FPR setting??? - Honda Prelude Forum

95PRELUDEVTEC · 03-27-2002, 08:36 PM

what are you guys setting your Fuel Pressure at? mine is at 38-40psi at idle?

I have ignition upgrade, intake, and exhaust, and Nitrous.....what is the best setting? my car kind of bogs once in a while when it's warmed up.....but when it's cold it's fine so i think i should pump it up a little say 44psi....what do you guys think?

Thanks

PreludeNYC · 03-28-2002, 09:54 PM

yea I just got my B&M fuel pressure regulator and i honestly don't know anything about fuel systems....

i know where it goes, i understand the whole lean and rich thing but how do i know whats good?

-Jose

Lude_conduct · 03-29-2002, 07:03 PM

Quote:

Originally posted by 95PRELUDEVTEC
what are you guys setting your Fuel Pressure at? mine is at 38-40psi at idle?

I have ignition upgrade, intake, and exhaust, and Nitrous.....what is the best setting? my car kind of bogs once in a while when it's warmed up.....but when it's cold it's fine so i think i should pump it up a little say 44psi....what do you guys think?

Thanks

Woah, that's high. What's your MPG like? I have all the same mods you do and I'm getting rail pressures of 30# at idle, 25# under vacuum, and 35# at WOT. 38-40# just seems a little high to me, especially with our 330cc injectors.

Using the Fuel Injector Worksheet on RC Engineering's website, I came up with the following, based on figures for an H22A with stock injectors putting out 200HP at the fly:

Actual desired crank HP: 200
Number of same-sized injectors: 4
BSFC desired: 0.45 (calculated from the BSFC worksheet at the bottom)
Maximum Injector Duty Cycle you will see: 80% (this is what OEMs normally figure for)
System fuel pressure @ fuel rail: 35 PSI

Static flow required: 330cc (just so-happens to be the stock injector size)

This lets me know Honda calibrated our injectors correctly and that my rail pressure settings are right-on. To further solidify this, my O2 sensor voltages at WOT in closed-loop mode read .860-.880. I suppose I could lean it out just a bit more, but I'm happy with my plug readings, fuel mileage (~23MPG), and O2 readings.

95PRELUDEVTEC · 03-30-2002, 09:33 PM

i don't know if the fuel rail and the fuel filter pressure is the same or not.....but mine is at 40psi at idle....are the pressure from the fuel filter and fuel rail the same???

i did put it at 35psi at idle but when i hit vtec it didn't feel as smooth....it also felt like it wasn't getting enough fuel....but again, after i shoot nitrous and i look at he plugs....it looked like there are left over fuel on the spark plug threading....and the plug is mostly light brown and in some places white.....

95PRELUDEVTEC · 03-30-2002, 09:40 PM

oh yeah with 40psi i usually get about 275 miles on a full tank of gas......

but when i hit vtec alot it's about 250 miles

Lude_conduct · 03-30-2002, 10:29 PM

Rail pressure and line pressure (between the filter and the rail) should be nearly the same. I put mine on the rail because it was easy (it has a test port fitting) and most accurate. With a 35# setting, I can get 300 mis. on a full tank with mixed city/highway driving and VTEC. Cruising at 70, the best I saw was 380 on a full tank with highway driving.

95PRELUDEVTEC · 03-31-2002, 12:17 AM

what kind of mods do you have? i have
i/e/ignition/nitrous....

what year is your lude and is it usdm or jdm????

maybe i should drop my fpr down to 35-36psi then

95PRELUDEVTEC · 03-31-2002, 12:17 AM

also what was best 1/4et time?

Lude_conduct · 03-31-2002, 12:57 AM

I have the same mods on a JDM H22A with a '95 USDM ECU. It traps in the high-90s.. 95-97MPH.