Fuel Pump Experiment

[Holden]

Folks,

I currently have a regular pressure Walbro fuel pump installed. I also have (uninstalled) a high pressure Walbro pump and the stock GSR pump.

I'm going to upgrade to the HO pump soon, and thought this would be a good chance to get some before and after readings.

I'm going to check before and after:

1) Fuel Pressure (idle with and w/o vacuum, WOT) (no changes to JR FPR)

2) A/F Ratio at WOT

3) A/F ratio closed loop range at idle


Any other ideas?

If someone thinks of a reason to install the GSR pump to check something that won't risk my engine, I'll do that too.

I don't know what I'm going to find here, but I can't resist solid before/after fact gathering.

Here's my setup:

96 GSR
JRSC @ 6psi
AEM cai
RSR 4-2-1 headers
Stock cat
Greddy PE catback


------------------
Greg Holden
96 GSR, JSRC, I/H/E, yada yada yada...
My JRSC Install Site

[GSRMatt]

There's an easy way to test fuel system output. Install the complete fuel system and set the pressure to a given level ( if you're using an FMU I'm not sure if you can set it to your peak pressure, which is what matters). Disconnect the fuel return before the fmu and run it into a bucket. Turn the car on so it primes the pump and maintains pressure. Measure the amount of fuel pumped in 30 seconds, then multiply by 180 to get the rate per hour. You now know your car's maximum output for the entire fuel system at the given pressure. Change the pressure and repeat to map the system's output. You'll want a minimum of 15% MORE than the car's maximum power output requires to return to the tank and keep pressures stable.