dhdenney

iTrader: (53)

Pardon my ignorance, but I bought fuel injectors that were too big for my app. What is the best way in LT1 edit to decrease their fueling to better suit my needs? I've played with offsets and constants a little but I didn't gain anything. Pointers? Should I just downgrade to something smaller?

samz28

lower the fuel pressure. if you're at 4bar go to 3 bar, or 2.5bar

makes big injectors behave alot better at idle/low load.

i can't speak for lt1edit, but on my 4 bangers i found this to help in two ways:
low load/emissions and mpg, and also relieves the fuel pump since at lower pressure they can sustain more flow safely.

just an idea.

dhdenney

iTrader: (53)

Something to think about. I'm just getting too much fuel and should do something!

samz28

yah i put 440cc on my 1.8 8v vw. in order to make 165whp i needed 260cc@3.8bar at 100% Duty cycle. When i put on the 3.8bar with 440cc obviously i had buttloads of fuel on the low end (emissions/idle/low load surging). I switched in a 2.5bar and this allows me a clean idle and sufficient flow. I can always use the old "squash the fpr" trick to alter the rate higher. Or if you are hardcore modify the fpr/spring to be adjustable. Or hell use a manifold referenced FPR so at idle/low load you'll vacuum some fpr out.

But if you can tune it with lt1edit then just do it. But there is a point at which you have a minimum injector open time that can become a pita with any efi that uses saturated injectors.

Why most big injectors are peak n hold, they can snap them open so fast so you can put 600cc injectors on a low VE@low rpm motor and rock them out like factory.

Obviously this won't fix your current injector situation..

dhdenney

iTrader: (53)

Thanks for the insight. The trick now will be to figure out how to change this in the editor. I might just have to get me an adjustable FPR. The stock one was so close to where I wanted fuel pressure anyway that I never bought one.