belt driven fuel pump pressure questions.
12-20-2008, 06:36 AM
#1
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belt driven fuel pump pressure questions. first off is there any CONS to running higher fuel pressures?
I know are stock fueling system = 4bar/58psi and most injectors are rated at 3bar/43.5psi
if you were to run an aeromotive 1105 belt driven fuel pump and proper FPR are there any cons to running to much fuel pressure?
can the injectors handle that much pressure? (70psi)
so could you run 8 high impedance injectors (75's) but run them at the higher pressure to make up the flow? or does it not work this way at all?
if you can't tell I'm really confused about all of this.
Chad
I know are stock fueling system = 4bar/58psi and most injectors are rated at 3bar/43.5psi
if you were to run an aeromotive 1105 belt driven fuel pump and proper FPR are there any cons to running to much fuel pressure?
can the injectors handle that much pressure? (70psi)
so could you run 8 high impedance injectors (75's) but run them at the higher pressure to make up the flow? or does it not work this way at all?
if you can't tell I'm really confused about all of this.
Chad
12-20-2008, 07:34 AM
#2
You may cause the injectors to become static and hang open if you run too high pressure I believe. You are not required to run any "given" pressure.
When I had an aftermarket fuel system with adjustable regulator, I set my base pressure to 43psi and tuned for that. Just because factory pressure is ~58psi does not mean you can't run lower than that, you just have to tune for it. I would run lower than higher if it is an option, especially if your regulator is boost referenced.
When I had an aftermarket fuel system with adjustable regulator, I set my base pressure to 43psi and tuned for that. Just because factory pressure is ~58psi does not mean you can't run lower than that, you just have to tune for it. I would run lower than higher if it is an option, especially if your regulator is boost referenced.
12-20-2008, 11:52 AM
#3
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You may cause the injectors to become static and hang open if you run too high pressure I believe. You are not required to run any "given" pressure.
When I had an aftermarket fuel system with adjustable regulator, I set my base pressure to 43psi and tuned for that. Just because factory pressure is ~58psi does not mean you can't run lower than that, you just have to tune for it. I would run lower than higher if it is an option, especially if your regulator is boost referenced.
When I had an aftermarket fuel system with adjustable regulator, I set my base pressure to 43psi and tuned for that. Just because factory pressure is ~58psi does not mean you can't run lower than that, you just have to tune for it. I would run lower than higher if it is an option, especially if your regulator is boost referenced.
so running to high of a pressure can cause the injectors to stick open...that'd be a bad day.
Chad
12-20-2008, 01:35 PM
#4
The reason I lowered my base pressure was because I was running a boost referenced regulator. So if I was at a base of 58psi, and I hit 15psi of boost, then my fuel pressure would spike to 73psi and higher. This was excessive to me and risked locking up the injectors.
Most fuel injected cars run around 43psi, and that is the pressure most injectors are rated at.
Most fuel injected cars run around 43psi, and that is the pressure most injectors are rated at.
12-20-2008, 01:38 PM
#5
Actually the injectors have to open against the pressure, so high fuel pressure will prevent them from opening. Once you hit the threshold, the car just shuts off until the pressure drops.
As for pressure, it is harder for a pump to run high pressures, so it is advisable to start with the 3 or 4 bar setting.
If running high boost, & boost referencing your pressure, it is advisable to limit pressure to 70 or 75max. Above this pressure, many injectors do not operate well. Some do, some don't, depends on the brand.
If you have enough power to truely need the volume of a belt drive pump, then there is no reason to skimp on injector size, or even consider a high impedance set.
As for pressure, it is harder for a pump to run high pressures, so it is advisable to start with the 3 or 4 bar setting.
If running high boost, & boost referencing your pressure, it is advisable to limit pressure to 70 or 75max. Above this pressure, many injectors do not operate well. Some do, some don't, depends on the brand.
If you have enough power to truely need the volume of a belt drive pump, then there is no reason to skimp on injector size, or even consider a high impedance set.
12-20-2008, 01:47 PM
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Actually the injectors have to open against the pressure, so high fuel pressure will prevent them from opening. Once you hit the threshold, the car just shuts off until the pressure drops.
As for pressure, it is harder for a pump to run high pressures, so it is advisable to start with the 3 or 4 bar setting.
If running high boost, & boost referencing your pressure, it is advisable to limit pressure to 70 or 75max. Above this pressure, many injectors do not operate well. Some do, some don't, depends on the brand.
If you have enough power to truely need the volume of a belt drive pump, then there is no reason to skimp on injector size, or even consider a high impedance set.
As for pressure, it is harder for a pump to run high pressures, so it is advisable to start with the 3 or 4 bar setting.
If running high boost, & boost referencing your pressure, it is advisable to limit pressure to 70 or 75max. Above this pressure, many injectors do not operate well. Some do, some don't, depends on the brand.
If you have enough power to truely need the volume of a belt drive pump, then there is no reason to skimp on injector size, or even consider a high impedance set.
harder for a belt driven setup?
only reason for the high imp. injectors is not quite yet ready to run a bs3 setup.
setup is going to be race/street (rarely) S91 ls2.
Chad
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12-20-2008, 09:21 PM
#8
The belt drive setup will be more than capable of providing the pressure, but the injectors may not open consistently at very high pressures.
Personally I would do what I had to do to use low impedance injectors if I was trying to build something with over 900rwhp.
Personally I would do what I had to do to use low impedance injectors if I was trying to build something with over 900rwhp.
12-21-2008, 04:25 PM
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The belt drive setup will be more than capable of providing the pressure, but the injectors may not open consistently at very high pressures.
Personally I would do what I had to do to use low impedance injectors if I was trying to build something with over 900rwhp.
Personally I would do what I had to do to use low impedance injectors if I was trying to build something with over 900rwhp.
thanks lonnie.
Chad
12-21-2008, 07:15 PM
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now to find out more about BS3....
Chad
02-25-2009, 01:47 AM
#12
This is not a true statement, if you are running boost and a boost reference FPR, the injector only see's the base pressure differential pressure. If you are running 58psi base and add 20# of boost the fuel pressure increases to 78#, the injector still acts exactly like it was at 58#. Because the difference between the inlet and outlet pressure is still the same...
02-25-2009, 03:10 AM
#13
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You don't need a BS3 to run low impedance injectors, the stock ecm can run them with a cheap($250-$400) converter box. AEM makes one as well as Acceleronics.
