Peoples thoughts on air filters and induction
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Just found this ram filter kit in the UK
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I am liking that weapon r claw type filter! No way Im paying that for it, be ok until you add shipping and customs!
Anyways, I just had a musing which Ive posted elsewhere and then the idea brought me back here, if you have a CAI the idea is that the air is colder, which makes it denser, so, if its more dense then it has more force when being moved against or forced into something. So if thats right, then the denser air will push more on the MAF sensor, which will tell it that there is more air entering the engine, which kind of nullifies the whole purpose?
Also, if we were to heat the petrol then the surface friction reduces, aswell as becoming more volatile, like any other solvent/spirit/alcohol does. Would that not mean that there would be better fuel atomisation and therefore a cleaner and more efficient burn?
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alot of kit cars inc atom that use cone style filters have a hydro sock to stop water being sucked in, will have a hunt around to find a link
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dont worry about it, i saw them already and dj posted a link, not the route im going down anyway, bought all my kit on ebay about an hour ago, except for the filter, waiting on a reply from a seller
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@2226633c46=Jesta:
Also, if we were to heat the petrol then the surface friction reduces, aswell as becoming more volatile, like any other solvent/spirit/alcohol does. Would that not mean that there would be better fuel atomisation and therefore a cleaner and more efficient burn?
I realise that this is an old dicussion, and might not get read. I have done quite a bit of motorcycle racing, and you want the fuel as cold as possible for all the same reasons as the air. Being so volatile, fuel becomes vapour with heat energy and has the physical properties of a gas - takes up more space/greatly reduced density. In short, hot fuel=less fuel.
Also given that cars only rev to 6 or 7000 rpm, atomisation is not really an issue. It only really becomes a problem with modern "Ford style" direct injection or revs over 16,000.
As for induction, the whole pupose of the air box is to provide a reservoir of high pressure and relatively still air. To bypass the air box, you need to increace the direct air pressure, so some sort of ducted ram air is a good idea. Obvously, the whole arrangement needs to be airtight so as to avoid the running problems caused by confused sensors thinking that you are running rich.
As for making it sound better, you could play a V8 through the stereo. lol
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Lol, you might have been one to appreciate my zx6r then. One thing I still dont get, why is having an air leak bad, when we put on air filters to improve air flow? Surely its much the same thing, admitedly a leak allows unfiltered air, but why does it cause so many problems when essentially an uprated air filter is doing the same?
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Maybe because the air filter is at the start of the air system, I suppose any air leak after the VAF causes the problems, not before, not too sure or how to 'word' it right, but I think I know what I mean LOL
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The difference is air leaking in after the VAF is unmetered, the ECU can't calculate for it. You could have no filter at all and just have the VAF as the first thing and it'd run fine, aside from the dirt.
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thats how I meant to word it!! :wink:
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Feel pretty daft for asking now, as that does make perfect sense. Not used to air meters and injectors yet
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The other big problem with leaks in the induction system is to do with the fact that the down stroke of the piston is what draws the mixture into the combustion chamber, and the amount of air between the valves and the filter has a specific mass. As you may or may not know Boil's laws of fluids, The main principal of hydraulics is that "you CANNOT compress a liquid" and air moves in a manner very similar to a liquid - you suck at one end of a tube and fresh air is drawn in to replace it at the other end. But air is also a spring (compressible). Springs resonate, which is why you have dampers on your suspension. The induction tubes between the filter and the valves has been carefully calculated to contain a mass of air which will resonate, springing the air into the cylinders, particularly at low revs which helps to make the car drivable. Top end power can be increaced at the expense of low end running by reducing the mass of filtered air.
Cracks in your pipe vent to atmospheric air, reducing the mass of the spring, increacing the resonant frequency, spoiling your idle running. This condition contributes significantly to turbo lag aswell.
Sorry if that's a bit dry and scientific, but it really is how it all works.
Bass reflex porting for speakers works on similar princpals. If anyone is interested I will explain.
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Thats a very interesting read thanks for writing it, dont worry about dry or scientific, atleast I have a better understanding of how it works now!
Cheers
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I'm glad not to have bored you. Still being a nube, I get carried away!
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Not at all, its hard to sort fact from fiction on the internet, so a well thought out and detailed explanation is always a worthy one to read! :)
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Basically if you let more air in after the air meter that measures how much air your engine is sucking in the engine will be running lean. On a high compression engine that is already tuned and timed lean then running leaner at high performance requirements IE WOT with high revs will produce detonation and rough burn patterns. Knock sensors will pull that timing right back resulting in quite hefty losses of power.
Basically computer see's X amount of air and puts X amount of fuel in and advances the timing to X producing the maximum power it can from any given engine. Put X+1 air in with the computer only seeing X air then The amount of fuel going in is not enough and the timing is too far advanced to light the mix properly. This is a big problem in turbo charged cars but still a factor in normally aspirated high compression performance engines.
