Fuel Pump recommendation
Burning Brakes
Joined: Aug 2008
Posts: 822
Likes: 214
From: Tampa, FL
Bigger pumps draw more amps and adds stress on 30 - 40 year wiring and connectors. With a walbro 255 I have had two wiring failures on my 86. The tank bulkhead connector mentioned by Racetronix failed, and a burned pin in a harness connector in front of the passenger door. I installed the Racetronix wiring kit that runs from the alternator to the pump and that solved the wiring issue.
Also, I see you're from San Antonio. I lived there for four years when I worked at NSA Texas over on Potranco. I loved the city. I lived up in Encino Park (north 281 above 1604). We used to hang out at the Pearl, the Sunken Gardens, the Botanical Gardens, I even miss the old school Pizza hut from the 50s down by Woodlawn, and the Central Market that was owned by HEB. I miss it every day.
Safety Car
Joined: Oct 2007
Posts: 4,189
Likes: 1,065
From: South Florida
As shown in the graphs, voltage changes flow rate.
Current like fluids through a restrictive tube at higher velocity create more friction and heat is produced in the tube/wires.
In majority of daily driver apps I will use this type of relay box for fuel pump reliability installation
Which is an OEM relay box from Saab or similar, with water proof for underhood container, and at least 1 60-amp relay from an OEM vehicle.
The big yellow relay is the 60amp notice the giant fuse. This will power 600rwhp stealth 340lph gasoline which is a truly tiny cheap fuel pump for 20+ years reliably given the wire size and fuse/relay quality in waterproof container. ;
When the fuel system is powerful with 2 to 4 pumps maybe it is more ideal to place the battery and relays right near the fuel pump system, prioritizing them to the battery.
I still prefer underhood battery if possible, because of cranking and alternator charging priority, but either way seems to work fine with a large enough battery cable to deliver current with low friction.
The main thing is to figure out how many amps you will need when voltage is lowest and size wires/fuses/relays appropriately, accounting for voltage spikes and current spikes, such as fans turning on and off, which tend to draw voltage down and current to spike when first starting as a digital statement.
Current like fluids through a restrictive tube at higher velocity create more friction and heat is produced in the tube/wires.
In majority of daily driver apps I will use this type of relay box for fuel pump reliability installation
Which is an OEM relay box from Saab or similar, with water proof for underhood container, and at least 1 60-amp relay from an OEM vehicle.
The big yellow relay is the 60amp notice the giant fuse. This will power 600rwhp stealth 340lph gasoline which is a truly tiny cheap fuel pump for 20+ years reliably given the wire size and fuse/relay quality in waterproof container. ;
When the fuel system is powerful with 2 to 4 pumps maybe it is more ideal to place the battery and relays right near the fuel pump system, prioritizing them to the battery.
I still prefer underhood battery if possible, because of cranking and alternator charging priority, but either way seems to work fine with a large enough battery cable to deliver current with low friction.
The main thing is to figure out how many amps you will need when voltage is lowest and size wires/fuses/relays appropriately, accounting for voltage spikes and current spikes, such as fans turning on and off, which tend to draw voltage down and current to spike when first starting as a digital statement.
