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Hello,

Just a new thought for an intake modification.

looking to achieve cheapness, minimal modification and power increases throughout the range.

based on the variable intake model, which has been around for a while, and am hoping will work. (all new bmw engines are beginning to integrate variable intake.....good thing maybe..)

This system will leave the OEM magna cold air intake in place (see pics) so that at idle/low rpm all those late nights from the magna engineers won't go to waste.

Modification is cutting out the bottom of the forward part of the airbox. Moulding a smooth plastic scoop to fit the fresh cut. Adding a door with appropriate seals (aluminium door..). Variable tension hinge to hold the door. (add heat shield to new scoop)

the exciting part? - when rpm increases, so does air flow, creating a negative pressure zone behind the lightweight door. Door starts to open at around 2500rpm. By 5000 rpm the door will be completely open, the engine gorging on all the air it can get.

This will take a while to trial and build, I will keep pics posted. There has to be something fatally wrong with this........if you see it, step in now.

Otherwise, am thinking about designing an evaporative cooling intake system also, with a feeder bottle (like that shoe polish with a sponge on the end) However, somebody tell me that this will kill the engine.....
thanks
john

hmmm this sounds very interesting!! :o

looks good.... i cant see any reason why it wouldnt work.... although im sure someone else can. One thought though.... is there enuff space in the engine bay to do that??? :?:

howz it goin...

tell us abit about yourself... :)
you have an interesting idea... but as said before, is there enough space to do this???

cheers

Kev

I wanna hear more about your evaporative intake cooling idea :D

I do see something wrong with it.
The phenomenon that affects the cylinder filling with different length pipes is that of pressure wave reflection. The pressure wave reflects when it reaches a sudden area change, like when the inlet manifold runners end at the plenum (the chamber that links them together). You need to vary the length of the individual intake runners, not the whole intake system.
Varying lengths after (from the p waves POV) the plenum doesn't do anything.

MIG can you explain further what you mean by the pressure wave reflection? I don't understand what effect they have.....

The initial thoughts were, having never seen a variable intake, were to basically keep what is standard at low revs, then gradually, as the gate opens, allow more and more air in, so say by 4000 rpm, the engine has a much greater breathing capacity. In theory, it should work, even if you take into account the pressure waves (proven by top end power of a pod filter)

space wise, it looks ok, although in 3D the intake is a little curvy, could get interesting. would have to be low profile, wide intake.

phonic, being from brisbane, and coming into summer, i can really feel the power output drop on warm days.... kindof annoying. will do some tests with vaccum cleaner, tube, and wet towel........ see if that air can be cooled down to the temp of a cold night...then, on the cold night, chilly.
thanks for the response, john

When the intake valve opens a low pressure pulse propagates along the intake runner. When it hits the end of the intake runner (hits a large open area), it reflects as a high pressure pulse. If this gets back to the intake valve just before it closes it stuffs more air into the cylinder.
These pressure pulses propagate at the speed of sound. The time that the intake valve is open varies in proportion to RPM. So for a given length of intake runner this only works optimally at a certain RPM. That's why you vary the length of the intake runner.

Another thing that is sometimes done is the volume of the intake runner is varied by shutting down a portion of the runner at lower RPMs (Toyota TVIS system). This increases the velocity, which up to point makes more power. I say up to a point because eventually it becomes a restriction and then it gets fully opened up.

Changing the length of the snorkel that's before the air filter doesn't do what factory variable intake manifolds do.

That reminds me of the Mazda intake syste used in the J-spec MX6s. I think they called it VRIS :roll: , they also close a portion of the intake runners to vary the lenght.

All I know is that some mighty clever engineering goes into variable intake runner lengths .. after the filter and as the air goes into the cylinders, via the intake runners.. pressure waves are precisely timed to provide maximum density of air into combustion area at top of cylinders, and of course, this varies with RPM. The best outcome is the most air, the densest air (which means cool air to begin with) being fed into the cylinders on the intake cycle, at ALL rpms. Does any engine manufacturer claim to be able to do this?

and, I have read where there is a multiplier effect, where the pressures can be enhanced by doing clever mathematics on the airflow.. etc... :D

Not over the whole rev range, but over the revs relevant during racing.
Check out the graphs on the right hand side of the page.
This is a naturally aspirated quad rotor rotary engine producing 515 kW
http://www.angelfire.com/vt/ustasa/rotor5.jpg

If you want to see it all along with a technical paper on a Honda turbo F1 engine, go here http://www.angelfire.com/vt/ustasa/cars.htm
Extremely interesting stuff as far as I'm concerned.
Unfortunately, you have to load everything at once because it's all on one page.

damn! i want one of those, how sweet would that be!!!

back to reality now... the new 3.8 has tuned variable (a twin system i think) intake runners, similar to what porsch use i guess. it will use one for lower revs until a point when the other or both will kick in!

-Al

hhhmm well if ur talking about using the existing CAI manifold and cutting out the bottom and piping a duct to the bumper then....

U STOLE MY IDEA!!!

if not then just ignore me, no worries.

Trav

the new 3.8 has tuned variable (a twin system i think) intake runners, similar to what porsch use i guess. it will use one for lower revs until a point when the other or both will kick in!

Yeah, I think it's called MVIC

Yeah the older V6's already had that system cept it was called VICS

i thought of this but cutting a 2 inch hole and piping and just shuffing it at the front

Evaporative cooling would be a bad idea, the water in the sponge/cloth/whatever would get sucked into the engine and it would blow (water doesnt compress like air/fuel)

and it would blow

it sure would

just a thought,

you wanted to make use of the low pressure produced by the engine to open the gate to the extra vent at high rpms right? I believe you would only achieve that if the car was stationary or slow moving. As at high speeds, the air pressure would just blast the gate open before you wanted it. So then you could say, that's even better, but then, why do you bother having a gate there in the first place? if you want more air going to the filter, you would want a big opening at the start, and duct it to a smaller exit to the air box, by doing so you would have achieved to speed up the air, and may actually condense it by a little.

I think it is a bad Idea cutting open the air box before the Filter from below or above or sides, as it would simply make the air in the box turbulant and or creat a vortex, we know our MAS sensors don't like spiral air going through the MAS sensor. I haven't tested it, it's only my guess, so the people who has tried it, please let us know if it works.. If I was doing it, I would actually employ some sort of Funnel intake at either the bumper or the grill. You really just want Faster Air, without it vortexing, to do that you need a vent that is smooth and relatively directional, i mean not too much twists and turns.

I have always wanted to test the theory of plumming the cold air from the airconditioning into the air intake.

Sure, you would loose power due to the compressor running although you may make it up by being able to run more fuel due to the cold air.

haha ive thought the exact same thing. it would be very interesting to see what effect it would have on output when you were actually running on COLD air, not just outside temp.

[quote:d476e09bbc]I have always wanted to test the theory of plumming the cold air from the airconditioning into the air intake.

Sure, you would loose power due to the compressor running although you may make it up by being able to run more fuel due to the cold air.[/quote:d476e09bbc]

If you set it up with a sort of intercooler, like a water-air intercooler except instead of water you used cold air from the ac then that could work, wouldnt be able to run just the air straight in because the engine would probably use more air than the ac could provide.

Would be interesting to see anyway

As interesting as the idea may be, I think that a supercharger is a better idea. And the A/C one probably wont work that well

But this wasnt the original point of the thread...Im digressing.

I like the idea that was first posted...any more info on it?

id like to say about the original idea, while initially it sounds like it could work and give an increase, when you think about it its actually completely pointless, because it doesnt matter how big the intake before the filter is at all. whats the point of having a pressurised door before the filter. you might aswell have it open all the time. i cant see how its going to have any effect when its closed or open. the engine is only gonna suck through as much air as it wants. no more.

Why couldn't we just have a sealed intake which has pure oxygen directly injected into it instead of air from the atmosphere? It would have basically a lot less emissions and would have a sh*t load of power!

Why couldn't we just have a sealed intake which has pure oxygen directly injected into it instead of air from the atmosphere? It would have basically a lot less emissions and would have a sh*t load of power!

because oxygen is highly flamable and it would explode ;)

because oxygen is highly flamable and it would explode ;)

yep , that's why they use nitrus oxcide because it isnt as flamable as oxygen but still a very dangerous accelerant.

hydrogen ;)

run cars on water...via electrolosys, remove the hydrogen and combust it (we all know how explosive hydrogen is lol = power, if it can be controlled) and then your exhaust is oxygen !

Bye bye oil companies lol

The idea has been done before..and it was shelved...because if we can run our cars on water then oil companies practically dont matter

hydrogen ;)

run cars on water...via electrolosys, remove the hydrogen and combust it (we all know how explosive hydrogen is lol = power, if it can be controlled) and then your exhaust is oxygen !

Bye bye oil companies lol

The idea has been done before..and it was shelved...because if we can run our cars on water then oil companies practically dont matter

actually extracting hydrogen from water is rather expensive and requires lots of energy.

[quote:e57df5582d="Killbilly"]hydrogen ;)

run cars on water...via electrolosys, remove the hydrogen and combust it (we all know how explosive hydrogen is lol = power, if it can be controlled) and then your exhaust is oxygen !

Bye bye oil companies lol

The idea has been done before..and it was shelved...because if we can run our cars on water then oil companies practically dont matter

actually extracting hydrogen from water is rather expensive and requires lots of energy.[/quote:e57df5582d]

More ideal method would be to have the hydrogen tank on the car. Then the tailpipe emissions would only be water, and it saves a $%#load of batteries.

Not expensive asomuch as requiring lots of energy. But it's possible..and it has been done before.

Hydrogen fuel cells are the next thing that a few car companies are looking into as well...they sound very promising.

I'm gunna put a big bug catcher on my engine so it can turn into a ram or scram jet!

hey guys,

thanks for the replies = after feeling how hot the black plastic intake gets after driving around for a while I don't think that the evaporation idea would work too well Iwouldn't be surprised if it didn't cool the air by less than half a degree -
prob better off waiting till winter arrives again for cold air........ also note that high humidity (being in QLD) dramatically reduces the effectivness of any sort of evaporative cooling - back to the drawing board!

As for the variable opening - if I ever get around to trying it - if you have a standard intake - take the front snorkel off, to expose the filter. Go for a drive, and (in my case) I found that the power curved changed - it was a bit mushy down low, but with an increase above about 4000 (and revved more freely). (I have also read about people who raced motor bikes in the old days - would take a selection of intake pipe lengths to alter the torque curve for different track types.)
the idea get the best of both worlds for power. ......will post if it ever gets done! (TButcher - its like your n plate - haha)
jt

in regards to the ducting A/C to the intake suggestion; a couple of things I thought about that it may be bad,

1) whenever you have A/C, you'll always get Condensation, condensation near or at the Air filter would mean possible saturation of air filter and possibly lead to blockage or even worse, water going through to the Cylinders.

Of-course, this could be avoided by controlling the temperature of the A/C, make sure it is above certain temperatures given the atmospheric pressure and humidity. You've got a seriously hard control system here.

2) Thermodynamics' Laws, I forgot which one, but one of them states that entropy is always created during work and it can never be converted back to work. In short, this means that you can not create a Perpetual Motion machine. This theory applies in Heating and Cooling as well, there will always be more loss than gain, so by using up the Engine's HP to run the A/C, there will be loss of Energy, and now you want the A/C to help the Engine breath, well, once again, A/C will have lost more energy. by the time the cold air gets into the engine, it would have lost heaps more energy than the slight gain in potential thermal energy from the cold air.

To overcome this, Run a stand alone A/C on another Battery. I'm still sceptic on how much cooling it can do in such a hot place and such a small area though... hmmm, I think, for something like this to work, you'll need Refridgerent coils all around your CAI and running always.... good luck on sustaining the battery for the standalone A/C though. maybe you could attach the Battery to some wind powered or Solar powered Charger.. HAHA

Anyway, that's enough thinking for today...

it is a good idea you have there, just need refining.