Gathering parts for my build and have some fueling questions??

[Matt_paco]

I've been doing car turbos for sometime now, but I'm new to bike turbos. I've already purchased mtc turbo pistons and a gt2560r. Looking for a good non stretched street build. I want to get to about 10.5:1, run maybe 6psi on the street and 12psi with meth when I feel like gettin crazy. No intercooler.

I'll ask my question and then list my proposed setup and mods so no one gets bored reading.

How does the stock fuel pump system work? No return line, is the pump constant current or does the ecu have some complex duty cycle algorithm and can it be tuned out. I'd like to run a custom fuel rail with return line and some stock s2000 injectors. Aftermarket pressure regulator, how does the stock fuel pressure sensor work(if it has one). I haven't even removed the air box to investigate this yet, sorry.

Here are my preposed mods

Turbo pistons
Spacer
Gt2860r dual ball bearing
Adjustable cam sprockets
S2000 injectors
Custom fuel rail, external pump with return line
Custom intake plenum, I'm pretty handy with a tig
Aem fic with harness for a busa. I'd like to use the built in software to eliminate the stock map sensor, I've read that it's not a linear output and is pretty much useless except for trouble codes.

I'll be posting many more of these brain teasers over the winter. Any help received is greatly appreciated.

 

[JRivera2002]

On my set up we eliminated the stock pump and added an inline pump and filter and a return. btw the stock pump is internal. I'm not sure the stock pump can move enough fuel for a turbo, I wouldn't want to over work it either, the stock pump is tiny in comparison to the aftermarket ones. On my first set up I ran stock pistons and a spacer and it ran fine on pump gas with no intercooler at 7psi, although if you did about 6 long runs in succession the motor would start to heat up and I'd have to just ride calmly and let the temps come back down. I'm assuming this is a gen1 busa? Anywhow, we ran a 1:1 fuel pressure regulator with a 3bar map sensor and tuned it with the ECU editor program which I highly recommend. On my gen2 we used the stock injectors and fuel rail, and had plenty of fuel utilizing the 8 stock injectors. If you have a gen1 however you may need to upgrade to the s2000s like you're planning and you'll be fine. I'm sure some of the other guys on here will have some good advice as well. The only issue I ran into was the turbo being a bit low and my exhaust smoked, I added an evac pump/sump to get the oil to flow back into the pan and it went away.

 

[Matt_paco]

+1

I have run scavenge pumps on cars before and I absolutely f****** hate them! They work, but are expensive, clumsy, some are noisy, and its a major bug in the back of my mind as to when its going to crap out. Definitely something I want to try to avoid.

This is a gen 1 bike. And I am getting an inline pump, planning on modifying the stock fuel bucket so I can still run my gauge.

The pump will have new heavy gauge power wires with fuse going to a relay pulled in by the stock fuel pump circuit. That part is all pretty simple, I just need to know if I have to do anything special to the stock ecu to make it tuneable with the piggy back.