maybe not so idiotic question time about intercoolers.....
 

OK, Started thinking about the workings of an engine and stumbled across this query... What exactly does an intercooler do???

You have a radiator, which contains water which is cooled by the air flowing through it, then the water keeps the engine cool enough right...

Then the intercooler is also filled with water yeah?!, so that water is cooled by the air coming into the scoop, so what does this cooled water cool?! Does it cool the aire that the air intake has taken in, before it gets any further??!?!

It's baffling me at the minute!! Apologies for such a newb question, but then, i am a 'good car newb'!!


Bongo!

Woah there.

Your getting mixed up with intercoolers and charge coolers.

An intercooler is a radiator for cooling the air that feeds the engine, it is filled with air, which is fed from the turbo. Because it comes from the turbo, it is hot, so needs to be cooled. Thus the intercooler, once the air is cooled (by outside air passing around the outside of it), the now cooled air passes out the other side of the intercooler, through the throttle body, inlet manifold and finally the engine.

Chargecooler is the same, but uses water to cool the heated air instead. This fitted to the older Lagacy turbo :)

The intercooler in an Impreza is "air to air" so it doesn't have any water in it... Apart from that, you're pretty much spot on - it cools the air going into the engine, making it more dense and therefore providing a bigger "bang" for each stroke.

*Doh! Beat me to it, Shark Man. Also, the Lotus Esprit is a good example of a turbo'd four with liquid cooled intake.... So they're not that uncommon*

air so there is air in the intercooler.

So air goes into the air intake/filter, and into the ___________?? turbo??!!

It comes out of the turbo into the intercooler??? hot, which the intercooler then cools, and sends it into the engine in a round about way...

Cheers for helping lol.

I originally thought it was filled with air, then was told it was filled with water, which i couldn't make sence of!!!

That's it covered in two posts ! Must admit i thought the same thing when I first bought my Scoob - so you're not alone ! (I looked up wikepedia ).

aww you're kind, trying to make me feel beter!!!

haha, cheers for the help though. Engines are ****ers to understand!

Remember the whole idea of the turbo is to recycle exhaust gases ie the air which is being fed into the turbo is recycled exhaust gases. As Redscoob says, it's important to cool these hot exhaust gases as when air is cooler it is also denser, ie the turbo doesn't need to spin as fast for any given power output.

Air doesn't go straight from the air filter to the turbo - the air filter feeds air into the engine directly.

Well, that's what I reckon anyway ! ;)

so what does that air do??!

It's mixed with the petrol, makes a nice explosion (well, several actually) after your spark plugs do their stuff , which chucks your pistons up and down, which turns the crank that ........... I feel a song coming on ! ;)

i mean the air that comes into the air filter, what does that do, if its the recycled air from the exaust gasses thats used to mix witht he fuel and explode lol, then whats the air from the indction kit doing?!?

Your turbo (and therefore your exhaust gases) aren't involved until about 2500 revs (unless Andy F's done his stuff :lol1: ). The air from your air filter is doing what it does in every normally aspirated car - feeding air through the fuel injection system to get the ball rolling. Sorry, could think of another song !

ah reet. i'm learning!! Can anyone tell i've not done too much with engines....

show me a bike anyday!!

I'm into mountain biking - dunno much about Gixers though - apart from the fact they're faster than cars (oops - better not start that one !).

Ok, ofta bed ! :thumb:

yeah i'm talking of the push bike variety lol.

Cannondale Scalpel by the way !

Anyway, nite nite mate ! :thumb: :sleep: :sleep: :sleep:

...:confused:

:confused: :confused: :confused: Yep me too! :confused: :confused: :confused: . Sounds all wrong to me.

so the air that comes through the turbo is only from exhaust gases.
or does the turbo get air from somewhere else as well?

and the exhasut gas goes into the turbo > intercooler > then how does it get into the engine to do the explosion... does it just get mixed with the normally aspirated air from the air filter when that goes into the engine?

i'm so happy that others are confused after me making this thread thinking it was only me!!!

OK, here's my non expert understanding of turbochargers. Happy to be shot down of course :)

The exhaust gases spin a turbine wheel, (the exhaust gas is then discharged via the exhaust system), which in turn drives a second turbine wheel. The second turbine draws air, via the intake filter, compresses that air and that air is then force fed to the engine, via the intercooler, where it becomes an air/petrol mix for combustion. That's how I've always understood it anyway :freak3:

we need a diagram of turbo air flow LOL

so the exhaust air fumes whatever NEVER go back into the engine to be part of the explosion? that would be daft

so the exhaust just drives the turbo to spin... the spin suckes more air in then? through the normal air filer?

the force of it spinning compress's the air?
if so where is the compressed air held?

doesn't it loose it's compression in the intercooler?

sorry I need to know now, it's X30NGO fault LOL!!!!

exhaust gasses never go back into the engine. They are used in our engines purely to drive the compressor wheel in the turbo. The air from the induction kit is sucked straight into the turbo and then put under pressure, pushed through the pipework to the intercooler and on to the intake.
Compression isn't lost through the intercooler although i can see how this could very temporarily be a factor and explain why you get more lag with a front mount (larger area to fill with air) but as its a sealed space pressure is built up almost immediatly.
Thats the basics as i understand it. I think some of the above posts are very innacurate to say the least and so would ignore them and wait till someone who knows posts. I could be wrong about this but i am pretty certain that i am right!

There is no way the air from the induction kit is put in the engine through the fuel injection system (the name says it all really) as this would mean that air would be flowing through the injectors too.. how is this possible when the fuel comes from the tank.. is pressurised through to the fuel rail and then straight into the engine through the valves (when they open).
If anyones in any doubt just go out and look at your induction kit/air box and see where it goes to.. straight to the turbo!!
(if people have been taking the piss above ive been properly tricked lol!! but i hope that is the case!!)

Maybe this will help:
Howstuffworks "How Turbochargers Work"

this thread is funny as

:lol:

:D And I thought I'd learnt a fair bit for 6 months of Scooby ownership - maybe not ! :lol1: ;)

Where's GC8 when you need him ? :norty: :lol1:

Andy I'm 90% sure you are wrong :)

The intake system on the Impreza is plumbed into the turbo and there is air filtration on the intake system. Exhaust gases drive the turbo as we all know. The exhaust gases don't mix with the intake gases. The exhaust gases push one end of the turbo to make the other end suck (if you like). I'm pretty sure at low RPM the turbo is still spinning with the flow of air through both ends - it's just not spinning fast enough to generate a build up of air trying to get into the engine (boost). Proof of this is when you switch off from idle you can hear the turbo spinning down.

On boost the turbo sucks air through whatever air filtration you have and then tries to force feed it through the throttle body via the intercooler/chargecooler.

helpful....

Am I right in thinking exhaust gasses can reach 800 or so degrees C? Would take one hell of an intercooler to cool that back down to say 30oC charge temps! ;-)