Been talking to a few people and it seems their injectors maxed out at 15psi!!

 

Now to some, the solution to this is new 550 injecotors but expensive!

 

An alternative but less desirable is an adjustable FPR, will delay the function of the injectors but might take up some slack of the old fpr and icrease the pressure to avoid detontation?

Yes upping the fuel pressure will put more fuel in per squirt but don't know how high you can go...

Upping the fuel pressure too high, means it delays the injectors opening so throwing the fuelling out!

Mark if you want a reliable answer then ask Eric;)

Mark if you want a reliable answer then ask Eric;)

 

or John Dixon :p

nope, you dont, i run between 15 and 16 and have never had any det!!! i suppose it would depend on how clean youre injectors were to start with though!!

If you're injectors are maxing out, it is not a very desirable position for the engine to be in!

i guess its gonna be safer to increase fueling at higher boost if you know your AFR is too weak at higher boost.

 

im running 16psi without probs (for the last 2 years as a daily driver) too tho

TBH, if it ain't broke don't fix it.

You're right that they're maxxed out but if it's not too lean then don't worry.

Having said that, there's no downside to it if you intend to upgrade further and it does allow you to up the boost a little.

Running stock tubs and stock injectors I was experiencing det at just under 15psi but I know that some people run beyond that with no problems. Rules of thumb are handy but each car is going to be different. Myself, I decided to fit a Nismo adjustable FPR and order some 555's (still waiting for the latter to arrive :( )because I agree with John in that as I intend to upgrade further I might as well sort the fuelling out sooner rather than later.