Fuel Injection - Pure-Pontiac EFI Buyer's Guide

Although not sold in a Pontiac since 1981, the traditional Pontiac V-8 engine continues to benefit technologically from a seemingly endless array of new parts that are being developed to increase power and improve reliability and efficiency.

Despite the fact that Rochester mechanical fuel injection was introduced in 1957 on the Bonneville, electronic fuel injection didn't become a factory-installed Pontiac option until the early '80s as a throttle-body system. Hence a traditional Pontiac V-8 engine was not factory-fitted with any type of fuel-injection system after 1958.

Automakers went to fuel injection to address several issues, chiefly the mandated Federal emissions standards and consumers who wanted a more refined engine package that would start, idle, and perform consistently under all conditions.

Basic Basics
Based on the opening of the throttle blades and the amount of air entering the unit, the carburetor determines the amount of fuel required to atomize with the air. The resulting mixture enters the intake-manifold plenum via the carb's throttle blades. It then flows through the intake-manifold runners and into the intake ports of the cylinder heads. When the intake valve opens, the mixture enters the combustion chamber.

The basics of electronic fuel injection are similar to the throttle-body style-other than the electronic part, that is! An electronic control unit (ECU) commands the fuel-injection system, be it throttle-body or port-type, via various sensors.

Port fuel-injection systems introduce the fuel via injectors placed in the intake manifold as opposed to through the throttle body, therefore the intake manifold only flows air and is considered a dry-flow system. By dispersing fuel in a fine mist right before it enters the port of the cylinder head, better mixture control can be maintained in a port-injection system than with a carburetor or throttle-body system. Due to the nature of their design, these wet-flow systems are more subject to fuel dropout and distribution issues.

According to David Butler of Butler Performance, "From a power perspective, there is very little difference between a carburetor that is properly sized and dialed-in versus an EFI system. The primary benefits of an EFI system are that rather than replacing jets or secondary rods to compensate for increased temperatures or atmospheric conditions, a street engine or full-race application can allow the ECU to adjust various parameters, ensuring consistent performance."

Converting a classic-Pontiac engine to electronic fuel injection is not the daunting task that it once was. Complete systems and high-quality parts are now available that allow the hobbyist to tailor an EFI system to their particular requirements.

Follow along as a selection of fuel-injection systems are highlighted. We will also explore a selection of other components available to transform your classic Pontiac into an electronically fuel-injected vehicle.

Butler Performance
For about a year, Butler Performance has been marketing and selling complete classic-Pontiac EFI kits that start at $3,499. The baseline kit supports up to 650 hp, and options are available to handle upwards of 1,000 hp. In kit format, the system is setup to utilize speed-density tuning via the F.A.S.T. XFI-computer Windows-based software. Fuel delivery is handled in an efficient bank-to-bank mode, firing half the engine's injectors every 360 degrees of crankshaft rotation for great fuel control and excellent drivability.

ECU: F.A.S.T. XFI ECU with O2 sensor provisions. Includes wiring, fuel-injection and ignition harnesses, a wideband O2 sensor, water and air temperature sensors, and a 1-bar MAP sensor. The base kit contains provisions to hook up the ignition harness to a standard GM HEI or a magnetic pickup distributor such as MSD's Pro-Billet (recommended).

Fuel Rails/Throttle Body: Edel-brock aluminum fuel rails with 91/416-inch-id fuel passage and accessories to support eight Pico-style injectors (1.5-inch O-ring spacing); includes Edelbrock 35 lb/hr injectors. The throttle body is an Accufab or F.A.S.T four-barrel unit rated at 1,375 cfm, and it includes a GM-based throttle position sensor (TPS) and idle air control valve (IAC).

Manifold: The intake is an Edelbrock Victor EFI (based on the Torker II) or Super Victor EFI. Super Victor EFIs are available to fit standard-bore and Dominator flanges. Any manifold, including custom sheetmetal units, can be converted to a fuel-injection-ready manifold.

Fuel System: Barry Grant (BG) model 171006 fuel-injection electric fuel pump, BG model 171023 bypass fuel regulator, and BG fuel filter.

Operating Modes: The F.A.S.T. XFI ECU is a microprocessor-controlled unit that utilizes F.A.S.T.'s C-COM XFI software. Its Windows-based software is tuneable while the engine is running and is done via laptop. The ECU is capable of sequential fuel injection or bank-to-bank operating modes. Additional capabilities include multiple ignition strategies such as HEI or IPU (inductive pickup unit), 1-3-bar MAP capabilities, and the ability to data log a host of other critical engine elements. The computer can control auxiliary components such as fuel pumps and fan controls and allows up to four custom ECU tunes to be stored with switching capability.

Not Included: Fuel lines, distributor.

Options: Butler Performance will design a system to meet the customer's needs. All systems can be optioned to support nitrous and power-adder (turbo or supercharged) choices. Options include larger fuel injectors (up to 160 lb/hr), a 2,000-cfm throttle body, and 2- and 3-bar MAP sensors. Complete fuel systems are available as well as custom fuel-tank modifications. An MSD Pro-Billet distributor with a fully phasable rotor is also available. For customers without experience in tuning aftermarket fuel systems, Butler will supply custom tunes ($200) that have been developed for street engines in the 500-600hp range.

System Availability: Systems are custom designed and available 1-2 weeks after order. All supply parts are available through Butler or the original manufacturer.

MASS-FLO EFI
Mass-Flo EFI has just released its classic-Pontiac EFI kits, which retail at $3,750. The baseline kit supports up to 600 hp, and options are available to bump that limit to upwards of 1,000 hp. In kit format, the system is set up to deliver sequential fuel-injection tuning via a MAF system based on the Ford EEC-IV ECU. A custom tune is created for each customer, and once the system is installed, no additional tuning is required.

ECU: Ford's EEC-IV ECU is the basis for the system. The computer is completely refurbished, and a custom Mass-Flo cover is fitted to facilitate mounting. It includes a stand-alone computer harness along with two O2 sensors, a water and air temperature sensor, a barometric sensor, and a mass airflow (MAF) sensor. The base kit contains provisions to hook up the ignition harness to a supplied custom distributor using Hall-effect electronics. This Mallory-based distributor utilizes a custom-machined base for the Pontiac engine and production electronics available at any auto parts store. Mallory's epoxy-core coil is provided.

Fuel Rails/Throttle Body: Mass-Flo aluminum extruded fuel rails with 91/416-inch-id fuel passage and accessories to support eight injectors (2.650-inch O-ring spacing). Includes Delphi high-impedance injectors ranging from 19-70 lb/hr depending on engine output. The four-barrel throttle body is custom-manufactured in-house at Mass-Flo and is rated at 1,000 cfm. It includes a progressive linkage system utilizing sealed roller bearings and has the airflow to support up to 750 hp. The throttle body includes a Ford-based throttle position sensor (TPS) and idle air control valve (IAC). The MAF is based on a GM LS6 85mm unit that is custom-machined to fit on top of the throttle body and inside the air cleaner (only 211/48-inches tall). Once the MAF is machined at Mass-Flo, the meter is flow-bench tested and the electronics are recalibrated for each application.

Manifold: The intake is an Edelbrock Torker II or Victor. Each manifold is modified in-house to accept the Mass-Flo injectors and fuel rails.

Fuel System: Fuel system not included, but available.

Operating Modes: The Mass-Flo Ford EEC-IV ECU is a modern OEM system that uses a MAF in order to meter incoming air and calculate load to determine fuel requirements. Mass-Flo burns a custom chip for each customer based on the customer's engine flywheel horsepower and displacement. The MAF-based system normally supports changes of up to 100 crankshaft horsepower without additional tuning. In cases outside of what the ECU can adjust for, Mass-Flo will recalibrate the MAF and complete a retune of the ECU for a nominal charge. The ECU can control auxiliary components such as fuel pumps and fans and allows up to two custom ECU tunes to be stored with switching capability.

Not Included: Fuel system.

Options: Mass-Flo will design a system to meet the customer's horsepower requirements. A bonnet and ATI tube with integrated MAF supports blow-through turbo and supercharger options. Other options include additional computer functionality such as rev limiters, adjustable timing retard for boosted applications, and CD and multi-strike ignition systems. Complete fuel systems that utilize either a Mallory S110FI electric external pump or a Walbro-based 250-lph in-tank pump are available from $625-$695. A socketless hose from Mr. Gasket is included in the base kit with stainless braided hose as an option.

System Availability: Systems are custom-designed and available 1-2 weeks after order. All supply parts are available through Mass-Flo or at a local auto parts store (distributor cap, throttle body electronics, and so on).