Hi all.

I have maybe newbie question. Is this normal that boost have a dependency on outside air temperature (with boost correction turned off)? For example, when it's -20*C outside - my Evo have only 1.15 bar on full boost. When it's 0*C - about 1.3. When +20 - 1.6 (which I want). And when it's more then +20 - it have a slight overboost (to 1.7-1.75 during hot sunny day)?

Or this tells us about some kind of malfunction? (boost control solenoid maybe)? I have 3-port boost control solenoid, Tephra v7, stock turbo and engine.

 

usually other way around.... when its cold, air is more dense therefore more boost pressure.
when its hot there would be less.

Not sure why your boost goes up in hot weather.

 

My logic was: when it's cold - air is more dense - so it creates more resistance to compressor wheel. So the boost is lower. Also, when it's cold - intercooler is more effective. So pressure drop during intercooling is higher.

But it's not so simple, because since air is more dense - more air/fuel mixture burnt in engine. So more exhaust gas energy produced, which spins turbo faster.

So I want to know real observations...

 

Yes my car does the same - More boost in colder temp.
But then again, he is in Russia!

 

Regarding the topic - is it possible that boost control solenoid reacts to the outside temperature and begins to work in other way?