Modern engine-management systems are being installed in traditional Pontiacs more today than ever before. The desire for more efficient power production, better fuel mileage, improved driveability, and of course, bragging rights are the main reasons. Following that trend, Cygan Speed Engineering has moved into EFI installations using the BigStuff3 GEN3 Pro SEFI (Sequential Electronic Fuel Injection) system.
Having just finished a build on a 468-stroker engine for customer Jeff Hopper from Michigan, we dropped in on Gary Cygan’s Renfrew, Pennsylvania, shop to see how much power the combo produces on his Stuska dyno and watch him tune it via laptop for more. Gary tells HPP, “Jeff wanted a 600-horse, pump-gas engine that was docile enough for easy street driving, so I decided on the SEFI, aluminum heads with SD Performance’s chamber modification, a very streetable 10.67:1 compression ratio, and a hydraulic roller cam that’s not too aggressive. Given the mild cam specs, I think the fuel injection and tuning added power over a carbureted combo.”
[1] The BigStuff3 Gen3 Pro...
[1] The BigStuff3 Gen3 Pro SEFI system (PN BS3-004-002) is delivered with a powdercoated aluminum Engine Control Unit (ECU), main wire harness, injector harness, wide-band oxygen sensor, and a communication cable. This particular part number also adds in DAI (internal data logging).
Cygan Speed Engineering is now a distributor/installer for the BigStuff3 system. Truth be told, Gary is so taken with the GEN3 and how it works, he told HPP he would rather do EFI installations and dyno tuning on existing engines than build complete engines.
BigStuff3 is the brainchild of John Meaney and his brothers, Leo and Joe. John created the DFI system sold through ACCEL, and also developed the FAST standalone system. In 2003, he and his brothers formed BigStuff3 to “focus on the design, manufacture, and marketing of state-of-the-art electronic engine and powertrain controllers for the performance aftermarket,” says the company mission statement. The result thus far is the development of the GEN1 and GEN3 systems.
The main features of the GEN3 Sequential Electronic Fuel (SEFI) system are wide-band oxygen (WBO2) air/fuel ratio control, injector phasing, and individual cylinder fuel and spark compensation, but there are many more. (See the sidebar for details.) BigStuff3 provides the electronics, wiring, and software for the system, but not the hardware. The throttle body, intake, fuel rails, injectors, fuel regulator, ignition system, and MAP sensor are chosen and sourced by the dealer/installer.
[2] Perched atop a Wilson...
[2] Perched atop a Wilson Manifolds 1-inch open spacer—which Gary says, “adds some more plenum area, but still maintains hood clearance”—is a Wilson High Flow (PN 472175) throttle body that’s CNC- machined from 6061-T6 aluminum with the goals of “maximum flow per-square-inch of cross-sectional area” and reduced mass in mind. It uses 1-to-1 linkage, unlike a typical four-barrel carb.
Once Gary assembled the engine and installed the SEFI system, certain values had to be input in the computer during the Main Configuration setup so it knows what engine it’s dealing with. Interface between a PC, the engine, and the GEN3 ECU is via BigComm software, which contains the tables required to calibrate the system.
Before the tuning can begin, Gary has to first dial-in the crank trigger to the software. With the engine off, he sets the crank trigger for 50 degrees before TDC. It’s important because it gives 5 degrees of time lag to cover the ECU to respond at the 50-degree reference angle with a max of 45-degrees timing. The engine will not be run at 50 degrees timing—the timing will be controlled by the ECU. He then dials in 30 degrees timing (as an example) via the ECU, so he can check it at the balancer with a timing light and compare that with the reading the software is providing on the PC’s screen. If they don’t match but are fairly close, fine correction can be made in the software.
[3] It flows 1,136 cfm, has...
[3] It flows 1,136 cfm, has tapered and radiused throttle bores, throttle shafts with less cross-sectional area to increase airflow, and brass throttle blades to limit vibration and thermal expansion. The blades open inward, Wilson says, to eliminate their part-throttle directional influence that can cause poor air distribution. They are installed with aircraft-quality fasteners with Loctite and are peened.
Prior to tuning, Gary also has to select the type of Throttle Position Sensor (TPS) being used to output the throttle angle to the ECU. (The GM TPS is 0.5V to 4.5V for 0- to 100-percent opening.)
The system can be tuned in a speed density (engine speed and engine load) or Alpha N (throttle angle and engine speed) algorithm. Though most engine applications will use the speed-density control algorithm, the instructions indicate that for engines with cam duration over 260 degrees at 0.050, the Alpha N mode should be employed due to lack of engine vacuum with the higher overlap cam.
[4] Gary chose an Edelbrock...
[4] Gary chose an Edelbrock Super Victor EFI intake featuring injector bosses that the company says are positioned for optimal fuel-spray patterns and best power. He also used the matching fuel rails.
[5] FAST says its 42-lb/hr...
[5] FAST says its 42-lb/hr high- impedance injectors (PN 304208) feature modern magnetics for quicker throttle response, a precision-ground pintle and wide-spray angle to enhance fuel atomization, and a valvebody design that thwarts clogging and aids hot starts. Gary also went with a FAST sensor kit (PN 307053) with a one-bar MAP, TPS, and water and air-temp sensors.
[6] Gary made this adjustable...
[6] Gary made this adjustable custom bracket from 6061-T6 aluminum to mount the Electrimotion crank trigger. The trigger sends its signal to the ECU, which is wired to the points terminal on the MSD box and the box is…