Vortech Engineering GM 7.4, GM 7.4 Light Truck Installation Instructions Manual

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GM 7.4 Light Truck

Supercharger System

Installation Instructions

50 State Smog Legal per CARB EO #D-213-17

1988-1995 Model Years

1650 PACIFIC AVENUE • CHANNEL ISLANDS, CA 93033-9901 • (805) 247-0226

FAX (805) 247-0669 • www.v ortechsuperchargers.com • M-F 8:00 AM - 4:30 PM PST

(88-95 GM Lt Trk(4GC))

ENGINEERING, LLC

FOREWORD

Proper installation of this supercharger kit requires general automotive mechanic knowledge and experience. Please browse through each step of this instruction manual

prior

to beginning the installation to determine if you should refer the job to a professional

installer/technician. Please call Vortech Engineering for installers in your area.

or translated into another language in any form, by any means without written permission

(88-95 GM Lt Trk(4GC))

of Vortech Engineering, LLC

Table Of Contents

FOREWORD ...................................................................................................................... ii

TABLE OF CONTENTS ..................................................................................................... iii

NOTICE.............................................................................................................................. iv

TOOL & SUPPLY REQUIREMENTS.................................................................................. v

PARTS LIST - 1988-1993 7.4 TRUCK ............................................................................... vi

PARTS LIST - 1994-1995 7.4 TRUCK ............................................................................... ix

1. COMPONENT REMOVAL ...................................................................................... 1

2. CRANKSHAFT PULLEY INSTALLATION .............................................................. 1

3. OIL DRAIN LINE..................................................................................................... 2

4. OIL FEED LINE ...................................................................................................... 3

5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM ... 3

6A. MAIN BRACKET AND POWER STEERING PUMP - 1988-1993 MODELS .......... 7

6B. MAIN BRACKET AND POWER STEERING PUMP - 1994-1995 MODELS .......... 8

7. COOLING FAN SPACER ....................................................................................... 9

8. SUPERCHARGER MOUNTING............................................................................. 10

9. FACTORY ACCESSORY DRIVE BELT AND SUPERCHARGER DRIVE BELT .... 10

10. DISCHARGE PLENUM .......................................................................................... 11

11. AIR FILTER, INLET DUCT AND PLENUM ............................................................. 12

12. FINAL REASSEMBLY & CHECK ........................................................................... 13

iii

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

NOTICE

This product is protected by state common law, copyright and/or patent. All legal rights therein are reserved. The design, layout, dimensions, geometry, and engineering features shown in this product are the exclusive property of Vortech Engineering, Inc. This product may not be copied or duplicated in whole or part, abstractly or fundamentally, intentionally or fortuitously, nor shall any design, dimension, or other information be incorporated into any product or apparatus without prior written consent of Vortech Engineering, LLC.

(88-95 GM Lt Trk(4GC))

1988 - 1995

GM 7.4 LIGHT TRUCK

Installation Instructions

50 State Smog Legal, as per CARB EO #D-213-17

Congratulations on selecting the best performing and best backed automotive

supercharger available today... the VORTECH

Before beginning this installation, please read through this entire instruction booklet and the Street Supercharger System Owner's Manual which includes the Limited Warranty Program and the Warranty Registration form and return envelope.

Vortech supercharger systems are performance improving devices. In most cases, increases in torque of 30 to 35% and horsepower of 35 to 45% can be expected with the boost levels specified by Vortech Engineering. This product is intended for use on healthy, well maintained engines. Installation on a worn-out or damaged engine is not recommended and may result in failure of the engine as well as the supercharger. Vortech Engineering is

not responsible for engine damage.

Installation on new vehicles will not harm or adversely affect the break-in period so long as factory break-in procedures are followed.

For best performance and continued durability, please take note of the following key points:

1. Use only premium grade fuel 92 octane or higher (R+M/2).

2. The engine must have stock compression ratio.

3. If the engine has been modified in any way, check with Vortech prior to using this product.

4. Always listen for any sign of detonation (pinging) and discontinue hard use (no boost) until problem is resolved.

5. Perform an oil and filter change upon completion of this installation and prior to test driving your vehicle.

Thereafter, always use a high grade SF rated engine oil or a high quality synthetic, and change the oil and filter every 3,000 miles or less. Never attempt to extend the oil change interval beyond 3,000 miles, regardless

of oil manufacturer's claims as potential damage to the supercharger may result.

6. Before beginning installation, replace all spark plugs that are older than 1 year or 10,000 miles with original heat

range plugs as specified by the manufacturer and reset timing to factory specifications (follow the procedures indicated within the factory repair manual and/or as indicated on the factory underhood emissions tag). Do not use platinum spark plugs unless they are original equipment. Change spark plugs every 15,000 miles and spark plug wires at least every 50,000 miles.

V-2® Supercharger!

TOOL & SUPPLY REQUIREMENTS

• Factory Repair Manual

• Timing Light

• 3/8" socket and drive set: SAE and Metric

• Drill motor, 3/32" and .046" drill bits

• 1/2" breaker bar and 4" extension

• Large screwdriver or pry bar

• 3/8" NPT tap and handle or socket

• Flat #2 screwdriver

• Phillips #2 screwdriver

• Center punch and 3/4" drift punch

• Open end wrenches: 3/8", 7/16", 1/2, 9/16", 5/8", 3/4", 7/8", 10, 13 & 15mm

a "Slimline" 19mm - Snap-On part # LTAM1719

• Power Steering Pulley Puller & Installer (1994 models only) Snap-On Puller #CJ117B2 Snap-On Installer #CJ113B

If your vehicle has in excess of 10,000 miles since its last spark plug change, then you will need:

• Spark plug socket

• NEW spark plugs

• Hammer

• Adjustable wrench

• Oil Filter Wrench

• Oil Filter

• SF Rated Quality

(or synthetic) Engine oil

• Heavy grease Silicone

sealer

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

1988-1993 7.4 Truck

Part No. 4GC218-090SQ

ENGINEERING, LLC

PARTS LIST

IMPORTANT: Before beginning installation, verify that all parts are included in the kit. Report any shortages or damaged parts immediately.

Part Number Description Quantity

2E228-090 V-2SQ SUPERCHARGER ASSEMBLY 1

4GC111-021 MOUNTING BRACKET ASSEMBLY 1

4GC010-034 Mounting Plate 1 4GC010-043 Attachment Plate 1 4GC010-054 Stiffener plate 1 4GC011-021 Mounting Bracket 1 4GC017-011 .125 Mounting Plate Spacer 1

7A375-550 3/8-16 x 5-1/2” Bolt 1 7F375-016 3/8-16 Nuts 3 7K375-040 3/8” AN960 Flat Washers 5 7J375-044 3/8” SAE Washers 8 7A375-100 3/8-16 x 1” Bolts 10 7C010-025 M10-1.5 x 25mm Bolts 2 7A312-100 5/16-18 x 1” Bolts 4 7J312-000 5/16” SAE Flat Washers 8

4GC010-010 Mounting Bracket Support 1

7A375-208 3/8-16 x 2” Bolt 1 7A375-276 3/8-16 x 2-3/4” Bolt 1 7F312-018 5/16-18 Nuts 4

4GB017-011 1” Throttle Spacer 1

7A375-124 3/8-16 x 1-1/4” Bolts 2

4GC116-010 CRANK PULLEY ASSEMBLY 1

4GB016-011 Crank Pulley 1 4GC017-041 Crank Pulley Spacer 1

7B375-400 3/8-24 x 4” Bolts 3 7J375-044 3/8” SAE Washers 3 7L375-075 3/8" Lock Washers 3

4GC017-010 Spacer Fan 1

7C080-055 M8 1.25 x 55 Studs 4 2A046-598 Belt 1 7B500-400 1/2-20 x 4” Bolt 1

4GC130-026 OIL FEED LINE ASSEMBLY 1

7U030-026 1/4” x 16" Oil Feed hose 1 7P525-067 .500 Crimp Ferrules 2 7P250-066 #4 Swivel x 1/4” Hose Barb Fittings 2 7P250-036 #4 Flare to 1/4” NPT 1 7P125-026 1/8” NPT 90° Fitting 1 7P250-034 1/4” NPT x 1/4” NPT Straight Tee 1 7U100-055 6” Nylon Tie Wraps 3

4GC130-036 OIL DRAIN ASSEMBLY 1

7R001-008 #8 Stainless Hose Clamps 2 7U030-036 1/2” x 36” Oil Drain Hose 1 7P375-033 3/8” NPT x 3/8” NPT Street Elbow 1 7P375-017 3/8” NPT x 1/2” Straight Hose Barb 1 7U100-055 6” Nylon Tie Wraps 4

5A001-004 FUEL INJECTION COMPUTER 1

Part Number Description Quantity

4GC112-010 AIR INTAKE ASSEMBLY 1

4GB012-010 Air Filter Cover 1 4GC012-012 Air Inlet Tube 1

4FA012-012 90° Intake Elbow 1

7P375-017 3/8” NPT x 1/2” Straight Hose Barb 1 7S350-200 3-1/2” x 2” Sleeve 1 7R002-056 #56 Hose Clamps 2 7R002-052 #52 Hose Clamps 4 7E010-046 #8 x 3/4” Sheet Metal Screws 2 7U035-000 3-1/2” x 10” Flex Hose 1 8H040-040 Air Filter 1 7U030-005 1/2” x 5” Oil Drain Hose 1 7U035-000 3-1/2” x 12” Flex Hose 1 7R001-008 #8 Stainless Hose Clamps 2

4GC112-020 AIR DISCHARGE ASSEMBLY 1

4GB040-060 Air/plenum Gasket 1 4GC012-020 Steel Discharge Tube 1 4GC050-011 Intake Plenum 1

7A312-050 5/16-18 x 1/2” Bolts 2 7J312-000 5/16” SAE Flat Washers 2 7P125-025 1/8” NPT to 5/32” Barb 1 7R002-044 #44 Hose Clamps 4 7S275-200 2-3/4” x 2” Sleeves 2 7P750-102 3/4" NPT x 1" 90° Hose Fitting 1 7P750-100 3/4" NPT x 1" Straight Hose Fitting 1 7R002-016 #16 Hose Clamps 4 8D001-001 Bypass Valve 1 7U030-046 5/32" x 24" Vacuum Line 1 7P156-082 5/32" Tee 1 7U034-016 1" x 3" Heater Hose 1 7U034-016 1" x 8.5" Heater hose 1 8H040-075 1" Filter 1

4FA111-032 BELT TENSIONER ASSEMBLY 1

7J012-092 12mm Flat Washers 3

4FA011-032 Belt Tensioner Plate 1

7C012-050 12mm x 1.75 x 50mm Bolt 1

4FA016-150 Smooth Pulley Tensioner 1

2A017-010 Idler Pulley Spacer 1 7C012-020 12mm x 1.75 x 20mm Bolts 2 7C012-022 12mm x 1.75 x 22mm Thin Head Bolt 1 7G010-175 12mm x 1.75 Nut 1

4GC160-010 FUEL CONTROL ASSEMBLY 1

4GC152-011 Spacer Block Assembly 1 4GB112-022 Plenum Rod Assembly 1

4GB101-002 FUEL PUMP ASSEMBLY 1

8F001-002 155 Inline Fuel Pump 1

7R003-024 1-1/2” Adel Clamp 1 5W001-011 16-14 GA Eyelet 1 5W001-001 Wire Tap 1 5W001-010 16-14 GA insulated Female Slides 6 5W001-014 Fuse Holder 1 5W001-015 Blade type 20A Fuse 1 5W001-017 Large Ring Terminal 1

8F101-200 T-Rex 5W001-002 Fuse Tap 1 7R001-008 #8 Hose Clamps 2

7P625-001 Fuel Adapter Fitting 1 7U030-050 12mm x 8” PCV Hose 1

7J010-001 #10 Flat Washers 4

7F010-032 10-32 Nylock Nut 2 7U100-055 6” Nylon Tie Wraps 4

7C011-075 10/32” x 3/4” Cap Screw 1

Wiring Assembly 1

vii

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

viii

1994-1995 7.4 Truck

Part No. 4GG218-090SQ

ENGINEERING, LLC

PARTS LIST

IMPORTANT: Before beginning installation, verify that all parts are included in the kit. Report any shortages or damaged parts immediately.

Part Number Description Quantity

2E228-090 V-2 SQ SUPERCHARGER ASSEMBLY 1

4GG111-021 MOUNTING BRACKET ASSEMBLY 1

7A437-600 7/16-14 x 6” Bolt 1 7J438-081 7/16” SAE Washer 1 7A375-300 3/8-16 x 3” Bolt 1 7F375-016 3/8-16 Nut 2

7K375-040 3/8” AN960 Flat Washers 7 4GG017-021 1.895 Spacer A 1 4GG017-031 1.083 Spacer B 1 4GG010-034 Mounting Plate 1 4GG011-021 Mounting Bracket 1 4GG010-044 Attachment Plate 1 4GG017-041 .220 Spacer C 1

7J375-044 3/8” SAE Washers 3

7A375-100 3/8-16 x 1” bolts 5 4GC010-010 Mounting Bracket Support 1

7A375-208 3/8-16 x 2” Bolt 1

7A375-276 3/8-16 x 2-3/4” Bolt 1 4GB017-011 1” Throttle Spacer 1 4GG017-043 1/2" Spacer 2

7K312-001 8mm Washers 2

7C080-025 8mm x 1.25 x 25mm 2

4GC112-010 AIR INTAKE ASSEMBLY 1

4GB012-010 Air Filter Cover 1 4GC012-012 Air Inlet Tube 1

4FA012-012 90° Intake elbow 1

7P375-017 3/8” NPT x 1/2” straight hose barb 1

7S350-200 3-1/2” x 2” Sleeve 1

7R002-056 #56 Hose Clamps 2

7R002-052 #52 Hose Clamps 4

7E010-046 #8 x 3/4” Sheet Metal Screws 2

7U035-000 3-1/2” x 10” Flex Hose 1

8H040-040 Air Filter 1

7U030-005 1/2” x 5” Oil Drain Hose 1

7U035-000 3-1/2” x 12” Flex Hose 1

7R001-008 #8 Stainless Hose Clamps 2

4GC130-026 OIL FEED LINE ASSEMBLY 1

7U030-026 1/4” x 16" Oil Feed Hose 1

7P500-067 .500 Crimp Ferrules 2

7P250-066 #4 Swivel x 1/4” Hose Barb Fittings 2

7P250-036 #4 Flare to 1/4” NPT 1

7P125-026 90° 1/8” NPT x #4 Fitting 1

7P250-034 1/4” NPT x 1/4” NPT Straight Tee 1

7U100-055 6” Nylon Tie Wraps 3

4GC130-036 OIL DRAIN ASSEMBLY 1

7R001-008 #8 Stainless Hose Clamps 2

7U030-036 1/2” x 36” Oil Drain Hose 1

7P375-033 3/8” NPT x 3/8” NPT Street Elbow 1

7P375-017 3/8” NPT x 1/2” Straight Hose Barb 1

7U100-055 6” Nylon Tie Wraps 4

Part Number Description Quantity

5A001-004 FUEL INJECTION COMPUTER 1

4FA111-032 BELT TENSIONER ASSEMBLY 1

7J012-092 12mm Flat Washers 3

4FA011-032 Belt Tensioner Plate 1

7C012-050 12mm x 1.75 x 50mm Bolt 1

4FA016-150 Smooth Pulley Tensioner 1

2A017-010 Idler Pulley Spacer 1 7C012-020 12mm x 1.75 x 20mm Bolts 2 7C012-022 12mm x 1.75 x 22mm Thin Head Bolts 1 7G010-175 12mm x 1.75 Nut 1

4GC160-010 FUEL CONTROL ASSEMBLY 1

4GC152-011 Spacer Block Assembly 1 4GB112-022 Plenum Rod Assembly 1

4GB101-002 FUEL PUMP ASSEMBLY 1

8F001-002 155 Inline Fuel Pump 1 7R003-024 1-1/2” Adel Clamp 1

5W001-011 16-14 GA eyelet 1 5W001-001 Wire Tap 1 5W001-010 16-14 GA Insulated Female Slides 6 5W001-014 Fuse Holder 1 5W001-015 Blade type 20A Fuse 1 5W001-017 Large Ring Terminal 1

8F101-200 T-Rex 5W001-002 Fuse Tap 1

7R001-008 #8 hose Clamps 2

7P625-001 Fuel Adapter Fitting 1

7U030-050 12mm x 8” PCV Hose 1

7J010-001 #10 Flat Washers 4 7F010-032 10-32 Nylock Nut 2 7U100-055 6” Nylon Tie Wraps 4 7C011-075 10/32” x 3/4” Cap Screw 1

5W001-024 Mini Fuse Tap 2

4GG116-010 CRANK PULLEY ASSEMBLY 1

4GB016-011 Crank Pulley 1

7B375-400 3/8-24 x 4” Bolts 3

7J375-044 3/8” SAE Washers 3 7L375-075 3/8” Lock Washers 3

4GC017-010 Spacer Fan 1

2A046-598 Belt 1

4GG017-042 Crank Pulley Spacer 1

7C080-055 M8 1.25 x 55 Studs 4 7B500-400 1/2-20 x 4” Bolt 1

4GG112-020 AIR DISCHARGE ASSEMBLY 1

4GC012-020 Steel Discharge Tube 1

4GB050-010 Intake Plenum 1

7R002-044 #44 Hose Clamps 4 7S275-200 2-3/4” x 2” Sleeves 2

4GB040-060 Air/Plenum Gasket 1

7J312-000 5/16" SAE Flat Washers 2 7A312-100 5/16-18 x 1” Bolts 2 7P125-105 1/8” NPT to 5/32” Barb 1

4CB017-011 1/2” Spacers 2

7P750-102 3/4" NPT x 1" 90° Hose Fitting 1 7P750-100 3/4" NPT x 1" Straight Hose Fitting 1 7R002-016 #16 Hose Clamps 4 8D001-001 Bypass Valve 1 7U030-046 5/32" x 24" Vacuum Line 1 7P156-082 5/32" Tee 1 7U034-016 1" x 3" Heater Hose 1 7U034-016 1" x 8.5" Heater hose 1 8H040-075 1" Filter 1

Wiring Assembly 1

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

1. COMPONENT REMOVAL

A. Disconnect the battery (negative lead). B. Remove and set aside the following compo-

nents:

• The top portion of the fan shroud

• The accessory drive belt

• The cooling fan assembly

• The crankshaft pulley

• The air filter canister assembly and hose

• The intake air resonator (detach from inner

fender)

• The power steering pump pulley (1994 models only)

NOTE: If the vehicle is a 1993 model year or later ,

it will be necessary to purchase the stock air inlet resonator. The Chevrolet part number is 25097949

2. CRANKSHAFT PULLEY INSTALLATION

A. Remove the crankshaft pulley from the engine if

not already done.

B. Place the Vortech provided crank pulley and

spacer inside the stock pulley. (See

C. Line up bolt holes and, if necessary, press

pieces together or pull them together by gradually tightening the bolts.

D. Reinstall the pulleys as a unit onto the crank-

shaft balancer assembly using three 3/8-24 x 4" bolts and supplied 1/2-20 x 4" center bolt. (See

Fig. 2-a

NEW ADDITIONAL PULLEY

3 BOLTS: 3/8-24 X 4"

SPACER

Fig. 2-a

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

3. OIL DRAIN LINE

A. Raise the front of the vehicle and support with

appropriate jack stands.

B. To provide an oil drain for the supercharger, it is

necessary to make a hole in the oil pan. It is best to punch the hole rather than drill. Remove paint around the hole area so that it does not flake into the pan.

C. Make a mark on the oil pan on the driver’s side

ahead of the oil filter. The mark should be 3" below the bolt flange and rearward of the fourth bolt 7/8". (See different place, if necessary; however, take care not to damage any internal parts. The drain hose should gradually drop with no dips or kinks and should be above the oil level.

D. Use a small center punch to perforate the pan

and expand hole. Switch to a larger diameter punch and expand the hole further to approximately 9/16" diameter. Most punches are made from hexagon material and may be placed in a socket with an extension to make this procedure easier.

E. Tap the hole with a 3/8" NPT tap approximately

1/4" deep. Pack the flutes of the tap with heavy grease to catch and hold the chips. Once the tap is removed, it must be cleaned and repacked before tapping resumes. Use a small magnet to check for any stray chips in the threads after completing the tapping procedure.

F. Thoroughly clean the threaded area with ac-

etone or other solvent. Apply a small amount of silicone sealer to the new threads. Apply a small amount of silicone sealer to the threads of the 3/ 8" NPT hose fitting and secure in hole. Make sure a seal is formed all around the fitting. Allow sealer to cure completely.

G. Route the line forward along the top rail of the oil

pan and secure to the oil cooler line with the tie wraps provided. Temporarily cover end of hose and secure out of the way. The return is a gravity drain and should be routed to provide a gradual drop.

H. Drain and replace engine oil and change filter.

Fig. 3-a

.) You may choose a

NOTE: This method of rolling over the lip of

the hole and tapping works well if CAREFULL Y done and should cause no problems.

DOWN 3"

7/8" TO REAR OF BOLT

(88-95 GM Lt Trk(4GC))

OIL PAN

PUNCH HOLE THROUGH

OIL FILTER

Fig. 3-a

4. OIL FEED LINE

A. The supercharger uses engine oil for lubrication

and must have an oil feed line connected to a filtered oil access on the engine and an oil return or drain. (See must be above the oil level.

WARNING: The oil system contains a small

B. Disconnect the wire connector and remove the

oil pressure sending unit. The sender is found on the left side at the front of the engine block. Install the TEE provided in the port with the branch pointing forward. Place the pressure sender in front branch of the TEE, secure and reconnect the wire. Place the flare fitting in the remaining port and secure.

C. Connect the hose to the flare fitting and secure

with tie wraps. Take care that the feed line will not rub on the sheet metal inner fender.

D. Temporarily cover the end of the hose and

protect it from dirt until connecting to the supercharger.

Fig. 4-a

.) Connection to the oil pan

orifice that is easily plugged. DO NOT use any type sealant on any feed line threads. Instead, use clean engine oil. Disassemble and blow out entire line if you have any doubts.

ENGINE BLOCK

OIL PAN

Fig. 4-a

5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM

A. Remove the TBI unit from the manifold. (See

Fig. 5-a

gasket surfaces.

B. To prevent pressurized fuel and air leakage

around the throttle shaft, it is necessary to normalize the pressure. To accomplish this, modify the throttle body by drilling two small holes from the base surface to the throttle shafts. You may “layout” the location by following the template on page 6 or transfer it directly from the gasket provided. Use a small center drill to start, then a #56 or 3/64" diameter drill bit and drill through the base of the throttle body until the bit firmly contacts the shafts.

C. Assemble the throttle body, the new injector

spacer block and gaskets. Place the gasket with the small vent holes on top of the spacer. Place the gasket without holes on the bottom. On some models dowel pins have been provided for alignment. Use the two special threaded rods, nuts and one longer bolt to secure the throttle body and the Vortech spacer to the manifold.

.) Remove old gaskets and clean the

Fig. 5-a

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM - Cont'd.

NOTE: Make sure all small holes are aligned and

not plugged with gasket sealer when installed.

D. Mount the additional fuel pump to the inner side

of the frame rail beneath the driver's side floor. Use the shorter hose provided to help locate the pump the correct distance from the filter. This hose has an adapter fitting on the filter end. Secure the pump to the frame and hose with the clamp and fastener provided. (See

Fig. 5-a

E. Mark and drill a 3/16" hole in the frame near the

fuel pump to mount relay and wiring harness. Mount relay with supplied #10 hardware.

F. From relay terminal #85, tap the yellow wire into

the solid gray wire in the harness running along the driver's side frame member. Use the supplied scotchlock.

G. Connect the short red wire from relay terminal

#87 to the (+) terminal on the fuel pump.

H. Connect the longer black wire from the (-) termi-

nal at the fuel pump to a clean ground.

I. Connect the short black wire from relay terminal

#86 to a clean ground (relay screw mount works well).

J. Connect the long red wire from relay terminal

#30 to a (+) battery lug located in the engine compartment.

K. Plumb the pump to the supplementary injectors

as per the schematic on page 5. Much of this assembly has been done by Vortech.

L. Plumb the new pressure regulator and outlet,

routing the regulator to the throttle body inlet using the adapter fitting and O-ring.

M. Route the Vortech SFIC wiring harness and

vacuum line through the firewall. Mount the SFIC unit inside the vehicle beneath the steering column using the Velcro

strips provided.

N. Connect the wires for the Vortech SFIC. Attach

the black wire to ground. Connect the red to the "4WD" fuse location in the stock fuse block (this location is also found on 2WD trucks) with the special adapter provided (on 1995 models, the fuse box containing the "4WD" fuse is located inside the vehicle on the left hand side of the dashboard). Connect the brown wire to the negative side of the ignition coil tach pickup (loose male connection located on coil harness).

(88-95 GM Lt Trk(4GC))

5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM - Cont'd.

NOTE: Factory fuel return line must be attached to original fitting on TBI unit.

3/8” HOSE

3/8” BARB

1/4 NPT

FEMALE

5/16” BARB x 1/4 NPT

FEMALE

5/16”

HOSE

PLACE 3/8" ADAPTER FITTING

INTO TBI FUEL INLET

THROTTLE SPACER BLOCK

UPPER FITTING

LOWER FITTING

SUPPLEMENTAL

INJECTORS

CONNECT TO FITTING ON

DISCHARGE PLENUM

INJECTOR CONNECTORS ARE INTERCHANGEABLE AND REVERSIBLE

VORTECH FUEL PUMP

USE 3/8" ADAPTER FITTING

AT STOCK FUEL FILTER

VORTECH FUEL PRESSURE REGULATOR

FUSE BOX

RELAY

TERMINAL #87

(-) GROUND

VORTECH SUPPLEMENTARY FUEL INJECTION COMPUTER

Fig. 5-a

GROUND

BROWN WIRE IGN COIL (-) NEG. BLACK WIRE GROUND

87a

RELAY WIRING

SCHEMATIC

25A

FUSE BOX

4WD

(+) FUEL PUMP

SOLID GRAY WIRE IN FUEL PUMP HARNESS (RUNNING ALONG THE DRIVER'S SIDE FRAME MEMBER

8586

(+) BATTERY LUG

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

5. SUPPLEMENTARY FUEL INJECTION COMPUTER AND RELATED SYSTEM - Cont'd.

TEMPLATE

THROTTLE BODY

DRILL TWO HOLES THROUGH BOTTOM OF THROTTLE BODY

UNTIL POSITIVE THROTTLE SHAFT CONTACT

USE 3/64" OR #56 (.046) DIAMETER

.100

(88-95 GM Lt Trk(4GC))

.100

4.550

Fig. 6A-a

6A. MAIN BRACKET AND POWER STEERING PUMP - 1988-1993 MODELS

A. Install the connector bracket to the front of the

stock bracket at the power steering pump with the two longer metric fasteners provided. Some vehicles use metric and others use standard SAE threads. Check the threads on the fasteners you have just removed against the ones supplied prior to installation. Both metric and standard fasteners have been provided for your convenience. Leave the fasteners slightly loose until all fasteners are started.

B. Position the main supercharger mounting plate

and install the fasteners as shown in the graphic. Make sure not to forget the 1/8" long tube spacer behind the plate on the inward bolt.

C. Remove the fastener securing the stock bracket

to the cylinder head on the outward side. Install the cast aluminum mounting bracket behind the new mounting plate and on top of the tab on the stock bracket (where you just removed the fastener). Place the 3/8-16 x 5-1/2" bolt through the plate and into the head, passing through the tab on the stock bracket.

D. Remove the smaller alternator fastener and

install the upper stiffener plate as shown. Do not secure the stiffener until the supercharger is installed.

E. Attach the stiffener rod between the cylinder

head and mounting plate. A one inch spacer is used at the cylinder head as shown in Fig. 6A-a.

F. Secure all other bracket fasteners at this time.

STIFFENER PLATE

MOUNTING PLATE

3/8-16 x 1"

5/16-18 x 1"

STOCK BOLT

3/8-16 x 5-1/2"

3/8-16 x 1"

3/8-16 x 1" OR M10-1" x 25

POWER STEERING PULLEY

ATTACHMENT PLATE

ALTERNATOR

.125 SPACER

MOUNTING BRACKET

1" SPACER

3/8-16 x 2-3/4"

SUPPORT

3/8-16 x 2"

5/16-18 x 1"

FOR 1988-1993 MODELS

Fig. 6A-a

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

6B. MAIN BRACKET AND POWER STEERING PUMP 1994 - 1995 MODELS ONLY

A. Disconnect all electrical connections at the al-

ternator.

B. Remove the alternator from the vehicle and set

aside.

C. Loosen the main cast iron accessory mounting

bracket.

D. Remove the power steering pump fasteners

and set pump aside temporarily. Remove mounting bracket.

E. Locate the power steering pump into the sup-

plied mounting bracket. Install the two right side bolts finger tight.

F. Fasten the new mounting bracket to the engine

leaving the bolts loose.

G. Attach the Vortech mounting plate by sandwich-

ing the lower left mounting plate hole in between the mounting bracket and power steering pump. Use spacer 'C' (0.22") in between the plate and the power steering pump mounting boss. Use the original bolt to secure the assembly.

H. Slide spacer 'B' (1.083) in between the mount-

ing bracket and the back of the supercharger plate as shown in 7/16-14 x 5-3/4" bolt into the bracket. Do not tighten.

I. Reinstall the alternator and all electrical connec-

tions.

J. Install the attachment plate onto the back of the

alternator mount using the original bolt. Place spacer 'A' (1.895) in between the attachment plate and the back of the supercharger mounting plate using a 3/8-16 x 3" bolt, 3/8" nut and washers.

K. Connect the support rod between the cylinder

head and the rear of the mounting plate. Use the 3/8-16 x 2-1/4" stainless steel bolt and a 3/8-16 x 1-1/2" bolt, nut and washers for attachment. A 1" spacer is used at the cylinder head as shown in

Fig 6B-a

. Tighten all bracket fasteners at this

time.

L. Reinstall the power steering pump pulley. M. 1995 models use a new style ABS control unit

that must be adjusted slightly to provide supercharger clearance. Remove the front two of the four 8mm bolts fastening the ABS mounting plate to the vehicle. Pry the front of the ABS mounting plate up approximately 1/2" to 5/8". Install the supplied 1/2" spacers underneath the mounting plate and secure with the supplied 8mm bolts and washers.

Fig 6B-a

. Thread the supplied

(88-95 GM Lt Trk(4GC))

6B. MAIN BRACKET AND POWER STEERING PUMP 1994 - 1995 MODELS ONLY, Cont'd.

3/8-16 X 3"

7/16-14 X 5-3/4"

FACTORY POWER STEERING PUMP BOLT

ALTERNATOR ATTACHMENT PLATE

SPACER 'A' 1.895

FACTORY ALTERNATOR BOLT

SPACER 'B' 1.083

POWER STEERING PUMP MOUNTING FLANGE

1" SPACER

SPACER C, .22"

3/8-16 x 2-3/4"

3/8-16 X 2-1/4"

STAINLESS

STAINLESS STEEL BOLT

STEEL BOLT

3/8-16 X 1" BOLT, AN 3/8" WASHERS

FOR 1994-1995 MODELS ONLY

7. COOLING FAN SPACER

A. Thread the four M8-1-1/4" X 55 threaded studs

into the holes on the water pump to the shoulder. Loctite mended on threads.

B. Place the 5/8" fan spacer over the studs and

onto the pilot.

C. Place the cooling fan assembly onto the spacer

and secure with the nuts and washers provided.

D. Reinstall the fan shroud upper half.

thread locking compound is recom-

3/8-16 x 2"

3/8-16 X 1-1/2"

Fig. 6B-a

SUPPORT ROD

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

ALT

TENSIONER

SUPERCHARGER

POWER

STEERING

WATER

PUMP

CRANKSHAFT

IDLER

A/C

TENSIONER

MOUNT TENSIONER WITH SUPPLIED FASTENERS YOU MUST USE THE WASHERS

8. SUPERCHARGER MOUNTING

A. Attach the supercharger drain hose to the fitting

on the bottom of the supercharger and secure with the clamp provided. Make sure to rotate the clamp so it does not interfere with the mounting plate.

B. Mount the supercharger to the mounting plate

with the four 3/8 16 x 1" bolts and washers and one 3/8-16 x 1-1/4" bolt and washer for the plate stiffener (See

Fig. 8-a

.) (For 1994-95 models, the supercharger is mounted with five 3/8-16 x 1" bolts and washers only. The stiffener is not used.)

C. Attach the oil feed line and secure.

MOUNTING PLATE

SUPERCHARGER MOUNTING BOLTS

WARNING: The oil system contains a small

orifice that is easily plugged. DO NOT use any type sealant on any of the threads. Instead, use clean engine oil. Disassemble and blow out entire line if you have any doubts.

3/8-16x1-1/4"

3/8-16x1"

FOR 1988-1993 MODELS ONLY

Fig. 8-a

9. FACTORY ACCESSORY DRIVE BELT AND SUPERCHARGER DRIVE BELT

A. Using the stock accessory drive belt, install as

originally installed.

B. Loosely attach the tensioner bracket to the

supercharger with the fasteners provided. (See

Figs. 9-a, 9-b

.) Make sure to use the washers on

all locations.

C. Adjust belt tension by rotating the adjuster plate

with a 1/2" drive socket and extension and secure.

NOTE: It will be necessary to reset the

belt tension after approximately 250 miles.

MOUNT TENSIONER WITH SUPPLIED FASTENERS. NOTE: WASHERS MUST BE USED ON ALL LOCATIONS.

Fig. 9-a

ALTERNATOR

(88-95 GM Lt Trk(4GC))

Fig. 9-b

10. DISCHARGE PLENUM

A. Thread the supplied 90° plastic fitting into the

3/4 NPT bung located on the discharge plenum. (The fitting should be screwed in until snug, pointing down & to the right at approximately a 45° angle.)

B. Attach the discharge tube between the plenum

and supercharger with blue sleeves; secure with clamps as shown.

C. Install the short 1" hose piece onto the 90° fitting

with hose clamps. Attach the supercharger bypass valve (vacuum pointing toward the outside of vehicle) to the short hose.

D. The discharge of the bypass may either be

routed to atmosphere by using the supplied 1"

K&N air noise on deceleration), or back to the supercharger air inlet tube by using the supplied 1" x 10" hose and 3/4" NPT x 1" plastic fitting. If routing the air bypass back to the supercharger inlet:

• Mock-up the steel supercharger inlet tube into

• Center punch and drill a 59/64" hole into the

• Thread with the supplied 3/4" NPT x 1" plastic

E. Connect a vacuum hose to the bypass valve and

a vacuum source.

F. Connect the 5/32" vacuum hose between the

small fitting on the side of the discharge plenum and the TEE that feeds the pressure normalizing holes in the spacer block (see Fig. 5-a on page 5).

filter (This installation will produce some

its approximate final location. inlet tube and thread with a 3/4" NPT tap. (See

Fig. 10-a

for hole position.)

hose barb into the air inlet tube. Connect the long length of 1" hose from the bypass to the air inlet.

Backside of Inlet Tube (Installed)

Backside of Plenum

Fig. 10-a

1-7/8"

Approx. Center (Vertically)

Drill: Tap:

(optional)

Supercharger Bypass Valve

15SEP01 V1.1

(88-95 GM Lt Trk(4GC))

59/64" 3/4" NPT

P/N: 4GC020-010

11. AIR FILTER, INLET DUCT AND PLENUM

NOTE: On model years 1993 and later, it will be

necessary to replace the resonator unit with the earlier type prior to modifying. The Chevrolet part number is 25097949.

A. Modify the stock resonator chamber by cutting

off the end at the point where the radius stops. (See

Fig. 11-a

B. Remove the internal baffle tube and deburr the

cut edge.

C. Fit the new end cover, with the air filter element

provided, over the end of the modified resonator. Secure the cover end by drilling two 3/32" holes (transfer the location from the cover) and fasten with the self-tapping screws provided.

D.Peel off the protective adhesive cover and

place the plenum gasket on the throttle body adhesive side down. Lower the discharge plenum on top of the throttle body and secure with the two acorn nuts and washers provided.

NOTE: Do not overtighten nuts or the ple-

num will be damaged.

E. Secure the inlet tube to the two bosses on the

front of the plenum with the two 5/16" x 3/4" fasteners. On some models, the dashpot assembly interferes with the tube. Two spacers have been provided to correctly position the inlet.

F. Connect the inlet elbow to the supercharger

inlet using the blue sleeve and clamps provided.

G. Connect the inlet tube and elbow together with

the 3-1/2" diameter flex tube and clamps.

H. Connect the new air filter end cover to the inlet

tube with the 3-1/2" diameter flex tube and clamps.

I. Attach the crankcase vent from the right valve

cover to the fitting on the inlet tube. Slight trimming of the plastic vent may be necessary.

(88-95 GM Lt Trk(4GC))

STOCK RESONATOR

CUT OFF END AT END OF RADIUS

VORTECH FILTER AND

END COVER

Fig. 11-a

12. FINAL REASSEMBLY & CHECK

A. Refit the upper fan shroud. B. Reconnect the battery. C. If your vehicle has gone over 10,000 miles since

its last spark plug change, you will need to change the spark plugs now before test driving the vehicle.

D. Check all fittings, nuts, bolts and clamps for

tightness. Pay particular attention to oil and fuel lines around moving parts, sharp edges and exhaust system parts. Make sure all wires and lines are properly secured with clamps or tie wraps.

E. Check all fluid levels, making sure that your

tank(s) is filled with 92 octane or higher fuel before commencing test drive.

F. Start engine and allow to idle a few minutes,

then shut off.

G. Recheck to be sure that no hoses, wires, etc. are

near exhaust headers or moving parts and for signs of any fluid leakage. Check ignition timing to make sure it is set to stock specifications before commencing test drive.

H. PLEASE TAKE SPECIAL NOTE: Operating

the vehicle without the Supplementary Fuel Injection Computer or any other subassemblies completely and properly installed and working may cause FAILURE OF MAJOR ENGINE

COMPONENTS.

I. Test drive the vehicle. J. The supercharger drive belt stretches initially

and will require adjustment between 250 and 400 miles.

K. Read the STREET SUPERCHARGER SYS-

TEM OWNER'S MANUAL AND WARRANTY REGISTRATION FORM within thirty (30) days

of purchasing your supercharger system to qualify.

Fig. 12-a

WARNING: Do not attempt to operate the ve-

hicle until ALL components are installed and ALL operations are completed including final check.

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

ENGINEERING, LLC

1650 PACIFIC AVENUE • CHANNEL ISLANDS, CA 93033-9901 • (805) 247-0226

FAX (805) 247-0669 • www.v ortechsuperchargers.com • M-F 8:00 AM - 4:30 PM PST

15SEP01 V1.1

P/N: 4GC020-010

(88-95 GM Lt Trk(4GC))

Vortech Engineering GM 7.4, GM 7.4 Light Truck Installation Instructions Manual

Specifications and Main Features

Frequently Asked Questions

User Manual