Difference between revisions of "Chevrolet Corvette GTP"

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The '''Chevrolet Corvette GTP''' was a GTP-class [[racing car]] which participated in the [[IMSA GT Championship]] from 1984 until 1989.  Used for [[General Motors]] factory effort in IMSA GT, the car was developed in conjunction with [[Lola Racing Cars|Lola Cars International]].  Although using the [[Chevrolet Corvette]] name, the car shared almost nothing mechanically with the Corvette and borrowed only some styling elements.


{| border=0 align=right
==Development==
|-
Prior to 1984, [[Chevrolet]] naturally-aspirated V8s and [[Buick]] [[turbocharging|turbocharged]] V6s were popular engines in the GTP class for privateer teams. However [[General Motors]] (GM) saw the opportunity to enter the [[IMSA GT Championship]] for themselves in the 1984 season in an attempt to bolster their image by fighting against [[Jaguar (car)|Jaguar]], [[Porsche]], [[Nissan]], and [[Mazda]].
|{{Infobox Automobile
|image=[[Image:Z06-Blk-7.jpg|250px|Corvette Z06]]
|name=[[Image:Corvette-Lettering.jpg|200px]]<br> C5 Z06
|aka=Z06
|manufacturer=[[Chevrolet]]
|parent_company=[[General Motors]]
|layout=[[FR layout]]
|platform=[[GM Y platform|Y-body]]
|body_style=2-door [[hardtop]] [[coupé]]
|engine=5.7&nbsp;L ''[[LS6]]'' [[V8]]
|predecessor=[[Chevrolet Corvette C4#ZR-1|C4 ZR-1]]
|successor=[[Chevrolet Corvette C6#Z06|C6 Z06]]
|production=2001&ndash;2004
|transmission=6-speed [[Manual transmission|manual]]
|designer=
|wheelbase={{Convert|104.5|in|mm|1|abbr=on}}
|length={{convert|179.7|in|mm|1|abbr=on}}
|width={{convert|73.6|in|mm|1|abbr=on}}
|height={{convert|47.7|in|mm|1|abbr=on}}
|weight={{convert|3115|lb|kg|0|abbr=on}}
|assembly=[[Bowling Green, Kentucky]]
}}
|-
| [[Image:Z06-Blk-5.jpg|250px|thumb|right|A 2004 Corvette Z06.]]
|-
|}
The '''Chevrolet Corvette C5 Z06''' is a high-performance version of the [[Chevrolet Corvette C5|C5 Corvette]] [[sports car]]<ref name="reference.com">Definition from Reference.com[http://www.reference.com/search?q=Z06]</ref>. Introduced by [[Chevrolet]] as their corporate and performance [[List of flagship vehicles by manufacturer|flagship]], production began in 2001 and ended with the 2004 model year.


==General==
General Motors turned to [[Lola Racing Cars|Lola Cars International]] of the United Kingdom, who had previous experience building cars for Mazda, to build their own chassis, termed the Corvette GTP in an attempt to improve the Corvette image.  Following testing on an older [[Lola T600]] with a Chevrolet V8, an all new car was built, termed the '''T710'''.  The first chassis were delivered to General Motors in 1984 and outfitted with a 3.4 litre turbocharged V6, similar to the Buick unit previously used.  A second chassis, known as '''T711''' used the alternative 5.7 litre naturally-aspirated V8, and arrived at GM before the close of 1984. This would allow GM to be able to keep on pace with at least one car, dependent on which engine better suited a track.
The successor to the [[Chevrolet Corvette C4#ZR-1|ZR-1]] made its debut in 2001 as the '''Z06''', giving a nod to the high performance Z06 version of the [[Chevrolet Corvette C2|C2 Corvette]] of the 1960s (See the [[C5 Z06#History of the Z06 & LS6|history]] below). Instead of a heavy, double-[[Overhead camshaft|overhead cam]] engine like the ZR-1, the Z06 used a high-output, tuned version of the standard LS1 Corvette engine (designated [[GM LS6 engine|LS6]]), which initially produced {{convert|385|hp|kW}}. Although its total power output was less than that of the last ZR-1, the Z06 was much lighter, and could out-perform the ZR-1 in every category except top speed. It also cost substantially less money than the ZR-1.


Like with the ZR-1, Chevrolet found that increasing the power output did the C5 platform little good without additional modifications to bring the rest of the car up to par. Starting with the most structurally rigid body style offered, the [[hardtop]] or "fixed roof coupé" (FRC), an uprated FE4 suspension, larger wheel rims and tires, revised gearing ratios, and functional brake cooling ducts became part of the total package. The Z06 is 38 pounds lighter than a standard C5 hardtop thanks to weight-saving measures such as a titanium exhaust, thinner glass, lighter wheel rims, non-EMT tires, reduced sound proofing, fixed rear radio aerial, and a lighter battery. Starting with the 2002 model year, the LS6 engine was uprated to {{convert|405|hp|kW}} by means of a larger volume air intake, stiffer valve springs, lighter sodium filled valves, more aggressive cam phasing and lift, revised pistons, and revised block. While Chevrolet officially claimed that the ultimate power output of the LS6 was {{convert|405|hp|kW}}, many [[dynamometer]] tests have shown that Chevrolet underrated the engine by {{convert|20|hp|abbr=on}}, giving it an actual total of {{convert|425|hp|kW}}.<ref name="GM High Tech Performance">Supercar Killer Chevy's '04 Z06 does 11s bone stock--and so much more[http://www.gmhightechperformance.com/features/0410htp_2004_z06_corvette_feature/]</ref>
The cars featured bodywork similar to a [[Chevrolet Corvette C4]] at the front, with a long pontoon-style tail featuring Corvette tail lights. Large side intakes would feed the radiators while the turbocharged chassis had a snorkel built into the top of the fender to feed the turbocharger.


==Performance==
===Later chassis===
Factory performance figures for the {{convert|405|hp|abbr=on}} version of the Z06 give an acceleration time from 0-60&nbsp;mph as 3.9 seconds. Owner-drivers have reportedly achieved quarter-mile times of 11.7<ref name="GM High Tech Performance">Supercar Killer Chevy's '04 Z06 does 11s bone stock--and so much more[http://www.gmhightechperformance.com/features/0410htp_2004_z06_corvette_feature/]</ref><ref name=Zimbio/> seconds. [[Car and Driver]] recorded 1/4 mile times of 12.4 seconds for the {{convert|405|hp|abbr=on}} Z06 and 12.7 seconds for the {{convert|385|hp|abbr=on}} Z06 In their December 2002 issue. Quarter mile drag times are made up of multiple factors. One such factor is "Driver Skill" and or "Driver Aggressiveness" (gear shift timing, reaction time, and optimum shift points); this accounts for various reported times, which can lead to controversy. The Z06 is capable of matching or besting the 0-60 acceleration times of some of the world's premier sports cars, including the [[BMW Z8]], [[Ferrari 360]], and [[Porsche 911#996 Turbo .282000.E2.80.932004.29|Porsche 911 Turbo (Type 996)]].
Following the first full season for the Corvette GTP in 1985, the cars were replaced with new chassis for 1986. Termed '''T86/10''' by Lola, the new cars featured evolved bodywork which included a smaller opening for the side radiator.  The rear pontoons were also able to be removed on the new chassis for courses that did not require longer tails. GM mostly abandoned the use of the naturally aspirated V8, opting instead for the turbocharged V6, now at a smaller 3.0 litre displacement.


{| class="wikitable"
A third chassis was also built in 1987 which introduced modifications made by GM subsidiary [[Lotus Cars|Lotus]]. Termed '''T86/12''' by Lola, this car featured an active suspension system that would allow the car to alter its suspension stiffness during the race. The car was used in competition only once where its suspension system failed.  It was then retained by GM mostly as a developmental prototype.
|-
! Event
! Performance
|-
| [[0 to 60 mph|0-60]] mph
| 3.9 sec<ref name=supercarsite>Super Car Site Ranks[http://www.supercarsite.net/supercar_ranks/0to62]</ref>     
|-
| 0-100 mph
| 9.2 sec<ref name=Car&Driver>Car & Driver 2002 Z06 Performance Review 0-100-0[http://www.corvetteactioncenter.com/specs/z06/z06perform.html]</ref>
|-
| 0-100-0 mph
| 13.56 sec<ref name=Car&Driver/>
|-
| 1/4 Mile
| 11.9 sec <ref name=Zimbio>Zimbio C5 Z06[http://www.zimbio.com/Chevrolet+Corvette/articles/13/C5+Z06]</ref>
|-
| Skid Pad
| 1.03 G<ref name=Car&Driver/>
|-
| Top Speed
| {{convert|186|mi/h|km/h|abbr=on}}
|-
| Nürburgring Nordschleife Lap Time [[C5 Z06#Nürburgring Circuit|*]]
| 7:56<ref name=crossedflags.com/>
|}
''(Source: <ref>[http://www.gizmag.com/go/5805/ The world’s fastest cars from 0-100-0 mph (in order)]</ref>)''


==Z06 refinements==
Two more chassis were added to the Corvette GTP fleet over the next few years, with one built at the end of 1987 for use in 1988, while the other would be completed midway through 1988.  Both would regain a naturally aspirated V8, now running at 6.0 litres, but feature only minor mechanical and visual differences from the T86/10s.
The Z06 received several other refinements in addition to its unique engine, suspension, wheels, and tires that either enhance functionality, differentiate its appearance from the base-model C5, or do both:


* Screened air inlets in the center of the front [[Fascia (car)|fascia]] that deliver additional cool air to the intake system.
===Eagle 700===
* Air scoop inlets on the sides of the front [[Fascia (car)|fascia]] that funnel air to the front brakes for better cooling. These inlets replaced the fog lamp housings and/or associated trim panels of the base-model C5.
Following the abandonment of the project at the end of 1988 by General Motors and the end of privateer competition by Peerless Racing in 1989, the decision was made to take Peerless' car into international racing, entering the [[1990 24 Hours of Le Mans]].  The car was used as a platform for Eagle Performance to attempt to use a 10.2 litre V8 engine to take on large manufacturers at Le Mans. The car was extensively modified to the point that Eagle chose to rename is the '''Eagle 700''', losing all Corvette branding in the process.  Beyond the modifications necessary to house the large V8 engine internally, the tail of the car was also modified with a new rear wing and shorter tail to better cope with the speeds at Le Mans.
* Air scoops on the rear rocker panels that funnel air to the rear brakes for better cooling. Z06 rear brake temperatures are reduced by as much as 10% under competition conditions; brake fade and wear are also greatly reduced.
* Flat underside body panels that provide superior [[Automotive aerodynamics|aerodynamics]] and help in achieving a 0.29 [[Automobile drag coefficients|drag coefficient]]. ''(<ref>[http://www.motortrend.com/cars/2004/chevrolet/corvette/z06_coupe/1799/specifications/] 2004 Corvette Z06 Coupe Specifications </ref>)''
* Z06 badges on the front fenders (see the [[C5 Z06#Resurgence|Z06 Emblem]] below).
* Different front and rear brakes pads than a normal C5 with distinctive red painted [[Disc brake#Calipers|calipers]] (compared to black or bare calipers on the base-model C5).<ref name=SDBC>{{cite book |last =Staff|first =GM |authorlink = |title = "2001 Specialist's Data Book Corvette" |publisher = Gail & Rice Productions, Inc. |location=Michigan |year = 2000 |pages =48 |id = }}</ref>


==LS6 engine==
==Racing history==
[[Image:LS6-Engine.jpg|thumb|right|250px|Cutaway diagram of Z06 Corvette LS6 Engine]]
Debuting in 1984 at the Grand Prix of Miami, the first Corvette GTP was run under the Racing Systems team name in a mostly all white paint scheme. The car managed to finish 13th overall after starting 29th. However the car would only appear two more times in 1984, failing to finish at [[Riverside International Raceway|Riverside]] and taking another 13th place finish at [[Infineon Raceway|Sears Point]].
The Z06 uses a high-output version of the [[GM LS1 engine|LS1]] small-block
engine. The named was changed to [[GM LS6 engine|LS6]] after substantial modifications. The new engine powerplant expels about 12% more power than the LS1 and physically looks identical in external appearance save for the red engine covers. The LS6 produces {{convert|405|hp|kW}} at 6000&nbsp;rpm, and {{Auto lbft|400}} at 4800&nbsp;rpm. The engine [[redline]]s at 6500&nbsp;rpm (versus the LS1's 6000&nbsp;rpm redline).
The LS6 utilizes a block made of [[aluminum]]. It has been modified to allow greater bay-to-bay breathing. Typically the LS1 engine allows too much air in its crankcase developing into parasitic loss of power. The LS6 relieves this unwanted pressure translating into a removal of parasitic loss thus gaining more power.
*'''New Pistons'''


The LS6 utilizes modified versions of the LS1 pistons. The new pistons are made from M142 aluminum alloy which has proved to be stronger and more durable then the material used in the LS1. The pistons have been reshaped to have a slight barrel shape difficult to see for the normal onlooker. The new design also reduces internal mechanical noise because of its increased efficiency.
For 1985, the second Corvette GTP chassis was initially given to Lee Racing for its debut at the [[24 Hours of Daytona]] but would suffer gearbox problems and not finish. This was followed by a seventh place finish at Miami, then another failure to finish at the [[12 Hours of Sebring]]. This would be followed by a string of failures at Charlotte, [[Mid-Ohio Sports Car Course|Mid-Ohio]], and [[Watkins Glen International|Watkins Glen]]. However by [[Road America]], NASCAR team [[Hendrick Motorsports]] would take over the former Racing Systems car, becoming the factory-backed team with [[GM Goodwrench]] sponsorship and leading driver [[David Hobbs]]. Unfortunately the team did not manage to finish any races by the end of the season, although Lee Racing did rebound to score an eighth place finish at the second race at Watkins Glen and then tenth at the [[Daytona International Speedway|Daytona]] season finale.
*'''Increased Compression'''
The LS6 cylinder heads have been cast with pent-roof [[combustion chamber]]s. This modification of the LS1 has decreased the cylinder size thus promoting a greater [[Compression ratio]]; from 10.1:1 to 10.5:1. The LS6 ports have been cast using tighter tolerances which has resulted in increase power, [[thermal efficiency]], and an increase in [[volumetric efficiency]].
*'''High-Profile Camshaft'''
The LS6 utilizes a [[camshaft]] constructed from [[steel]][[Billet (manufacturing)|billet]] materials. The timing of the camshaft has been altered by increasing the lift from those of the LS1 to provide quicker opening times. To accommodate higher lift and longer duration of the camshaft the valve springs have been manufactured to become stiffer. The springs are wound tighter then those in the LS1 which results in stronger springs able to handle the increase strain from the camshaft. These modifications result in more efficient air-flow into the combustion chambers and thus an increase in power.
*'''Fuel Injectors'''
The LS6 utilizes new and larger fuel injectors. The new injectors deliver 3.6 grams of fuel per second an increase of 10% above the LS1. The injectors were designed to deliver more fuel as a result of the increase in air flow from the increased compression and camshaft opening duration modifications. The fuel to air mixture ratio needs to remain proportional to achieve operational status.
*'''Internal PCV System'''
The LS6 utilizes a newly designed Positive [[PCV valve|Crankcase Ventilation valve]]. The new PCV valve now
rests in the "V" of the engine. The "V" aluminum cover contains composite oil separating baffles with unique
tubing. This results in less overall oil tubing thus reducing the potentiality of oil leak sources. The presence
of the oil baffles also reduces oil consumption and increases the performance capabilities of the ventilation system during high performance maneuvers (greater then 1 lateral [[g-force|G]]) which the Z06 is capable of.
*'''Exhaust Manifolds'''
The LS6 utilizes newly designed exhaust manifolds. These manifolds are constructed of cast-iron material and
have been designed to reduce weight by utilizing thin walls.


==Active Handling==
Into 1986, Hendrick Motorsports and Lee Racing would continue their campaign with mixed results.  Although both teams failed to finish the first three races of the season, Hendrick would manage to take the first victory for the Corvette GTP at [[Road Atlanta]] for [[Doc Bundy]] and Sarel van der Merwe. However by that time Lee Racing abandoned their effort.  Hendrick would continue on and manage a fourth place finish at Charlotte, seventh at [[Lime Rock Park|Lime Rock]], and third at [[Mid-Ohio Sports Car Course|Mid-Ohio]].  The Corvette GTP would follow this with its second victory on the streets of [[Palm Beach]], defeating a [[Porsche 962]] by four tenths of a second. Unfortunately the car would fail to finish at [[Watkins Glen International|Watkins Glen]], but return for an eighth place finish at [[Portland International Raceway|Portland]]. By [[Infineon Raceway|Sears Point]], Hendrick would purchase Lee racing's former chassis to start a two-car campaign. Unfortunately Hendrick would not be able to see the same success by the end of the season, leaving [[Chevrolet]] to take third in the constructors championship to [[Porsche]] and [[Jaguar (car)|Jaguar]]
[[General Motors]] developed a system they called "Active Handling" in 1998. This system is a stability control feature that utilizes on-board sensors that measure a vehicles lateral acceleration, [[Yaw angle|yaw rate]], and steering wheel position. These sensors work in conjunction with the vehicle's [[Anti-lock braking system]] and [[Traction control|Traction Control System]] which automatically assist a vehicle's driver in [[understeer]]ing and [[oversteer]]ing situations. The Z06 came standard with the second generation "Active Handling" system. The second generation system added the following substantial improvements to the original system:
*'''New Pressure Modulator'''
The second-generation Active Handling system utilizes the [[Bosch]] version 5.3 hydraulic pressure modulator. Bosch improved this version to become smaller, quieter and more efficient at lower temperatures. The new modulator can operate at -4°F (-20 °C) resulting in accelerated functioning capacity after cold startups. The pressure sensor originally located in the master cylinder was also integrated into the new pressure modulator.
*'''Dynamic Rear Proportioning'''
The second-generation Active Handling system utilizes a newly designed dynamic rear brake proportioning system.
The new enhancement is a [[software]] driven improvement which balances the rear brake pressure electronically
thus preventing rear brake bias also known as "Brake Lockup". The new system replaces the physically standard
brake proportioning valve and its tubing components thus reducing weight and overall complexity.
*'''Sideslip Angle Rate Control'''
The second-generation Active Handling system received a major addition in the form of a sideslip angle rate control. This addition is [[software]] based and senses a driver's response time to changing vehicle movements
during handling maneuvers. The system compensates for driver errors by utilizing the vehicles braking and traction
control systems to maintain the stability of the vehicle based upon the parameters programmed by General Motors.


*'''Coefficient of Friction Estimation'''
Hendrick started 1987 the same way they had 1986, failing to finish the first three races of the season, even suffering from a fire during the Miami event.  Unfortunately Hendrick continued to have problems until they were finally able to finish a race at [[Mazda Raceway Laguna Seca|Laguna Seca]], the sixth round of the season, and managing a second place result, then a third and eleventh for the two car team at Mid-Ohio.  Following a short stint of problems, the duo would finish fourth and seventh at Portland, followed quickly by a lone third at Sears Point. One final third came in the streets of San Antonio before Hendrick would close out the season with a series of problems. However, problems at Jaguar helped Chevrolet secure second in the manufacturers championship, once again losing to Porsche.
The second-generation Active Handling system received another software upgrade in the form of improved
calibration algorithms that estimate the [[Coefficient of friction|friction coefficient]] of road surfaces.
As traction on roads decreases (such as slippery road surfaces), a vehicle is biased towards slipping sideways.
The new coefficient estimation takes this traction problem into account and factors it in with the rest of the
Active Handling system inputs.
*'''Rear Brake Stability Control'''
The second-generation Active Handling system also added another software enhancement in the form of
a rear brake stability control. This addition releases brake pressure on the inside rear wheel during high
lateral acceleration maneuvers. This system assists drivers who do not estimate radius turns correctly during
high speed and light braking. The system compensates for driver errors by utilizing the vehicle's braking system
thus allowing for a more predictable maneuver while keeping the vehicle on its initial vector.
*'''Better Coordination'''
As has already been stated the Active Handling system works in conjunction with the Traction Control System. The second generation system continues this relationship but has been modified and refined to target specific rear brake pressures and control engine torque based upon the parameters programmed by General Motors. This modification results in improved acceleration and fewer engine sags.
*'''Competitive Mode'''


The second-generation Active Handling system incorporated into the Z06 has a unique featured labeled "Competitive Mode". When activated this feature turns the vehicle's Traction Control system off while still employing all the other components of the "Active Handling" system. To enable this feature a driver merely presses down on the Active Handling button for five seconds. This can be done even while the vehicle is in motion.
By 1988, the Corvette GTPs were becoming slightly more consistent as the team managed to overcome their mechanical woes, helped by a switch to the naturally aspirated V8s.  The season again began slow, with an eighth place finish at [[Road Atlanta]] be the first finish by a Corvette GTP that season. A seventh at Lime Rock and Mid-Ohio would be followed by a third at Watkins Glen, tenth at Road America, and finally ninth at Sears Point before the Hendrick team would be joined by the new Peerless Racing squad, using the newest Corvette GTP chassis. Peerless would take a fourth place at Columbus, followed closely behind by Hendrick in fifth.  Hendrick would close the season with a fifth at Del Mar. Chevrolet would however manage to finish fourth in championship.


===Sensors===
After the 1988 season, General Motors chose to cancel their funding for the Corvette GTP project, and Hendrick Motorsport did not return to IMSA GT.  Peerless Racing would attempt to continue into 1989, but a series of accidents led to them failing to finish any of the races they entered, forcing them to quit midway through the season.  Peerless' car would later be used by Eagle Performance as an experiment with their large 10.2 litre V8 engine, entering it in the [[24 Hours of Le Mans]]. The car would however suffer electrical problems during the qualifying sessions and would not be able to make the race, marking the end of the Corvette GTP.
*'''Steering Angle Sensor''': This digital sensor actively monitors the driver's steering inputs and communicates the applied steering wheel angle back to the system. It is accurate to within one degree of steering wheel angle change, and is located inside the steering wheel column.


*'''Yaw-Rate Sensor''': This solid-state device utilizes a tiny pair of ceramic [[tuning fork]]s to measure the actual rate at which the vehicle is pivoting (or yawing) about its [[Center of mass|center-of-gravity]]. This data is continuously fed into the Corvette's computer where the yaw rate is compared to the steering angle. Any variation beyond a pre-programmed set of values will result in activation of the appropriate assist feature(s) of the Active Handling System. The yaw-rate sensor on the Corvette is located inside the center console.
==Chassis==
In total, seven cars would be built under the Corvette GTP name, although nearly all had different designations by Lola.


*'''Lateral Acceleration Sensor''': The lateral [[accelerometer]] measures the [[centrifugal force]] created during a turn, and is located beneath the passenger seat. The data it provides is weighed against all of the other inputs and is used to calculate whether or not the performance limits of the vehicle are being exceeded under the current speed and traction conditions.
'''T710-HU01'''
* Racing Systems (1984)
* Hendrick Motorsport (1985-1986)
:Winner at Road Atlanta (1986)
'''T711-HU02'''
* Lee Racing (1985-1986)
* Hendrick Motorsport (1986)
'''T86/10-HU01'''
* Hendrick Motorsport (1986-1987)
:Winner at Palm Beach (1986)
'''T86/10-HU02'''
* Hendrick Motorsport (1986-1988)
'''T86/12-HU03'''
* Hendrick Motorsport (1987)
:Equipped with [[Lotus Cars|Lotus]] active suspension
'''T87/10-HU01'''
* Hendrick Motorsport (1988)
'''T88/11-HU01'''
* Peerless Racing (1988-1989)
* Eagle Performance (1990)


The Second-Generation Active Handling System provides better performance with less perceived intrusion, and is more adept than the original system in controlling the vehicle whenever necessary. The improved agility of the vehicle allows average drivers to perform better during spirited driving, and provides a greater safety margin in emergency situations.
==External links==
* [http://www.lolaheritage.co.uk/history/register/Corvette/Leicester/T8811_01.htm Lola Heritage] - Corvette GTP T88/11-HU01 history
* [http://wsrp.ic.cz/chassis/chassis_lola_c.html World Sports racing Prototypes] - Lola Group C/GTP chassis history


===Summary of Active Handling System Modes===
{{Lola Sports Cars}}


* '''ON''' — Active Handling is automatically enabled when the vehicle is started. This is also true of the ABS and Traction Control systems.
[[Category:Chevrolet Corvette|GTP]]
* '''OFF''' — Like Traction Control, the Active Handling System may be manually disabled if the driver so desires. This is not true of the ABS, which is always enabled.
[[Category:Lola Racing Cars|Chevrolet Corvette GTP]]
* '''COMPETITIVE DRIVING''' — In this mode, Active Handling and ABS are both enabled, but Traction Control is disabled.
[[Category:IMSA GTP cars]]
 
The "OFF" and "COMPETITIVE DRIVING" modes are important features on a high-performance sports car, as skilled drivers may find that some wheelspin and oversteer can be beneficial to their lap times in competitive events. The Corvette's system allows them to operate the car in this fashion when appropriate, although Chevrolet recommends against selecting these modes for street use.
<ref name=SDBC/>
 
==Transmission==
 
The Z06 utilizes the specially-built M12 6-speed manual transmission. While outwardly similar to the base-model MM6 manual transmission, the M12 transmission is unique to the Z06, and is the only transmission available for that model; it is not available on Corvette coupés or convertibles. The M12 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" message if transmission temperatures approach their operating limits, and which could lead to damage if the transmission were not allowed to cool down. As with all C5 Corvettes, the transmission is located toward the rear of the vehicle, as a rear-mounted [[transaxle]] assembly. This allows a better overall weight distribution for the vehicle, as the weight of the transmission offsets some of the weight of the forward-sitting engine.
 
The M12 6-speed causes the Z06 model of C5 Corvette to have a lower top speed than a normal C5 despite having a higher RPM limit and more power, this is due to its gearing.
 
'''Gear ratio comparisons of MM6 (base-model C5) vs. M12 (Z06):'''
{| class="wikitable"
|-
! Gear
! LS1/MM6
! LS6/M12
|-
| 1st Gear
| 2.66:1
| 2.97:1
|-
| 2nd Gear
| 1.78:1
| 2.07:1
|-
| 3rd Gear
| 1.30:1
| 1.43:1
|-
| 4th Gear
| 1.00:1
| 1.00:1
|-
| 5th Gear
| 0.74:1
| 0.84:1
|-
| 6th Gear
| 0.50:1
| 0.56:1
|-
| Reverse
| 2.90:1
| 3.28:1
|-
| Axle Ratio
| varies
| 3.42:1
|-
| Final Drive Ratio
| varies
| 1.91:1
|}
<ref name=SDBC/>
 
==Suspension==
A special suspension (the FE4) was developed exclusively for the Z06, and is not available on other Corvette models. It features unique shock calibrations, a larger front stabilizer bar, a stiffer rear leaf spring, and revised [[Camber angle|camber]] settings — all calibrated with a bias toward maximum control during high-speed operation.
<ref name=SDBC/>
 
===Specifications===
* Front stabilizer bar diameter (hollow): 30 mm with 4.5 mm thick walls
* Rear transverse composite spring leaf: 125 N/mm (versus 113 N/mm in the base-model's optional FE3 Sport Suspension)
* Camber, front and rear: -0.75° (compared to -0.25° on the base-model C5)
 
The greater negative wheel camber used on the Z06 helps to keep the tire flatter in relation to the road, and increases the tire [[contact patch]] for greater grip while cornering. When coupled with other special Z06 components, the combination provides exceptional racetrack performance.
<ref name=SDBC/>
 
===Nürburgring Circuit===
These suspension refinements came as a result of extensive testing and development, including several high-speed test sessions at Germany's famed [[Nürburgring]] circuit. The 2004 Corvette C5 Z06 is one of only a precious few cars to have broken the 8-minute barrier for lap times at the Nürburgring circuit <ref name=crossedflags.com>{{Cite web|url=http://www.crossedflags.com/modules.php?name=News&file=article&sid=70|title=Ask Dave Hill, December Edition|accessdate=2008-01-04|work=crossedflags.com}}</ref> (see [[Nordschleife fastest lap times]] for complete list). However, the Corvette testing at Nürburgring wasn't just about raw speed: engineers learned important lessons about tuning the chassis to enhance the poise, confidence, and "smoothness of response;" attributes that become increasingly important when subjected to the severe demands of a {{convert|14|mi|km|sing=on}} course that has approximately 170 turns, and virtually constant elevation changes. "Nürburgring, at the extreme edge of the envelope, provides conditions that can't be easily duplicated anywhere else," said David Hill, vehicle line executive and Corvette chief engineer. "But, even for the Z06, we spend considerable time ensuring we don't make adjustments that compromise the normal daily driving character of the car." ''(Source: <ref>[http://www.corvettemuseum.com/specs/2004/index.shtml 2004 Chevrolet Corvette: Commemorative Edition Celebrates Racing Success, and Improves the C5 Breed]</ref>)''
 
==Wheels==
 
Also unique to the C5 Z06 are wider wheel rims and tires, which increase contact with the road and are essential to providing better grip. The design aesthetics of the new wheel rims are also one of the visual identifiers for the Z06, and are the most mass-efficient aluminum wheels ever produced for Corvette. They are painted a light gray metallic, and serve to show off the red brake calipers used on the Z06, especially when the car is in motion. The center cap of each rim also displays the red Corvette "crossed-flags" emblem for added identification at rest.
 
'''Wheel Size Comparison'''
{| class="wikitable"
|-
!
! Base-model C5
! Z06
|-
| Front Wheels
| 17 in x 8.5 in
| 17 in x 9.5 in
|-
| Rear Wheels
| 18 in x 9.5 in
| 18 in x 10.5 in
|}
<ref name=SDBC/>
 
==Tires==
[[Goodyear]] specifically designed new wider, "grippier" tires for the Z06. Called Goodyear Eagle F1 SC (Supercar) tires, they allowed the Z06 to handle, brake, and perform better than any production Corvette yet tested. These same tires can be found other super-high-performance vehicles such as the [[Ford GT]], and differ from the Goodyear Eagle F1 GS EMT tires provided as factory equipment on C5 coupés and convertibles as follows:
 
'''Tire Size Comparison'''
{| class="wikitable"
|-
!
! 2001 C5<br>Eagle F1 GS
! 2001 Z06<br>Eagle F1 SC
|-
| Front
| P245/45ZR-17
| P265/40ZR-17
|-
| Rear
| P275/40ZR-18
| P295/35ZR-18
|}
<ref name=SDBC/>
 
==Titanium exhaust==
The 26-pound titanium muffler and tailpipe assembly of the Z06 replaced the 44-pound [[stainless steel]] system used in the base-model C5. This provided a 41% weight savings which directly translated into improved performance: faster acceleration, better handling, higher cornering speeds, shorter braking distances, and increased fuel economy. In addition, titanium's natural resistance to corrosion and durability give the exhaust system of the Z06 a virtually unlimited life span.
 
The Arvin design addressed the differences between titanium and stainless steel, including characteristics such as springback, vibration and resonance frequency. New muffler components were custom-developed for titanium fabrication, and a unique acoustic tone to meet GM sound requirements. To meet both performance and production rate demands, TIMET and Arvin collaborated to develop a new "exhaust grade" of commercially pure titanium. Special surface conditioning allows efficient fabrication to help meet the cost criteria set by GM for the use of titanium on a performance car. The titanium system is as strong as the equivalent steel system, but weighs substantially less.{{Facts|date=September 2008}}
 
Titanium has a natural oxide layer that provides immunity to external corrosion from road salts, as well as to internal corrosion from sulfur-rich engine exhaust. The system will experience no pitting or rusting, even at the welds. Corrosion immunity also means that the exhaust is designed with no trade-off to the weight savings; in a production vehicle, the system will far outlast anything made of stainless steel, resulting in fewer warranty claims and increased customer satisfaction. When titanium emerged as the solution to the GM performance challenges, the manufacturing technology to produce titanium mufflers in mass-market quantities didn't exist. Working with TIMET to optimize an exhaust grade of titanium, Arvin successfully adapted its stainless steel stamping, bending, cold forming and welding methods to accommodate the structural differences between stainless steel and titanium. New testing and computer models were also developed to ensure GM durability requirements were met. Titanium is environmentally sound. It is completely inert, non-toxic, 100% recyclable, and its production leaves no harmful by-products. Titanium does not degrade or release anything into the air, water, or ground.
 
To create the distinctive Z06 exhaust outlet scoop, Arvin developed new technology to cut the metal on an angle and curl it on a tight radius. Further showcasing the unique look, titanium's oxide film takes on shimmering tones of blues, purples, and golds as exhaust raises the temperature of the pipes. These colors evidence and enhance titanium's natural corrosion resistance. Finally, to produce the singular Corvette exhaust resonance, Arvin designed a new internal muffler configuration and used advanced acoustic techniques to tune the muffler.
 
Although common in 2008, titanium exhausts where virtually non existent in 2001.  At the time GM introduced the concept of the usage of titanium in exhaust systems only the [[mclaren F1]] supercar had such an exhaust.
 
==24 Hours of Le Mans Commemorative Edition==
 
For the 2004 model year, a '''24 Hours of Le Mans Commemorative Edition''' of the Z06 (dubbed the Z16 after its [[Regular Production Option|RPO]] code) was offered in celebration of the C5-R "1-2" in-class finishes at Le Mans. The option package consisted of a special paint color ("Le Mans Blue Metallic"); wide, silver-and-red stripes optionally applied down the center of the car; a [[carbon fiber]] hood (saving an additional 10 pounds of weight); special commemorative badging and headrest embroidery; and brightly-polished wheel rims (a first on the Z06) with unique centercaps. Though not as outwardly apparent, the Z16 also received shock damping tuning for improved handling. The Z16 was the most produced Z06 in 2004 totaling 2025 units; of that number, 325 went overseas, leaving North America with approximately 1700.
 
==History of the Z06 & LS6==
===Z06===
[[Image:Zora-Arkus-Duntov.jpg|150px|thumb|right|Zora Arkus-Duntov, legendary Corvette Guru.]]
 
In 1962, [[Zora Arkus-Duntov|Zora Duntov]] Chief [[engineer]] at [[General Motors|General Motors (GM)]] first brought forth the concept of the Z06 following a ban on factory-sponsored racing by the [[Sports Car Club of America|SCCA]]. Duntov knew customers would continue to race Corvettes even though the ban, which initially had full support from GM management, was in effect. During the planning of the Sting Ray project, Duntov suggested that it would be a good idea to continue with parts development in order to benefit racers, and as a way of surreptitiously circumventing the racing ban. Eventually, when GM management relented from their support of the ban, Duntov and his colleagues created "[[Regular Production Option|RPO]] Z06" as a special performance equipment package for the Corvette. The '''Regular Production Option (RPO)''' was a GM internal ordering code designation. The package was specifically designed for competition-minded buyers, so they could order a race-ready Corvette straight from the factory with just one check of an option box (whereas previously, the optional racing parts were literally hidden in the order form so that only the most knowledgeable and perceptive customers could find them). The RPO Z06 package was first offered on 1963 Corvette, and included:
<ref name=SDBC/>
* Front antiroll bar with a 20% larger diameter
* Vacuum brake booster
* Dual master cylinder
* Sintered-metallic brake linings
* Power-assisted Al-Fin drums cooled by front air scoops and vented backing plates
* Larger diameter shocks and springs — nearly twice as stiff as those on the standard Corvette
 
These Corvettes came to be known as "Big Tanks" because the package initially included a 36.5-gallon gas tank (versus the standard 20-gallon) for races such as [[12 Hours of Sebring|Sebring]] and [[24 Hours of Daytona|Daytona]]. Initially, the package was available only on coupés, as the oversized tank would not fit in the convertible, although the rest of the Z06 option package was later made available on convertibles as well.
 
Thus, the 1963 Chevrolet Corvette was technically the first Corvette that could be designated as "Z06." The only engine option on the Z06 was the L84 {{Auto CID|327}} engine using Rochester [[fuel injection]]. With factory exhaust manifolds, required to run the cars in the SCCA production classes, Chevrolet rated the engine at {{convert|360|hp|kW }}. The Z06 option cost an additional $1,818.45 over the base coupé price of $4,252. Chevrolet later lowered the package price and eliminated the larger gas tank from the Z06 package, though it remained available as an add-on option for any coupé. All told, Chevrolet produced 199 of these "original" Z06s.{{Fact|date=September 2008}}
 
===LS6===
In 1971, Zora Duntov's team created a special {{convert|425|bhp|kW}} [[Chevrolet Big-Block engine|big-block]] V8 for the Corvette, again with racing in mind. GM offered this as the "LS6" engine RPO for just one year: a {{Auto CID|454}}, cast-iron engine with aluminum heads. In terms of both power and legend, these original LS6 engine were second only to the L88 full-blown racing engine offered from 1967 through 1969. The LS6 produced {{convert|425|bhp|kW}} and was the most powerful engine offered in 1971. Only 188 cars were produced with this powerplant — less than 1% of Corvette's production run of 21,801 vehicles for the model year. The LS6 option price was $1,221.00, or 22% of the $5,496.00 sticker price for the [[Chevrolet Corvette C3|1971 Corvette C3 coupé]]. When tested by a leading automotive magazine, an LS6-equipped C3 with a four-speed manual and a 3.36:1 limited-slip differential produced the following numbers:
 
* 0 to {{convert|60|mi/h|km/h|abbr=on}}: 5.3 seconds
* Quarter-mile: 13.8 seconds @ {{convert|105|mi/h|km/h|abbr=on}}
* Fuel economy: 9-14 mpg
 
Also during that model year, a ZR2 RPO package was offered, priced at $1,747.00. The ZR2 package included the LS6 engine; a heavy-duty, close-ratio four-speed manual transmission; heavy-duty power brakes; transistorized ignition; lightweight aluminum radiator; special springs, shocks, and front and rear stabilizer bars. Twelve ZR2-equipped C3 Corvettes were produced, making them far more rare than the Z06-equipped C2 Corvettes.
 
===Resurgence===
[[Image:Z06-405hp.jpg|300px|thumb|right|Z06 fender emblem appearing on 2002-2004 C5 Z06 Corvettes]]
The Z06 and LS6 name designations were resurrected in the fall of 2000 as a new performance package for the 2001 model year of the C5. Using the previously-introduced FRC body style, the Z06 option offered improved suspension components and, initially, a {{convert|385|hp|abbr=on}} engine designated as "LS6." The modern LS6 is an improved, high-output version of the base-model C5's {{convert|350|hp|kW}} LS1 engine, but recalled the mighty 425&nbsp;hp, 454 cubic inch big block of 1971. For the 2002 model year, the LS6 was further refined and rated at {{convert|405|hp|kW}}; this power increase was achieved through deletion of two of the catalytic converters in the exhaust system, improvements to the air induction system, and a more aggressive camshaft along with a lighter valvetrain. Correspondingly, Z06 Corvettes produced from 2002 until 2004 displayed unique "405&nbsp;HP" badges on both front fenders as a testament of the vehicle's engine power.
 
==See also==
{{commonscat|Chevrolet Corvette C5}}
* [[Chevrolet Corvette]]
 
==Notes and references==
<references/>
 
{{Corvette timeline}}
 
[[Category:Chevrolet Corvette|C5 Z06]]

Latest revision as of 16:01, 3 February 2009

The Chevrolet Corvette GTP was a GTP-class racing car which participated in the IMSA GT Championship from 1984 until 1989. Used for General Motors factory effort in IMSA GT, the car was developed in conjunction with Lola Cars International. Although using the Chevrolet Corvette name, the car shared almost nothing mechanically with the Corvette and borrowed only some styling elements.

Development

Prior to 1984, Chevrolet naturally-aspirated V8s and Buick turbocharged V6s were popular engines in the GTP class for privateer teams. However General Motors (GM) saw the opportunity to enter the IMSA GT Championship for themselves in the 1984 season in an attempt to bolster their image by fighting against Jaguar, Porsche, Nissan, and Mazda.

General Motors turned to Lola Cars International of the United Kingdom, who had previous experience building cars for Mazda, to build their own chassis, termed the Corvette GTP in an attempt to improve the Corvette image. Following testing on an older Lola T600 with a Chevrolet V8, an all new car was built, termed the T710. The first chassis were delivered to General Motors in 1984 and outfitted with a 3.4 litre turbocharged V6, similar to the Buick unit previously used. A second chassis, known as T711 used the alternative 5.7 litre naturally-aspirated V8, and arrived at GM before the close of 1984. This would allow GM to be able to keep on pace with at least one car, dependent on which engine better suited a track.

The cars featured bodywork similar to a Chevrolet Corvette C4 at the front, with a long pontoon-style tail featuring Corvette tail lights. Large side intakes would feed the radiators while the turbocharged chassis had a snorkel built into the top of the fender to feed the turbocharger.

Later chassis

Following the first full season for the Corvette GTP in 1985, the cars were replaced with new chassis for 1986. Termed T86/10 by Lola, the new cars featured evolved bodywork which included a smaller opening for the side radiator. The rear pontoons were also able to be removed on the new chassis for courses that did not require longer tails. GM mostly abandoned the use of the naturally aspirated V8, opting instead for the turbocharged V6, now at a smaller 3.0 litre displacement.

A third chassis was also built in 1987 which introduced modifications made by GM subsidiary Lotus. Termed T86/12 by Lola, this car featured an active suspension system that would allow the car to alter its suspension stiffness during the race. The car was used in competition only once where its suspension system failed. It was then retained by GM mostly as a developmental prototype.

Two more chassis were added to the Corvette GTP fleet over the next few years, with one built at the end of 1987 for use in 1988, while the other would be completed midway through 1988. Both would regain a naturally aspirated V8, now running at 6.0 litres, but feature only minor mechanical and visual differences from the T86/10s.

Eagle 700

Following the abandonment of the project at the end of 1988 by General Motors and the end of privateer competition by Peerless Racing in 1989, the decision was made to take Peerless' car into international racing, entering the 1990 24 Hours of Le Mans. The car was used as a platform for Eagle Performance to attempt to use a 10.2 litre V8 engine to take on large manufacturers at Le Mans. The car was extensively modified to the point that Eagle chose to rename is the Eagle 700, losing all Corvette branding in the process. Beyond the modifications necessary to house the large V8 engine internally, the tail of the car was also modified with a new rear wing and shorter tail to better cope with the speeds at Le Mans.

Racing history

Debuting in 1984 at the Grand Prix of Miami, the first Corvette GTP was run under the Racing Systems team name in a mostly all white paint scheme. The car managed to finish 13th overall after starting 29th. However the car would only appear two more times in 1984, failing to finish at Riverside and taking another 13th place finish at Sears Point.

For 1985, the second Corvette GTP chassis was initially given to Lee Racing for its debut at the 24 Hours of Daytona but would suffer gearbox problems and not finish. This was followed by a seventh place finish at Miami, then another failure to finish at the 12 Hours of Sebring. This would be followed by a string of failures at Charlotte, Mid-Ohio, and Watkins Glen. However by Road America, NASCAR team Hendrick Motorsports would take over the former Racing Systems car, becoming the factory-backed team with GM Goodwrench sponsorship and leading driver David Hobbs. Unfortunately the team did not manage to finish any races by the end of the season, although Lee Racing did rebound to score an eighth place finish at the second race at Watkins Glen and then tenth at the Daytona season finale.

Into 1986, Hendrick Motorsports and Lee Racing would continue their campaign with mixed results. Although both teams failed to finish the first three races of the season, Hendrick would manage to take the first victory for the Corvette GTP at Road Atlanta for Doc Bundy and Sarel van der Merwe. However by that time Lee Racing abandoned their effort. Hendrick would continue on and manage a fourth place finish at Charlotte, seventh at Lime Rock, and third at Mid-Ohio. The Corvette GTP would follow this with its second victory on the streets of Palm Beach, defeating a Porsche 962 by four tenths of a second. Unfortunately the car would fail to finish at Watkins Glen, but return for an eighth place finish at Portland. By Sears Point, Hendrick would purchase Lee racing's former chassis to start a two-car campaign. Unfortunately Hendrick would not be able to see the same success by the end of the season, leaving Chevrolet to take third in the constructors championship to Porsche and Jaguar

Hendrick started 1987 the same way they had 1986, failing to finish the first three races of the season, even suffering from a fire during the Miami event. Unfortunately Hendrick continued to have problems until they were finally able to finish a race at Laguna Seca, the sixth round of the season, and managing a second place result, then a third and eleventh for the two car team at Mid-Ohio. Following a short stint of problems, the duo would finish fourth and seventh at Portland, followed quickly by a lone third at Sears Point. One final third came in the streets of San Antonio before Hendrick would close out the season with a series of problems. However, problems at Jaguar helped Chevrolet secure second in the manufacturers championship, once again losing to Porsche.

By 1988, the Corvette GTPs were becoming slightly more consistent as the team managed to overcome their mechanical woes, helped by a switch to the naturally aspirated V8s. The season again began slow, with an eighth place finish at Road Atlanta be the first finish by a Corvette GTP that season. A seventh at Lime Rock and Mid-Ohio would be followed by a third at Watkins Glen, tenth at Road America, and finally ninth at Sears Point before the Hendrick team would be joined by the new Peerless Racing squad, using the newest Corvette GTP chassis. Peerless would take a fourth place at Columbus, followed closely behind by Hendrick in fifth. Hendrick would close the season with a fifth at Del Mar. Chevrolet would however manage to finish fourth in championship.

After the 1988 season, General Motors chose to cancel their funding for the Corvette GTP project, and Hendrick Motorsport did not return to IMSA GT. Peerless Racing would attempt to continue into 1989, but a series of accidents led to them failing to finish any of the races they entered, forcing them to quit midway through the season. Peerless' car would later be used by Eagle Performance as an experiment with their large 10.2 litre V8 engine, entering it in the 24 Hours of Le Mans. The car would however suffer electrical problems during the qualifying sessions and would not be able to make the race, marking the end of the Corvette GTP.

Chassis

In total, seven cars would be built under the Corvette GTP name, although nearly all had different designations by Lola.

T710-HU01

  • Racing Systems (1984)
  • Hendrick Motorsport (1985-1986)
Winner at Road Atlanta (1986)

T711-HU02

  • Lee Racing (1985-1986)
  • Hendrick Motorsport (1986)

T86/10-HU01

  • Hendrick Motorsport (1986-1987)
Winner at Palm Beach (1986)

T86/10-HU02

  • Hendrick Motorsport (1986-1988)

T86/12-HU03

  • Hendrick Motorsport (1987)
Equipped with Lotus active suspension

T87/10-HU01

  • Hendrick Motorsport (1988)

T88/11-HU01

  • Peerless Racing (1988-1989)
  • Eagle Performance (1990)

External links

v • d • e
  1. REDIRECT Template:Country data United Kingdom Lola sports cars

Early Projects (1958-1968): Mk1 | Mk6 | T70

Group 7 / Can Am (1967-1974): T120 | T160 | T220 | T260 | T310

Group 6 (1970-1981): T210 | T280 | T290 | T380 | T390 | T600

Sports 2000 (1976-2007): T490 | T590 | T86/90 | T87/90 | T88/90 | T89/90 | T90/90 | T91/90 | B07/90

Group C / GTP (1982-1992): T385 | T600 | T610 | T710 | T810 | T86/10 | T89/10 | T90/10 | T92/10

LMP / SR (1998-Now): B98/10 | B2K/10 | B2K/40 | B01/60 | B05/40 | B06/10 | B08/60 | B08/80

Daytona Prototype (2008-Now): B08/70

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