At what ambient temperature does the ECU control the max amount of boost? Ive noticed getting on the highway on colder days, when the car is at operating temperature of course, that I max out 7-9 psi. Anyone have an answer? I was just curious.

 

it all depends on the temp.. lol

the colder air is more dense, the engine makes more power and requires less boost to hit the 260 tq mark set by the ecu.

 

bet u if u rev it up to 4500rpm, ud make it to 15psi. on stock tune mine goes to about 8 psi, and slowly goes up to 15 as the rpm goes higher. And at the 8 psi it does not feel like it has 260hp/tq. I dont think it is it trying to keep it at 260hp, i think its the computer not knowing what to do with that much cold air. cause the power leval definatly drops, and there is no way its doing 260 hp at 8psi.

My proof, a truck was trying to beat me to the single lane part of the highway going out of town, it was cold out and i was on stock tune, i bas only boosting to 8psi and the truck was pulling past me very easily, that should not have happened. once my rpms got high enough and i went to 15psi, i started to pull away from him.
Anything under -10 on stock tune boosts to 15 psi like normal, anything over, the boost lags and slowly creaps up and i only get full power and it feels right when i get to 15 psi.

Love the tune in cold weather, just goes straight to 22 psi and i swear in -15 i have about 30whp more then i do in the 0 degree weather out there now. It pulls noticably less in this warmer weather.