Give just about any musclecar guy a carburetor, and he'll tell you how he could tune, rebuild, or modify it. Ask that same guy about fuel injection, and he'll start to stutter like a boy who just got caught stealing a cookie from the cookie jar. The truth is, there are a lot of confusing situations and misconceptions about EFI. One of the main reasons many people shy away from EFI is the tuning aspect. Let's face it, tuning an EFI setup requires a knowledge of ohms, impedance, timing, reading an air/fuel meter, and finally, a computer to program everything.
Why go through the hassle of installing fuel injection if your carburetor is working just fine? Having a well working EFI setup can make your Mopar so much more fun to drive-that's one. Fuel economy will also be improved, due to the EFI naturally metering the fuel by knowing what the engine needs at any given moment, via the O2 sensor-that's two. Finally, giving your muscle Mopar a modern fuel-injection system that looks like a carburetor is just plain cool-that's three. Yep, we said fuel injection that looks like a carburetor. Now, don't mistake this for a stock-looking, throttle-body injection system like a GM car might have. This unit looks remarkably like a performance carburetor, but with injectors hidden inside the false float bowls.
Adding the Retrotek injector/carb unit is as easy as replacing a square-bore flanged carburetor. If your carb is a spread bore-such as a ThermoQuad-you'll need an adaptor plate, like one from Mr. Gasket.
The company making this bolt-on-yes, we said it-kit is Retrotek Speed located in Corona, California. The kit functions with the use of some key components. First are the injectors. Standard Bosch "port"-style injectors are used and are basically worry free. The big item on the list is the Engine Management System (EMS), which controls everything. In order for the EMS to know what's going on with the engine and what its needs are, the EMS relies on three input signals. One is from the Coolant Temperature Sensor (CTS). the computer needs to know what the engine coolant temperature is so it's able to regulate the fuel requirement for efficient operation. The second input is generated by the Manifold Absolute Pressure (MAP) sensor. This sensor takes a vacuum (or boost signal in supercharged applications) and turns it into an electronic signal. The computer uses this vacuum-converted electronic signal to measure the load on the engine. This allows the computer to adjust the ignition timing-advancing it and retarding it as needed. It performs essentially the same job as the vacuum advance diaphragm on an old-fashioned mechanical distributor. Finally, the Throttle Position Switch (TPS). The TPS is mounted on the throttle shaft of the "carburetor" body and changes resistance as the throttle opens and closes. The computer uses this information to monitor engine load, acceleration, deceleration, and when the engine is at idle or wide open throttle. The sensor's signal is used by the EMS to enrich the fuel mixture during acceleration, and to retard and advance ignition timing. Ok, we told you the basic parameters of what the system is, but how easy is it to install and how does it work?
Ease of installation is dictated by which kit your engine needs. If you are building an engine with more than 500 hp, you need to add more plumbing for the return line. If your engine is making less than 500 hp, you will be able to use the return-less system. The hardest part of the install is making the final decision of where to mount the external fuel pump, the EMS unit, and the fuel filter. Other than that, it is literally plug and play.
Before you mount the EMS controller, run your wires through the firewall and make your connections at the engine. Retrotek recommends that you DO NOT cut or shorten the wires for the kit.
The great thing that the Retrotek kit has over other aftermarket EFI kits is its ability to "learn" the engine it's mounted on. The "Smart Tune" technology will learn the engine's needs within a couple of days driving, and it's also completely tunable if you're one of those guys that can't keep your hands off things.
The system as installed on our 360-powered Dart Sport was a bit on the rich side. The unit seemed to work ok, but you could tell that the setting was rich. the guys at Retrotek Speed designed the initial program to run a little fat because it saves people from ruining a perfectly good engine by running it overly lean. Once we got a few small details worked out, it was fine.
The small details were in no way a reflection on the Retrotek kit. In fact, the guys at Retrotek were more than helpful over the phone when we had problems. So, if you want EFI for your Mopar, and you want it to resemble a stock carbureted system, look no further than Retrotek Speed for what you need.
