Fuel Injection System - New-Age 455

In addition, the necessary software to create a fuel and ignition curve can be too complex for the average enthusiast. Even though the conventional wisdom may be that EFI would be better on a Pontiac engine, many of those who tried stand-alone systems in the past often struggled with problems they never had with a carburetor-enter Mass-Flo with a fix.

Mass-Flo Fuel Injection System: Seeing a market for a self-tuning EFI system for Pontiacs that employed a MAF sensor, Mass-Flo Fuel Injection Systems came out with an ingenious design that eliminates most, if not all, of the headaches a Pontiac hobbyist incurs converting a traditional engine to injection-a true bolt-it-on-and-forget-it conversion kit.

To achieve the desired results, Mass-Flo owner Chris Richards went shopping in the OE market. This may be a hard pill for a GM-based readership to swallow, but the Ford EEC IV (Electronic Engine Controller, Fourth Generation) system is considered the most reliable, accurate, and tuneable of any made. Thus, the heart of the Mass-Flo design is a Ford 5.0 Mustang EFI controller. When it came to the MAF sensor, the GM LS1 design is respected for the same qualities the Ford ECU enjoys, and through much effort, the GM airflow meter and the Ford engine controller were joined in marriage-truly the best of what Detroit has to offer.

The obstacle with the MAF sensor was always its packaging or how to place it in the airflow stream. With an EFI-converted Pontiac V-8, there was no practical method for doing this. That was until Mass-Flo came on the market. With a design that is surely making the competing EFI companies kick themselves, Mass-Flo took the problem and solved it by attaching the MAF sensor directly to the company's custom-made, four-barrel throttle body. Then a traditional air-filter assembly can be employed, so a Shaker hoodscoop could still be mounted on a T/A, for instance. Since the system is Ford-based, all of the sensors are Dearborn-specific.

On The Dyno

With the engine completed, Bob and Craig Wise of RaceKrafters bolted it on to their Stuska dyno along with a set of Hooker Super Comp 171/48-inch, Second-Gen, F-body headers. RaceKrafters has one of the most accurate and sophisticated dyno cells around, and it's set up to properly test both EFI- and carburetor-equipped engines. The dyno cell is equipped with the latest Depac brand-control and data-acquisition software. In addition, the cell has two fuel-flow meters, so brake-specific fuel-consumption (BSFC) values for EFI can be determined. Since fuel-injection systems pump more fuel than they use, both the feed and return needs to be measured so the consumption rate can be determined.

After a normal break-in period, the oil was changed and the first full-load pull was made with the Demon carburetor in place on the EFI manifold. The engine performed flawlessly, and the carburetor did likewise. When HPP ordered the Speed Demon, we provided all of the engine specifications so Barry Grant could ship the proper calibration. The company sent us the 750-cfm carburetor with 76/83 jets, and after some trial and error, they proved to be right on the money. All that was required was an idle-speed and mixture adjustment.

With the wet-flow fuel system, the Pontiac produced 520.1 hp and 547.1 lb-ft of torque at 5,300 and 4,400 rpm, respectively, on 92-octane pump gas. The average horsepower and torque from 3,500 rpm to 5,500 rpm was 453.73 and 530.26, respectively.

Even more interesting was the fuel efficiency of the SD-455. The average BSFC value was 0.354 and at peak torque it was 0.30. This means on the average it took 0.354 pound of fuel to produce 1 hp-a remarkable rate of chemical-to-mechanical energy conversion.

Executing the same test with the engine now fueled through the Mass-Flo EFI, the results showed just 3.5 percent less power than the carburetor. At peak, the 455 produced 502.9 hp and 522.5 lb-ft of torque. The average readings showed a similar drop. The horsepower aggregate was 437.48 and the torque came in at 511.54 lb-ft. Also, the engine consumed more fuel as represented by the BSFC readings. The average BSFC increased to 0.468 from 0.354 with the carburetor. In addition, the 455 wanted only 28 degrees of total ignition advance with the carburetor, but the EFI system desired 32 degrees BTDC to produce the best power. With the Speed Demon, the engine would idle nicely at 750 rpm, but the EFI demanded an idle speed 100 rpm higher to achieve not quite the same level of happiness.