Fmic question about fuel cut

[Awyman18]

So i heard that when u add a fmic and hard pipes, it could push ur fuel cut back a bit? Since ur engine is receiving more air? is that correct or no?

[pandrade]

im not expert but changing the intercooler and pipes wouldent do anything whith the fuel cut off because they are unrelated to each other. they work together of coarse but the fuel system is unrelated. the reason you hit fuel cut of is because your stock fuel system cant handle the level of boost your reaching and cant give you any more fuel or the computer paramiters wont allow you to go any higher for safty and what not

dont know if im explaning my self properly

[cre]

Fuel cut is based on a couple different factors but 90% is the measured incoming airflow. A larger intercooler has no effect on the 7M-GTE's cutoff.... on some different systems it's a different story. BUT, it does help the engine run more efficiently and can make more power given that the final charge is cooler and denser and a bit less susceptible to ping.

[pandrade]

and thats why im no expert. So upgrading the intercooler is always benifital but on the 7mgte it wouldent do anything to the fuel cut off basicly

now if you where to use the lexus afm upgrade throttle body ext..as well as upgrading the fuel system as a whole. would be more of a deciding factor whith fuel cut off than an intercooler and pipes alone?

[Awyman18]

how exactly would upgrading the throttle body help u? and wat throttle body could u use?? but yea i just heard from some source that i cant remember that with a fmic upgrade and hard pipes u might be able to squeeze 13lbs or something of the sort

[pandrade]

im not saying it would im asking any one that knows if that sounds about right. in my mind the afm tells the ecu hey x amount of air dump x amount of fuel and when you hit fuel cut off its the ecu saying to much air not enought fuel, so i would think more air thus throtle body and other intake upgrades ext.. + upgraded fuel system equals no fuel cut off

[cre]

The throttle body does nothing with regard to fuel cut.

Swapping out the AFM for the Lex AFM shifts how much air the ECU THINKS is entering the engine because it lets in more unmetered air. So the ECU still sees a pattern which reflects 50kPa with the normal housing, but there's air sneaking in the back door and the engine is really getting 65kPa.

The thing about the IC letting you run more boost is rather simple.... Well, I'll try to simplify it and keep it accurate enough. There is a pressure drop across the IC. An inefficient IC may see a 5psi drop. This means that while your turbo is cranking out 15psi your intake manifold and engine are only seeing 10psi. By putting in a more efficient IC (with only a drop of 2psi) your intake manifold will see 13psi instead of the lowly 10psi. The turbo is still cranking out 15psi. The air is just having an easier time reaching the engine and is considerably cooler now too. But the volume of air moved at any period of time shifts too though and as such your fuel cut doesn't shift too much. Long story short: Fuel cut is determined by the measurements taken on the turbo side of the IC whereas what the engine sees and what you see on the gauge is determined at the intake plenum.

[pandrade]

that cleared up things quite a bit