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Fuel Pressure
- Thread starter Pumpkin
- Start date
Pumpkin
Donation Time
Duke
Donation Time
Smarty pants no wonder your still in Kanasas, I need the pressure..
That is a good question. I searched all of my tech material and the web to no avail. It is safe to say it is between 4-10 psi.
HEY..............whats tha matter with Kansas anyway? I am 1000 miles from EVERYTHING! That includes in-laws...
Pumpkin
Donation Time
hEY THANKS FOR THE WIDE VARIATION. i HAVE TRIED ALL OVER TO FIND THE CORRECT QUOTE, dang caps. sorry for hollaring.
I think I'll suggest a different pump for this gal, she has a bigger V8 with a modified Holly RACE DEMON carb that requires 6-7.5 pounds pressure.
And about Kansas, I grew up in Alma Nebraska, then moved to Colorado. No biggy there either. But I could see Kansas. and 1000 miles from every thing can't be all that bad either..
Cheers
Chuck
I think I'll suggest a different pump for this gal, she has a bigger V8 with a modified Holly RACE DEMON carb that requires 6-7.5 pounds pressure.
And about Kansas, I grew up in Alma Nebraska
, then moved to Colorado. No biggy there either. But I could see Kansas. and 1000 miles from every thing can't be all that bad either.. Cheers
Chuck
Duke
Donation Time
I could be wrong but I belive you will need a 9 psi pump for the carb. Go with a Holly pump and you should be glolden.
V_Mad
Donation Time
Carburettors themselves do not normally have any minimum pressure requirement, only a maximum, as this is determined by how much pressure a closed float needle valve can withstand before fuel starts to flow, and flood the carburettor.
You need firstly to choose a pump that can deliver the peak flow rate (eg gals/hour) which your engine/carb setup requires under maximum throttle, maximum rev conditions. Once this is known, you need to select a pump with a pressure which is adequate to lift the fuel from the lowest level in the tank, up to the carb level, and overcome the pressure drop through the hoses, unions and the needle valve, but this value must not be higher than that which a closed carb float valve can withstand.
For example, if you have a high flow demand system (eg big V8) with a typical Holley street carb (usually max pressure 7 psi) then you may need large bore fuel pipes to ensure you achieve the required maximum possible flow rate. One trick to achive a high rate without flooding your carb is to use a high pressure pump with a pressure regulator at the carb input.
In summary, pump selection procedure:
1. Determine float valve limit pressure.
2. Decide on flow rate required.
3. Decide on pressure required to attain flow rate. If pressure is higher than max allowed, either change carb/float valve; increase hose sizes or use regulator.
4. Select pump to achieve the above.
I have found that Facet pumps can overpower Holley carbs. One pump I can recommend is the Carter rotating type. They have a fantastic flow rate with modest pressure suitable for the Holleys.
You need firstly to choose a pump that can deliver the peak flow rate (eg gals/hour) which your engine/carb setup requires under maximum throttle, maximum rev conditions. Once this is known, you need to select a pump with a pressure which is adequate to lift the fuel from the lowest level in the tank, up to the carb level, and overcome the pressure drop through the hoses, unions and the needle valve, but this value must not be higher than that which a closed carb float valve can withstand.
For example, if you have a high flow demand system (eg big V8) with a typical Holley street carb (usually max pressure 7 psi) then you may need large bore fuel pipes to ensure you achieve the required maximum possible flow rate. One trick to achive a high rate without flooding your carb is to use a high pressure pump with a pressure regulator at the carb input.
In summary, pump selection procedure:
1. Determine float valve limit pressure.
2. Decide on flow rate required.
3. Decide on pressure required to attain flow rate. If pressure is higher than max allowed, either change carb/float valve; increase hose sizes or use regulator.
4. Select pump to achieve the above.
I have found that Facet pumps can overpower Holley carbs. One pump I can recommend is the Carter rotating type. They have a fantastic flow rate with modest pressure suitable for the Holleys.
