240cc 50psi 97-98% duty cycle
It has been proven that it loses HP starting at 90%
So in theory with 60psi lower than 90% should be gain hp?

 

It isn't losing HP just because the fuel injector duty cycle is above 90%. Until you lose fuel control, the duty cycle is immaterial. When the engine leans out uncontrollably, then you will experience power loss, but not until then. If your A/F is proper and your ignition timing is optimized... you will make maximum HP.

 

I mean humbleperfomance and another channel that check it with some RC, so you say that the original ITR would be losing hp?
It would be interesting to do a test, since 90' ​​technology is not the same as it is now

 

If we’re talking about a totally stock B18C5/6 then no, there’s no power to be gained by simply increasing the fuel pressure. Honda already increased it from 3 bar to 3.5 bar (50.75 psi) on those engines to make the 195-205hp targets without upsizing the injectors. That being said, they are pretty much at their functional limit out of the box.

You could add pressure to give yourself more headroom for modifications, but it’s pointless without a re-tune and these old EV1 style injectors and your stock pump and wiring) don’t do so well at higher pressures. Better bet would be be to swap in a set of reasonably sized for your goals modern injectors and re-tune.

 

Post your dyno sheet (HP, Torque, and A/F on an RPM "X" axis) so that I can explain this better using your data as a real example.

 

I'll run a test on my H22 310cc OEM K20 (afr 13:1 43.5psi 95% @ 60psi afr 13:1 lower than 90%) and report it here. My dyno is always 1/4, so that's just indicative

 

Ready when you are.