[nels0300]

I've noticed when the weather is warmer, temps in the 90s or above, the power seems to be way down, even with the AC turned off.

Curious as to what this may be. Is the intake air that much hotter? Is the ECU holding things back when it's hot out? Is this a characteristic of turbocharged engines, because my Camry V6 seemed to haul the same @ss no matter the temperature.

 

[coffeeslug]

It's all about the density of air. Heat and altitude make for less density, as does humidity. Less dense air means less power in all engines but turbo engines are affected more. Just wait until the weather cools, you'll be in for a treat.

 

[nels0300]

It's all about the density of air. Heat and altitude make for less density, as does humidity. Less dense air means less power in all engines but turbo engines are affected more. Just wait until the weather cools, you'll be in for a treat.

My understanding is that the ECU knows what psi the turbo is operating at and manages the boost accordingly.

I thought this was one of the advantages of a turbocharged engine, whether at 7,000 ft or sea-level, if the ECU calls for 16 psi, that's what it gets because that's what a turbo does, pressurize the air to a given psi.

This is what makes me think the ECU is holding back power when it's hot out.

 

[Ja'Crispy]

Heat soak. I've noticed the same here in NC. Upgraded FMIC should help.

 

[nels0300]

Heat soak. I've noticed the same here in NC. Upgraded FMIC should help.

I guess what I don't understand is that 16 psi is 16 psi, whether hot or cold air, high or low altitude.

I think I might be confusing density vs psi.

I think what is being said is that 16 psi of cold air has more oxygen than 16 psi of hot air, is that right?

 

[Ja'Crispy]

I guess what I don't understand is that 16 psi is 16 psi, whether hot or cold air, high or low altitude.

I think I might be confusing density vs psi.

I think what is being said is that 16 psi of cold air has more oxygen than 16 psi of hot air, is that right?

Yes, a bit. So while the psi may stay the same, the density of the air matters in terms of how powerful combustion is. As heat soak occurs, the intercooler cannot effectively keep up this, hotter than desired air is being forced into your motor. The hotter the air, the less dense it is meaning less molecules are packed in that air charge. When the air is colder, it's more dense so there are more molecules packed in the same air charge. Psi can be the same, but depending on the temperature and humidity of the charge you can have differing effects in the quality of combustion.

 

[Voodoo Idol]

I'm just gonna leave this right here.

http://www2.sunysuffolk.edu/mandias/met101/Pressure-Density.pdf

 

[Ja'Crispy]

I'm just gonna leave this right here.

http://www2.sunysuffolk.edu/mandias/met101/Pressure-Density.pdf

Oh, snap! Voodoo taking us to school!

 

[Ja'Crispy]

As Voodoo linked to, this is why geographical specific tuning is a huge benefit. Mass deployment bench tunes are great for squeezing more juice out of a vehicle, but the variables of your specific geographical location can make a bench tune in say, Colorado, feel unimpressive for a vehicle that's driven in Florida. Air pressure, air density, average temperatures and humidity all play a valuable roll in the performance of turbocharged motors. This is the main reason, for me, that I will have tuning performed by a shop in my vicinity.

 

[solo_gen]

I guess what I don't understand is that 16 psi is 16 psi, whether hot or cold air, high or low altitude.

I think I might be confusing density vs psi.

I think what is being said is that 16 psi of cold air has more oxygen than 16 psi of hot air, is that right?

In my Torque Pro log, I only can hit 14.5-15.1 peak in the afternoons when temperature is above 90F.
In the morning when it's 78-80F I can hit 16psi consistently.