Fuel Pumps: Best Internals or Complete Units.

[Sassimac]

Hello All...

Simple. What are the best CDFP internals or full assemblies to buy..???

Thanks...!!

[mituc]

I think there are many opinions on this. At some point the CP-E pumps had the smallest failure rate.
The first versions of the KMD internals had some issues, but v2 and v3 were fine. Also, the autotech internals have a pretty good popularity. If installed properly any of these will work just fine.

[richy-m-g]

I installed the Autotech internals in my CDFP. They deliver +2000 PSI when going WOT. However what I did find is that they found weaknesses in the end cap seals and the main union, I'm guessing due to the higher pressure developed. I changed the two end cap seals, and used fuel proof thread lock compound on the main union and all is good. There are some good threads on the American Mazda forums with pictures on how to do the HPFP mod. It's not hard to change them yourself. A bench vice is highly recommended.

[mituc]

Do you have a link about this cap seals issue? I've had the autotech internals for 11 months and 20k km but I've never had any issue, so in case I'm close to having one I'd like to know more.

[richy-m-g]

Mituc,

I think I was just unlucky. Once I changed the internals, and tried it, I chased the leaks and fixed them.

There are two seals under the cap furthest away from the camshaft. There is a main fat O ring that sits in a square notched groove, and a thin one that looks to be a dust seal. The dust seal one on mine was that chewed up/aged, that it may have been a flat seal. I replaced them with the best fit NBR O rings I could find. I tried to see a part number for them on the Mazda part number graphics, but the only one I could see referenced was the main one at the front where the spring loaded portion slides in to locate against the camshaft (I got one from the dealer and changed this as a matter of course, the original one once removed was too slack). I also found that the two Torx screws used to hold the end cap on were weak, and of the security type with a projection in the centre (so you need a hollow Torx key). I replaced them with high quality ones used on Stihl Saws; very strong, great finish and can take plenty of torque if necessary.

If you have no leaks then I would leave things be, and worry not.

[mituc]

Ah, I see what you mean. The guys at the dealer told me straight that I need to change that o-ring if I pull the pump out just because of that possibility of it to leak.
As for the other seal I guess it was just bad luck in your case...

[MPS2NV]

Hi,
What limits are people willing to raise their HPFP limits? Are they upgrading the rail relief valve and how close are you getting to the rail pressure sensor? What is the injector limit?
Basically without going a 5th port injection where do you stop?
I currently run a CP-e pump and a GTX3071 and have no intention of adding extra fuelling.

Thanks!

[mituc]

With no extra fueling and pump gas I'm at 100% injector duty cycle at about 6100-6150rpm and load 2.1-2.15. the AFRs are around 10.3-10.6 in that area. I could lean it a bit but I will not be able to run that much boost and/or timing if I do that (and now I'm running 12-13 degrees above 6300rpm), pump gas is pump gas.

On a dyno my car made 354bhp (estimated at about 328 at the wheels I think), and the conditions were terrible (equivalent with doing the same run in +37C/99F weather). With WMI you can get or exceed 400bhp easily not because of the slightly extra fueling but because of the insane timing values you can run (16-17 degrees keeping the boost around 24PSI), just keep the torque in spec and do not exceed about 450-460Nm

Upgrading the fuel rail valve will make the fuel rail pressure exceed 2050PSI easily. You can get that much pressure without an upgraded fuel rail valve. When the fuel rail pressure sensor is maxed out the ECU cut fuel. Just command around 1790-1800PSI FRP, with upgraded internals (especially autotech) you will get at least 150psi more anyway.
I think that without upgraded injectors (which are not available for out platform) increasing the FRP doesn't do much, the injectors simply can't flow more.

[MPS2NV]

Will raising your FRP effect your inj DC (lower it) or are you at the point where the injector just doesnt play the game and there is no point in raising FRP?

[mituc]

Yes, the increased FRP will lower the injector duty cycle up to a point, simply because the desired amount of fuel will flow in less time due to the increased pressure.
However, past to a threshold increasing the pressure will not result into an increased fuel quantity passing through the injectors. It has something to do with the viscosity, turbulences and hydrodynamics stuff that I never had reasons to study in depth. Up to a point the flow will increase almost linearly with the pressure. After a while it will tapper down to a value and then later even huge pressure increases will not affect almost at all the flow figures.