KC95SC400

iTrader: (3)

Does having more than one pump increase pressure or just potential flow?

Thanks,

KC

vangb2

iTrader: (2)

I think the purpose of 2 pumps is for more CFM and to decrease the possibility of fuel starvation.

KC95SC400

iTrader: (3)

I think you mean LPH (liters per hour)??

I assume it increases flow am just wondering about pressure.

KC

JakeBreyck

iTrader: (1)

two pumps that are setup in parallel will not increase the pressure, they will help maintain the pressure under high fuel demands tho. because you are doubling the flow.

KC95SC400

iTrader: (3)

Thanks, thats what I was looking for!

New question though. First, let me start with the problem:

Went drag racing the other night, been along time since I've gone. Went to run and about the time the car was shifting to second (max RPM) it just fell flat, lean. Like if it were running out of fuel or hitting fuel cut or something. I've ran many times and have never had this happen even when running a bit lean.

I took out the pump (Walbro 255), found nothing wrong. Put it back but left the covers off so I could see it running. It is leaking fuel past a small hole next to where the hose connects. I pinched the other small line to increase the pressure and fuel was coming out of the hole like a fountain! I looked at my old pump and it has the same hole in the same place. Looks like there is a spring in there. I assume its a pressure relief valve but I don't think it should leak at static pressure.?.?

Any input? I put a small screw in the hole for now which has stopped the leak. I guess a new pump should be on my list though assuming it is not normal for it to leak there.

Also, can't find the connector for my original pump. Was going to wire it up to see what it did.

KC

JakeBreyck

iTrader: (1)

that extra little hole is a pressure relief but it should be releving at a lower pressure then the fpr, it might have gone bad.

I would say upgrade to a better pump then a walbro, get a welden they are FAA rated for a reason.

http://www.weldonracing.com/

KC95SC400

iTrader: (3)

Thanks for the link.

So after doing some searching I have found that I am not the first to "modify" a Walbro pump. Apparently, the pressure relief valve is set to around 80psi and you can use a punch to push in the plug that the spring sits on.

http://www.driven2modify.com/showpos...15&postcount=1

I don't think that doing this to my pump will help since its likely that the check ball is just not seating or is damaged in some way. I really don't think its supposed to be spewing fuel at a normal idle pressure, I think mine is set at around 50psi with the pump running and the engine off. I have a Bell/Cartech FMU and last I had a gauge on it, I had it going to like 75-80psi with max boost if I remember correctly. Definately wasn't over 90psi.

Anyway, took it for a drive with the hole plugged and it has definately made a difference in fueling. Running quite a bit richer now, will likely need to do some re-tuning. Not 100% sure that it was causing my loss of power / almost dying problem but time will tell. I will in the near future put a gauge back on it just to make sure I'm not hitting some stupid high pressure. Getting near 100psi just plain scares me and I don't think it's needed anyhow.

KC

RedPhoenix

iTrader: (10)

didnt read the thread, but parallel = flow, series = pressure