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MazdaSpeed6 Fuel Pressure Tuning?
Posted: June 1st, 2026, 12:54 am
by WilliamWeng
Good morning everyone, I'm a Tune newbie. My setup is: stock engine, 76mm intake and exhaust, HPFP internal parts, turbo is Pulsar G25-660 AR.70, MAF installed on the turbo line, between BOV and the throttle body. I'd like to ask if our Fuel Pressure Target needs to be changed? Because I observed on my FORScan that the fuel pressure reaches 2240psi at full throttle, I'm wondering if this setting needs to be increased.
Horsepower Target :350-380-400 whp
Re: MazdaSpeed6 Fuel Pressure Tuning?
Posted: June 3rd, 2026, 5:02 am
by mituc
I do not recommend upping the fuel rail pressure targets, because with aftermarket HPFP internals the pump will already make 50-100PSI over target, and if you up the target then the pressure relief valve (which is mechanical) will work full time an will eventually fail. The flow is proportional with the square root of the fuel rail pressure, so an increase in the fuel rail pressure will not only throw the pressure above the opening threshold of the PRV, but will bring absolutely no benefits other than wear (unless you have an upgraded PRV).
Also, Forscan may see something wrong, because the maximum pressure of these sensors is about 2050PSI.