Corksport Performance High Pressure Fuel Pump Internals


Zoom Zoom Boom.

It is the one thing Mazdaspeed owners dread to hear of: the dreaded ZZB’s. There are many tales from owners who have modified their cars but fell prey to this beast, their beloved car’s motor now a paperweight.

How does it happen?

The high pressure fuel pump (HPFP) is designed to compress the fuel delivered by the electric fuel pump in your tank, to the pressure required for high pressure injection used by vehicles with direct injection motors (of which the Mazdaspeed 3 and 6 are, respectively). In the case of a Mazdaspeed 3, this pressure is in the neighborhood of about 1600-1700 p.s.i. In stock form, the HPFP can supply that pressure regularly with no problems. A car that is well maintained, with regular oil changes, will usually not have a problem with their HPFP (knock on wood). But when you start adding aftermarket parts to your car, that is when the issues begin.

When you begin to mod your car, and add an intake for example, you are now adding more air than the stock tune is calibrated for. Now modern cars are fantastic machines, they are designed with a little leeway for the electronics on the car to compensate for a wide range of conditions and situations. The ECU will make corrections for the new influx of air, and the ECU will also bump up the fuel p.s.i. to compensate. What once was a HPFP that was operating within a safety margin of its specifications, is now being asked to deliver a bit more pressure than required by a stock engine. You keep forcing in more air (because we love the sound of spool and the feel of boost) and now your HPFP is struggling to keep up. When that happens, the ECU is basically opening the floodgates, dumping as much fuel as it can to keep up, your p.s.i. starts to fall, your pump starts to fail and………..BOOM.

But fear not intrepid reader, there are ways to fight this menace! If you have been reading previous articles (and you should be), we have already covered one of the necessary tools we will need on this crusade, the Cobb Accessport V3. The other is the reason for today’s article: I present to you Corksport’s HPFP internals.

The Corksport Performance High Pressure Fuel Pump Internals Kit

HPFP kits are available from a number of manufacturers: Cobb Tuning, Autotech, CP-E, some offer just the kit and others offer complete pumps with the upgraded internals. The kits usually run about $345.00-$349.00. I ordered mine from Corksport Performance (, and the kit comes in an aluminum case that included a new piston, sleeve, high-rate spring, retainer, a retainer installation assembly, instructions with color pictures, and some Corksport stickers (for the mad street cred).

What you get inside of the nice case.

Corksport claims that their HFPF kit was *designed specifically for the MZR engine platform (Mazdaspeed 3, Mazdaspeed 6, and CX7 Turbo) and that their internals were 50% larger than the OEM stock internals for increased fuel volume flow. The included instructions helped make sense of the installation process when I got stuck, and the installation assembly made the retainer installation on to the end of the piston a snap. For more on the installation, make sure to watch the Corksport Performance High Pressure Fuel Pump Internals Installation video that is available here on the site (you are watching the videos aren’t you? Don’t forget to like and subscribe!).

Once the installation was done, I then connected my Cobb Accessport V3 to the car, loaded up a Stage 1 map and set the gauge screen to monitor my fuel pressure. Previously my car on the stock internals would not go past 1686 p.s.i. at WOT in 4th gear. I drove the car around for a bit to allow the new parts a chance to break in before I started testing. Even in relaxed driving conditions, the car seemed to be a bit smoother while accelerating, but that could be my butt dyno that needs calibrating. After doing a couple of 4th gear pulls (in Mexico), my fuel p.s.i. was now reaching over 1800 p.s.i. and even into the 1900’s! The HPFP internals aren’t as glamorous as say an intake or a front mounted intercooler, but the peace of mind that can be gained from knowing that the HPFP can supply the proper pressure with modifications is well worth it!

With the fuel system now upgraded, I can safely move on to the power adder mods and some more aggressive tuning maps. Should I add a downpipe? 3″ full exhaust? Or should I try running a new map to get more boost?

Stay tuned.


*from the Corksport website: