It's the first decent weekend of spring. You've had your hot rod hidden in the garage all winter while you planned your image assault on the drive-in crowd. The usual suspects have been milling around at the local drive-in telling each other new lies, but you waited for this moment to make your appearance. Dusk approaches as you slowly pull into the driveway to make one quick loop around the cruise site. Almost in unison, everyone looks.
Sticking triumphantly out of the hood of your righteous ride is a killer calliope collage of eight injector stacks contributing to a lumpy idle that just reeks of horsepower. A couple of knowledgeable rodders pass immediate judgment saying,"Yeah, that's a mechanical-fuel-injection setup. The problem is they don't work on the street. Too bad, it sure looks cool."
That's when you stake out a parking spot and pop the hood. An eager crowd quickly gathers to eye your new induction. Then someone in the crowd exclaims,"Hey, that's an electronic-fuel-injection setup! That's too cool. How'd you do that?"
If you're looking for the hottest new trend, it doesn't get any better than this. Our pals at Blower Drive Service (BDS) are riding the crest of a new wave that's converting '60s-style mechanical-fuel-injection manifolds to electronic fuel injection (EFI). This is pure image horsepower and promises to be the hottest thing since Dare To Be Different.
Think about it. Everyone wants an exotic induction system, but the penalties are always poor driveability, no power, fouled plugs and terrible gas mileage. In the past, hot rodders were willing to put up with a skewed version of Billy Crystal's line,"It's better to look good than it is to run good!" According to Don Enriquez at Hilborn,"We don't recommend that anyone try mechanical fuel injection on the street. The average guy can't make it work." The typical mechanical-fuel-injection system is an individual-runner-style intake, which is generally difficult to set up properly for part-throttle operation. This is because mechanical fuel injection was originally designed for racing with an emphasis on wide-open-throttle metering. Unfortunately, street operation is practically all part throttle. All these limitations are eliminated with EFI.
Mechanical devices like a carburetor or mechanical fuel injection rely on a manifold vacuum signal or crude mechanical controls to meter fuel at part throttle, and therefore are a compromise throughout most of the engine's part- and full-throttle rpm range. Most EFI systems, on the other hand, utilize a fuel map that controls the engine's entire load and rpm range with specific fuel-metering commands. Therefore, the tuner has more control over the fuel curve to detail exactly the amount of fuel the engine needs with EFI. To put this into perspective, Craig Railsback at BDS says even the most basic EFI fuel map has a metering capability equivalent to between three and five million jetting combinations. Try that with your Holley carburetor!
Add the advantage of digital spark timing to precise fuel control and the tuning power of EFI is far superior to any mechanical system. In addition, most aftermarket EFI systems allow the tuner to run the engine in"closed loop" using an O.E.M. oxygen sensor in the exhaust. Closed loop runs even serious performance engines with big cams, heads and a wild intake at 14.7:1 air/fuel ratio at part throttle for excellent throttle response and mileage.
BOUNDLESS OPPORTUNITIES
But enough tech, let's take a look at the fun part of all this. The barriers to creating a wild-looking induction system have just been torn down."The only limitation," Railsback says,"is your imagination." Right this minute hip hot rodders are buying used Hilborn, Crower and Enderle mechanical-fuel-injection manifolds and converting them to EFI. A typical used Hilborn intake with linkage and stacks is selling for between $200 and $500. Often these manifolds will need to be rebuilt with new throttle shafts. Hilborn, for example, will rebuild a used unit, but the cost can add up to more than the price of a new unit. Currently, a new Hilborn manifold with stacks for a small-block Chevy sells for just under $1100.
But the basic intake is just the beginning. The next step is to take the unit to BDS, where new or used mechanical-fuel-injection manifolds are converted to EFI by adding bungs to mount the electronic injectors. To this you must add a complete EFI wiring harness, sensors and a computer control such as an ACCEL/DFI system, BDS's system of choice. All of this isn't cheap, because a total conversion by BDS could run from $3500 to $5000, depending on added options. Compared to a $500 manifold-and-carburetor investment, EFI is unquestionably expensive, but high fashion has never been cheap.
Of course, there are less expensive ways to go. BDS offers a complete do-it-yourself EFI conversion kit that features everything you need to convert any kind of manifold into an electronic-fuel-injection system. The kit includes a complete ACCEL/DFI computer, a wiring harness, injectors, a fuel pump, fittings, sensors and all the rest for $2500, excluding the stainless-steel tubing that connects the fuel block to the individual injectors. BDS also offers the stainless-steel fuel-line kit for roughly another $100. Of course, if you can find a used EFI computer and wiring harness, that would reduce costs somewhat.
While it is possible to combine a stock GM or Ford EFI computer and wiring harness with a converted mechanical-fuel-injection intake, Railsback doesn't recommend this as an option. The problem for the end user with factory EFI is the lack of tuning ease once (or if) the system is up and running. Factory fuel and spark maps are burned into dedicated chips that cannot be reprogrammed easily, and while it's certainly possible to customize a chip to make the system driveable, this should be left up to only the most EFI knowledgeable.
The key to making any nonemission-hot-rod EFI package work is integrating an ACCEL/DFI, Haltech, Motec, Electromotive or other programmable EFI computer with your trick manifold so you can fine-tune the system. This usually requires a laptop computer, which can be rented or borrowed for the short time needed to tune. How well can you make one of these systems work? As an example, Railsback recently finished an Enderle mechanical-fuel-injection manifold conversion on Mike Hurley's 467ci Hemi-powered '34 Plymouth. Harv's Automotive, next door to BDS, did the EFI installation, and then Railsback spent a few hours tuning the spark and fuel curves. With the tuning accomplished, Hurley drove his '34 from San Diego to Pleasanton, California, for the annual Goodguys street rod show and knocked down more than 14 miles per gallon on top of wowing the crowd with his too-trick induction system.
There's far more to trick EFI inductions than we can possibly detail in a short story like this. Perhaps even more exciting is the creativity that should soon spring from the street rod/street machine artists once they embrace this idea. While this may be bold new territory, it's also classic hot rodding to combine the aesthetics of a killer-cool induction system with '90s technology to produce a too-hip hot rod that's also a ton of fun to drive. You can't ask for more than that!
