My setup:

L15A stock engine , no internal mod
1 x TD04 start boost at 1900 RPM
Max boost 0.6 Bar
Stock injector but extra 1 injector before trottle body.
AFR: 14.7 at idling
0.6 bar AFR around 12.1

My tunner told me that my fuel pressure is enough and don't need to add any fuel pump and regulator.

But some other workshop said must increase.

Question 1: what is our stock fuel pressure?

Question 2: If i increase pressure, does it mean fuel comsumption will increase?

Question 3: what is the best pressure for my current setup?


for question 2, i have doubt, because one of the workshop told me it will not drain more fuel. He gave me a example: If i turn on the tap water and ask me to time how long to fill up a pail and compare to those pressurize car wash, which one fill up faster. I tried and result is direct tap fill up faster. That mean surprise is pressurize water take longer time. So can we apply to fuel?

Sorry my english suck.

 

anyone know?

 

what size are your injectors?

 

Stock injector but extra 1 injector before throttle body.

 

The stock Fit fuel system (on the L15A1 anyway) runs at a STATIC 50psi.

There is no fuel pressure regulator like there is in older Honda setups. This means that as the manifold pressure rises, the effective fuel pressure (differential between the fuel rail and the intake charge pressure) drops. At some point the effective pressure will get too low for proper fuel atomization, but at .6 bar (which is I think about.. 8psi?) you won't see this problem. 50-8=42, which is still pretty high, so no worries. Older Hondas ran at a constant relative pressure of about 35psi.

So, to answer your questions:
1. 50psi
2. It will only increase consumption if you cannot retune the injector map to compensate (if you cannot adjust the stock ecu directly/with a piggyback fuel controller, it will throw all sorts of things off - don't do it).
3. 50psi. You're doing a pretty mild setup here, and the only way to adjust the fuel pressure would be to rip out the WHOLE fuel system and replace it with a return-style system like in earlier Hondas.

 

Thank for the infomation.

So i i change my fuel setup with return line and increase example 50 to 55 PSI, it will increase HP?
also do I need to retune my AEM piggyback?