Theory correct?

[TrailerRider]

Please excuse the paint picture but here is what I am thinking.

My air box pulls air from the top of the box. While this is good it still makes the carb have to pull air in. If you where to create a custom air cleaner unit that is pointing towards the front of the engine, wouldn't that give it more power? Thats why people put CAI's on their cars.. Does this principal apply correctly?

[The Goat]

my typhoon intake on my car doesn't point anywhere near the front of the engine...it's inside my bumper actually.

[overdressed1]

My air box pulls air from the top of the box. While this is good it still makes the carb have to pull air in. If you where to create a custom air cleaner unit that is pointing towards the front of the engine, wouldn't that give it more power? Thats why people put CAI's on their cars.. Does this principal apply correctly?

Just like on aTri Z by the look of that sketch:wondering

[MyMistress86R]

I believe your are confusing the concept of a "cold air intake" with that of a "ram air intake".

The design principal behind the CAI is to simply get the intake air source away from the heat of the engine. Most automotive kits relocate the filter to an internal fender area or down into the leading nose area of the car.

In comparison, the RAI is designed to straighten the intake path and create as unobstructed a path as possible from the front of the vehicle to take advantage of the oncoming air as the vehicle accelerates.

[RedRider_AK]

I've used ram-air induction with varying degrees of success on snowmobiles before. On a Puma 340, I once stuck a 440 engine into it. The engine would bump the headlight inside the housing and vibrate it to death, so I trashed the headlight and made a funnel out of steel plating, then ran a vacuum cleaner hose down from it to the carb mouth. Stuck the funnel in the headlight housing, it ended up looking like an induction hood scoop on a muscle car :lol:.

It worked, but only noticeable after you got the sled above 50 mph or so. Otherwise there's just not enough air being pushed in to make a difference (not enough pressure building up to make "boost")

Unless you're making some sort of sick drag trike that will go 70+ mph in a straight line and not see much dirt, I doubt it's worth the hassle.

[Erics350x]

the bent you have to make would do more harm than good.

[TrailerRider]

Ok how about this. Remove Air box and run direct to carb. Add a computer fan just behind filter and help push/pull air though susyem.

Fan imaeg for those who don't work on comps. http://www.hardwarecooling.com/images/SFF21F.gif

new diagram.

[MyMistress86R]

Not enough volume of air can be supplied by that fan. It would be more restrictive than beneficial.

[RedRider_AK]

I agree. Maybe if you found some industrial grade fan that could move more than 1 cubic foot of air every 30 seconds...

[MyMistress86R]

All in all, you are simply trying to redesign something that works just fine as it is and will not benefit you enough to waste the time and effort it would take to pull it off. Besides...if you do design such a system, you will force the motor into a lean state unless you also spend some time on jetting to balance out the intake air.

Just not worth the effort...IMO

[TrailerRider]

I agree. Maybe if you found some industrial grade fan that could move more than 1 cubic foot of air every 30 seconds...

This moves 63.7CFM and it's $12 bucks. Gonna buy one now for my comps case ..lol http://www.directron.com/sff21f.html

My next question would be if that would increase the flow of air to carb or limit it. So I guess I need to know what the stock flow of air would be to the carb. Anybody know that?

[MyMistress86R]

Again...redesigning a concept which will yield little or no potential.

The airflow of the carb is variable based on the throttle position. The more you push the throttle, the further the slide opens, the more air and fuel are delivered. Just like any other demand based induction system. The intake stroke of the motor (2 or 4 stroke) creates a vacuum designed to pull the necessary amount of air into the chamber. If the motor needs less air than your little fan supplies, you will be instantly lean...if it needs more air, you will be instantly rich. There will only ever be (if ever) one point from idle to WOT that your fan will ideally match the necessary air needs of the motor and that point will only last for the portion of a second that it takes to climb past it or drop past it in the RPM range.

[TrailerRider]

Hmm, did not think of it that way. I will do some thinking on that one. Thanks for the info. :)

[RedRider_AK]

Hey MyMistress, what about having a fan setup with a pot (like a volume control on a guitar, etc) that makes the fan spin faster when you give it more gas? :wondering

[MyMistress86R]

Uh well...

I would tend to lean more towards an automatically variable resistance module that you could run off the stator. Think Throttle Position Sensor. That way, it could all be controlled by the motor itself per demand.

Then again, whole lotta work for negligible gain. Why go to all that trouble to create a system that would just get in the way of what already works as good as it needs to?

There's a reason cars have Ram Air and Cold Air option kits and ATVs don't.

[RedRider_AK]

From what I've heard, a stock airbox pretty much IS a cold air kit (no hood to accumulate heat in)

[Kevo225dx]

A 250cc, 2-cycle engine displaces .0088 cubic feet per revolution. At 8000 rpm you will need 70.6 cfm (8000 x .0088). So, you'll need a bigger fan.

I wouldn't even try it. You will get much more "bang-for-your-buck" with a milled head or aftermarket pipe. The variable fan will be very difficult to calibrate. You will most likely make it run worse. You could cause a lean engine siezure.

Just my opinion. Take it for what it's worth.

[RedRider_AK]

I agree with that, it's just too hare-brained and stupid to be seriously considering (especially with turbos costing as much as they are now) but it's just blue-sky theorizing, for me anyway.

[Aka_am]

yeah if you want to do something like that..get a gt12 (???) turbo and go that route..

[300rman]

the fan will not help......you need pressure, not volume for a power increase. hook a in-line filter to the end of a leaf blower to keep the air clean, and hook it to the air intake. and then link the leaf blower to to yur thumb throttle so they both rev up at the same time. it adds like 15 extra HP to a car.