Going lean, dropping pulsewidth

[Stangguy]

2001 Twin Turbo Vette w/ 42lb ford injectors and bigger pump. 10psi. Stock engine. At about 4500rpm my injector pulsewidth starts to drop and car goes lean. Tuning mass air. I am hitting 13400 hz on the maf. I've played and added a lot to the PE, but still drops. My cylinder mass drops too. What am i missing?

[SSUte01]

512g/sec ?

[Stangguy]

Yes i've maxed out the airflow on the maf

[xrelapse13]

Need a log, but you're maxing out the airflow hardcoded limits in the PCM. Either scale the tune to register under 512g/s so that you have an accurate measure of airflow going into the motor, or add a 2-3bar map sensor and tune the car in speed density.

[mowton]

Need a log, but you're maxing out the airflow hardcoded limits in the PCM. Either scale the tune to register under 512g/s so that you have an accurate measure of airflow going into the motor, or add a 2-3bar map sensor and tune the car in speed density.

Scaling wont help as he has exceeded the physical capabilities (Hz) of the MAF it sounds like. One alternative is to increase the diameter of the Charge Pipe which will "slow" down the air and regain some range in the Hz arena. The second is as xrelapse13 says to tune in speed density. You can also upgrade to a 2-3 bar enhanced OS to improve boosted PCM control.

Ed M

[Stangguy]

I figured adding PE would overcome this though?

[mowton]

I figured adding PE would overcome this though?

It will to a point, but isn't the correct or accurate way to set air-fuel model....that is what we call 'Rapping the PE"

We don't know where your IPW is now but if maxed (>19ms at 6000 rpm or higher) then no PE in the world will increase the fueling.

Ed M