Adding power to your Mazdaspeed 3 and Mazdaspeed can be amazing and very rewarding. One of the most important decisions you can make when tuning these cars is which fuel pump to use. Since we have never seen a proper comparison of the currently available models we decided to test them for the Mazda community. In this multi-part series, we will talk about the basics, the differences and the advantages with all of the available options.
Most aftermarket fuel pump upgrades consist of changing the internal parts of the factory pump with an enlarged piston and sleeve. By enlarging the piston, you increase the volume of the pump; thus creating more flow and the ability to maintain pressure at higher power levels.
When you first start taking the fuel pump apart, the first thing you are met with is the sight of a strange black deposit in the cap of the pump. Shown above are the deposits common to most caps. The bottom is a machined surface that should be clear of debris. In order for us to more clearly understand the situation we sent the cap out to undergo chemical analysis.
The spectrum analysis shows that the buildup is made of motor oil and defoaming agents that are added to motor oil. The oil in the cap is from the camshaft case that drives the pump, a slight amount leaks by the seal and into the pump. When installing new internals it would be a very good time to clean that area as best as you can and possibly replace the O-ring that seals the area inside the cap.
Once we understood what the substance was we then set out to see the options available. We purchased a CP-E pump (APR), Autotech internals and KMD internals to compare and test. Next time we will be measuring all the internals and comparing expected increases while determining what the real differences were. If you already have a pump, are thinking about getting one or are still scared, you’re going to want to see the next blog in this series.