Whipple Supercharger Installation on a 1993 Big Block Chevy Engine
Dominant Whipple Charger Power
From the June, 2009 issue of Sport Truck
By Steve Warner
Photography by Steve Warner
Older non-Vortec-equipped big-block Chevys are in definite need of a large dose of power. There is no quicker, easier, or more exciting method of upping the dose than installing a Whipple Charger twin-screw compressor. By simply bolting on the supercharger, 68 additional rear-wheel horsepower was realized. Now if that isn&8217t enough to whet your appetite, read on to discover just how easy the installation truly is.
With a Whipple Charger fit...
With a Whipple Charger fit to a 1993 big-block Chevy engine, peak, passing, and towing power have dramatically increased. Everyday driving isn&8217t hurt one bit by the horsepower gains, and the vehicle will now have its way on the freeway without any problem.
The twin-screw compressor...
The twin-screw compressor comes in a satin black powdercoated or polished finish and is designed to fit all 1988-1995 pre-Vortec big-block Chevy engines found in all C/K 2500, 3500 and Suburban sport trucks. The kit includes the necessary hardware and brackets, new, longer serpentine belt to drive the supercharger, pulleys, high volume fuel pump, fuel regulator, and free-flowing air filter.
Installation of the Whipple...
Installation of the Whipple Charger requires removal of the stock TBI (throttle-body injector), factory radiator hose, and thermostat housing. Drain the radiator down to an imaginary line just below where the upper radiator hose attaches to it. Remove the entire radiator hose and thermostat housing and fit the new Whipple Industries thermostat housing, 180-degree thermostat, and new re-configured radiator hose to the engine. Because of the supercharger&8217s snout and the serpentine drivebelt it becomes necessary to reroute the radiator hose.
Once you have scraped all...
Once you have scraped all of the throttle body’s gasket off the intake manifold, fit the stock intake manifold with the Whipple Charger&8217s lower adapter base. Using the provided Allen-headed countersunk bolts to attach the base, dab the bolts in Loctite thread-locking compound to insure the bolts will not work their way loose, and torque them to 22 lb-ft. Rub the top of the adapter base with white grease or petroleum jelly and install the small rubber O-ring. This O-ring will help prevent any vacuum leaks once the engine is fired up.
Remove the protective layer...
Remove the protective layer of film covering the supercharger discharge port, and taking care to not disturb the rubber O-ring, fit the Whipple Charger to the blower adapter base. Attach it in place with the 12 bolts. DO NOT fully tighten the bolts. The Whipple Charger should still be able to move slightly from side to side.
Fit the new Whipple Industries...
Fit the new Whipple Industries support brackets to the Whipple Charger&8217s snout. The support bracket fits where the previous accessory drivebelt tensioner-idler pulley was. Once the upper portion of the bracket that surrounds the blower snout is in place and all of the new idler pulleys and the 6 psi boost pulley are in place and inline with each other, fully secure the adapter base manifold bolts to the Whipple Charger.
Fit the throttle body to the...
Fit the throttle body to the back of the Whipple Charger and attach it with the mounting hardware. Remove the factory fuel lines from the bottom of the fuel filter located under the driver-side door in the frame of the vehicle. Replace the fuel lines with Whipple Industries braided stainless steel fuel lines. The 90-degree fitting fits into the return port on the throttle body. The other inline fitting will be attached to the side port of the fuel pressure regulator.
The adjustable fuel-pressure...
The adjustable fuel-pressure regulator attaches to the metal plate that is connected to the lower adapter plate. Once it is in place, fit the flexible fuel line from the throttle body to the intake port on the pressure regulator.
Two 90-degree pipe fittings...
Two 90-degree pipe fittings must be installed at the back of the Whipple Charger. Once installed, using sealant on the threads, remove the heater hose from the top of the radiator on the passenger side of the vehicle and connect it to the new water fitting on the throttle body adapter base plate. Connect the driver-side water fitting on the throttle body adapter back to the radiator using the hose clamps. These two hoses supply the throttle body with warm water from the heater during cold weather in order to warm up the fuel so it will be easily atomized in the throttle body. That way, when the accelerator is stomped on hard, the engine will not be in a lean condition.
Install the new throttle body...
Install the new throttle body and transmission linkage plates at the rear of the Whipple Charger and reconnect the lines to their respective pieces. Both lines snap into place once they have been fit to the new brackets. When removing the linkages at the outset, care should be taken not to damage the retaining clips because new clips are not included in the Whipple Charger kit.
A new air cleaner stud must...
A new air cleaner stud must be fit to the top of the throttle body to hold the provided air plenum in place. Fit the plastic air cleaner adapter to the top of the throttle body and attach the wing nut. For the plastic piece to fit, the factory plastic electrical terminal cover must either be removed or notched for clearance. Also, the transmission dipstick must be slightly bent to clear the new air cleaner assembly so that you&8217ll still be able to check the fluid level without removing the air cleaner assembly. The air filter housing base installs in place of the factory air cleaner noise suppression box at the air inlet opening in the fenderwell. Fit the free-flowing lifetime air filter and its base assembly into its plastic housing.
Attach the air cleaner tubing...
Attach the air cleaner tubing to the plastic throttle body air plenum with the provided rubber tubing and large hose clamps.
Install the new tension-idler...
Install the new tension-idler pulley to the previously-installed blower support snout bracket. Route the provided serpentine belt around all of the existing factory pulleys and newly installed Whipple Industries pulleys. Once the belt has been installed on all of the pulleys, place the proper tension on it and check to make sure the belt is on all of the pulleys’ ribs. If it’s off one rib or two, release the tension on the belt and reinstall making sure it contacts all of the pulleys&8217 ribs.
Remove the vent hole plug...
Remove the vent hole plug cover and fill up the supercharger’s gear case using the special 5-50-weight oil supplied in the Whipple Charger kit. Whipple Industries recommends changing the gear case oil every 10,000-12,000 miles. Use the dipstick at the front of the gear case to measure the oil level and don&8217t overfill it.
Before removing the fuel tank...
Before removing the fuel tank to install the new high-output electrical fuel pump located in the gas tank, fire up the engine and check for any leaks--both gas and vacuum--that can sometimes occur. If there are any leaks, odds are you may have damaged the rubber O-ring that fits between the Whipple Charger and the adapter base. If there are no leaks, shut the engine off and remove the gas tank. A lift rack helps but you can also remove the tank with the vehicle on the ground. It is better to start with a gas tank that is nearly empty, otherwise you must siphon out as much of the gas as you can because a full gas tank is too heavy to remove. Disconnect the fuel inlet line from the filler tube. Unplug the electrical harness and breather vent tubes. Remove the two retaining straps, and then the gas tank should fall out. If you are doing the installation on a pickup truck, the easier way is to simply remove the truck&8217s bed to gain access to the top of the gas tank.
After the lock-retainer ring...
After the lock-retainer ring has been removed from the top of the gas tank, pull the old fuel pump out of the tank. Replace the old fuel pump with the new Whipple Industries high volume fuel pump and gas screen. Reinstall the new fuel pump into the gas tank and reconnect the lock-retaining ring. Lift the gas tank back up under the vehicle and reconnect all of the disconnected hoses and the electrical wiring harness.
Whipple Industries supplies...
Whipple Industries supplies all of its pre-Vortec kits with a replacement PROM computer chip. It is a simple remove and replace procedure. Locate the computer behind the glovebox liner and remove it. Two small retaining screws hold the computer chip’s protective cover in place. Remove the cover and install the new Whipple Industries computer chip and reinstall the computer into the vehicle. Start the engine again and check the ignition timing. Set it to the manufacturer&8217s recommended settings. Test drive the vehicle with the fuel pressure gauge attached at the top of the fuel pressure regulator and verify that it has at least 12-13 pounds of pressure at idle. Under WOT (wide-open throttle) conditions the fuel pressure should be 17-18 pounds.
If you own a pre-Vortec 1988-1995 big-block-equipped Chevy sport truck, SUV, or Suburban, you are not alone. There are over 200,000 of these vehicles on the road today doing service in a variety of activities; everything from hauling the kids to school and back, to transporting the family on vacation trips, and to long-distance treks with horse, boat, or car trailers in tow. And yet the single most common complaint the factory gets is customers bemoaning the engines serious lack of power.
Unless you had the 454 SS version of the old 7.4L V-8, the peak power output was critically limited. The older 454 SS 1/2-ton Super Sport truck produced 255 hp at 4,000 rpm and some stump-pulling 405 lb-ft of torque at 2,400 rpm. But it was only in that truck's configuration the 7.4L engine created any semblance of power. Non-454-SS-equipped vehicles only produced 230 hp at 3,600 rpm and 385 lb-ft of torque at 1,600 rpm. The reason for the 25hp decrease was to broaden the appeal of these vehicles to the market for which they were designed; a market covering every intended use, including work trucks, ambulances, and family haulers. The engines were never meant to be the power machines we sport truckers all crave.
Enter supercharging to save the day. Although typically considered extreme by the more conventional horsepower gurus, supercharging the engine is the biggest and fastest way to boost all-around power. Spend a mere weekend installing one of these powerful smog-legal additives and most pre-Vortec engines will see power gains from 50 to 75 hp.
That’s the inducement behind Whipple Industries Whipple Charger supercharger kits. The company offers its twin-screw superchargers for all Chevrolet 1988-1995 pre-Vortec engines and 1996-1998 Vortec-equipped big- and small-block engines. A twin-screw blower is by design an axial-flow supercharger that compresses air as it moves between the twin screws of the blower. The twin-screw supercharger is believed to have advantages over less efficient, non-internal compression designs because the outlet temperatures are typically lower than more conventional roots or centrifugal supercharging systems, thereby providing increases in all-around power.
Because these older pre-Vortec engines are not as powerful as their replacements, many people have indeed turned to supercharging as a means to an end. Getting up steep-grade highways is no longer an issue and with a supercharger installation on the pre-Vortec engines your all-around power and torque will be much greater than that of the new Vortec engines.
With our test truck running a pre-Vortec 1993 big-block 7.4L V-8, equipped with a set of Doug Thorley headers and a Walker Ultra Flow back-cat exhaust system, a series of baseline tests were staged to establish the truck’s "before" rear-wheel horsepower and torque. Using Whipple Industries’ Rancho Cucamonga, California, test facility, the 1993 big-block made 185 rear-wheel horsepower at 3,700 rpm and 319 lb-ft of torque at 2,900 rpm. Once the Whipple Charger was installed, however, the big-block produced 253 hp at 4,100 rpm and 372 lb-ft of torque at 3,100 rpm running with a 6 psi maximum boost pulley.
Whipple Industries Inc.
3292-1/2 N. Weber