it's probably been thought about before but has anyone designed or built a cai/air filter based around the same principals used in the dyson vacuum cleaners, ie cetrifugal force to seperate the larger dust/water particles from actually gettting to the filter itself?

would the cyclonic airflow be "wrong" when it hit the filter, ie does it need to be smooth or rough?

also, the vacuum cleaners are designed to keep the larger particles trapped whereas i think we'd rather have it removed/dropped, but then the current system doesn't really reject dirt anyway, it just sits on the filter instead (or perhaps drops to the bottom of the box - if it's in one).

btw, considering how much crap there is on the roads how exactly does the filter stay so clean ? does it just pass through most of the crap or are you supposed to clean it more often?

First things first, there's no such thing as centrifugal force :P It's centripetal force and it acts at a tangent to the circle you're whirling around, not away from it.

Anyway!

I believe the air flow sensor in the Magnas has some serious issues with whirly air, which is why K&N make that special oval pod filter for cars that have this kind of sensor - the round pods are supposed to create a cyclonic type air flow which gets misread by the sensor and bad things happen.

You could set something up to twirl the air after the filter, but chances are the restriction it posed would outweigh any benefits, and I don't know enough to know if there's any benefit to whirly air as it passes the T/B anyway. :confused:

As for keeping the filter clean, sure there's lots of crap on the roads, but, at least in the stock CAI setup, you're drawing air from over the radiator which is a good 1m above the surface of the road. If you run piping down into the lower bumper, as I've done, you're probably going to get more crap in faster.. I'll let you know in a few '000 kms :)

Also, Autospeed ran a test a little while back, measuring the post-filter pressure drop in one of their cars. They tested it with an after market filter, with the stock really really dirty filter, with a replacement factory filter element, and with no filter at all. They found barely any difference at all in either situation, meaning that even when your filter is thick with dust and crap, it still flows almost as good as new! Go figure.

Interesting thought but the complexity would probably not justify the benefits. There would have to be an impeller running all the time even at idle which would probably be noisy. It could probably be made to work but would it offer any major advantage over existing filter systems?


.

Interesting thought but the complexity would probably not justify the benefits. There would have to be an impeller running all the time even at idle which would probably be noisy. It could probably be made to work but would it offer any major advantage over existing filter systems?
.

think really, really basic for the moment, like just putting a dyson vacuum canister before the filter box. so no impeller, the suction from the engine (presumably even in idle) would be (significantly) more than your average vacuum cleaner so it should be sufficient by itself. i'm not talking about supercharging the actual air intake just cleaning it up.

most benefit would be from less crap hitting the filter, ie cleaner air, longer filter life, it would also mean in a cai situation, which because it's piped lower has a tendency to suck in more crap (and potentially water) that the risk of that causing damage could potentially be reduced/eliminated.

If anyone knows anything about the Dyson-type vacuum cleaners, they all have HEPA FILTERS after the cyclone as it cannot filter out the fine dust particles. Great for the bigger stuff though....

I would imaging the fine particles would cause glazed bores, buildup around valve seats, and generally gum up the whole works.

Anyone wanna put a HEPA filter in their airbox???

I am impressed with the lateral thinking however... it's almost like the whole idea came outta my brain!

(off topic)

First things first, there's no such thing as centrifugal force :P It's centripetal force and it acts at a tangent to the circle you're whirling around, not away from it.

Anyway!

There is such thing as centrifugal force. It is equal in magnitude and opposite in direction to the centripetal force.
But the centrifugal force doesnt act on the body in motion (only the centripetal force)
The centrifugal force acts on the source of the centripetal force to displace it radially from the center of the path

So you're correct cthulhu centripetal force is what you should be talking about... :) (But there is also centrifugal force)
/rant...

Peace

Tim

they also use this process in chemical plants. Its called a cyclone and is used to filter out small particles. Hard to explain without going into great detail but it creates an outer vortex which the air gets sucked downwards carrying the particles. As the cyclone tapers off at the bottom a second vortex which is smaller and tighter moves up the center of the cyclone leaving the particles to drop out of the bottom while the clean air goes out the top. Its kinda like a supercharger and filter in one. Would be a cool idea to use it on a car but our cars would seriously hate the vortexed air but if you want to design one from scratch for a different car your welcome to.

it's explained here How It Works (http://www.dyson.com.au/nav/inpageframe.asp?id=TECH/DYSONCYCLONE/HOW/CENT)

Apparently there is tangible benefit to having air 'swirl' thru a cars induction system. Essentially this is the principle used by normal 'pod' filters. As we all know - magnas, like many other cars are fitted with a MAF sensor - which is innaccurate at reading air which is 'swirling' - thus causing the car the run either rich or lean.... I never could work it out - but bad either way.

Quite a few performance places produce products similar to this one from herrod motor sports designed for fords ----> http://www.herrodmotorsport.com.au/index.asp?id=111

As you can see - this unit actually swirls the air after the throttle body, before the intake manifold (or plennum chamber in our case). The theory behind it is simple, and kinda makes sense - but I can't quite get my head around wether or not it would be of any benefit in a magna given the design of the plennum chamber. Whadda you guys think??

So you're correct cthulhu centripetal force is what you should be talking about... :) (But there is also centrifugal force)
/rant...

Peace

Tim

Right you are. I lied *cough* :shifty:

As you can see - this unit actually swirls the air after the throttle body, before the intake manifold (or plennum chamber in our case). The theory behind it is simple, and kinda makes sense - but I can't quite get my head around wether or not it would be of any benefit in a magna given the design of the plennum chamber. Whadda you guys think??

Generally, to transport air in enclosed area, like CAI tube, it moves faster when it's circulating. But, as u said, the very odd design of Magna plenum would most likely stop that circulation. Also, Magna MAS apparently doesn't like circ air. Hence the airbox/filter would stop the circulation motion once air enters the box from the CAI tube.
But, if one has an individual intake manifold per cylinder, then it would be different story. This kind of set up can be seen for example on 4 cyl 2 twin carb engines, just to mention.
Bell-mouth intake in CAI would create some circulation, thus enabling fast flow. STD snorkel would not aid in this manner at all.
That gadget on the website - hmmmm..... :doubt:

Swirling air isn't that good. Firstly it can give gunny readings with the MAF and secondly, it's a waste of energy if it's going from point A to point B.

Swirling air isn't that good. Firstly it can give gunny readings with the MAF and secondly, it's a waste of energy if it's going from point A to point B.

Dear Redav. Incorrect. Air travels faster in a tube when it's circulating. But, once it hits the MAS (MAF?) it requires to go in more steady flow to enable the MAS to provide correct reading. But, notice, my statement is referring to CAI tube application, not STD snorkel - where there is jack all happening, hence we use CAI. Once the air flow exits CAI tube, it enters the airbox and sthe circulationg movement reduces. If it didn't, my car wouldn't work.... :cool:

Dear Redav. Incorrect. Air travels faster in a tube when it's circulating.
You might have a fun time convincing our fluid dynamics guys about that. I spoke to them and they said that spiraling air is bad. They model this stuff all day long. Air is a finiky element. Bends as subtle as 3 degrees cause air pockets past the hinge point which effectively reduces the pipe diameter and stuff like that.

You might have a fun time convincing our fluid dynamics guys about that. I spoke to them and they said that spiraling air is bad. They model this stuff all day long. Air is a finiky element. Bends as subtle as 3 degrees cause air pockets past the hinge point which effectively reduces the pipe diameter and stuff like that.

Heh, not going to. I rely on practical experience and knowledge, not just my own but my bro's who builds and tunes turbo Calibra's. As in - fully worked 200 + Kw donks.
True, any kink or unsmooth surface reduces the airflow. Hence, it's necessary to make CAI tubes as large as possible to avoid such loss
I guess we are perhaps talking about different volumes and speeds of air, but it is beneficial for the air to travel in spiral motion, against a surface (like inner side of CAI tube) to avoid restrcitions. Perhaps your fluid guys are looking in to hi speeds or something, dunno.
Since we are in the subject, could they provide any charts or stuff for all to study - just for curiosity?

Perhaps your fluid guys are looking in to hi speeds or something, dunno.
Since we are in the subject, could they provide any charts or stuff for all to study - just for curiosity?
They've done stuff like tunnel ventilation and stuff like that. Not sure what else they've done. I'll pick their brains some more. I'm not in their office anymore so might take some time. They use 3D models and software to analise stuff. I guess that means they can generate stuff but would need a model in the first place. I just asked one of them about their thoughts on car induction and they said that the principles are pretty much the same for most application. He also said that if air takes a longer path they it's wasting energy when it could be going a lot straighter therefore quicker or maintain momentum better and reducing the chances of it being disrupted. He laughed at the thought of using some of the ribbed / flexible pipe that some people use. At the end of the day it gets to a point where it won't matter how well the stuff flows as the engine will only suck in so much. It's all about giving it the best chance at reducing pressure drops and keeping the most continuous source of air.

Redav don't forget that with air being sucked through a round pipe, (like the pipe/hose of a vacume cleaner or the intake of an engine etc...)it will always have the tendancy to spiral it's way through. It's just like the nature of water to spiral down a drain.

While spiralling air through the intake of a car might travel slower from end to end, there will be more of it as it gets packed closer together due to the increased spiralling velocity of the air caused by the vortex action.


:P

I realise that, it's making it spiral more that's a waste of time.

A little project for you both:

Get 2x 2 litre soft drink bottles. Fill them up with water.

you need two people, one for each bottle.

turn them upside down to let the water out. Let one fall out normally, and swirl the other one so that it gets a vortex.

Which one empties first?

Well that's an easy one.

This might sound a bit bizarre, but if there were small lead-in fins around the inner circumference of the intake after the filter, might this help to break up the swirl and encourage direct flow? Why I am asking I do not know cos it would be a bugger of a modification... I am just curious.

http://neilk.customer.netspace.net.au/flow.jpg

I realise that, it's making it spiral more that's a waste of time.

Possiblly, I just wanted to point out spiralling air is not complettly useless. Anyway in my opinion, spiralling or not it make no differance in CAI piping leading to the filter/airbox.




A little project for you both:

Get 2x 2 litre soft drink bottles. Fill them up with water.

you need two people, one for each bottle.

turn them upside down to let the water out. Let one fall out normally, and swirl the other one so that it gets a vortex.

Which one empties first?

Booth will end up swirling, the one you don't "pre-spin" will prolly start visually swirling once the water volume drops inside the bottle.

This might sound a bit bizarre, but if there were small lead-in fins around the inner circumference of the intake after the filter, might this help to break up the swirl and encourage direct flow? Why I am asking I do not know cos it would be a bugger of a modification... I am just curious.

http://neilk.customer.netspace.net.au/flow.jpg


This therory works with those swimmer body suits, makes the water glide over the body smoother.

But weather "more but spiralling air" is better or worse than "less but faster/straghter air" will only be known on a dyno on the same car.

A little project for you both:

Get 2x 2 litre soft drink bottles. Fill them up with water.

you need two people, one for each bottle.

turn them upside down to let the water out. Let one fall out normally, and swirl the other one so that it gets a vortex.

Which one empties first?

Heh, we know. Not perhaps 100% comparable, cos in this bottle case the water is replaced with air, so the air travels in to the bottle in the middle, in the non-water area (woowh, sounds very scientific...) where as the other just bubbles out and actually occasionally stops when the air cannot get in cos the water blocks the mouth etc.
Engine air is filled by surrounding air pressure. So, it's not really replacing anything but a vacuum area. But - in a way same principle applies, air travels faster, when it's not "bubbling".
Yee, those CAI tubes made out of wrinkly flexi tubes are awful - no wonder some guys experience bad results with CAI tubes like that, the air just babbles about and flow is in the ass - ammh, sorry, not being very professional now. It only works (better) on higher revs, when vacuum/pressure fill is higher.
So, make thea CAI tube from very smooth material and make as light bends as possible.
Example: 100 mm tube with 360 bend (?) has similar flow properties to 80 mm straight tube. So, the 360 makes a 20% reduction.

fluid dynamics sux big hairy balls so shut up. Ive done it for 2 years at uni and i still dont get most of it and im not going to try and find out which is better coz i dont want to know. :rant:

But weather "more but spiralling air" is better or worse than "less but faster/straghter air" will only be known on a dyno on the same car.

Air-flow bench, my man, air-flow bench. That's what engineers, who do cyl heads and intakes use to maximise the airflows.
Dunno if I trusted dyno results 100% - too many times I have seen them giving odd results on same car/engine within 30 min or so. But, not getting in to that.

~not going to try and find out which is better coz i dont want to know. :rant:

But - we do. Want to know, that is.... So keep reading! :cool:

you have no idea how much i hate fluid dynamics. the maths of it sux soooo much. when im in a better mood i might think about it and even look at a book but since i just finished work i dont think thatll occur for at least an hour or 2.

Air-flow bench, my man, air-flow bench.

Ok lets make one, who has a spare vacume cleaner laying around :D . After that all we need is some duct tape and a presure gauge lol

Ok lets make one, who has a spare vacume cleaner laying around :D . After that all we need is some duct tape and a presure gauge lol

Ahhh - I was afraid u would suggest that.... :D
OK, we liine up all hundreds of CAIs from AMC ppl and do a survey. Who wants to start?? :shock:

OK, we liine up all hundreds of CAIs from AMC ppl and do a survey. Who wants to start?? :shock:
Me. I'm the baseline one though as I've done the stock induction. I don't have a spare vacuum so I tried the water swirling method but it stuffed the motor :cry:

~so I tried the water swirling method but it stuffed the motor :cry:

:bowrofl: :bowrofl: :bowrofl: :bowrofl:

U're madder than me!!!!!!!!

i think the best idea is to rip of the old ****ty big ass box, the left should be a mesh kinda part thing thats were the air goes in :confused:....... well dahh, ne ways, get pod attachment put it strait on like so, then find some pices of alloy or metal to hold in its place and there u go, ill post up the pic tonight to show you guys, oh and for the dead spot well i have it no more since ive done this..........

were i work we sell ducting pvc pipe n all, tryed nearly everything this is the best.....

i think the best idea is to rip of the old ****ty big ass box, the left should be a mesh kinda part thing thats were the air goes in :confused:....... well dahh, ne ways, get pod attachment put it strait on like so, then find some pices of alloy or metal to hold in its place and there u go, ill post up the pic tonight to show you guys, oh and for the dead spot well i have it no more since ive done this..........
were i work we sell ducting pvc pipe n all, tryed nearly everything this is the best.....

1. In NSW open airfilters are illegal - wouldn't wanna give the pleaure to Radar Operators to bust ME for it.
2. Sucking/feeding hot/warm engine bay air - not really good. Unless u install a CAI....

Ahhh - I was afraid u would suggest that.... :D
OK, we liine up all hundreds of CAIs from AMC ppl and do a survey. Who wants to start?? :shock:

Well have you got a better idea about making a flow testing unit for minimum $$ lol



Me. I'm the baseline one though as I've done the stock induction. I don't have a spare vacuum so I tried the water swirling method but it stuffed the motor :cry:

:slap:

Always the comedian huh !

Well have you got a better idea about making a flow testing unit for minimum $$ lol

Nope - cos that's what we did in the early -80's before we had anything else we could afford....!!!! :)

:slap:

Always the comedian huh !

Hu? I always take him (Redav) seriously....!!!!! :shock: