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.

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Two street-worthy beasts with completely different appetites. We love it.

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).

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Top: Project Blank Slate (foreground) is naturally aspirated, and benefits from the self-learning FAST EZ-EFI 2.0 with an LS conversion.
Bottom: That shiny tube is the passage for boost from the F-2 ProCharger on Project MaxStreet, and that means we have some custom tuning to do.

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.

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Before we can run MaxStreet on the Dynojet, we needed to make sure we could get a good idle and the correct air/fuel ratio. You have to learn to walk before you can run like a bat out of hell.

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.

Top: The F-2 ProCharger sounds great when it's winding up, but before we romped on it we needed to make sure we were getting the right amount of fuel.
Bottom: We're running pump gas on Max, and adding boost and water meth on top of that. This means some tuning with a laptop is mandatory.

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.

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To get our base parameters set and plot out the fuel curve, we pulled in the expertise of David Page from FAST to help us make sure we start out on the right path.

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.

Top: It might look inundating to the novice, but Westech's Joe Trujillo has been tuning for years and said that it's not too hard to learn if you're patient.
Bottom: We started out slow, just getting some basic lower-rpm runs on the Dynojet before we started romping the skinny stick and making power. Baby steps is what it's all about when you're taming a beast like MaxStreet.

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.

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After some initial tuning and setting up the fuel mapping, we pulled in 900.00 RWHP and 799.10 lb-ft of torque from our 1966 Nova.

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.

With the help of Joe Trujillo and Westech Performance, we're able to get some tuning parameters set and make MaxStreet a driveable. Next phase is to really hammer on it and lay down some stronger numbers so MaxStreet can live up to its name.

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.

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We still have some tuning to do, but with some good solid numbers we were able to hit the pavement and have just a little fun with Max.