Fuel pump wiring and amperage questions

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Mar 5, 2016 | 01:08 PM

#11

ZSAK

Joined: Apr 2003

Posts: 2,885

Likes: 66

From: Cary, NC

with the 450 it looks like you have to buy the install kit too. SOS sells the whole thing for almost $250 which is a lot more than a $139 aem pump. Hmm decisions to make lol

Mar 5, 2016 | 10:28 PM

#12

TUKES2k

Joined: Aug 2012

Posts: 168

Likes: 0

Quote:

Originally Posted by ZSAK

to piggyback off this topic, what fuel pumps have been successful for the aforementioned power level on e85? Would a walboro 450 be overkill or would a aem/fb drop in fuel pump work just as good.

i have the 450 and supposedly its good for 700 I'm shooting for 600 and thats not gonna be an issue for me at all with the 450 i also have the sos wiring kit and pump kit as well because the 450 doesn't fit well in the hanger unless you make your own rig

Mar 6, 2016 | 03:22 AM

#13

rmerchant3

Joined: Jun 2014

Posts: 604

Likes: 15

Quote:

Originally Posted by s2000Junky

Quote:

Originally Posted by rmerchant3' timestamp='1456963902' post='23897421

I agree with all above, and will add that you need an adjustable FPR as well. I had an AEM 320lph pump with the SOS wiring kit and it overpowered the stock FPR and bent the diaphragm. I couldn't get the pressure I needed under boost, as it essentially made it a static FPR instead of a rising rate. It cost me a money in dyno time, as I had to schedule another appointment.

That's because OEM is a static fpr regardless of it being damaged. You simply just ran out of fuel.

If the OP needs more then stock pressure to hit his fuel demands regardless of injectors or fuel pump size, then yes upping the pressure at the rail is a way to help. But its by no means the rule in this situation. Ive never heard of "bending" the diaphragm in the stock fpr by simply upgrading the fuel pump capacity to the number of standard up sizes we have to select from. It should be able to handle it. I never had a problem myself running a FB340 with stock fpr when I was boosted with ID1000.

The stock regulator is not a static regulator. It is vacuum referenced and rises at a 1:1 ratio with psi. It also drops around 10 psi at idle due to the vacuum assistance.(essentially creating the same delivery at a higher fuel pressure) Honda uses this to overcome pressure differences in the manifold/engine at different intake environments. At idle, the throttle plate is closed and the engine is creating a vacuum. This vacuum creates less work on the fuel system as it doesn't have to overcome intake manifold pressure to spray fuel from the injectors. When the throttle is opened the FPR sees no more vacuum, the pressure rises around 10 psi to get back to a "normal" state of pressure under zero boost/vacuum. In a factory setup, the pressure will stay relatively the same off throttle. Honda of course never intended for extra pressure in the manifold from forced induction, but the fact that they decided to tune their fuel system like this (with a dynamic regulator) on non drive-by wire cars is a plus for most forced induction guys. The fuel pressure regulator will also see the same pressure the intake sees under boost since it is vacuum referenced. This pressure that it sees forces the diaphragm down in the regulator and thus increasing the pressure. It rises around 1psi for every 1psi of boost.

I am not the first person that this has happened too. There are other instances in the SOS FAQ thread. I did exactly the opposite. I ran into TOO MUCH fuel. The extra amperage provided with smaller gauge wires on a healthy A/M pump puts out a lot of flow and pressure as compared to a factory wired A/M pump. I wasn't increasing my pressure either. MY tune is set off of a non vacuum assisted pressure of 45psi. So that gives me a range of 35-56 for my setup.