How much fuel pressure can an au take?

[Stav]

i am playing with my fuel system and was wondering if anyone knows where the limits are with say upping the fuel pressure to 58 psi on a standard fuel rail.I have got a 500hp pump and adjustble reg.Does anyone know? Maybe the turbo guys?

[XR8Master]

You can't go past 50psi on a EA 3.9.

Im not sure how that would apply to an AU though.

I think they have the same FR

[Stav]

Why? What is the limiting factor?What is fr?

[XR8Master]

I just found out that the information I posted above was incorrect.

If I where to give a practical answer. 58 psi is a relativity low pressure. and you will have problems with ur fuel lines well before the rail itself.

The rail itself could quite possible handle a few hundred PSI

You may incounter problems with ur vacuum lines.

[xr8ute]

The CAPA website recommends against pressures above 90psi when using an FMU.

The earlier pintle-style injectors had problems opening/closing at higher pressures, although the EV6 injectors in the AU and B-Series dont have this problem.

The fuel pump flow volume drops off pretty quickly as fuel pressure increases.

To be honest, I cant see a problem running 58psi....XR6T's run ~54psi rail pressure (aka 3.7 bar) from the factory, and that is with a 1:1 ratio fuel pressure reg, so at 6psi boost the fuel pressure would be 60psi (and at 10psi boost it would be 64psi and so on....).

Just make sure changes in fuel pressure are followed up with a retune. Probably just some mucking around with injector slopes to get it right.

[Stav]

Originally Posted by xr8ute

The CAPA website recommends against pressures above 90psi when using an FMU.

The earlier pintle-style injectors had problems opening/closing at higher pressures, although the EV6 injectors in the AU and B-Series dont have this problem.

The fuel pump flow volume drops off pretty quickly as fuel pressure increases.

To be honest, I cant see a problem running 58psi....XR6T's run ~54psi rail pressure (aka 3.7 bar) from the factory, and that is with a 1:1 ratio fuel pressure reg, so at 6psi boost the fuel pressure would be 60psi (and at 10psi boost it would be 64psi and so on....).

Just make sure changes in fuel pressure are followed up with a retune. Probably just some mucking around with injector slopes to get it right.

I have a tune for 30pund injectors and one for 20 pound standard ones. I will throw in each tune and see how it goes.

[Stav]

I have just done some reading.70 psi the limit.Injectors dont work properly above this.The xr6turbos run the same injector .Na ba's run 40psi and xr6t's run 58 psi odd.The fuel rail on the ba is stamped 906 .The au is also 906.The rail is interchamngeable.. I am going to upmy pressure and see what happens.I got some injectors rated about 50rwkws more than the standard au item .The thing they did not state is that it is at 58 psi. I have run 55psi before..now that I think of it. It was quite a few months back.I forgot.I am sorry for that. It ran fine. 58 psi should not be a problem