HOW IT WORKS
Any naturally aspirated engine, regardless of brand, size, or combination of parts, requires a given air/fuel ratio at a given load. These ratios do not change from engine to engine, until you get into forced-induction applications. (We'll get to that later.) The needed air/fuel ratio changes with such things as engine temperature, air temperature, and atmospheric pressure, and the changes are the same for all engines. The task for any management system is to add the correct amount of fuel to the air the engine uses. Carburetors do it mechanically, so accuracy is limited. Speed-density systems do it by comparing the readings from various sensors to tables within the engine controller to determine the amount of air the engine is using. This actually works very well, if the values in the tables are correct, and therein lies the challenge. A professional tuner is required to enter the correct values into all of those cells in all of those tables. The next step is to drive the vehicle in the real world and adjust those values to tune out all the drivability issues. The other problem is speed density's limited ability to self-adjust, so your laptop must permanently reside in the passenger seat.
Worse than that, nonprogrammable or preprogrammed speed-density systems arrive at your door pretuned at the manufacturer on a dyno with a predetermined combination of parts on a specific engine. Well, with these systems, you can't fix them. And if you want to make a change to your engine, you can't adjust for it.
Mass-Flo does it differently. The MAF meter can measure the amount of air entering your engine, and again, if you know how much air the engine is using, then you just add the correct amount of fuel. It's that simple. The air/fuel ratio is adjusted accordingly to compensate for the load and variances in engine temperature, air temperature, and atmospheric pressure by reading values from the sensors. If you decide to upgrade your engine, Mass-Flo adapts to those changes. Remember, an engine is just a big air pump, and changing heads, camshafts, intakes, exhaust systems, and displacement are just ways of making your air pump more efficient (use more air). With speed density, it's back to the dyno to start all over again.
Speed density relies heavily on the signal from the MAP sensor to determine how much fuel to add. So what happens when your camshaft produces poor vacuum? You guessed it, horrible driveability. The Mass-Flo does not use a MAP sensor, and you can use any camshaft you want with the system. Pretty trick.
In forced-induction applications, the ratios are different, and a different tune is needed. Mass-Flo has a tune to cover those applications and can be adapted just about anywhere. If you want something custom, just ask. The company can do dual-quads and other applications where two MAF meters are required. In all cases, no tuning is ever required by the customer.
Q&A WITH CHRIS RICHARDS OF MASS-FLO EFI
CHP: Can the end user expect to see any significant increase in fuel economy by using Mass-Flo?
Chris Richards: That's a good question, and a tough one to answer accurately, especially since every engine combination will vary. What we can tell you is this: You are almost assured of an improvement. We've sold systems to customers who were previously using other brands of aftermarket fuel injection and saw large gains in economy (as much as 25 percent), as well as gains in drivability and power. Even more over a carburetor. Some customers have reported more than a 75-percent increased fuel mileage over their carbureted setup. We routinely hear of figures in the area of 21-25 mpg on engines making well over 500 hp!
CHP: How about emissions? Will I pass?
CR: Another tough one. Whether or not you pass will be determined by your combination of engine components. No induction/ management system can make an absolute fire-breathing gas hog pass emissions. However, we have never had a customer fail emissions, including engines that maybe should have failed. What we can say is that the Mass-Flo system will make it as clean as possible, and if there is a chance, the Mass-Flo system is your best shot.CHP: How much horsepower will the Mass-Flo system support?CR: We have used it with great success with engines producing as much as 1,000 hp.
CHP: I don't have much hood clearance. Will the Mass-Flo system fit?
CR: The Mass-Flo system will fit anywhere a conventional 4-bbl carb and intake manifold will fit. In many cases, it can go where a carburetor won't fit. Our throttle body is 11/4 inches lower than a typical 4-bbl carburetor.
IT'S ALL INSIDE
One call does it all! The kit for the small-block Chevy includes:
* Intake manifold
* 1,000-cfm 4-bbl throttle body w/idle-control motor and throttle position sensor
* 9/16-inch-diameter fuel rails w/ mounting assembly
* Mass-Flo ultracompact high- flow MAF
* Complete stand-alone wiring harness
* Choice of 19-, 24-, 30-, 36-, or 42-lb/hr flow injectors (larger sizes available)
* All required sensors
* High-performance coil w/heat sink and mounting bracket
* All assorted hardware and fittings necessary for system installation
* Detailed installation instructions