Upgrading a C3 to FiTech Go EFI
Although there are still fans of the carburetor, one cannot deny the improvements that an EFI setup braing. EFI is a more precise way of metering the air-fuel mixture of the engine, which typically results in better drivability across broader temperature ranges, improved fuel economy and of course increased performance. What's not to like about switching your Vette over to fuel-injection?
A New Age
The folks over at FiTech Fuel Injection seem to have perfected the formula for converting your fuel delivery system from a carbureted setup over to electronic fuel injection. Sure, EFI conversion kits are nothing new, but FiTech has developed a simple, cost-effective system that is easy for the home mechanic to install and performs incredibly well. Their most basic system, the Go Street EFI, is a bolt-on setup that uses a simple oxygen sensor and coolant sensor to allow for closed-loop fueling, and even has the ability to self-learn for precise mixture control and increased performance. With pricing starting at $795 (similar pricing to that of a high-end carburetor) it is a system that is definitely worth considering for your C3 Corvette!
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FiTech Options
Whether the engine in your Corvette is stock or has had significant performance upgrades, FiTech offers several different EFI systems that will cover just about any setup. The entry-level Go Street EFI supports up to 400 horsepower and is their most popular model, with most of the same features as the higher-end units, but the best bang for the buck. Similar to the basic Go Street unit is the Meanstreet EFI, which supports up to 800 horsepower via its 8 high-flow fuel injectors (instead of 4 on the Go Street Unit). The Go EFI 4 is the middle-man in the product lineup that supports 600 horsepower and includes the ability to control and adjust ignition timing. Finally there are the Go EFI 4 Power Adder and 8 Power Adder units that are compatible with power adders like blowers, turbos, or nitrous, and incorporate laptop tuning. In general, most find the Go Street EFI with its handheld programmer to be the way to go, but if you need additional fueling for a higher horsepower engine or want the ability to control ignition timing, the Go EFI 4 is also hugely popular.
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Fuel Supply
Except for the 1982 Corvette and its crossfire injection system, C3 Corvettes came from the factory equipped with a carburetor and mechanical fuel pump. In order to get the fuel up to the throttle body injection unit at the proper pressure, FiTech has two options, both simple. The first allows you to continue using a mechanical fuel pump by routing the line into FiTech's Fuel Command Center fuel delivery system, then another line from the command center to the injection unit. This setup pumps up the low pressure of the mechanical fuel pump to high-pressure (58psi) on demand, and eliminates the need for any return lines to the tank. Better yet, C3 owners have found that the command center fits perfectly in place of the original fuel vapor canister, thus making install a breeze. The alternative option is to run either a frame-mounted electric fuel pump or in-tank pump with a fuel return line. FiTech offers their own Fuel Delivery Kit that includes a 255 liter-per-hour pump and all necessary accessories to complete the install. Similarly, those who are budget-minded can easily piece together their own components and plumbing in order to save a few bucks.
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Installing the Throttle Body
Installation of the FiTech injection unit is as simple as it gets; it bolts right on top in place of your carburetor. Simply disconnect the fuel line, vacuum hoses, and throttle linkage before removing the entire carburetor. As with installing a Holley carb, clean the intake manifold mating surface, install a new gasket, and bolt down the injection unit. The throttle body injection unit has 5 vacuum ports to accommodate power brakes, vacuum ignition advance, or transmission modulators. Similarly, FiTech provides 3 inlet fuel ports and one outlet that can be used as necessary depending on which fuel supply method you have chosen. The throttle linkage is standard Holly style, which should allow the linkage to be simply hooked in place with no modification.
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Electrical Hookups
Electrical hookups for the FiTech system are simple and straightforward. The system requires an oxygen sensor that can be placed into either side of the exhaust system, preferably a few inches behind the collector. A bung can be welded into the exhaust, or a Clamp On Bung Kit can be used. With the sensor installed, it connects directly into a harness included with the throttle body. A coolant temperature sensor is also required, and installs in the cylinder head or intake manifold, also plugginf directly into the throttle body electrical harness. FiTech also includes a wiring harness to tie into a 12v power source, the ignition switch, the fuel pump/command center, ignition coil, an electric fan (if applicable), and ground. With everything connected, it is only a matter of using the handheld programmer (which connects to the throttle body injection unit) to input a few parameters such as engine displacement, desired idle speed, and camshaft size. Finally, just crank the engine, and it ought to fire and quickly learn any quirks of your set up. Within minutes you will be enjoying the pleasures of a modern fuel injection setup.
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For help with service of your car, check out the how to section of CorvetteForum.com