Carburetor Vs.Electronic Fuel Injection - Tech

Understanding the limitations of the original Weber carburetors, Dynatek Racing decided to offer a system that provided all of the classic good looks of the 48 IDA downdrafts without all the tuning headaches associated with keeping them running properly. Externally, the Classic Fuel Injection certainly looks the part, with eight individual 48mm throats ready to feed each of the eight cylinders through billet-aluminum radiused air horns. Unlike the original Webers, the Classic Fuel Injection from Dynatek Racing is not carburetion at all, but rather a sophisticated injection system housed inside the retro throttle bodies. Hidden from view between the throttle bores, where you would originally fi nd the emulsion and jetting circuit on a Weber carburetor, are a pair of fuel injectors. Naturally, the injector sizing can be adjusted to suit the needs of your motor (ours relied on a set of 36-pounders). Continuing with the retro theme (for Cobra or street-rod owners wanting to further conceal their counterfeit carburetion), the Classic Fuel Injection is fed through the original Weber fuel inlets. Ours were sized to accept pipe fi ttings, but original-style (though high-pressure) banjo fi ttings can also be employed.

More than just a replacement for a set of original Weber IDA carbs, the Classic Fuel Injection offers improved performance over the downdrafts thanks both to precise tuning and enhanced airfl ow. The tuning aspect is fairly self-explanatory, as modern fuel injection (the system comes with a stand-alone management system) can provide precise tuning only dreamed of by the carbureted contingent. Additional power over a Weber setup is further improved with additional airfl ow. While retro in appearance, the throttle bodies supplied in the Classic Fuel Injection system are anything but. Each throttle bore outfl ows its carbureted counterparts by almost 90 cfm. That means the Classic Fuel Injection offers an additional 700 cfm over the original Webers, and this doesn't even take into account the differences in the lower manifold. After extensive testing, Dynatek saw the need to design its own lower intake for the 351 (other applications are in progress as well). Extensive work was needed on the original Weber intake to help match the fl ow potential of the throttle body. After all, what good does a 380-cfm throttle body do on an intake that fl ows only 250 cfm?

On paper, the new Dynatek injection system scored high marks in terms of looks and fl ow potential. I have to admit, I'm a sucker for multicarb induction systems, and havinga quartet of dual-throat carbs (or injection in this case) makes for one heck of a visual statement. On the cool scale, an individual-runner system, especially a retro-modern version, has to rank near the top, but how would this new system perform?

Given its obvious fl ow superiority to the original Weber system, we decided to test the new Dynatek injection against the tried-andtrue Victor Jr. intake. Feeding the impressive carbureted manifold was an equally impressive fuel mixer in the form of a Holley 750 HP carb. From a visual standpoint, the single four-barrel carburetor couldn't hold a candle to the more impressive quartet of throttle bodies, but owners don't always purchase their induction system on looks alone (though many do). On paper, the combined flow rate of the eight bores in the Classic Fuel Injection offered nearly 3,000 cfm. This compares to 750 cfm offered by the Holley carb, but when it comes to making power, airfl ow isn't everything. Intake design features such as runner length and port volume play a major role in determining the shape of the overall power curve.

There was only one way to demonstrate the power potential of the new injection system, and that was to actually run it on the dyno. Truth be told, the Victor Jr. had one more advantage in the form of porting. Though we wanted to run the test using an out-of-the-box Edelbrock intake, all we had was a ported version. The odds were certainly stacking in favor of the carburetor.