Upgrade from 255 Walboro to bigger?

[G. Wiffington]

Hey do you guys think I should upgrade from a 255 Walboro to a bigger pump to lower duty cycle? I have attached two datalogs.

I have the old fat body style RC 750cc's & the fuel pump is not relayed by the pump, so I am just using the stock wiring as of now. Would a relay setup at the pump help give more pressure?

I also have a JDM stock fuel rail so I used a longer, skinnier -4AN hose for the rail to stock fuel filter line. I was wondering if that is way too restrictive causing the duty to be higher.

I do have a stock fuel regulator & no fuel pressure sensor. I guess I should Install those? (fuel pressure gauge & adjustable regulator)

Setup is F22B non vtec stock head & bottom end, 98 EK hatch chassis.

Finally spun third pretty good on street tires Hankooks (9psi, 82% duty 13 degrees timing).

[Spunkster]

You need to see what the pressure is doing. You may need larger injectors. This is something you may want to discuss with your tuner.

[G. Wiffington]

I am my tuner in this case lol. Still learning for sure

Okay I will see what the fuel pressure is doing.

Thank you!

[G. Wiffington]

Okay update:

I have an adjustable fpr now installed & it is set at base 43psi. The duty cycle is a little lower about 82% for the same pull as I uploaded before.

Would 50psi base pressure on RC750's too high?

[Spunkster]

It is probably ok.

[G. Wiffington]

Thank you.

Raised the pressure a little more & looks like I definitely lower the duty cycle.

Here is another pull finally hitting 11lbs.

New wastegate with 7-8lbs spring, the old one had a rip in the diaphragm & the spring was only about 4lbs.