@ronwitt posted:Hi Doug, yes pain for sure. Your suggestion on testing the line disconnected for the fuel tank in another gas can is a good one. Will try that first. Don't want to go the route of line feed from drain plug at the bottom of tank, although an option, but way down the list. I'll let you know how it goes. I assume you feel that 4.5 PSI is also good to get the job done as a boost prime pump? I wonder, but not sure if a 10-14 PSI boost or lower 7 PSI would cause any issues with my Motorcraft 4300D carb...and make a difference on pull. Not sure of your carb setup or if FI. What PSI are you running for EFP. Thanks for taking the time to respond to each of my questions/comments...much appreciated! Ron
The pressure that you get out of a stock mechanical fuel pump is plenty.
On carburetored engines you need to be concerned about the needle & seat and floats to consistently be able to handle pressures higher.
The 7psi that you read about in "Hot Rod" magazines is completely wrong for a street car. You might need that at the dragstrip on cars that really "lock up" because of the g-forces pulling fuel away from the transfer slots in the carbs but other then that it is in fact a little dangerous.
The Webers that I am running are running on 3.5psi of pressure. It supplies them with sufficient volume.
As an aside, it took a long time to get some details on some of the Shelby and Ford mid '60s race cars like the Cobras and the GT40's running Webers but guess what? They didn't even run pressure regulators, just plumbed directly from the mechanical pumps which put out....ta ta da! You guessed it! 3.5 to 4.5 psi. The EFP was there to PRIME the system, since they were constantly being torn down in between races and otherwise would need to start dry.
Anyone who has problems with not enough pressure has issues elsewhere and is confused about where to look.
The electric pump you are installing is for PRIMING the system when it is dry...and MAYBE breaking vapor lock BUT if you have vapor lock, there is an issue elsewhere, like the fuel lines are getting cooked somewhere.