I am about to do a fuel flow check of my fuel system prior to flight testing after rebuild. The engine is a VW fitted with a engine driven pump and a CD150 Stromberg carb.
Can anybody advise what the minimum fuel pressure should be for this set up?
Stuart Penfold
VW engine with CD150 Stromberg Fuel Flow
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Noel Howard
- Posts: 34
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Sturt,
You probably know that there is an LAA technical leaflet TL20-2 (I think it is). However, that does not quote a fuel pressure.
The specified maximum pressure that a VW mechanical fuel pump is supposed to give is 3.5 psi, though mine gives more than that. The procedure is to bleed off fuel downstream of the pump but not so much as to prevent the engine from running at full power and to measure the quantity of fuel bled off over a measured time. I seem to remember that my then inspector suggested 1 psi, which certainly was sufficient to keep the engine running at 3300 rpm. Unless there is a restriction somewhere, the VW pump is more than adequate for the duty.
Why don't you ring the LAA Engineering Department and ask them?
Noel.
You probably know that there is an LAA technical leaflet TL20-2 (I think it is). However, that does not quote a fuel pressure.
The specified maximum pressure that a VW mechanical fuel pump is supposed to give is 3.5 psi, though mine gives more than that. The procedure is to bleed off fuel downstream of the pump but not so much as to prevent the engine from running at full power and to measure the quantity of fuel bled off over a measured time. I seem to remember that my then inspector suggested 1 psi, which certainly was sufficient to keep the engine running at 3300 rpm. Unless there is a restriction somewhere, the VW pump is more than adequate for the duty.
Why don't you ring the LAA Engineering Department and ask them?
Noel.
Fuel flow test
Noel,
Thankyou for the reply. I have since I posted, discussed this with my inspector and we have agreed on how we are going to do this test. The plan is to add a T piece into the fuel line and loop a pipe off this Tee upwards and then down into my measuring jug with a clamp to close this feed as required. This upwards loop will create a head pressure that will hopefully keep fuel flowing into the carburettor. Currently I am getting the parts ready and will be running the test this weekend.
Stuart
Thankyou for the reply. I have since I posted, discussed this with my inspector and we have agreed on how we are going to do this test. The plan is to add a T piece into the fuel line and loop a pipe off this Tee upwards and then down into my measuring jug with a clamp to close this feed as required. This upwards loop will create a head pressure that will hopefully keep fuel flowing into the carburettor. Currently I am getting the parts ready and will be running the test this weekend.
Stuart