Z06 Spec/Info - 2001 Model
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2001 Z06 Corvette - The Best Vette Yet?
By Joe Oldham (PM Mag.) - 3/18/2001
Pics courtesy of General Motors
Dave Hill, vehicle line executive and Corvette chief engineer, calls his new Z06 model "a car for the extreme driving enthusiast." Indeed, with a power-to-weight ratio of 8.09 pounds per horsepower, the Corvette Z06 is the quickest, fastest Corvette ever built. Yes, bar none. Our testing confirms that the Z06 goes from 0 to 60 mph in a strong 4.59 seconds and rips through the quarter-mile in 12.81 seconds at 111.19 mph. This clearly puts the Dodge Viper and Porsche Turbo into the sights of a Corvette Z06 driver in any given situation on the street or track.
Based on the former hardtop model already the lightest, stiffest and quickest Corvette Chevrolet claims it's not only the quickest, but also the best-handling production Corvette of all time, setting new standards in every part of the high-performance spectrum. The car is also a tribute to the first Corvette chief engineer, Zora Arkus-Duntov, himself a legend in racing. In fact, several of the designations used on the new car Z06 for the model name and LS6 for the engine are an homage to the man who shaped the car's history for many years.
Providing the grunt for all this performance is a new version of the venerable small-block engine that delivers almost 12 percent more horsepower than the 2000 LS1. Called the LS6, it shares many components with the LS1 found in every other 2001 Corvette, and would look the same as the LS1 were it not for its red engine covers.
The LS6 produces 385 hp at 6000 rpm, and torque of 385 ft.-lb. at 4800 rpm. The engine is redlined at 6500 rpm (versus the LS1's 6000 rpm redline), and its torque curve is slightly biased toward the upper end where that power will be most appreciated on the track. LS6 power output is achieved as the result of dozens of refinements to increase volumetric efficiency and maximum rpm.
The aluminum block casting on the LS6 deletes machined holes in the LS1 bulkhead and adds cast-in "windows" that allow better bay-to-bay breathing. On the downstroke, the pistons push air back toward the crankcase, creating backpressure or resistance, and that translates into parasitic horsepower loss because it resists piston motion. With the overtravel windows, air is allowed to move more freely between crankcase bays, thus relieving the unwanted pressure.
LS6 pistons are cast from high-strength M142 aluminum alloy and reshaped with a slightly different profile than those in the LS1. In side view, the LS6 pistons have a slight barrel shape, almost imperceptible to the naked eye. The new alloy increases engine durability at racetrack operating levels, while the shape reduces internal mechanical noise.
The LS6's aluminum cylinder heads are cast with pent-roof combustion chambers that are smaller than the LS1's. Compression ratio increases from 10.1:1 to 10.5:1, improving thermal efficiency and increasing horsepower. Intake and exhaust ports in the LS6 head are refined and more precisely cast, contributing to the engine's overall increase in volumetric efficiency.
The LS6-specific, steel-billet camshaft contributes more than any other single piece of hardware to the LS6's horsepower gain. In simple terms, the cam opens the valves quicker and allows more air to flow into the combustion chambers. Cam lift increases from the LS1's 12.7mm to 13.3mm.
Stronger Valve Springs
To accommodate valve operation with the high lift/long duration cam, the LS6's valve springs are stiffer and sturdier. They are made from the same steel wire as those in the LS1 but are wound tighter for a higher spring rate.
Additional air flowing into the LS6 heads would serve no purpose without an equivalent increase in the amount of fuel to take advantage of it. New injectors increase maximum fuel delivery from the LS1's 3.3 grams per second to 3.6 grams per seconds, for a 10 percent improvement.
Internal PCV System
The LS6's application in the Corvette Z06 creates additional demands on the crankcase ventilation system. The Z06 is capable of cornering at more than 1 lateral g, requiring a special high-performance ventilation system.
To prepare the Z06 for all-out driving, the LS6's PCV system is moved into the engine's V, or valley. The unique aluminum valley cover incorporates composite oil-separating baffles and PCV plumbing. All of this reduces oil consumption during high-performance driving and, as an added benefit, also reduces the amount of external plumbing, eliminating potential oil-leak sources.
Thin-wall cast-iron exhaust manifolds replace the previous stainless steel manifolds to improve durability, given the LS6 engine's potential for being involved in sustained high-speed driving.
To further maximize the breathing capabilities of the LS6 and significantly reduce vehicle mass, a new titanium exhaust system was developed for the Z06. This marks the first-ever use of titanium in the exhaust system of a mass-production vehicle. The titanium portion of the Z06's exhaust system starts just forward of the rear axle, then goes over the top of the axle to the muffler. The entire muffler, all of its internal parts and exterior skin, the outlet pipes, including the exhaust tips, are constructed of titanium. The Z06 muffler is a completely new design featuring larger-diameter louver tubes inside the mufflers to reduce backpressure and provide less restriction for the exhaust gases flowing through the system. The exhaust tips are different too, with four 3.5-in.-dia. tips to visually set the Z06 apart from the standard Corvette.
Titanium offers a lower density than steel, and higher strength than either magnesium or aluminum at all temperatures. It reduces the Z06's weight by 17.6 pounds a whopping 50 percent reduction compared to the weight of the stainless steel exhaust system used on the Corvette coupe and convertible. In addition to easing exhaust gas restrictions, reducing mass and looking distinctive, this exhaust system sounds more aggressive than that of the standard Corvette. Considerable time and effort went into the design and tuning of the mufflers to ensure an exhaust note that would be unique to the Z06.
In addition to providing more power and better fuel economy, Corvette engineers upgraded the operation and durability of the rest of the Corvette powertrain.
The driveshaft is upgraded from a metalmatrix composite to aluminum alloy 6061, and it is increased in diameter from 55mm to 63mm. Driveshaft couplings have also been upgraded on manual-equipped models for additional strength and durability.
Lighter Automatic Transmission Case
By optimizing the design of the automatic transmission case, Corvette engineers were able to trim some material and reduce thickness in some areas to reduce mass by 3.3 pounds.
All Corvettes with the six-speed manual transmission (optional on coupes and convertibles, standard on Z06), feature a revised clutch with greater clamping power to accommodate increased engine torque. This new clutch design also provides for lower pedal effort, making manual-equipped Corvettes easier to drive.
M12 6-Speed Manual
This transmission is unique to the Z06, and is the only transmission available for that model. It is not available on Corvette coupes or convertibles. It has more aggressive gearing to increase torque multiplication in most forward gears, allowing for more rapid acceleration and more usable torque at higher speeds.
A transmission temperature sensor was added to protect the M12 from higher thermal stresses. The sensor warns the driver via the Driver Information Center with a TRANS OVER TEMP light if thermal loads become excessive, meaning that the transmission could be damaged if not allowed to cool down.
Carbon blocker rings have been installed on all manual transmission forward gears to provide for smoother shifts and additional robustness.
For 2001, a Second-Generation Active Handling system, much enhanced over the original, becomes standard equipment on all Corvettes.
The original Bosch 5.0 hydraulic pressure modulator is replaced by an improved Bosch 5.3 modulator. It is reduced in size, transmits less noise, and works better at low temperatures. It weighs 3.5 pounds less than the previous modulator and provides better apply response at lower temperatures (minus 20° Celsius), meaning that the system will become fully functional more quickly after a cold startup.
Dynamic Rear Proportioning
The enhanced system has dynamic rear brake proportioning capability, electronically balancing rear brake pressure to prevent rear brake bias, or lockup. This new software feature eliminates the need for a rear brake circuit-proportioning valve, resulting in fewer assembly parts and fewer brake pipe connections. In addition, the master cylinder pressure sensor is now integrated into the new Bosch pressure modulator.
Sideslip Angle Rate Control
Another upgrade for 2001 is the addition of sideslip angle rate control to Active Handling's core software algorithm. It senses whether the driver has been too slow (or too fast) to react to changing vehicle dynamics during evasive handling maneuvers, then dials in just the right amount of control to help maintain vehicle balance.
Coefficient Of Friction Estimation
Obviously, the rate at which a car tends to slip sideways is magnified on slippery road surfaces, so more sophisticated calibration algorithms have been developed to estimate the friction coefficient of the road surface and modify the Second-Generation Active Handling system's response accordingly.
Rear Brake Stability Control
Another software change results in better rear brake stability control. It assists the driver in maintaining control under light braking and high lateral acceleration conditions, such as might be encountered if a driver is caught off guard by a decreasing radius turn. This new feature more precisely releases brake pressure on the inside rear wheel during high lateral acceleration maneuvers and allows for more predictable vehicle response so the driver doesn't have to work as hard to keep the vehicle on its intended path.
As noted earlier, Active Handling works in conjunction with the traction control system, and for 2001 that part of the system has been much refined. A new control philosophy of targeting specific rear brake pressures and modulating engine torque around those points has resulted in fewer engine sags and superior vehicle acceleration when compared to the 2000 system. This new calibration allows drivers to enthusiastically experience Corvette's power and handling while still maintaining control over excessive wheelspin. Average drivers may now elect to leave the traction control system on when navigating autocross or gymkhana courses.
Corvette's Active Handling system has a unique feature called Competitive Mode, which allows the driver to disengage the car's traction control feature without giving up Active Handling's other benefits. Holding down the Active Handling button on the center console for 5 seconds enables Competitive Mode. This feature recognizes that, at the hands of a highly skilled driver, a bit of rear wheelspin may actually be desirable in autocross or other racing events. In previous years, it was necessary to bring the vehicle to a full stop to enable Competitive Mode. But for 2001, this requirement has been eliminated.
The Corvette's 2001 Second-Generation Active Handling system is smarter, less intrusive, and more adept at making the total driving experience precisely what Corvette owners have come to expect from their cars.
The Z06 features a suspension system all its own designated FE4. It's not available on other Corvette models but is standard equipment on the Z06. It features a larger front stabilizer bar, a stiffer rear leaf spring, revised camber settings and unique shock calibrations, all engineered with a bias toward maximum control during high-speed operation. The suspension component specifications are:
Z06 wheels are wider front and rear than those on the standard Corvette:
The new wheels are also one of the visual identifiers for the Z06, letting onlookers know that this car is something special. They are uniquely styled, and are the most mass-efficient aluminum wheels ever produced for Corvette. They are painted a light metallic gray, and show off the Z06's red brake calipers, especially when the car is in motion. Each wheel's center cap has a red Corvette crossed-flags emblem for added identification when the car is at rest.
Goodyear has specifically designed new wider, stickier tires for the Z06. Called Goodyear Eagle F1 SC (Supercar) tires, they allow the Z06 to handle, brake and perform better than any production Corvette, ever. Sizewise, the new tires differ from the Goodyear Eagle F1 GS EMT tires on coupes and convertibles as follows:
While larger, these tires are much lighter than the EMT tires, reducing mass by a total of 10.6 kilograms (23.4 pounds). The new Eagle F1 SC tires have an asymmetric tread pattern to enable the fantastic cornering capabilities of the Z06. With the asymmetric pattern, the outside shoulder of the tire performs well in the dry, while the inside tread performs well in the wet. Taking mass out of the tires is extremely beneficial for wheel control because it reduces unsprung weight. It also reduces rotational mass, which improves acceleration and braking performance. Wheel control on the Z06 is also improved due to the more compliant sidewalls on these new, non-EMT tires.
Because these tires do not have the "run flat" capabilities of the EMT tires, it was necessary to develop a process for dealing with tire punctures, since Corvettes do not come equipped with a spare tire. In the case of the Z06, a GM Tire Inflator Kit is included that is capable of sealing punctures up to 5mm in diameter. The kit consists of a squeeze bottle filled with a non-flammable latex compound in an aqueous base, a nozzle that attaches to the tire valve, and a mini air compressor with a 12-volt adapter that plugs into the car's accessory power outlet. The kit functions safely in temperatures ranging from minus 20° F to 1400° F, under wet or dry conditions, and is easy, fast and clean to use. Similar inflator kits are successfully used by Mercedes and BMW, and Corvettes sold in Japan have been using this inflator kit since the introduction of the C5 in 1997. The latex compound in the tire inflator kits is not compatible with the tire valves used in Corvette's standard tire pressure monitoring system, so regular tire valves are used and that option is not offered on the Z06. There is a mass reduction of just over a half-pound as a result.
The Z06 receives several other refinements in addition to its unique engine, suspension, wheels and tires that either help it to be more functional or serve to differentiate its appearance, sometimes both.
On the Z06 only, both the windshield and backlite have been thinned to save weight. But resistance to stone chipping has been maintained. A total of 5.7 pounds was eliminated. There is cabin quietness as a result. But in a car like the Z06, we don't think anyone will care. Reducing the Z06's overall weight, boosting its power output by 40 hp, and broadening its operating range, made a significant improvement in the car's power-to-weight ratio. All told, Z06 is the lightest Corvette 38 pounds lighter than the former hardtop, 99 pounds lighter than the 2001 coupe and 95 pounds lighter than the 2001 convertible at just 3115 pounds. And remember, it's all about power-to-weight ratio. The result puts it in some very good company, as indicated in the chart.
Having the best of both worlds reduced weight and increased power makes the Corvette Z06 a force to be reckoned with, on or off the track.
Functional air inlets in the center of the front fascia deliver cool air to the intake system. New air scoops on the rear rocker panels funnel air to the rear brakes for better cooling. Z06 rear brake temperatures are reduced by as much as 10 percent under competition conditions. Brake fade and wear are greatly reduced.
Z06 emblems are placed on the front fenders. Front and rear disc brake calipers on the Z06 are painted red. Inside, the Z06 includes a different instrument cluster with stylized graphics and a higher 6500 rpm redline.
The Z06's solid-black leather-trimmed seating surfaces include additional side bolstering to hold driver and passenger firmly in place during high lateral load maneuvers, and a Z06 logo is embroidered into the headrests. An optional interior with red accents on the seats, lower instrument panel and lower door panel is also available. In the glovebox, all Corvette owners will find a portfolio and a video that explains how (and how not) to use the car. The Z06 comes with its own unique portfolio, covering the features that are special to it. The Z06 video provides valuable tips on how to drive the car, including an interview with John Heinricy, famous Corvette engineer and race driver. The video also provides technical information regarding special GM High-Performance service parts that have been released for the car, such as special brake pads, additional chassis enhancements and a transmission oil cooler, plus other competition information. There is even information on driving schools where owners can go to learn to race, or hone their existing skills.
Every GM car and truck is subjected to certain durability test schedules, and Corvettes go through all of them. Then the fun begins. Corvette has a well-earned reputation for being a car that you can drive out of the showroom and onto a racetrack with little or no modification. To protect that reputation, Corvette engineers do things to the car that would tighten the sphincter muscle of the average driver. All Corvettes, not just the Z06, undergo 250 miles of full-bore autocross testing, 24 hours of road-course testing at competition speeds, and a grueling wide-open throttle test that has the car run at its 175-mph top speed until the gas tank runs dry about 30 minutes later. No question, the Z06 comes up as a very special version of a very special car. Somewhere, Zora Arkus-Duntov is smiling.
Copyright 2002 - Z06Vette.com - Photo Credits: General Motors Inc.