stock m44 injector size?

[DustenT]

Anyone know what size the stock fuel injectors are on a m44? Is it possible to put bigger ones in?

[DustenT]

bump, sorry I'm impatient. :biggrin:

[ZeroG]

Anyone know what size the stock fuel injectors are on a m44? Is it possible to put bigger ones in?

If I recall correctly the stock injectors are 15 Or 16 Lbs/Hr. Could you put bigger ones sure, you will need adapters as most injectors are not air shrowded like the M42 and M44.

Why would you want to put a bigger injector? For my power? If you do you will need a piggyback unit to control the fuel. If you don't use one the LTFT's and STFT's will trim out any gain that you got.

-Chad

[DustenT]

If I recall correctly the stock injectors are 15 Or 16 Lbs/Hr. Could you put bigger ones sure, you will need adapters as most injectors are not air shrowded like the M42 and M44.

Why would you want to put a bigger injector? For my power? If you do you will need a piggyback unit to control the fuel. If you don't use one the LTFT's and STFT's will trim out any gain that you got.

-Chad

Now I'm confused, someone on the .net list said they were 19 lbs/hr. What is the advantage of the "air shrowded" injectors? On NickG's upgrade, the replacement injectors don't use the shrowd.

What the heck is LTFT's and STFT's? Excuse my ignorance, I can't fit anymore acronyms in my brain!!!

[ZeroG]

Now I'm confused, someone on the .net list said they were 19 lbs/hr. What is the advantage of the "air shrowded" injectors? On NickG's upgrade, the replacement injectors don't use the shrowd.

What the heck is LTFT's and STFT's? Excuse my ignorance, I can't fit anymore acronyms in my brain!!!

I am not sure about the injector flow rating it was just a number that I reacall. As far as I know air shrowded in jector assist with the CARB/SMOG qualifications. It bypasses air from the throttle body so that the engine can idle. It works along with the ICV (Idle Control Valve).

As for STFT & LTFT.

STFT = Short Term Fuel Trim

LTFT= Long Term Fuel Trim

The LTFT and STFT assist with the way the ECU runs the car. While the car is being driven at <WOT the car is running in what is called closed loop, where the ECU tried to keep the Air/Fuel ratio at 14.7. Optimum for power and fuel economy. When the car goes >=WOT the car is in what is called open loop and runs off a predetermined fuel map.

If you add larger injectors the car will be running rich when it should be running 14.7, and the ECU will got to the fuel map look up table calculate a leaner value and replace the old value in the table there for making the car run at 14.7 with the bigger injector. With the ECU leaning the LTFT and STFT when you go WOT in turn you will run leaner as well.

-Chad

[sabbath130]

i am currently running a full supersprint exhaust system( headers, racing resonator, and cat-back)

what effect does that setup have on my car as far as lean/rich goes (no cat)? performance?

what effect will it have when its supercharged...?

[ClubSport]

i am currently running a full supersprint exhaust system( headers, racing resonator, and cat-back)

what effect does that setup have on my car as far as lean/rich goes (no cat)? performance?

what effect will it have when its supercharged...?

1. Probably none. You computer will automatically compensate for any increased airflow the exhaust allows, and add more fuel. Will probably increase performance a little.

2. That's what the RRFPR is for. It keeps compensating with more fuel, past the limits of the stock computer.