Fuel Pressure On Holly Carb
 

What effect if any does increasing the fuel pressure from 7 psi to 8 psi have on the way the carb perfoms? Is the ideal pressure on a 1050 Dominator 7 or 8 psi?

Going from 7# to 8 # probably won't make a difference. You do need to consider the flow volume also. I.E the size of the fuel lines and GPH of the pump.

if you go up in pressure it will enrichen the mixture at all points ,
7 or 8 is fine some people like less but it will work great there

Less pressure leaner ,,,more pressure richer this is a short answer ,hope it helps ;)

thanks for the reply, the short respones make sense. Would it be safe to say that a reduction of 1 psi would be the equivalent of one or two jet sizes either way?

I have about 8 psi on my dominators and 540's with 1/2" fuel line all the way from the tank. Works fine for me.

That's measured right at the carbs with a remote guages on the dash so it can be seen ay WOT not just idle.

I cant wait to hear the explanation on this one. Since the fuel line (pressure) supplies the float bowl which is vented to atmosphere ( no pressure), I cant for the life of me figure out how fuel pressure would affect jetting as long as the fuel level in the float chamber is maintained.

I am with formula 31 on this one. As far as I know, the pressure is measured before the needle and seat. The bowls have no pressure in them. Jetting and power valves determine rich or lean. Fuel pressure will not change the mixture. I will go along with the extremes. If the pressure is say 3 #, I could see that causing a lean condition. If the pressure is 12#, it will blow the needles off the seats and flood the bowls with fuel.

Cheskmate is RIGHT on this one.

o.k. if you raise the pressure and don't adjust the float level the fuel level will come up in the bowl and be richer ,,, as I said this is a generalization but true I've watched it 10 mins ago on a dyno
it got richer but I follow your line of thought and it can be argurde
either way (if you set the float for the new fuel pressure the mixture will stay about the same)) ,I hope this is understandable
i don't have time to argue it out , any further ,hope it helps alittle
with my thinking ,I do follow you guys ;)

As I said its got to be tuned at that point (fuel pressure)

With higher fuel pressure it will take more pressure on the float to turn off the fuel supply ( pressure of the needle against the seat) That pressure comes from a higher float level. If you adjust the fuel pressure and don't readjust the float level it will richen the mixture because the float level will be higher. If you readjust the float level than it will have no efect on the mixture.