Cooler weather

[1SerieStud]

Again, you're emphasizing how much worse the Audi runs in humid/hot temps compared to the BMW; this is about how much better the BMW reacts to cooler temps than the Audi. You're looking at it backwards. We all know hot temps can make cars run like crap, some more than others.

Originally Posted by ///M1

I have, in fact most of my dynos are in February (though do them also in the summer). The 4.2 FSI is notorious of its (overly) temp sensitivity, in fact some of the credible tuners have modified the (2) ECUs to decreases knock sensitivity due to higher IATs. Way more than the N54. Trust me, I have both and the difference in temps is a lot stronger felt on the Audi. I basically don't even drive it in hot and humid days.

[tracer bullet]

Originally Posted by 1SerieStud

How is it a different subject?

Cooling compressed air /= compressing cooled air. IMO before & after the turbo are very different subjects.

Originally Posted by 1SerieStud

Again, you're emphasizing how much worse the Audi runs in humid/hot temps compared to the BMW; this is about how much better the BMW reacts to cooler temps than the Audi.

He said twice that his FI car is relatively unaffected by temp and his NA car is very much affected. Winter vs. Summer dyno. You're telling him to look at something he already just described. You seem to be implying that if he checked his FI BMW's power in Winter that it would be much higher than in the summer. Seems he already did that and said they were pretty similar.

Just to be sure, you believe that a FI engine is not very affected by less dense air, but greatly affected by more dense air? By this logic, taking a FI car from the coast to Denver wouldn't cause a huge drop in power, but taking a FI car from Denver to the coast would cause a big gain? Can you see why I think these two things are opposite of each other? The term "relativity" comes to mind.

[GotM]

A Turbocharged or supercharged engine will have less variation in power with changing conditions (altitude or temp) than a naturally aspirated engine.

The NA engine can only fill its cylinder with the ambient air density.

The turbocharger or supercharger will create a higher density charge than NA. It is also using a boost control providing a more consistent charge to the cylinder thus less variation in power.