How many guys run 2-3 fuel pumps all the same time
#2
Its best to turn them on with a hobbs switch or get them to turn on at a certain boost level thru the PCM or boost controller.
#4
Trending Topics
#8
#9
#10
If you have a large enough return line it will be ok. I have my second pump set up to come on with a hobbs switch. I chose to do it that way only because it's unnecessary to run both pumps at the same time... The "heating the fuel" thing is probably minor, but it is less wear on that second pump, and quite frankly it's not all that much more complicated to wire a separate pump on a switch.
https://ls1tech.com/forums/fueling-i...g-install.html Post 9 has a diagram.
https://ls1tech.com/forums/fueling-i...g-install.html Post 9 has a diagram.
#11
IMO there is no need to have both pumps on at idle. It will be circulating, and heating far more fuel than you need at idle. If you have the option to have the 2nd pump come on at boost why not do it?
I use the holley 1800 pump 2nd half is trigger by pcm at above 3psi & above 60% tps
I use the holley 1800 pump 2nd half is trigger by pcm at above 3psi & above 60% tps
#16
its more wear and tear turning pumps on and off.....
you can also have fuel surge issues when you turn on and off a pump
I run both on all the time...
Holley 12-1800 dual fuel pump
-10 feed
-8 return
no problems
fuel really doesnt get heated up from pumps being on all the time..
it gets more heated up from being in lines in a hot engine bay and touching fuel rails that get hot because they are made of metal...
I put a charger on my battery, turned the fuel pumps on, and just ran them for about 20 minutes with a thermometer in the 20 Gallon fuel cell..tank was approximately 2/3 full
saw a 2* rise in fuel temps....
you can also have fuel surge issues when you turn on and off a pump
I run both on all the time...
Holley 12-1800 dual fuel pump
-10 feed
-8 return
no problems
fuel really doesnt get heated up from pumps being on all the time..
it gets more heated up from being in lines in a hot engine bay and touching fuel rails that get hot because they are made of metal...
I put a charger on my battery, turned the fuel pumps on, and just ran them for about 20 minutes with a thermometer in the 20 Gallon fuel cell..tank was approximately 2/3 full
saw a 2* rise in fuel temps....
Last edited by soundengineer; 01-02-2014 at 01:32 AM.
#17
its more wear and tear turning pumps on and off.....
you can also have fuel surge issues when you turn on and off a pump
I run both on all the time...
Holley 12-1800 dual fuel pump
-10 feed
-8 return
no problems
fuel really doesnt get heated up from pumps being on all the time..
it gets more heated up from being in lines in a hot engine bay and touching fuel rails that get hot because they are made of metal...
I put a charger on my battery, turned the fuel pumps on, and just ran them for about 20 minutes with a thermometer in the 20 Gallon fuel cell..tank was approximately 2/3 full
saw a 2* rise in fuel temps....
you can also have fuel surge issues when you turn on and off a pump
I run both on all the time...
Holley 12-1800 dual fuel pump
-10 feed
-8 return
no problems
fuel really doesnt get heated up from pumps being on all the time..
it gets more heated up from being in lines in a hot engine bay and touching fuel rails that get hot because they are made of metal...
I put a charger on my battery, turned the fuel pumps on, and just ran them for about 20 minutes with a thermometer in the 20 Gallon fuel cell..tank was approximately 2/3 full
saw a 2* rise in fuel temps....
Surge? Really that is what pressure regulators are for. GM used to put pulsators inline in the fuel system in the tank to control the surge because the factory regulator couldn't control the pulsing surge. Later on they disappeared because they figured out that with a higher pressure and a better regulator design they weren't needed. So, if the OEM's figured that out years ago, don't you think the aftermarket had that already covered?
True you are correct in that just the pump being on doesn't heat fuel but being near fuel rails that are heated in the engine bay is how they get heated.
Think of this though: Lets take your example, 20 gallons of fuel has 3 pumps in it. If one pump is on and the car is driving down the road the return fuel is somewhat heated in the engine bay and is returned to the tank where there is roughly 19 gallons left that is still cool. So that little bit of return fuel gets to cool back off. Now lets turn on all 3 pumps and now you have roughly triple the fuel going up front getting heated and sent back to the tank while you are still street driving. So now, we know we don't build our car for fuel economy, what happens when that 20 gallon fuel cell drops to 10 gallons? You lose that extra fuel to drop the temp of the return gas a couple of degrees. So heating the fuel is starting to happen unnecessarily. IMO I'm not running a pump if I don't need to.