- Mar 10, 2006
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what is the purpose of injectors?
- Thread starter mustangkid05
- Start date
speedfreak98r
Banned
Injectors inject fuel into the intake manifold.
The pound measurement refers to how many pounds of fuel per hour the injector will flow.
http://auto.howstuffworks.com/fuel-injection.htm
The pound measurement refers to how many pounds of fuel per hour the injector will flow.
http://auto.howstuffworks.com/fuel-injection.htm
JBushman73
Founding Member
mustangkid05 said:
One reason for needing larger fuel injectors would be for a supercharger or turbo application. More air = the need for more fuel.
4.6_02_Black_GT
Founding Member
Stock 4.6 GT injectors are in 19-22 lbs typically usually recommended for up 300-320 hp.. If you plan more power than that you will need to plan for a tune and bigger injectors... Most blower(supercharger kits) will come with the necessay injectors 36,42,50 are common.
I think you guys need to take it easy on him, I think he just wants to learn why people change out to bigger injectors.
Skidzz
Tinkerbell
I think he just meant to say "What's the point of changing your injectors for bigger ones". I'd say he probably knows what injectors do.....or I hope so
its simple.
adding more air(via forced induction, or nitrous(since it adds more oxygen to the mix)) means you will have to add more fuel to the mix to obtain the right air/fuel mixture.
larger injectors flow more fuel per pulse width. but larger injectors will need some tuning behind them to be controlled correctly, as the stock ecu cant tell how much they flow, so while it will run the same injector cycles as the stock ones, the engine will be flooding with fuel under the area where the injectors were needed. the key is to tuning them to where the ecu compensates by running shorter pulses when all that fuel is not needed (like cruising), but then tuning the injectors for the correct amounts of fuel when it is needed.
also with larger injectors, come a larger fuel pump and/or rail and pressure regulator (not applicable in some situations, as in non-return style setups). the larger injectors have the ability to actually drain the rail of fuel before the pump can supply enough to keep the demand up. thus you lean out and go boom. also a pressure regulator helps keep the pressure inside the rail at a constant, which is a key factor to tuning. its hard to tune if your rail is at 40psi, and when boost hits it flies up to 60psi and youre then pushing 30% more fuel, because the stock system cant hold it back and is overrun. this can lead to a rich condition under load, and in some instances ive seen "rich knock" in buddies cars.
adding more air(via forced induction, or nitrous(since it adds more oxygen to the mix)) means you will have to add more fuel to the mix to obtain the right air/fuel mixture.
larger injectors flow more fuel per pulse width. but larger injectors will need some tuning behind them to be controlled correctly, as the stock ecu cant tell how much they flow, so while it will run the same injector cycles as the stock ones, the engine will be flooding with fuel under the area where the injectors were needed. the key is to tuning them to where the ecu compensates by running shorter pulses when all that fuel is not needed (like cruising), but then tuning the injectors for the correct amounts of fuel when it is needed.
also with larger injectors, come a larger fuel pump and/or rail and pressure regulator (not applicable in some situations, as in non-return style setups). the larger injectors have the ability to actually drain the rail of fuel before the pump can supply enough to keep the demand up. thus you lean out and go boom. also a pressure regulator helps keep the pressure inside the rail at a constant, which is a key factor to tuning. its hard to tune if your rail is at 40psi, and when boost hits it flies up to 60psi and youre then pushing 30% more fuel, because the stock system cant hold it back and is overrun. this can lead to a rich condition under load, and in some instances ive seen "rich knock" in buddies cars.
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