A few important rb 25 q's

[czy18e]

G'day,just after some info if anyone can help?

What fuel pressure is ideal?(i run 30 at idle 42 on load and 22 when off)I have a fuel pressure reg.

How do you know when your fuel pump is too small?Some tell me it wont hurt any thing it will just cut out and back fire others tell me it will lean your engine out.

What is the max boost for a 25 with a medium to small turbo?

Thanks alot team.

[cameron]

How do you know when your fuel pump is too small?Some tell me it wont hurt any thing it will just cut out and back fire others tell me it will lean your engine out.

That doesnt make sense, but i'll try and answer it anyway.

Basicaly their no answer to your question i can only give you guides to follow, number one don't run boost pressure over 12psi if you have stock fuel pump.

It can only provide your engine a certain amount of pressure and fuel so by increasing your boost pressure your stock fuel pump will still be at its normal flowing rate and you'r enigne will have more air then fuel which is bad = Leaning out. If its back firing that just means its running rich and the excess fuel is being burnt in your exhaust which is the pop you hear.

"Some tell me it wont hurt any thing it will just cut out and back fire" ???

Is this actually happening to your car ?

What is the max boost for a 25 with a medium to small turbo?.

As long as you have the surporting systems with the bigger turbo eg; fuel pump, ecu etc. Your standard internal RB25 should handel 18psi before your head gasket is reaching its limit and not sealing anymore, but I wouldnt run that much all day every day. Your also risking your internals, but this shouldnt happen if you'r ecu is tuned correctly.

Jun

[czy18e]

O.k well my car did do it and we fixed it by upping my fuel pressure.

I dont think my pump is stock cos it has a fatter wire running to it than usual and it is noisy but i dont know.