disco192

So im doin heads and im thinking that i need to upgrade my fuel system. I have an AFPR and im wondering if i can just bump up the fuel pressure to about 50 psi to handle the added fuel requirement. I plan on putting down about 425-450 rwhp. Would you recoment replacing injectors, pump, or both.

I was thinking about getting some SVO 24 or 30 lb injectors because those injectors handle higher pressure beter.

Can my stock injectors handle 50-55 psi and can my pump handle that too?

Thanks for any help,
Stu

Injuneer

Let's do some math.... you want 450rwHP.... that means you need to be making somewhere between 525flywheelHP (M6) and 550flywheelHP (A4).

To make that much power, you need an injector that can supply at least 36 to 38#/HR. That assumes you have a very well tuned motor that can produce an 0.46#/HR/HP brake specific fuel consumption, and that you are running a max of 85% duty cycle on the injectors.

It isn't realistic to try and get 36#/HR out of a 24#/HR injector.... that would take almost 100psi rail pressure. With a 30#/HR SVO injector, flow rated at 2.7bar (39.15psi) you could make it into a 36#/HR injector by running 4bar (58psi).

But, since you are changing injectors anyway, why not just buy a 36#/HR or a 42#/HR injector, and run is at the stock fuel pressure. When the PCM is tuned, the injector constant will need to be based on the size of the injector, the brand of the injector, and the fuel pressure you are running. If it was my engine, I'd buy 42's and have a nice low duty cycle.

Dave88LX

3 charts that might help (Tabs at the bottom)
http://paradox.shacknet.nu/dave88lx/.../injectors.htm