Warm air makes the engine produce less HP.
What is the increase of HP when the car is using very very cold air.
Does anyone have a diagram?
[Edited on 22/3/09 by l0rd]
It's all down to air density...
Colder air is more dense than warm.
This means more air into the engine....more air means more fuel ... leads to bigger bang....
[Edited on 22/3/09 by stevebubs]
PS Huge oversimplification...but it is 1am Saturday night...
There is a percentage chart in the mini tuning book I have, but my scanner's down.
I can say though, that assuming the air enters the cylinder at 150 F/65 C, then lowering it to 100 F/38 C, you can expect a gain of roughly 5%.
Remember though that it is the cylinder entry temp that matters. IE a lot of heat will be absorbed from the inlet manifold, inlet tract in the head
and passing over the inlet valve itself, so having a cold feed to miles of pipe work won't have such a big effect. The theoretical maximum is 1%
gain for every 3.3 C drop in temp, but you'll get maybe 50-60% of that in practice, due to the above reasons.
Cold damp air is even better, more BHP on a very cold misty day. Few years back water injection was used on some high performance engines, however, it caused problems with rusty and oil emulsifying.
Water injection is still used in some high boost forced induction cars as a way of avoiding detonation.
I've never heard of rust being a problem due to water injection. The main problem from what I've read is that you actually need a fair bit
of water if you're going to use enough to have a significant effect and that introduces a weight penalty...
IIRC from my college days a long time ago it's all down to volumetric efficiency? . Some engines are better than others which is what you are trying to improve by tuning.
quote:
Originally posted by rusty nuts
IIRC from my college days a long time ago it's all down to volumetric efficiency? . Some engines are better than others which is what you are trying to improve by tuning.