I know that cars will perform differently depending upon the ambient conditions (e.g. temperature, pressure and perhaps humidity?). However, I still feel that there are some days when my scoob seems to fly (well as much as a WRX PPP can) and others when it feels almost pedestrian (o.k. a bit of an exaggeration there).

Do others have the same feeling and is this symptomatic of turbo engines? I used to feel the same thing in my VX220 turbo, but not so much with previous cars that were normally aspirated.

Sometime I wonder whether it's all in the head, but I really don't think so!

 

Do you take drugs








But seriously, I had the same feeling on cooler days where the air is denser. The car would slightly overboost even though standard. Warm days was smoother but seemed less powerful - weird

 

There is no "perhaps humidity" about it. Cold dense damp air makes a huge difference to the power released by combustion. You can buy water injection kits to add water into the air/fuel mix for this very reason. Some regular rolling road users try to book early morning winter sessions because of this as well.

WATER INJECTION as featured by TOTB

 

I know NOTHING about the enginey part of a car however I noticed this too. Going out on a late spring evening when the roads are dry and the air is really cool used feel like driving a different car.

 

All to do with intake temperatures. Mostly unnoticeable in a normally aspirated car, but with the effects of turbocharging it makes a big difference.