Stock pump? How much fuel will it push

[hubz91talontsi]

Well im running a big 16g at 17psi.. I figured i would be running out of fuel.. Turns out im running rich. How much more boost can this thing hold. I bought the car slightly modded could be a 190 in it.

 

[DeNoZZo]

I heard you can't go past 15-16psi on the stock pump

 

[pboglio]

Enjoy:

RRE Instructions

Fuel pump flow is related to horsepower but also the boost pressure can physically slow down the fuel pump. To do it right you install a fuel pressure gauge and check injector duty cycle and a/f ratios. If your running unusually high injector duty cycles or if all of the sudden it leans out at higher rpms, then its the fuel pump not keeping up.

 

[hubz91talontsi]

I have 680 injector's so im not having an issue with the cycles. And im at 17psi and still running rich

 

[pboglio]

I seriously doubt you have a stock 1g fuel pump in the tank then. Its very typical to strip mods off the car and leave an upgraded fuel pump in the tank when selling it. A 1g fuel pump at anything over 15 psi is in the danger zone without a rewire or an upgrade.

 

[JayRolla]

How do you know your rich. WBO2? Remember when you add boost, fuel pressure also rises. So you can run richer with more boost. The stock fuel pump usually runs out at high rpms. So you could be fine till 6k then run real rich and killing the motor without even knowing it. An upgrade is like $100 so not worth the risk.

 

[hubz91talontsi]

Well i have a 190lph but i was just wondering why should i even install it if im not close to running out of fuel yet

 

[steve]

And im at 17psi and still running rich

How do you know your rich. WBO2?

Again, how do you know your running rich. What's your AFR?

The stock fuel pump is going to have problems keeping up with 680s at 17 psi boost.

RRE rates it at between 73.8 and 100 l/h at 58psi depending on voltage.

Your 650 injectors are about 594 cc/m at 36.3psi base pressure. (2.3l/m @100%, 1.9l/m @80%)

At 80%DC you need a 114 to 134 l/h pump depending on safety margin to supply them. If you run up the IDC you'll need even a bigger pump.