Fuel Pressure

[rafyleafar]

What would be the recommended fuel pressure for a D16Z6 with minor bolt-ons, as of CAI, headers, exhaust, MSD modified distributor cap & rotor with MSD blaster SS coil, I already know the stock fuel pressure is around 34-36psi, I also know I need a AFPR so I'll might get the AEM AFPR, would I need to change the fuel pump and fuel injectors? what fuel pressure is recommended for this little setup? any suggestions? thanx in advance.

[kommon_sense]

No real benefits in increasing your fuel pressure at this point. Not really beneficial until you start improving airflow like a cam, porting, or intake manifold.

Normal bolt-ons won't really benefit from raising fp.

[rafyleafar]

ok cool, so if I get any of these 3 mods what psi over stock would you recommend?

[EnJoiThaRex]

after you really increase the air like with all 3 of the mods stated then yes go wit bigger injectors or increase the pressure either way will work but injectors may be more expensive

these equations might help if you kno yuor hp alrdy and some other info.. But REMEMBER PERENTHESSES ARE NEEDED!!!

1st find out if there are specs for stock injectors rated with these units lb/hr or pounds of fuel-per hour, to find out what your stock injectors can supply
take this number (lb/hr) X number of injectors or 4 (hondas anyway) X 2

then take that answer and divide it by .85 or the realistic duty cycle of an injector..this answer is how much hp these injectors can safely deliver

Now for injector sizing
injector size=(engine hp now)xBSFC(Brake specific fuel consumption)which is roughly .50 all over or divided by (the number of injectors) x (injector duty cycle) or.85

if thats confusing this is what it should look like

IS=HPx.50/4x.85 the answer should be pound/hour or lb/hr

now this is based off the standard pressure that most injectors work at around 40 psi


..and a performance fuel pump

to figure out the injector rating with a higher fuel pressure with the same injectors
you will hav to take the square root of the deisred fuel pressure/the stock pressure times the stock injector rating

or
______________________________
\/(desired pressure/stock pressure) X injector rating= new flow rating

then take that last answer, your new flow rating, and substibute it in the 1st eqaution where the old flow rating was and the answer should b the horsepower you are at now..

if its too high lower the fuel pressure

too low raise it..


hopes this helps!!

[CapnToll]

Making a mild motor build work by just using bigger injectors, and raised fuel pressure is not the way to go. I'm pushing ~60whp over stock and instead of raising the fuel pressure and/or getting bigger injectors, I have a properly tuned fuel map using Uberdata. Before I had Uberdata, I used my B&M AFPR to bump the fuel pressure way up to ensure I was running a safe Air/Fuel ratio. However, since an AFPR can only be manually set, and won't change over the RPM range, my idle was terrible, and I did not have the correct fuel flow at certain rpms.

AFPRs are just crutches for tuning. It's not a bad thing to use in CONJUNCTION with proper fuel/ignition map tuning via ECU programs like Uberdata/Crome/Hondata, but usually, the tuner will just set the AFPR back to stock anyways.