600+ and fuel setup

OldBoy · 11-01-2013, 04:32 PM

Quote:

Originally Posted by phunk

One of OEM's reasons for keeping the pumps small are very strict EVAP emissions regulations. This is also one of the several reasons for a factory return-less fuel system.

Very interesting about the EVAP emissions regulations, didn't think of that one. I guess the more you move fuel, the more vapors will be created in the gas tank, but I don't see why a return-less system might be better tho?

Quote:

Originally Posted by phunk

What you mention about a twin pump setup.. that is very close to what is already being done. The Nissan GT-R uses 2 pumps from the factory in a comparable configuration.

We offer a twin fuel pump unit to our customers. We always recommend that people wire it to be staged, where one 255lph pump is on full time, and the second pump is energized at higher engine load.

Haha, just as I thought, I knew they were smarter people than me that thought about that one way before I did.

Quote:

Originally Posted by phunk

It isnt a good idea to wait until fuel pressure drops to engage the secondary pump.

Based on your post, there is a product series I believe you may find interesting. Fuelab has a line called "Prodigy". The prodigy pump is controlled by their fuel pressure regulator. The regulator monitors volume of return fuel. It has a target volume it tries to meet, and it will increase or decrease pump speed to achieve as close to that return volume as within its range. This means the system is providing the "just right" amount of fuel at all times, proactively, before there is any pressure drop or increase.

We have been waiting to see how the Prodigy line up proves itself for reliability before designing any fuel system kits that depend on it.

Well if OEM specs are 52+/- PSI @ idle on our Z, I thought it wouldn't be that bad if it was dropping to 50 before turning on the second one. I'm sure it drops more than that on most guys' FI setup running in the high 500's whp?

That being said I agree it wouldn't be the most elegant way of doing it. The electronic fuel pressure regulator from Fuelab you're talking about would be a much more efficient way of doing it.

Thank you for that very interesting info good sir

Odds are, I'll be contacting you around next spring. I'm contemplating doing a return system conversion on my Z before I get tuned next year.

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