Tech Tip "Fuel flow Test"
03-14-2005, 02:33 PM
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Tech Tip "Fuel flow Test" This is one the topics I was asked to talk about. Kind of hard to describe, but I think it will show all how to test there pumps in a standalone system.
Remember this is gasoline and extreme care should be taken at all times. So please be careful.
Fuel Flow Test with standalone system.
High Pressure single or dual nozzle efi fuel pressure exp. 40-60 psi:
To do this with out taking your nozzles out of there installed location you will a 3/16 compression fitting per nozzle. Take the nut and farel and throw those 2 pieces away. Remove your lines and fuel jets from the nozzle. Install the jets into your compression fitting were the farel was, now put the hoses onto that fitting and tighten. Place the hose and fitting into a proper contain to catch the gasoline. Turn the system on and energize the fuel solenoid. Fuel will start spraying out of the nozzles. Look at the fuel pressure, this will be your flowing fuel pressure. There should be no drop in psi between the open and not open on your fuel gauge. A twitch is ok but if must bounce back quickly. Now you have your base line to tune from. So if your gauge reads 55psi noid close it should read 55 psi with the noid open spraying fuel. If your gauge falls and does not recover your fuel pump is inadequate for the hp setting you are trying to run or there is a plumbing issue that needs to be looked at.
Setting to a high pressure with noid closed to achieve the 55psi with noid open is ok also, the main thing you are checking is that the system can sustain 55psi with the fuel noid open. If it cannot not change the pump.
High-low pressure with a nozzle system. With this one you will not need the compression fitting but you will need a flow check tool. http://www.nitrousexpress.com/Instru.../flowcheck.pdf
This gives you the fittings needed to go from a –6 line to a –3 that can hold the jet. You will attach the fuel line going to your solenoid to a –6 manifold. The outlet of this manifold will hold the –6X-3 fitting that will hold a jet. Now we need to figure what jet needs to go into this –3 fitting. You will take your fuel jet size X itself X the number of jets, and then square root it. So for a 26 fuel jet it would be 26 x 26 x 8 = 5408 and the square root of that is 73.53 so you can use a 73 or 74 jet. This will get you into the ball game with your set up. NX sheet give a true jet that might differ from this formula, that is because the flow bench showed a different jet than the math said would work.
You now install that jet into your flow check tool and tighten the B-nut that holds the jet into place. Put this into a container proper for gasoline and turn the pump on. Read your pressure gauge and it should be at the predetermined pressure. Again if you cannot get to the proper flowing fuel pressure the pump is not adequate for the hp level you are trying to maintain.
Ricky
Remember this is gasoline and extreme care should be taken at all times. So please be careful.
Fuel Flow Test with standalone system.
High Pressure single or dual nozzle efi fuel pressure exp. 40-60 psi:
To do this with out taking your nozzles out of there installed location you will a 3/16 compression fitting per nozzle. Take the nut and farel and throw those 2 pieces away. Remove your lines and fuel jets from the nozzle. Install the jets into your compression fitting were the farel was, now put the hoses onto that fitting and tighten. Place the hose and fitting into a proper contain to catch the gasoline. Turn the system on and energize the fuel solenoid. Fuel will start spraying out of the nozzles. Look at the fuel pressure, this will be your flowing fuel pressure. There should be no drop in psi between the open and not open on your fuel gauge. A twitch is ok but if must bounce back quickly. Now you have your base line to tune from. So if your gauge reads 55psi noid close it should read 55 psi with the noid open spraying fuel. If your gauge falls and does not recover your fuel pump is inadequate for the hp setting you are trying to run or there is a plumbing issue that needs to be looked at.
Setting to a high pressure with noid closed to achieve the 55psi with noid open is ok also, the main thing you are checking is that the system can sustain 55psi with the fuel noid open. If it cannot not change the pump.
High-low pressure with a nozzle system. With this one you will not need the compression fitting but you will need a flow check tool. http://www.nitrousexpress.com/Instru.../flowcheck.pdf
This gives you the fittings needed to go from a –6 line to a –3 that can hold the jet. You will attach the fuel line going to your solenoid to a –6 manifold. The outlet of this manifold will hold the –6X-3 fitting that will hold a jet. Now we need to figure what jet needs to go into this –3 fitting. You will take your fuel jet size X itself X the number of jets, and then square root it. So for a 26 fuel jet it would be 26 x 26 x 8 = 5408 and the square root of that is 73.53 so you can use a 73 or 74 jet. This will get you into the ball game with your set up. NX sheet give a true jet that might differ from this formula, that is because the flow bench showed a different jet than the math said would work.
You now install that jet into your flow check tool and tighten the B-nut that holds the jet into place. Put this into a container proper for gasoline and turn the pump on. Read your pressure gauge and it should be at the predetermined pressure. Again if you cannot get to the proper flowing fuel pressure the pump is not adequate for the hp level you are trying to maintain.
Ricky
