When you’re planning to go EFI from a typical carburetor setup on a classic car, the choice has been clear for quite a few years. Converting over to a throttle body style conversion kit is the simplest way to better starts, smoother idle, and better economy.
Trying to find all the components at a wrecking yard is a thing of the past. Companies like Fuel Air Spark Technology (FAST) have removed the hours of trying to figure out what goes where and provides a simple to install, self-learning, fully functional EFI conversion system.
Most classic cars are running the standard 4150-style flange that makes the conversion simple to switch to systems like the FAST EZ-Fuel system stand alone EFI kit. Even LS swaps in classic cars can benefit from a self-learning system in the FAST EZ-EFI 2.0 kit, where a simple plug and play process allows you to do the fun work (installation) while the computer does the hard work (tuning).
These systems allow you to take care of the install – like we did with Project Blank Slate, our 1969 Camaro road race build – and once you start the car for the first time the system immediately begins learning and making its own adjustments. That’s right, no laptop needed to get your engine running smoother and delivering better economy at the same time.
Project MaxStreet Breaks The Rules
But then there’s Project MaxStreet – our 1966 Chevy Nova – and then all the rules have changed. While Max is intended to be a street car and not a track star like Blank Slate, there’s nothing about Max that is simple. For starters, under the hood is a couple of power adders, like the F-2 ProCharger and the water methanol injection kit. For this setup, we relied on the FAST XFI 2.0 system, a fully tunable EFI conversion for engines like this BBC.
The 555 cubic inch big-block is putting down close to 1,000 horsepower at the wheels, and while some FAST EFI conversion systems can handle up 1,200 horsepower, putting boost to the BBC means that a custom tune is mandatory. Boost not only adds compression, but it also plays with the wideband O2 sensor a little, making it think you need more or less fuel when the engine really needs the opposite. This is where the laptop is mandatory, and allows you to make more of the decisions than the computer does.
Detonation is not something you want from a high-power build, and that’s where the expertise of Joe Trujillo from Westech Performance entered the garage. As Joe explains, you can’t just set up an EFI system when you’re dealing with boost, and expect the computer to figure out what’s going on with the fuel delivery on it’s own.
Too many parameters need to be addressed, because you get a different fuel requirement at the same rpm depending on whether you’re throttling up, throttling down, or just cruising. Joe’s job was to make a few initial runs and see where the air/fuel ratio (A/FR) was sitting and then see where the pattern took things when the power was building.
Joe was able to take some initial readings and then help map the best path for fuel to make sure that MaxStreet was getting enough fuel when it was needed, and then back off the timing when it was advancing too much. Throw water-meth into the mix, and you’re making further changes to make sure that you’re not going to put a hole in a piston by not allowing the computer to deliver the right amount of fuel.
When all was said and done, we weren’t completely finished with tuning the Nova, we managed to see 900 RWHP and 799.10 lb-ft of torque on our Dynojet 224xLC dynamometer. We know there’s more potential, but as Joe stated in the video, to tune the XFI is not going to be too difficult, but you do have to watch your fuel maps and see what happens as the transmission shifts and the load changes to make sure that you smooth out the transitions and keep the A/FR where it needs to be.
Self-Learning And Laptop Tuning
As you can see, two different classic Chevrolets with high horsepower in common – but completely different attitudes – requires different measures for each. While the FAST EZ-EFI lives up to its name in ease of installation and driveability, the FAST XFI conversion will require some expertise and a laptop to get the fuel mapping to where it needs to be.
Adding boost changes the game, but all is not lost when it comes to an EFI conversion. Much like a carburetor, you can tune your FAST XFI 2.0 to deliver the right amount of fuel when needed. And unlike a carburetor, the computer can be taught how to react and where the fuel mapping needs to be when the variables have changed.
If you have more questions about which EFI conversion system is right for your build, be sure to visit the FAST website and contact the tech support team for any questions you may have. Even when you’re dealing with a high-horsepower application with boost, like MaxStreet, there’s a solution for EFI for you, you just have to know where to turn.