Quick Speed Cars

Speed Density and Mass Air Flow are two different systems used by Ford to help an engines computer regulate the amount of Fuel and timing adjustments the engine will require in order to run effectively and efficiently. In very simple terms, I’m going to attempt to explain how each one works and what you should do if you own a vehicle with one of these systems.

Ford came out with Speed Density first, and basically an engineer sat down and wrote a program based on the current data he had on hand, as in engine size, design, and what ever other variables where involved with that engine and that vehicle operating program is pretty much set in stone. When you turn the key on, and start a vehicle with this system, you will get the same result each and every time. The room for varying any parameters if very minuscule.

Ford eventually got a bit wiser and switched over to Mass Air Flow. Mass Air Flow (MAF) is very different in the sense that it has a meter in the air induction tubing that measures the volume of air ( the Mass of Air Flowing over a meter that calculates the volume of air flowing past it) going into the engine and based on that volume, it makes instantaneous decisions about how much fuel to add and where the ignition timing should be.

Based on these simple facts, when you start to modify an engine in a car with a Speed Density system, you are going to in fact make the engine run more poorly, even though you may have done some exhaust upgrades or installed a better flowing intake or bigger cam, because that computer is programmed to run according to its original engine design, and it will never recognize all the upgrades you have done. Basically, if you want your Speed Density Vehicle to run to the best of its ability, don’t do anything but change the oil and filters, that is if you choose to leave it Speed Density.

On the other hand, with a MAF equipped system, every modification you make will be instantly recognized and the computer will adjust to the new parameters, based on the additional air flowing into the engine, past the registering meter that is reading the air flow volume.

So you can change your exhaust, or do head work, or put a better flowing intake manifold, and your vehicle will perform better and in many cases, more efficiently. In some cases, you may need to have your actual meter recalibrated, for instance, if you were to put higher flowing fuel injectors in the engine, then you would have to recalibrate the meter based on those new injectors. This can only be done by a professional shop, but it isn’t a big deal to do, and doesn’t cost a whole lot of money either.

The good news for you Speed Density guys is, there is a conversion kit readily available for most of your vehicles. So you are not stuck leaving that engine stock. If you decide to make any changes or upgrades, you will want to go out of your way to find one of these conversion kits, no matter where you get it from.

Even without doing any modifications, people have reported smoother idle, better drive ability and in some cases, better gas mileage too. Based on these simple facts, it is generally in your best interest as well as your vehicles best interest to make this upgrade, if you still have a Speed Density System commanding your ride.