I was wondering how much you have to have done to your car before you need to put better injectors and higher flowing fuel pump in it??

 

When it stops pumping fuel

 

When you start going with ported heads, different cam, nitrous, supercharger or turbo. I believe stock injectors are good for 400hp.

 

Put in larger injectors when you get ported heads and a cam, especially if you are making around 400rwhp. Then hook up a fuel pressure guage to the car and if your fuel pressure drops at WOT, you need a better fuel pump.

 

but if i just get a cam like 224/230XE i prolly wont need to upgrade my fuel system will i??

 

Your right, you almost definitly won't need to upgrade yet.

I recieved this information from an expert tuner, it's not word for word:

It depends what RPM you are making your power too. 380 HP at 5k rpms might be alright, but 380 hp at 6500 rpms might be starving for fuel because you are asking the same injector to deliver approx the same amount of fuel in a smaller time window. Just trivial example numbers there.

That is some of the reason why you hear different max HP figures for a stock fuel system quoted by different people. Not to mention the minor differences between peoples pumps, condition of filters, and the injectors themselves.

 

this is a subject that's been puzzling me as well. and from what i understand, you can go two ways: you can either increase the fuel line pressure or get bigger injectors.

i have to wait till i get to the dyno before i decide which route i'll go.

once you get your mods, get your car dynoed...the graph will explain alot. as was mentioned earlier, depending on what your curve looks like, you'll know if you need more fuel or if you're fine as is.


oh yeah, my mods are on my sig...stock injectors/pump though.

 

Well, increasing the pressure in the lines is a temp fix. What you don't want to do is exceed approximately 85% of the duty cycle of the injectors if I remember right. Above that, you're getting sketchy.

 

If your stock injectors and pump are working fine then you won't need to upgrade just for that cam. I ran a 226/226 cam for a year with stock heads, injectors and fuel pump. My curve on the dyno looked great and my fuel pressure would not drop at WOT. I also had an adjustable fuel pressure regulator and it was set to 45psi. (Not sure if it was necessary though)