Thread: Cold air intake

They do in Norway Finland Sweden ..... couldn't help myself....sorry

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Originally Posted by Pedro_The_Swift

Do they work, or just another Hyclone idea?

If you can get "cold" air into your engine it will produce more power than "hot" air, cold air is denser than hot air, so you get "more" oxygen to combust than hot air, dense air will have more oxygen, Regards Frank.

This pic by ozscott made me think a bit,,
unsure if thats inlet AIR temp(bottom right)
as the ECU runs off coolant temp a colder air temp should be managed by the MAF?
How does a MAF know if its cold air or just high revs?

often a CAI allows the engine to breathe better but the intake isnt necessarily getting colder air. so its a win but not for the right reasons.

on my VY ute, im about to go a over the radiator (OTR) CAI.
so its taking in cool outside air (as compared to hot engine bay air)
the piping will still get heat soaked but the air inside generally is being consumed before it has a chance to warm up.

Originally Posted by Tank

If you can get "cold" air into your engine it will produce more power than "hot" air, cold air is denser than hot air, so you get "more" oxygen to combust than hot air, dense air will have more oxygen, Regards Frank.

This is why i prefer driving or riding my bike at night, nice cool night air with a clear sky and full moon - perfect driving conditions.

Yep. Works. Adds a few kW.

Originally Posted by Pedro_The_Swift

How does a MAF know if its cold air or just high revs?

some cars measure the temperature of the air.


otherwise it doesnt matter.

lets say on a warm day, at 2000rpm the engine is consuming 200l of air, 20kg of air per second (number made up)
on a cold day, at 2000rpm, the air being denser, its still 200l, but its now 22kg.

the maf senses this, the ECU reacts and put more fuel in.
so at the same rpm, you have more air, more fuel equals bigger bang.


depending on the sensor, its measures mass or volume.

Originally Posted by Pedro_The_Swift

How does a MAF know if its cold air or just high revs?

to add to that (as i didnt answer the question)

a hot wire MAF, (which is most common compared to VAF MAF's) registers denser air, as its measure mass. (engines work on mass, not volume, but volume is often close enough)

to an engine, it doesnt matter if its cold air or lots of air, it just needs to know, so it can put the right amount of fuel in.

the more accurate it can read the air mass, the more accurate the fueling can be.