Erm, whilst not 100% sure on the gasses part, running less fuel runs hotter, more fuel cools it down.

 

Thanks for all your inputs.

I'm purely judging/gauging based on experience and the feel of the temperature around and behind my car when I get off on the same route/same driving style home.

Whilst it is true that my mods previous are probably causing the car to run leaner than stock, I cannot say how much the car is running richer/leaner now as I wasn't provided with this information. Hmm.. what Voboy and MaXX have said are conflicting (though interesting to think about for sure) to some degree... But thank you.

All in all, I'm a happy driver with the full tune.

 

Yeah, they contradict, but only one is correct.

http://scienceforums.com/topic/3055-...ngine-run-hot/

 

Interesting read.. Thanks for sharing.

That leads me to think that our cars are tuned to be running slightly rich stock, and after tuning, running leaner is more efficient, hence my power gains. The side-effect is the car runs slightly hotter now.

Either the above is true, or somehow I still got more power with a bad tune (i.e. too lean), probably through other aspects such as variable valve timing/ignition tuning, etc.