The GMC Typhoon is a high-performance SUV , produced from 1992 until 1993 by GMC . The Typhoon was based on the 1991 GMC Syclone .
41-658: Like the GMC Syclone , the Typhoon is powered by a 4.3 L LB4 V6 engine with unique pistons, main caps, head gaskets, intake manifolds, fuel system and exhaust manifolds, producing 280 hp (209 kW) and 360 lb⋅ft (475 N⋅m) of torque. The engine is a modified version of the Vortec engine found in the standard Jimmy, which originally produced 190 hp (142 kW). The engine uses a Mitsubishi TD06-17C/8 cm turbocharger producing 14 psi (0.97 bar) of boost and
82-436: A Garrett Water/Air intercooler , as well as revised intake manifolds , fuel system, exhaust manifolds, and a 48 mm (2 in) twin-bore throttle body from the 5.7 L GM Small-Block engine . The Typhoon sends power to all four wheels through a 4L60 4-speed automatic transmission and a BorgWarner 4472 transfer case splitting torque with 35% forward and 65% to the rear wheels. Other features include upgraded brakes,
123-407: A bi-metallic spring which changed tension according to the heat in the manifold. Today's fuel-injected engines do not require such devices. A variable-length intake manifold ( VLIM ) is an internal combustion engine manifold technology. Four common implementations exist. First, two discrete intake runners with different length are employed, and a butterfly valve can close the short path. Second
164-444: A few thousand dollars under their market value. In 2009, a poor-condition GMC Syclone was scrapped under the U.S. federal government Car Allowance Rebate System (colloquially known as "cash for clunkers"), despite being highly collectible. There were two special-edition 1991 Syclones offered by third parties: The special-edition Marlboro Syclone was the grand prize for the ten winners of The Marlboro Racing '92 Contest. To enter
205-467: A limited-slip rear differential and sport modifications to the standard suspensions. Unlike the Syclone, the Typhoon featured an air-operated self-leveling rear suspension . During tests by Car and Driver , the Typhoon was capable of accelerating from 0–60 mph (0–97 km/h) in 5.3 seconds and could do a quarter-mile run in 14.1 seconds at 95 mph (153 km/h). Car and Driver compared
246-501: A sticker package. One of these Indy trucks was later converted into the PPG Syclone Pace Truck (though it was not the official pace car ) with significant modifications to be used on the track, including a multi-colored silver, magenta, and aqua paint scheme, and a molded in light bar in the roof, a racing fuel cell , a built-in halon fire suppression system, water-cooled brakes, and color-matched leather interior to
287-417: A volumetric efficiency above 100%: the air pressure in the combustion chamber before the compression stroke is greater than the atmospheric pressure. In combination with this intake manifold design feature, the exhaust manifold design, as well as the exhaust valve opening time can be so calibrated as to achieve greater evacuation of the cylinder. The exhaust manifolds achieve a vacuum in the cylinder just before
328-592: Is the part of an internal combustion engine that supplies the fuel / air mixture to the cylinders . The word manifold comes from the Old English word manigfeald (from the Anglo-Saxon manig [many] and feald [repeatedly]) and refers to the multiplying of one (pipe) into many. In contrast, an exhaust manifold collects the exhaust gases from multiple cylinders into a smaller number of pipes – often down to one pipe. The primary function of
369-480: The 4L60 4-speed automatic transmission . A BorgWarner 4472 all-wheel-drive transfer case splits torque with 35% of power going to the front and 65% of power to the rear wheels. Both trucks featured sport modifications to the standard suspensions. The Syclone was the first production truck to receive a 4-wheel anti-lock braking system . With this engine, the Syclone produces 280 hp (209 kW) and 350 lb⋅ft (475 N⋅m) of torque. The Syclone, when new,
410-421: The fuel injectors spray fuel droplets into the air in the manifold. Due to electrostatic forces and condensation from the boundary layer, some of the fuel will form into pools along the walls of the manifold, and due to surface tension of the fuel, small droplets may combine into larger droplets in the airstream. Both actions are undesirable because they create inconsistencies in the air-fuel ratio . Turbulence in
451-473: The 113 Saudi Syclones, 31 trucks remained unsold and were eventually brought back to the United States. Rather than selling the 31 trucks to the public, GMC set up a lottery where employees could enter their name to be drawn to have the chance at purchasing a Saudi Syclone as a significantly reduced price ($ 12,500) and had to take delivery through a dealership. It is alleged that not many employees knew of
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#1732783421026492-533: The 150 trucks, there were an estimated 113 destined for resale in the Middle East and were modified with a metric dash cluster, leaded fuel chip, and a resonator in place of the catalytic converter . These 113 trucks were shipped to Saudi Arabia to be sold as export sales. These 113 trucks were known as the Saudi Syclones. Not all of the exported Saudi Syclones were sold immediately overseas. Out of
533-532: The 2,995 Syclones built in 1991 and started life as a standard black production Syclone. Marlboro Syclone custom features include: The ten grand prize winners of the Marlboro Sweepstakes not only won a 1991 GMC Syclone Marlboro Edition truck, but were treated to an all-expenses-paid day of racing alongside the Indy racing team and pit crew with a VIP access and tours, pit passes, photo session with
574-549: The Marlboro Indy team, and a prize pack full of various Marlboro apparel. After the raffle had taken place and the trucks claimed by the winners, Phillip Morris had each truck delivered to an allocated dealership nearest to each winner’s residence. The winners were responsible for luxury taxes and fees. Three Indy Syclones were used at the Indianapolis 500 race on May 24, 1992, with the only modification being
615-436: The Syclone and Typhoon trucks feature a Mitsubishi TD06-17C 8cm² turbocharger and Garrett water/air intercooler attached to a 4.3L LB4 V6 engine featuring upgrades that included hypereutectic pistons, nodular iron main caps, upgraded head gaskets, intake manifolds , exhaust manifolds , and a 48 mm (1.9 in) twin-bore throttle body from the 5.7L Chevrolet small-block engine . All Syclones and Typhoons used
656-639: The Syclone's performance favorably to the Ferrari 348ts , Chevrolet Corvette , and Nissan 300ZX Turbo . It cost US$ 29,970, though the magazine criticized the plastic interior pieces. All three model years were built for GMC by Production Automotive Services of Troy , Michigan . Aside from a handful of prototypes, only 4,697 Typhoons were built by GMC: 2,497 for 1992, and 2,200 for 1993. Unlike regular production Syclones, Typhoons were offered in various exterior color configurations (body color/lower-body cladding color) that differed by year, with black/black being
697-402: The air intake are connected to an Y (sort of main plenum). The air oscillates between both sub-plenums, with a large pressure oscillation there, but a constant pressure at the main plenum. Each runner from a sub plenum to the main plenum can be changed in length. For V engines this can be implemented by parting a single large plenum at high engine speed by means of sliding valves into it when speed
738-470: The cross-sectional area of the runner, the higher the pressure changes on resonance for a given airflow. This aspect of Helmholtz resonance reproduces one result of the Venturi effect . When the piston accelerates downwards, the pressure at the output of the intake runner is reduced. This low pressure pulse runs to the input end, where it is converted into an over-pressure pulse. This pulse travels back through
779-527: The cylinder head which emanate from a central volume or "plenum" beneath the carburetor. The purpose of the runner is to take advantage of the Helmholtz resonance property of air. Air flows at considerable speed through the open valve. When the valve closes, the air that has not yet entered the valve still has a lot of momentum and compresses against the valve, creating a pocket of high pressure. This high-pressure air begins to equalize with lower-pressure air in
820-412: The engine's crankcase . This is known as a positive crankcase ventilation system , in which the gases are burned with the fuel/air mixture. The intake manifold has historically been manufactured from aluminium or cast iron, but use of composite plastic materials is gaining popularity (e.g. most Chrysler 4-cylinders, Ford Zetec 2.0, Duratec 2.0 and 2.3, and GM's Ecotec series). The carburetor or
861-745: The exterior paint scheme. The bed has a multi-piece tonneau cover that folds with the tailgate in the fashion of an accordion to reveal the fuel cell, batteries, and halon canister mounts. The PPG Syclone was retired to the GM Heritage Collection where it was stored and occasionally taken out for car shows until it was auctioned at Barrett Jackson in 2009, selling for $ 66,000. It is now privately owned, with its last location known to be in Colorado. Intake manifold An inlet manifold or intake manifold (in American English )
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#1732783421026902-409: The intake helps to break up fuel droplets, improving the degree of atomization. Better atomization allows for a more complete burn of all the fuel and helps reduce engine knock by enlarging the flame front. To achieve this turbulence it is a common practice to leave the surfaces of the intake and intake ports in the cylinder head rough and unpolished. Only a certain degree of turbulence is useful in
943-414: The intake manifold is to evenly distribute the combustion mixture (or just air in a direct injection engine) to each intake port in the cylinder head(s). Even distribution is important to optimize the efficiency and performance of the engine. It may also serve as a mount for the carburetor, throttle body, fuel injectors and other components of the engine. Due to the downward movement of the pistons and
984-455: The intake runner and the speed of sound. The traditional solution has been to tune the length of the intake runner for a specific engine speed where maximum performance is desired. However, modern technology has given rise to a number of solutions involving electronically controlled valve timing (for example Valvetronic ), and dynamic intake geometry (see below). As a result of "resonance tuning", some naturally aspirated intake systems operate at
1025-399: The intake runners can be bent around a common plenum, and a sliding valve separates them from the plenum with a variable length. Straight high-speed runners can receive plugs, which contain small long runner extensions. The plenum of a 6- or 8-cylinder engine can be parted into halves, with the even firing cylinders in one half and the odd firing cylinders in the other part. Both sub-plenums and
1066-570: The intake. Once the fuel is sufficiently atomized, additional turbulence causes unneeded pressure drops and a drop in engine performance. The design and orientation of the intake manifold is a major factor in the volumetric efficiency of an engine. Abrupt contour changes provoke pressure drops, resulting in less air (and/or fuel) entering the combustion chamber; high-performance manifolds have smooth contours and gradual transitions between adjacent segments. Modern intake manifolds usually employ runners , individual tubes extending to each intake port on
1107-453: The latter is the Honda J engine which converts to a single plane manifold around 3500 rpm for greater peak flow and horsepower. Older heat riser manifolds with 'wet runners' for carbureted engines used exhaust gas diversion through the intake manifold to provide vaporizing heat. The amount of exhaust gas flow diversion was controlled by a heat riser valve in the exhaust manifold, and employed
1148-451: The lottery to purchase one of the Saudi Syclones, so almost everyone who entered got the chance to buy one, which upset a lot of GM employees in various other divisions who felt they missed out. The remaining 69 trucks were distributed throughout Europe for sale where a small number ended up in a German compound for sometime. GMC, desperate to be rid of them, sold them on a "make us an offer" basis. Lucky purchasers managed to get hold of one for
1189-407: The manifold. Due to the air's inertia, the equalization will tend to oscillate: At first the air in the runner will be at a lower pressure than the manifold. The air in the manifold then tries to equalize back into the runner, and the oscillation repeats. This process occurs at the speed of sound, and in most manifolds travels up and down the runner many times before the valve opens again. The smaller
1230-517: The most common. 1991 1992 1993 GMC Syclone The GMC Syclone is a high-performance version of the GMC Sonoma pickup truck . Produced in 1991 by GMC along with Production Automotive Services (PAS) —the same company credited with building the 1989 Pontiac Turbo Trans Am —the GMC Syclone was the fastest production truck for 1991. Following the Syclone's production,
1271-419: The piston reaches top dead center. The opening inlet valve can then—at typical compression ratios—fill 10% of the cylinder before beginning downward travel. Instead of achieving higher pressure in the cylinder, the inlet valve can stay open after the piston reaches bottom dead center while the air still flows in. In some engines the intake runners are straight for minimal resistance. In most engines, however,
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1312-489: The plenum volume can be smaller. To avoid standing waves within the plenum it is made as compact as possible. The intake runners each use a smaller part of the plenum surface than the inlet, which supplies air to the plenum, for aerodynamic reasons. Each runner is placed to have nearly the same distance to the main inlet. Runners whose cylinders fire close after each other, are not placed as neighbors. In 180-degree intake manifolds , originally designed for carburetor V8 engines,
1353-544: The restriction caused by the throttle valve, in a reciprocating spark ignition piston engine , a partial vacuum (lower than atmospheric pressure ) exists in the intake manifold. This manifold vacuum can be substantial, and can be used as a source of automobile ancillary power to drive auxiliary systems: power assisted brakes , emission control devices, cruise control , ignition advance, windshield wipers , power windows , ventilation system valves, etc. This vacuum can also be used to draw any piston blow-by gases from
1394-464: The runner and rams air through the valve. The valve then closes. To harness the full power of the Helmholtz resonance effect, the opening of the intake valve must be timed correctly, otherwise the pulse could have a negative effect. This poses a very difficult problem for engines, since valve timing is dynamic and based on engine speed, whereas the pulse timing is static and dependent on the length of
1435-409: The runners have curves, some very convoluted to achieve desired runner length. These turns allow for a more compact manifold, with denser packaging of the whole engine, as a result. Also, these "snaked" runners are needed for some variable length/ split runner designs, and allow the size of the plenum to be reduced. In an engine with at least six cylinders the averaged intake flow is nearly constant and
1476-524: The similarly powered 1992–1993 GMC Typhoon SUV was based on the GMC Jimmy platform. Also following the Syclone, the 1992 GMC Sonoma GT truck was offered as a sport package with the looks of a Syclone but without the price and performance of its turbocharged predecessor. Only 806 Sonoma GTs were produced. The GMC Syclone, Typhoon, and Sonoma GT were built by GMC and PAS ( Production Automotive Services ) of Troy, Michigan , and sold through dealerships. At
1517-542: The sweepstakes, a form was filled out which included a questionnaire. All ten trucks were provided to American Sunroof Company (ASC), by Shinoda Design Associates, Inc., in conjunction with Phillip Morris, Inc. With the help of Larry Shinoda , designer of the Corvette Stingray and Boss Mustang, a transformation of the originally black Syclones took place. All ten of the Marlboro Syclones were among
1558-577: The time it was introduced, the Syclone was the fastest stock pickup truck being produced in the world. Auto magazines compared its acceleration favorably to a variety of sports cars including the Chevrolet Corvette and—in a memorable comparison test in Car and Driver magazine —a Ferrari 348 ts . The Syclone features a 4.3L turbocharged V6 engine with an automatic transmission and an AWD (all-wheel drive) driveline and 4-wheel anti-lock brakes. Both
1599-457: The two plane, the split plenum intake manifold separates the intake pulses which the manifold experiences by 180 degrees in the firing order. This minimizes interference of one cylinder's pressure waves with those of another, giving better torque from smooth mid-range flow. Such manifolds may have been originally designed for either two- or four-barrel carburetors, but now are used with both throttle-body and multi-point fuel injection . An example of
1640-430: The upcoming 1992 production, a wider range of colors was to be offered; however, the Syclone was cancelled before full production could begin. In total, 2,998 Syclones were built. Out of the 2,998, only three were built in 1992. The first 1992 Syclone was used for DOT crash testing while the remaining two are privately owned. During the 1991 Syclone production, roughly 150 Syclones were officially exported by GMC. Out of
1681-494: Was capable of accelerating from 0–60 mph (0–97 km/h) in 5.3 seconds and could do a quarter-mile run in 13.4 seconds at 98 mph (158 km/h) according to Car and Driver 's comparison test. The Syclone and Typhoon's gauge cluster is the same one as used in the Pontiac Sunbird Turbo, which was discontinued in 1990, one year before the Syclone was introduced. The 1991 Syclone was only available in black. For