of compressed air per revolution and achieves a maximum boost level of 10.5 psi.

The compressed air is transferred to a “dual brick” Behr air-to-liquid intercooler capable of reducing intake-charge temperatures by as much as 140 degrees F. It is then blown through valves that are the same size as the LS3’s but use titanium construction on the intake side and sodium-filled stainless steel on the exhaust. The pistons are forged aluminum instead of cast, and the connecting rods are machined out of titanium.

Standard LS3 ignition coil packs mounted to the rocker covers ignite the pressurized mixture. A unique, electronic fuel-pressure regulator switches between 87.0 psi and 36.3 psi settings based on engine speed, while an 11-rib V-belt runs the supercharger, power steering, and water pump.

Keeping a high-pressure, high-temperature engine such as the LS9 engine alive requires enhanced oiling capabilities. In addition to its dry-sump system, the LS9 is the first small-block Chevy to use oil squirters to boost cooling and reduce engine noise. The exhaust system of the LS9 is identical to the Z06’s, with manifolds and catalytic converters designed to meet 150,000-mile durability tests. No official EPA fuel-mileage ratings have been published to date, but the LS9 may fall victim to the gas-guzzler tax.

The ZR1’s drivetrain has also been enhanced with a twin-disc Luk clutch that has dual 260mm discs. It boasts more clamping power than the Z06’s single 290mm unit, with no extra pedal effort. Power then runs through a revised TR6060 six-speed manual gearbox with dedicated ratios, including a steep First gear that helps launch the car and a shorter Sixth gear to enable the ZR1’s 200-plus-mph top speed.

It wasn’t long ago that even racing Corvettes didn’t have this much cool hardware. But then again, there’s never been a $100,000-plus Vette available from your local Chevy dealer. If you haven’t yet placed your order, you just might have to wait for the ‘10 model. Will the ZR1 coast through the rest of the C6 run unchanged as the flagship Corvette, or does Chief Engineer Tadge Juechter have a few more tricks for the ZR1? Stay tuned!

Here's the Story...
Illustrated Corvette Series No. 133 - 2009 ZR1 Corvette
"Chevy's World-Class Supercar"

The Internet rumor mill worked three shifts for nearly two years on the recently introduced ‘09 ZR1. Fuzzy spy photos kept fans stoked, while all sorts of colorful names were bandied about. The buzz was that the Corvette team was hard at work on a new super-Vette. The only solid information was that the car would be based on the existing Z06. Everything else was up for delicious speculation. Automotive bloggers and magazine writers taunted us with names such as “Blue Devil,” “Stingray,” “Corvette SS,” and “Z08.” Then, in December ‘07, Chevrolet stopped torturing us and announced the return of the king: The ZR1 was back!

The new ZR1 is arguably the most aggressive production Corvette ever made. As we wrote last month, the ZR1 name was originally a racing option from ’70-1/2 to ‘72. The ’90-‘95 ZR-1, with its jewel-like LT5 engine, was a terrific machine, but it didn’t look that much different from a regular Corvette. Such is not the case with the latest ZR1. One has to go all the way back to the ’65-’69 big-blocks—with those amazingly loud side-mounted exhaust pipes—for more visual testosterone. The ‘09 ZR1 bears a strong resemblance to the L88 Corvettes, with their flared fenders and race-car-inspired details.

But unlike the earlier super-Vettes that were intended for track use only, this is a mega-muscle machine you can live with everyday. Forty years after the L88 and ZL1, we now have a Corvette that delivers unimagined performance in every area. Let’s draw some comparisons.

The new ZR1 packs 620 horsepower and 595 pound-feet of torque. The L88 and ZL1 engines never received accurate published power ratings, but real output was estimated to be close to 550 gross hp. The new ZR1’s LS9 engine is rated in net hp. It also passes emissions tests and is capable of over 20 mpg on the highway. The beasts of old got 8-10 mpg and had no emissions controls whatsoever. The new ZR1 also has a suspension that won’t hammer out your fillings and brakes that don’t have to be hot to work. Yes, 40 years of development have paid off big-time.

The ZR1’s stunning good looks are obvious from every angle. While the Z06 is a very aggressive-looking car, the ZR1 takes things to the next level. The entire front end and the roof section are made of carbon fiber. Chevy decided to show off the exotic material by using a $60,000-a-gallon clearcoat over the new chin spoiler, rocker panels, front fenders, and roof. The new hood is one inch taller than a regular Vette’s, bears a slight resemblance to the C3 big-block hoods, and features a Plexiglas window that shows off the LS9’s engine cover. The front and rear fender flares are the same as the Z06’s, but the front fenders have larger, more aggressive vents. The back end is finished off with a short, full-width spoiler. The only things missing are the side-pipes, rendered unnecessary by the car’s ultra-efficient conventional exhaust system. New ZR1 badges adorn the front fenders and rear bumper cover.

The new ZR1 couldn’t have much more exotic hardware. The all-aluminum LS9 engine is not only supercharged, it has an intercooler, port fuel injection, a 10.75-quart dry-sump oil system, and a LUK dual-disc clutch. The TR6060 six-speed transmission has been beefed up, and the gear ratios are closer than those in the Z06.

Now let’s talk about those wheels and brakes. The Speedline forged-aluminum wheels measure 19x10 inches in the front and 20x12 inches in the rear. For the first time since ’77, a Corvette will not be wearing Goodyear tires. The Michelin Pilot Sports measure 285/30-19 on the front and 335/25-20 on the rear. The brake system uses Brembo carbon-ceramic rotors that are vented and cross-drilled. They measure 15.5x1.6 and 15x1.4 inches fore and aft, respectively. Six-piston calipers are employed in the front, and four-piston units are used in the back. The brake pads are twice the size as those used on the Z06 and will last the car’s lifetime in street use. The basic Z06 suspension is modified with next-generation Delphi Magnetorheological (MR) variable shocks, softer springs, larger anti-roll bars, and revised rear-suspension geometry.

The interior has only slight addThe interior has only slight additions. The seatbacks feature “ZR1” embroidery, a boost gauge and “ZR1” tach face plate spruce up the instrument cluster, and the door-sill plates also bear the car’s model designation. And so you don’t forget how fast the ZR1 can take you, the speedometer goes up to 220 mph!

The interior has only slight additions. The seatbacks feature “ZR1” embroidery, a boost gauge and “ZR1” tach face plate spruce up the instrument cluster, and the door-sill plates also bear the car’s model designation. And so you don’t forget how fast the ZR1 can take you, the speedometer goes up to 220 mph!