EFI Versus Carburetors & Other News- Engine Masters

EFI Versus Carbs
The inclusion of fuel-injected engines for the 2009 Engine Masters Challenge opens the door for one of the most anticipated events yet. This change is a marked departure from all previous competitions, wherein only a single four-barrel carburetor was allowed. With the inclusion of fuel injection, many questions and theories will be put on the line for scrutiny where it matters most--in the heat of competition.

Perhaps the most significant debate that will be put to the test will be the question of how carbureted engines will perform when in direct competition with those equipped with EFI. This debate has raged on for decades, with strong opinions held on each side. How will it play out when the goal is all-out power over a wide operating range? While the 2009 Engine Masters Challenge will definitely provide some clues, right now it's all strictly speculation.

There is no doubt that fuel injection has some inherent advantages when compared to a carbureted engine. Topping the list here is a precise means of controlling fuel distribution to each cylinder of an engine. It is intuitive that an engine with some holes running rich, while others are running lean, will be compromised in terms of power output. EFI easily remedies this possibility, and does it easily with electronic control of the amount of fuel metered at each injector. With EFI, it is even possible to individually tune a cylinder for optimal air/fuel ratio by means of a simple keystroke command to the processor via a computer. With a carb, this kind of electronic tuning isn't possible; however, a carbed system can also be optimized through traditional means, such as manifold and runner modifications and stagger jetting. It is another means to the same end result.

Another potential edge with an EFI system stems from the fact that the engine's intake manifold no longer has to carry an air/fuel mixture, with the manifold typically handling only dry air up to the point of injection. In contrast, a carb requires a wet manifold, and design considerations include limitations associated with the requirement to carry suspended fuel as well as air. Although this represents a definite design constraint as far as manifold layout, there is no denying that carbureted manifolds have benefited from decades of extensive racing development.

Aside from the potential advantage arising from an EFI intake manifold handling only dry air, a multi-point EFI system also has the benefit of introducing the fuel at eight individual locations corresponding to the eight cylinders of an engine. This alleviates the need for the runners to accommodate fuel introduced from a central location, as would be the case with a single four-barrel carb. The result is far greater flexibility in intake manifold design, with the opportunity to create tuned, equal-length runners, and to optimize the plenum volume to suit the engine's requirements. In contrast, a carbureted single four-barrel intake manifold's geometry is dictated by the single fuel introduction point at the plenum of the intake manifold. Nevertheless, the picture for carburetor intake manifolds changes considerably when multi-carbs are permitted. Multi-carbs allow the point of fuel introduction to be varied by manifold design, providing far greater intake manifold design flexibility. This will be the first year in which multi-carbs are allowed in the Engine Masters Challenge.

So, will the 2009 Engine Masters Challenge definitively settle the EFI versus carb debate once and for all? There's no doubt that this event will bring a new level of insight, and perhaps a few surprises, but it's my hunch that the Challenge will provide each side with more theories and ideas to debate for years to come.

Wes Roberson Named Competition Director For 2009 Jegs Engine Masters Challenge
In an unpredictable turn of events, our previously announced competition director, David Freiburger, has been hired to take the helm of our sister publication, Hot Rod Magazine, as Editor In Chief. While we are delighted at Mr. Freiburger's new role within the company, our immediate concern was to fill the important position of competition director for the 2009 Jegs Engine Masters Challenge. Good fortune prevailed in that experienced NHRA tech official and Engine Masters Challenge veteran Wesley Roberson is able to make room in his busy schedule to accept the competition director position. Those of you who have competed in or followed the Challenge are familiar with Wesley's fair and even-handed approach to rules enforcement, and maintaining the flow of the competition. As a valued and highly regarded member of our Engine Masters event team for the last three years, we are proud to have Wesley back for the 2009 event.