How to Install the Holley Terminator EFI on a Small-Block - Feeding Fuel

A high-tech EFI System teaches our small-block a few new tricks

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When new technologies come out it doesn't mean what you used in the past was bad, it just means that some "cat" with a pocket protector figured out a way to do things just a bit more efficiently. In the automotive world, many new technologies are developed by the OEs and later trickle down to the aftermarket. This is exactly what happened with the growth of electronic fuel injection (EFI). EFI has been around for a long time, but it wasn't until the mid-'80s when Americans went "all in" and started dropping the use of carburetors. For OEs, the driving reason for the switch was to meet new government emissions and mileage regulations. EFI also allowed for a car's ECU to self-tune and adjust to changing conditions like altitude and temperature.

In the '90s, the easiest way to get EFI under the hood of your classic was to swap in something like an LT1 or LS1 engine along with all the OEM wiring and ECU. But recently, the aftermarket has come up with systems that let those with older engines easily make the move over to EFI. One such company to offer up EFI to the masses is Holley. Long known as the "top dog" in terms of carburetor technology, Holley figured that they could put all their fuel-delivery expertise to good use. They've recently taken their initial system and further refined it, resulting in their Terminator EFI kit. Their goal was to make the switch from carb to EFI as painless as possible. To this end, the kit is very simple to install. The throttle body bolts on and hooks to the linkage just like one of their carbs. Almost all of the sensors come mounted to the throttle body, and the wiring is clearly labeled and mostly a plug-and-play affair. They also designed the ECU to be capable of self-tuning, which is a great feature for those who don't have access to a chassis dyno tuner.

To see how easy it really is, we decided to install their kit on our carbureted 383 stroker that powers our '67 Camaro.

We should note that while the kit contained everything for the EFI install, it didn't address the fuel system needed to support it. This is an area where you can spend very little or quite a bit. As opposed to carburetors, EFI requires a higher fuel pressure and this typically means a return-style fuel system.

Now, if funds are tight, you can modify your stock tank to accept a return line and run an inline electric pump and filters. Keep in mind though that without internal tank baffling you could run into fuel-starvation issues during hard turns when the fuel level is low. But, for just cruising about, tank baffles aren't necessary. For a bit more time and money, you can add baffling to your tank or spend even more and get a ready-to-run, pre-built tank like we did. Our point is, the way we addressed our fuel needs isn't the only way to get there. Still, expect the swap to EFI to set you back between $2,000-$3,000.

950 Cfm Throttle Body 2/27

01. The centerpiece of the Holley Terminator EFI kit (PN 55-406, $2,050) is this 950-cfm throttle body. The air entry area has been CFD computer-designed for max airflow, and much of its design was patterned off the unit used in the NASCAR Sprint Cup series. Our unit came in Holley's Hardcore Gray (hard coat anodized) finish, but they also offer it in tumbled polish for a few bucks less.

Throttle Body Housing 3/27

02. The key to this unit having such a small footprint is the integration of all the sensors and fuel injectors into the throttle body housing. The four 80 lb-per-hour injectors can support 250-600hp engines.

Throttle Body Sensors 4/27

03. The sensors in the throttle body, like the Idle Air Control (IAC) Motor, Throttle Position Sensor (TPS), MAP sensor, Intake Air Temp Sensor, and fuel injectors are easily replaceable if needed. Most of the sensors will eventually be hidden by the air cleaner.

Fuel Ring 5/27

04. One cool design feature of the Terminator system is the switch to an annular discharge fuel ring. This way of injecting fuel into the airstream doesn't suffer from the delay and restrictions found in booster designs.

383 Stroker Small Block 6/27

05. This was our starting point: a 383 stroker small-block with an 850 Holley double-pumper carb.

Water Temp Sensor 7/27

06. After removing the carb, we installed the water temp sensor that came in the Terminator kit. We placed it in the rear port of our RHS intake manifold. Later, we found that the water temperature back there was more than 20 degrees cooler than at the front port, so we eventually relocated the sensor to the front of the intake manifold. This was necessary since the Terminator's ECU won't go into learn mode until it registers a water temperature of at least 160 degrees.

Terminator Throttle Body 8/27

07. The new throttle body bolted into place just like the 4150-flange carburetor it replaced. We decided to reuse our billet Lokar linkage plate, but the Terminator did include brackets for throttle and transmissions like the TH350, 200-4R, and 700-R4.

Throttle Return Spring 9/27

08. The linkage should be familiar to anyone that's messed with carburetors, and the kit included all the throttle and linkage studs. It's highly recommended that a throttle return spring be used.

Negative Wire 10/27

09. Included in the kit was this main system harness. The Holley instructions (which is a free download on their website) are very clear, but in short, the harness needs to be run clear of any high-voltage "noisy/dirty" wires and, of course, away from high-heat items like headers. There's also a main power harness included in the kit. For this, the negative (black) wire was run directly to the negative post of the Optima battery, and the positive (red) lead was run directly to the positive post on the battery. Again, both of these must go directly to the battery.

Holley Ecu 11/27

10. We decided to mount the Holley ECU in the Camaro's interior, so we used a 2-inch hole saw to make a hole in the lower section of the firewall. The ECU can be mounted in the engine bay, but it needs to be in a somewhat protected area and in a place where you can still hook up the handheld module. Under the dash seemed like a cleaner option.

Terminator Ecu 12/27

11. The Terminator ECU is weather-sealed to protect the internals from the elements. The easy-to-use handheld programming module is the key to getting the system up and running. One very cool feature of this ECU, which sets it apart from some other systems on the market, is that if needed, the ECU can be fine-tuned via a laptop just like Holley's top-of-the-line HP and Dominator ECUs.

Wires Grommet 13/27

12. With the wire loom run though the grommet and into the car's interior, the hook up process was a simple matter of plugging the clearly labeled connectors into their corresponding sensors. The Terminator system has provisions to control up to two electric radiator fans and an A/C Shutdown output that will deactivate the A/C at higher throttle positions. If the car has an ignition box, the Terminator can also adjust engine timing.

Bosch Wideband 14/27

13. We then installed the system's Bosch wideband O2 sensor. To do this, we first drilled a 7⁄8-inch hole in the passenger-side Hooker header. The included boss was then fully welded to prevent leaks. Holley recommends that the sensor be located 1-10 inches after the collector, with a minimum of 1 to 24 inches of exhaust tubing after the sensor.

Holley Efi System 15/27

14. The Terminator kit included a lot of parts, but it was left to us to bring the fuel system up to EFI standards. This is an area where price can vary wildly depending on how you want to tackle it. In short, the system requires a pump capable of supplying 400 lbs-per-hour at 45 psi, and the proper filters (down to 10 microns) need to be installed. Holley offers a variety of kits, but we chose the EFI kit (PN 526-3, $600) that included an in-line fuel pump, billet regulator, billet 100- and 10-micron fuel filters, Earl's Super Stock hose, and Super Stock push-on fittings. Since we ended up replacing the tank, we would have been better served to buy what we needed from Holley à la carte.

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