HELP! fuel pressure/ 9psi max boost b4 130% duty cycle.
10-02-2013, 07:34 AM
#22
Does the fuel pump draw more power when more fuel is being used?
Sounds like a silly question, I know, but my thinking is that it may not take much more power to maintain the correct line pressure regardless of actual flow numbers. I could be wrong, but I believe the fuel pump only has one speed. When its not flowing a lot of fuel that just means its fighting the pressure regulator harder.
I'm thinking of it like a battery powered drill. Does it take more power when it you pull the trigger and it spins freely, or when you have your hand on it trying to hold it back? Does that make sense to anyone else? In other words, it doesn't really add up to me that its the wiring that's causing this problem at higher boost and RPM when fuel is flowing with less restriction.
Sounds like a silly question, I know, but my thinking is that it may not take much more power to maintain the correct line pressure regardless of actual flow numbers. I could be wrong, but I believe the fuel pump only has one speed. When its not flowing a lot of fuel that just means its fighting the pressure regulator harder.
I'm thinking of it like a battery powered drill. Does it take more power when it you pull the trigger and it spins freely, or when you have your hand on it trying to hold it back? Does that make sense to anyone else? In other words, it doesn't really add up to me that its the wiring that's causing this problem at higher boost and RPM when fuel is flowing with less restriction.
10-02-2013, 05:21 PM
#23
The pump voltage determines its speed. The amperage going to the pump determines its output pressure. Both of these factors together determine its output. So if your initial wiring is insufficient, not enough current gets to the pump, there is a voltage drop, and the output suffers.
Will upgrading the wiring help? It will decrease resistance in the wiring and therefore the voltage drop to the pump so it should output more. Without knowing the voltage now though, its hard to say if it will actually help.
For your drill, it takes less to free spin. This is because it requires the least power, which is voltage times current. Your drill has a speed limit, based on the voltage (trigger position), and a torque limit, based on the current from the battery. Free-spinning is a voltage limiter, not a current limiter, but when you grab it and hold it its a voltage and current limit, so basically the maximum voltage times the maximum current so the most power consumed.
Getting this back to fuel pumps, better wiring will allow the pump to consume more power, but if that wasnt the issue in the first place it obviously wont fix it.
Short answer, the fuel pump doesnt care about how much fuel you actually use, it only cares about the voltage you give it and the current capacity of the wiring.
So as a thought experiment lets say you have your pump and internal regulator that doesnt have a boost reference.
At idle fuel demand is less than supplied so the regulator is open and maintains pressure by allowing excess fuel to bypass the feed line. The pump is still spinning full speed regardless.
When you are at the fuel pump limit, it can supply exactly as much fuel as the engine needs and the regulator is not bypassing anything.
When you are past the fuel pump limit, the regulator is still completely closed but the pump cant move enough fuel so the pressure starts to decline. It declines to a point where the pump can supply just enough to balance the demand so the regulator stays closed. All pumps move less flow at higher pressures, which means if you decrease pressure you actually move more fuel. This also means if you increase pressure (boost pressure against injectors, for instance) then your available pump flow decreases.
Look at the thread I made that is stickied in the fuel section for more info.
Will upgrading the wiring help? It will decrease resistance in the wiring and therefore the voltage drop to the pump so it should output more. Without knowing the voltage now though, its hard to say if it will actually help.
For your drill, it takes less to free spin. This is because it requires the least power, which is voltage times current. Your drill has a speed limit, based on the voltage (trigger position), and a torque limit, based on the current from the battery. Free-spinning is a voltage limiter, not a current limiter, but when you grab it and hold it its a voltage and current limit, so basically the maximum voltage times the maximum current so the most power consumed.
Getting this back to fuel pumps, better wiring will allow the pump to consume more power, but if that wasnt the issue in the first place it obviously wont fix it.
Short answer, the fuel pump doesnt care about how much fuel you actually use, it only cares about the voltage you give it and the current capacity of the wiring.
So as a thought experiment lets say you have your pump and internal regulator that doesnt have a boost reference.
At idle fuel demand is less than supplied so the regulator is open and maintains pressure by allowing excess fuel to bypass the feed line. The pump is still spinning full speed regardless.
When you are at the fuel pump limit, it can supply exactly as much fuel as the engine needs and the regulator is not bypassing anything.
When you are past the fuel pump limit, the regulator is still completely closed but the pump cant move enough fuel so the pressure starts to decline. It declines to a point where the pump can supply just enough to balance the demand so the regulator stays closed. All pumps move less flow at higher pressures, which means if you decrease pressure you actually move more fuel. This also means if you increase pressure (boost pressure against injectors, for instance) then your available pump flow decreases.
Look at the thread I made that is stickied in the fuel section for more info.
10-02-2013, 05:54 PM
#24
The pump voltage determines its speed. The amperage going to the pump determines its output pressure. Both of these factors together determine its output. So if your initial wiring is insufficient, not enough current gets to the pump, there is a voltage drop, and the output suffers.
Will upgrading the wiring help? It will decrease resistance in the wiring and therefore the voltage drop to the pump so it should output more. Without knowing the voltage now though, its hard to say if it will actually help.
For your drill, it takes less to free spin. This is because it requires the least power, which is voltage times current. Your drill has a speed limit, based on the voltage (trigger position), and a torque limit, based on the current from the battery. Free-spinning is a voltage limiter, not a current limiter, but when you grab it and hold it its a voltage and current limit, so basically the maximum voltage times the maximum current so the most power consumed.
Getting this back to fuel pumps, better wiring will allow the pump to consume more power, but if that wasnt the issue in the first place it obviously wont fix it.
Short answer, the fuel pump doesnt care about how much fuel you actually use, it only cares about the voltage you give it and the current capacity of the wiring.
So as a thought experiment lets say you have your pump and internal regulator that doesnt have a boost reference.
At idle fuel demand is less than supplied so the regulator is open and maintains pressure by allowing excess fuel to bypass the feed line. The pump is still spinning full speed regardless.
When you are at the fuel pump limit, it can supply exactly as much fuel as the engine needs and the regulator is not bypassing anything.
When you are past the fuel pump limit, the regulator is still completely closed but the pump cant move enough fuel so the pressure starts to decline. It declines to a point where the pump can supply just enough to balance the demand so the regulator stays closed. All pumps move less flow at higher pressures, which means if you decrease pressure you actually move more fuel. This also means if you increase pressure (boost pressure against injectors, for instance) then your available pump flow decreases.
Look at the thread I made that is stickied in the fuel section for more info.
Will upgrading the wiring help? It will decrease resistance in the wiring and therefore the voltage drop to the pump so it should output more. Without knowing the voltage now though, its hard to say if it will actually help.
For your drill, it takes less to free spin. This is because it requires the least power, which is voltage times current. Your drill has a speed limit, based on the voltage (trigger position), and a torque limit, based on the current from the battery. Free-spinning is a voltage limiter, not a current limiter, but when you grab it and hold it its a voltage and current limit, so basically the maximum voltage times the maximum current so the most power consumed.
Getting this back to fuel pumps, better wiring will allow the pump to consume more power, but if that wasnt the issue in the first place it obviously wont fix it.
Short answer, the fuel pump doesnt care about how much fuel you actually use, it only cares about the voltage you give it and the current capacity of the wiring.
So as a thought experiment lets say you have your pump and internal regulator that doesnt have a boost reference.
At idle fuel demand is less than supplied so the regulator is open and maintains pressure by allowing excess fuel to bypass the feed line. The pump is still spinning full speed regardless.
When you are at the fuel pump limit, it can supply exactly as much fuel as the engine needs and the regulator is not bypassing anything.
When you are past the fuel pump limit, the regulator is still completely closed but the pump cant move enough fuel so the pressure starts to decline. It declines to a point where the pump can supply just enough to balance the demand so the regulator stays closed. All pumps move less flow at higher pressures, which means if you decrease pressure you actually move more fuel. This also means if you increase pressure (boost pressure against injectors, for instance) then your available pump flow decreases.
Look at the thread I made that is stickied in the fuel section for more info.
10-04-2013, 01:31 PM
#25
The pump voltage determines its speed. The amperage going to the pump determines its output pressure. Both of these factors together determine its output. So if your initial wiring is insufficient, not enough current gets to the pump, there is a voltage drop, and the output suffers.
Will upgrading the wiring help? It will decrease resistance in the wiring and therefore the voltage drop to the pump so it should output more. Without knowing the voltage now though, its hard to say if it will actually help.
For your drill, it takes less to free spin. This is because it requires the least power, which is voltage times current. Your drill has a speed limit, based on the voltage (trigger position), and a torque limit, based on the current from the battery. Free-spinning is a voltage limiter, not a current limiter, but when you grab it and hold it its a voltage and current limit, so basically the maximum voltage times the maximum current so the most power consumed.
Getting this back to fuel pumps, better wiring will allow the pump to consume more power, but if that wasnt the issue in the first place it obviously wont fix it.
Short answer, the fuel pump doesnt care about how much fuel you actually use, it only cares about the voltage you give it and the current capacity of the wiring.
So as a thought experiment lets say you have your pump and internal regulator that doesnt have a boost reference.
At idle fuel demand is less than supplied so the regulator is open and maintains pressure by allowing excess fuel to bypass the feed line. The pump is still spinning full speed regardless.
When you are at the fuel pump limit, it can supply exactly as much fuel as the engine needs and the regulator is not bypassing anything.
When you are past the fuel pump limit, the regulator is still completely closed but the pump cant move enough fuel so the pressure starts to decline. It declines to a point where the pump can supply just enough to balance the demand so the regulator stays closed. All pumps move less flow at higher pressures, which means if you decrease pressure you actually move more fuel. This also means if you increase pressure (boost pressure against injectors, for instance) then your available pump flow decreases.
Look at the thread I made that is stickied in the fuel section for more info.
Will upgrading the wiring help? It will decrease resistance in the wiring and therefore the voltage drop to the pump so it should output more. Without knowing the voltage now though, its hard to say if it will actually help.
For your drill, it takes less to free spin. This is because it requires the least power, which is voltage times current. Your drill has a speed limit, based on the voltage (trigger position), and a torque limit, based on the current from the battery. Free-spinning is a voltage limiter, not a current limiter, but when you grab it and hold it its a voltage and current limit, so basically the maximum voltage times the maximum current so the most power consumed.
Getting this back to fuel pumps, better wiring will allow the pump to consume more power, but if that wasnt the issue in the first place it obviously wont fix it.
Short answer, the fuel pump doesnt care about how much fuel you actually use, it only cares about the voltage you give it and the current capacity of the wiring.
So as a thought experiment lets say you have your pump and internal regulator that doesnt have a boost reference.
At idle fuel demand is less than supplied so the regulator is open and maintains pressure by allowing excess fuel to bypass the feed line. The pump is still spinning full speed regardless.
When you are at the fuel pump limit, it can supply exactly as much fuel as the engine needs and the regulator is not bypassing anything.
When you are past the fuel pump limit, the regulator is still completely closed but the pump cant move enough fuel so the pressure starts to decline. It declines to a point where the pump can supply just enough to balance the demand so the regulator stays closed. All pumps move less flow at higher pressures, which means if you decrease pressure you actually move more fuel. This also means if you increase pressure (boost pressure against injectors, for instance) then your available pump flow decreases.
Look at the thread I made that is stickied in the fuel section for more info.
Seriously... haha love it.
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