trying to understand fpr...

[jaden_007]

I've been doing some reading and I can't seem to understand the need to raise the base fp. If the fpr adds 1 psi per 1 psi of boost you would always have a 1:1 ratio. The only thing I can think of is that 1 psi of boost would be more than 1 psi of fuel and to keep from running lean at higher boost you must start at a higher fp or have a higher base fp. Any help understanding this would be greatly appreciated as I'm only a newbie just trying to get some of these concepts in my head.

 

[T3/T4GST]

One reason people raise the base FP is that by doing so it is like having bigger injectors. There is a formula where you input your injector size at 43 psi base pressure then you put in the new pressure and it tells you what the new injector size is. It is a cheap way to get a bit more fuel. Other people do it for tuning purposes, maybe to get the trims to come in close to stock.