Wastegate Boost Issue

[Rock2610d]

So, I just got my s16G on and took it for a spin. With stock boost control system it will hit 10 psi and stop. Air/Fuel ratio at WOT is 10.2. Pretty good.

However I decided to test my actuator. I disconnected the vacuum line from it and plugged the vacuum line. Took it for a spin and let up at about 4000 rpm when it hit 18 psi. Air/fuel ratio still good at 10.2

Funny thing is I have a stock fuel pump rewired and thought 18 psi would have made the a/f ratio a little leaner, and how is it that waste-gate only pressure sends the boost to 18 psi?

 

[WES_393]

Because without a boost line, the wastegate only opens once exhaust pressure overcomes the actuator and blows the wastegate open.

Your not going to run leaner without a tune (or a fueling issue). The ECU is programmed to deliver X amount of fuel for Y amount of airflow. Increase airflow and the ECU increases fuel to achieve the same AFR. Too much airflow and the ECU cuts fuel, which I bet will happen if you wind it out past 4,00rpm.

 

[Rock2610d]

Great, then what you are saying is if I stay under 4000 rpm and boost stays less than 18 psi, and my af ratio stays around 10 or 11, I should not hurt anything due to wg being disconnected? Or would you suggest hooking it back up for safety?

I did the wg unhook with my T-25 and it opened at about 10 psi....are MHI WGs different, open at 18 psi, that seems high. But I guess it all has to do with how much exhaust pressure there is.

I will be getting a ECM link for Christmas....If I am lucky and will give the car a good tune.

Forgot to mention I live at 7000 ft, so air up here is pretty thin.