My first plunge into the world of electronic fuel injection happened way back around 1990. I plugged a DFI fuel injection system into my ’65 Chevelle, and there are vestiges of that system (I’m embarrassed to say) still on the car. Suffice to say I’ve been playing with EFI systems for more than 30 years, so you might think I’ve seen it all. But the truth is, I still consider myself to be a bit of a novice – especially when I watch how quickly tuners navigate around this latest batch of software. So, when I learned that FAST’s David Page was putting on a seminar on the basics of tuning both the EZ-EFI 2.0 system and the XFI Sportsman system, I couldn’t sign up quickly enough.

On class day, I found myself at Westech Performance in Mira Loma, California, where we do nearly all of our dyno testing. There were perhaps 25 guys in the class, and the first day was all about EZ-EFI 2.0. I figured there were still things to learn, and I was correct. In fact, I easily filled four pages of notes on different aspects, which will quickly turn into a story as soon as I can transcribe those notes into an intelligible collection of thoughts.

Even though I’ve been involved with EFI for all these years, there was still plenty to absorb, especially about the new adaptive learning systems like FAST’s EZ-EFI 2.0. I’ve tried this system on a big-block Nova, and it worked very well. But I was interested in a second car on which I have tried other self-learning EFI systems and they did not perform well.

Perhaps the most important piece of information I learned was these self-learning systems are designed for a typically mild street engine with decent manifold vacuum numbers at idle. When you try to combine an engine with a big cam that has very low idle vacuum, these entry-level throttle body systems are limited in their range of operation. Page said for the EZ-EFI 2.0 system, his experience is engines with an idle vacuum of less than 10 inches Hg will not respond as well. That’s exactly what I experienced, so I think that 10 inches of manifold vacuum is a great go-no-go gauge for these self-learning systems.

In my case, the engine barely idled at 6 inches of vacuum, so no wonder I had difficulty making these throttle body systems work properly. Page says the solution is to retain the use of the EZ-EFI throttle body but step up to the XFI Sportsman EFI package. This system allows far more specific tuning abilities with a full 16×16 grid of specific tuning points. Plus, you can also open up certain areas like idle and part throttle to allow even more specific tuning points. This compares to the EZ-EFI system where you choose one idle air-fuel ratio and that’s it – one data point versus perhaps 10 or 15 possible tuning points.

This is a quickie photo taken by my pal Richard Holdener as David Page illustrates changes to the engine running an EZ-EFI throttle body on a small-block on the dyno. The class was held at Westech Performance with help from Rick Stoner, Steve Brule and crew.

For guys who don’t want to learn all about part-throttle, partial-load tuning to improve drivability (which, I think is by far the most difficult of all the tuning parameters), then the EZ-EFI 2.0 is the best choice. But this means you will have the best luck when using that system on an engine that idles at 12 inches of vacuum or higher. If your engine idles below 10 inches, then the more sophisticated Sportsman XFI system will be necessary to give the tuner the tools he needs to make the engine run properly.

Face it. Despite how much power the engine makes at 6,500 or 7,000 rpm, if it is a street engine, it will spend 90 percent of its time at part throttle. So having a system that offers the tuner the ability to fine-tune the engine at part throttle will make the driving experience much more rewarding.

So, I’ve just done one whole column on just one point I learned in David Page’s two-day FAST EFI class. There’s a story brewing in my head right now that will outline more of the great points offered in the school that anyone can apply to all the different adaptive learning fuel injections systems. The point is that it’s never too late to learn something new, and you just might discover that all this technology can really make an engine run far more efficiently than you ever thought possible. It works for me!