I'm probably going to buy a Walbro soon, but I was wondering how many lph our stock pump is rated at (if anyone even knows). People say the 190lph Walbro would be a good replacement stock pump, but I haven't ever seen anyone install one or talk about numbers. I have gallons/hr ratings for Walbros, but I don't know how to relate the PSIs to the gallons/hr. I would imagine there is some formula to figure out how many gallons/hr you need based on your PSI and injector pulse width, but I don't know what the formula it is.

The reason I'm asking is that I want to upgrade my pump without getting a FPR if necessary. Walbro now has a 190lph High Pressure pump that should work great for my application, but if I still need a FPR I'll just get a 255lph HP.
-hype

 

but even with the 255 and no FPR, doesn't the pressure only increase ~3-4psi over stock??( I think thats what I heard) thats not too bad to deal with.

 

3-4psi is quite a bit. That's like sitting at 50% throttle everytime you're idling. I'd like to maintain some sort of gas mileage

Also per Auto Performance Engineering
"Notice that the only difference between the 'normal' 255 ltr/hr pump and the 'high pressure' 255 ltr/hr pump is the flow above 50 psi of fuel pressure. Unless you are running a high base fuel pressure, or are running some serious boost levels, the normal 255 pump should be enough. "

"The pump will flow the same as the 190 ltr/hr pump up to about 60 psi. After that, the 190 high-pressure pump will push more fuel than the normal 190 pump."

The high pressure pumps only flow more at high PSIs, so a 190lph shouldn't bump up the idle FP much (if any at all) since the 255lph only moves it up a few PSI.
-hype

 

Only bad gas mileage on cold start (or when in open loop)... SR20DEN was trying figure the flow but I think no one wanted to pitch in, I think.

 

Isn't the PSI always higher while idling because the OEM FPR isn't able to adjust the flow by the required amount?
To your knowledge has anyone ever used a 190lph?
-hype

 

The 190lph version should be fine for an NA replacement/upgrade. Even the standard 255lph (non hipressure) version may have a near stock baseline fuel pressure.

Yes the hipressure version has a higher base fp but when the car is in closed loop (normal driving) the computer will shorten the injector pulses to keep it "correct". It will only be during near WOT and cold starts when you will be rich.