The point here is that the atomization efficiency provided by electronically-operated fuel injectors, especially when placed in proximity of the combustion space, offer tangible benefits. EFI systems enable more control over many of the rudimentary requirements of efficient internal combustion engine oper-ation, leading to an opportunity for increased power with reduced fuel consumption and (believe it or not), a chance to decrease exhaust emissions.
Of the arguments frequently offered by non-proponents of EFI in racing, one deals with the use of electronics and the possible sensitivity of these components in a harsh racing environment. Any concerns in this particular area are dwindling, as witnessed by some robust racing engines doing well with not only iterations of OEM systems but aftermarket conversion packages that simply replace carburetors with throttle bodies and supporting electronics. Some companies provide multi-point EFI induction systems that locate injectors in closer proximity to combustion spaces to reduce upstream effects of pulsating and circuitous flow paths. Obviously, mechanical fuel injection systems stand in the gap between carburetors and EFI, but there appears to be movement afoot among providers of mechanical systems to blend electronics into some of these packages.
In previous columns, I've also suggested that an engine's brake specific fuel consumption performance typically occurs at or near peak brake torque. Of the factors that affect this condition, one is engine speed and the other is quality of atomized fuel delivered by a carburetor. At speed below peak torque, inlet mean flow velocities are below those required to aid atomization efficiency. This can be verified by evaluating the extent of unburned hydrocarbons (unspent fuel) in the exhaust gas.
Similarly, at higher rpm, the tendency for a mechanical separation of fuel from the air grows, thereby increasing the chances for poorly atomized fuel in the combustion space, verifiable by the same analysis process. Improvements in carburetor main fuel booster design (or modifications) can help the problem but not remove its influence altogether. As a result, combustion efficiency as evidenced by BSFC data typically shows higher numerical values for this data below and above peak torque.
On the other hand, fuel injectors used in an EFI system tend to supply a higher percentage of atomized fuel throughout a broader range of engine speed. Throttle response generally improves, as does on-track power and fuel economy. Reflecting on these conditions, BSFC curves tend to be somewhat flatter and nearer peak torque values above and below this engine speed, further indicating a wider span of improved combustion efficiency. Add to the package an opportunity to electronically vary cam timing and a new perspective can be taken on the benefits of on-track, electronically-controlled circle track engines . . . don't you think?