The chart is a fairly comprehensive representation of the more advertised EFI systems available today. While you are in the shopping mode you might want to condsider which of two basic camps you want to set up shop in — either speed density or MAF based EFI systems.
The speed density uses a MAP (manifold pressure) based fueling algorithm while the MAF based system actually measures the mass flow of air and calculates a corresponding injector pulse width (for your injector size) to provide the corresponding mass flow of fuel to hit your commanded air fuel ratio, which is a mass referenced metric.
The other thing you might want to spend some time considering is the
MSPro-Ultimate (<=clickable) system from AMP/EFI. This is a productized, factory manufactured modern day version of the original Bowling & Grippo MegaSquirt do it yourself Heath-kit style EFI system — except factory manufactured with a Lifetime Warranty.
The MSPro-Ultimate will provide you the ability to use speed density or MAF based fuel control (or several others) while providing a large number of engine management options that you would need to go to a Haltech or Motec system to duplicate. The MSPro-Ultimate is likely the least expensive most fully featured system available with more inservice time than any other commercially available EFI system today.
Most EFI systems use a constant flow fueling model with a pressure regulator to return unused fuel to the tank. The MSPro-Ultimate provides the same capability but also offers a returnless model strikingly similar to some of the Detroit returnless models that allows the operation of the engine w/o a pressure regulator.
The big deal about no regulator is if you have an 800 hp capable fuel system and are driving around town using 25 - 50 HP to move the car, you need to continuously return 750HP+ worth of fuel through your pressure regulator back to the tank. Aside from the obvious flow restriction and squirrely AFR management issues this creates, it also heats your fuel to engine compartment temps.
The fuel heating is unlikely to cause a vapor lock issue because of the higher fuel pressures EFI systems operate at. However the higher temperatures in a return style system will boil off the light ends that the refinery adds to the fuel to create high octane fuel from refinery base stock. This loss of octane will occur in the return line under low pressure as the unused fuel is returned to the tank.
Gasoline light ends vaporize below 100˚F usually around 87 to 90˚F. The upshot is you go from a mid to high 90 octane fuel to a high 80's to low 90's octane fuel in a matter of an hour or so of driving. Which begs the question, why did you spend the additional money for the high octane fuel? We all understand low octane and the impact it has on engine performance and tuning. This is one of those situations where you don't have to suffer self inflicted victimization.
BTW the MSPro-Ultimate comes with one of the more attractive and easy to understand / use tuner interfaces. It is written by TunerStudio and runs native on either PC or Mac platforms. You can download a copy to look at for free off their site.
Check them and check out the downloadable version of their TunerStudio tuning software. I think you will be impressed.
Ed
p.s. You might want to think that you won't be doing the tuning because you will buy that service from someone. I will suggest there is no one more interested in tuning your engine correctly than you are and at around $500 per shot (or more) for dyno and tuning time you will be many dollars ahead doing it yourself. Of course if you are totally disinterested or incapable, then its just a matter of finding the right guy and paying him. Most systems today do have a self learning capability that can get you in the ball park and let you finesse your tune from there.
MSD fuel injection
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Linear Mode
