Currently I am running 315cc injectors and boosting 6psi with a GSX intank fuel pump. Same pump that came out of a 92 1st gen GSX Eclipse. Right now, I see ~60psi of fuel pressure at 6psi.

I will be running the 8 injector setup soon at 15 - 18psi. I planned on getting a Walbro 255lph intank pump, however was wondering.... Because fuel pressures will be much lower with a 1:1 setup and 8 injectors, is tthe Walbro fuel pump really necessary. I do not know the exact specs of the pump I am running now, except that it works and I am running a tad rich. I would like to continue with this pump for several reasons: Time of swapping, money for new pump, and sound. The pump I run now is whisper quiet, unlike the Walbro255.

Let me know what you think. If it can do 60psi now...shouldn't the far lower pressures with more injectors be fine?

______________________________

Ryan
IRyanHester@Hotmail.com

'03 Mazda 6s

I think the stock turbo pumps only 140 lph or something right in that area. I would just swap in a Walbro 255 for just peace of mind. I have one and it is no where noisy at all, the installation is an hour tops, and you'll have much more room for error when tuning for high boost levels.

If you don't know the specs on your existing pump, then you'd be using it on blind faith alone. I'd suggest that you determine your fuel needs at max boost and then purchase a pump that meets those needs. Calculations are here:

http://www.geocities.com/vttalon/tech.html

Corbin

'95 ESI-T
Now with more power and fewer leaks



Gimme fuel...Gimme fire...Gimme that which I desire

The stock turbo FP is 100 liters per hour @ 43 psi @ 12V.

Walbro makes 2 versions of the 255lph pump, a regular (GSS-317) and a high pressure (GSS-342). You only need the high pressure version if you have stock or smallish injectors and need stupid high fuel pressures.

I have the Walbro 255lphHP and it is damn near silent. Only a little whirr. Then there's my HRC inline pump...

PLEASE use corbins website and formulas-^ they are gold.

More really good links:
http://www.roadraceengineering.com/fuelpumpflowrates.htm
http://www.roadraceengineering.com/fuelpumptechtip.htm

Ill just go ahead and get the Walbro255lph. My goals are too high for this pump obviously...thanks guys -- its nice to know the specs too.

______________________________

Ryan
IRyanHester@Hotmail.com

'03 Mazda 6s