Lower temperature - more power?

[thepest]

Ok in theory the colder the air that's comming to the engine the more powerful it gets. Right? At least I've heard so. And if I recall correctly there was a video where they put ice in the holes, from where the air comes to the engine.

So my question is if that is true, so a car must be more powerful in the winter when it's colder, right?

Is it possible to figure out how much more powerful?
What do you think

[saadie]

yeah goto a dyno ...
what happens is .. cold air is dense then hot air .. so you get a better compression ratio ... thus more ower ... i doubt tht ice will work ...
imo its not gonna be all that powerfull .. all u'll get is 0.001 more bhp ?

[inso]

yes the colder it gets you get more power, but there is also the possibility that engine runs too lean, thou melting pistons and having majore problems. And also frictions tend to go high, when the oils run thick because of the cold.

[mindgam3]

Well air is roughly 10% more dense at 30 C than at 0 C at atmospheric pressure so you'll get approximately 10% more air into the cylinder...

But then you've got to take into account differences in pressure between the cylinders and around the cylinders and it all gets fairly complicated. Plus you've got to take into account that the air close to the intake is going to be a lot warmer than the general atmospheric temperature as its near the hot engine.

So basically, you may get a couple more bhp when its alot colder, but its definately not going to be much

[pzgren]

i can tell you i can feel it in my car. in winter times it feels like it accelerates faster than in summer times.
you can also see it if you're going to a dyno. on a dyno with good cooling system you'll get better figures than on a dyno with poor cooling. maybe i'll find my figures of my dinos and post it here to see the difference.

i've seen that thing with the ice too. i guess it was the mtm team with their audi tt bi-moto. i've seen that they put some ice into the intercooler for better cooling because they had problems with cooling. and i'm not shure if it was last year or more. at the 24h race at nuerburg the bm3 m3 team also used ice for cooling their cars also caused by problems.

[RC45]

Well - the difference is measurable.

My car dynoed at 325rwhp in mid summer, and 341rwhp in mid winter. Same car, same mods, same dyno - fuel might have been a factor as there are summer and winter formulations, but the cooler denser air was the major contributor.

That is a 4.9% change.

A good indicator is to look at the SAE correction factor that changes to STP require you apply to the raw dyno produced.

[sikx5]

It also depends on the car you have dude, mine pulls and moves great early in the morning, but during the day it is sluggish(30degress+ weather) and at night...huge difference in power, i love driving at night!!

Thats in my GT4, Where as my bros M3 there is a slight difference in power through the weather changes, but no way near as much as my car.