I See So Many Great Motors with Small And ****ty Air Cleaners

[VanceH]

Ok so lets get some advise!! I am not a mechanic, but it seems to me that the air intake is based off the size of holes on the top of the carb??? So if this is true or not what is the correct size of aircleaner to get the most out of a engine?

[ll____b0t____ll]

Let's start with the basics. This will be old hat to some of you, brand new knowledge to many others. I really hope that you are learning something here, that's the only reason that I wrote this. Any engine, regardless of induction system, is basically an air pump. The more air you pump through your engine, the more fuel you will burn, and the more power you will produce. The components of the engine, from the plastic air scoop at the front of the wire and paper air cleaner intake tube located on the front radiator support to the very tip of the chrome exhaust pipe, either enhance or retard this pump's ability to produce power. Every single, last, individual component.

Every last one.

Think of your vacuum cleaner at home. It makes a wonderful sound when you fire it up, doesn't it. And the air blowing out the exhaust port is free flowing, isn't it? Well, what happens when you put the vacuum cleaner to the floor, or get something caught in the vacuum tube that restricts the intake charge? You notice a change in power and in exhaust flow, don't you. The engine works harder to overcome the blockage or the extra load, but it's not breathing as well now, and it's not as efficient at its job. Cover up the vacuum cleaner's exhaust and you'll notice another similar difference. Loss of power. The same thing can be said of your car's engine. It's all just plain physics. Your engine is an air pump, pure and simple, and you want to keep the velocity of air through your engine a constant, high velocity, with the least amount of restrictions possible anywhere in the system.

If you have a large free flowing exhausts but a highly restrictive air cleaner assembly, you are not going to get the full use of your exhausts, because your pump will never flow enough air (breathe properly) in order to produce enough exhaust to fill and utilize your large exhausts. Think of this example as trying to run the Boston Marathon and all you can do is breathe through your mouth, through a soda straw stuck between your pursed lips. That's the only way you can breathe. Now, take off and run as fast as you can, for as long as you can, breathing only through that soda straw.

How long before you stop 'making power'? Getting the picture yet?

If you have a large free flowing air filtration system leading to your induction system and tiny exhausts or a restricted exhaust system, your engine will never be able to fully utilize the added breathing capability. It will be 'constipated' by the tiny exhaust system, unable to evacuate it's cylinders fast enough to benefit from the increased intake advantage. You've got potential, but another part of your performance train is keeping you from realizing this potential power.

I like to think of engines in the same way that physicists think of energy. You have two types of energy; potential, and kinetic. Potential energy is what can be, like a rock on top of a hill. It's motionless, for now, but it can start rolling down the hill at any moment. Kinetic energy is what power you are making right now, like when the rock starts rolling, it will have a lot of kinetic energy. It's potential will have been converted into kinetic, or actual energy. Potentially, it just sits there, but potentially it can do a lot more. Kinetically it is doing something, it is living up to it's full potential.

I like to think of engines as having potential power and kinetic power. A particular engine might have a lot of potential power but very little kinetic power. You need to shift this balance as much as you can to an engine with very little potential power and a whole bunch of kinetic power.

[ll____b0t____ll]

However going to a larger open element air cleaner isnt always the best idea as we know that the ideal situation is large amounts of cool dense air.
Open elemwnts let in more air but also pull in warm air around the engine.
So in theory the best case would be a closed in air element of greater size.
Thats my 2 cents

[Stocker]

Originally Posted by ll____b0t____ll

Open elements let in more air but also pull in warm air around the engine.
So in theory the best case would be a closed in air element of greater size, fed by a cold air intake.

Fixed it for ya

Great posts -- excellent explanations of things that some people seem to know almost instinctively but may be unable to verbalize, and that others may have more trouble grasping the theory of.

[Tx Firefighter]

Here is a great little calculator that allows you to enter your engine size and air filter size and determine how much, if any, horsepower loss you are experiencing.

http://www.secondstrike.com/Technica...leanerCalc.asp

For example, using the 8 inch filter example above on a 350 cubic inch engine, 325 horsepower, the 8 incher shows a loss of one single horsepower over an equivalent 14 inch unit. 1 Horsepower !

[Sinister]

To add to this conversation. Bigger is not always better. I had a 14" air cleaner that was about 3" tall, went to a taller air cleaner and lost throttle response. I assume the air/fuel charge lost velocity with the too big air cleaner.

['72customdeluxe]

Originally Posted by Tx Firefighter

I'm way ahead of you. My 327 has two mouths to breathe through.

Are you going to run two heat risers, or just didn't want to take the valves off? I have that factory style cleaner with the tube taken off (valve got stuck closed) and the lid flipped with a bead of sealant on the filter so dirt can't get in. It looks terrible, but works There is alot of vaccuum going on with the stock size 12x2 or so paper filter as all the pleats were severely distorted in a day or two.

[Tx Firefighter]

I will just leave them like they are. I never bother to fool with hooking them up.

[PanelDeland]

Most of the above info leaves out one big factor.The filter itself.There are differences in filter material.In oil filters they are measured in microns,I assume the same in Air filters.This is the size of the small openings in the filter that allow air to flow thru.The more of them there are the more air can flow,unless they are small clogged or restricted by something.That is why a dirty filter flows less.The smaller the filtration areas the smaller particles need to be to clog one.The total area left open by the filter may be less than than the area allowing air into the housing.An oversize filter should not affect the airflow except by disrupting the airflow as it enters the carb.Velocity and flow thru the carb are the areas where power is made.Cool air is also denser than warm air meaning it contains more oxygen per square ft.

[ll____b0t____ll]

Originally Posted by Tx Firefighter

For example, using the 8 inch filter example above on a 350 cubic inch engine, 325 horsepower, the 8 incher shows a loss of one single horsepower over an equivalent 14 inch unit. 1 Horsepower !

I agree with that to a point , its seems to me the advantages of getting more air seem to be benifited more by larger dicplacment engines and engines built with more than 325 h/p.
But then again the more h/p and t/q you build the harder it is to make more of both.
Good example of more air more power, look at turbo's they force more dense air creating more power also look into what nitrous oxide realy does.

Of course everyone is diferent and some may scoff at at 1 or 4 hp/ and tq but I have always chased that last 1 hp and tq rating looked for that last pound I could shed safely.
In the end Ide say if your not seeking to get the very optimum out of your engine than its a moot point and realy opens the door for a persons desire to what looks best to them but if you are interested in your engine running the best it can than dont take my word for it go to the drag strip and ask around .
Do research outside of wikipedia, some of this stuff boils down to opinion , then again some of it boils down to physics and is irefutable.

[Pont406]

I am planing on running 2 small air filters soon. Hopefully these filters wont restrict the air too much.

[pissonNOS]

i know you guys are mostly talking carbed motors here and horsepower but heres a little blurp i found about newer engine and fuel mileage
"Decrease AIR !! This flies in the face of what is sold out there today, but if you can decrease the amount of air entering the engine (due to the fact that this is a closed loop system as of 1996 OBD2) you will use less fuel, too. Ideally, you want to maintain the same horsepower required to combat air friction, rolling mass losses, etc...but do it with LESS AIR !!

Let me illustrate. A closed loop system maintains the air fuel ratio at 14.7 lbs air to 1 lb of fuel. This is maintained for idle, cruise and in some cases, even at wide open throttle.

If you have 60 grams/sec air entering the engine at cruise, you're using 4.08 grams of fuel per second. If the cylinder pressures are increased without creating harmful exhaust byproducts, or if these byproducts are controlled by the catalytic converter, we can gain mileage by decreasing airflow through the engine while enhancing the spark curve to maintain the same rear wheel HP.

On the chassis dyno, we can get vehicles down to 45-50 grams air/sec maintaining the same air fuel ratio, and same wheel HP as stock--and the overall result is less fuel consumed ! 45 g/secs works out to 3.06 g/fuel used in the same time period--or an almost 25% saving. We can't gain this in all vehicles of course--this example was resultant data from a 2007 6.0L HD 3500 GM truck.

This flies in the face of every aftermarket product out there claiming that it saves fuel--you will never gain mileage by increasing airflow through a gasoline engine in a mass airflow type system
" end quote

['72customdeluxe]

restricting air increases pumping losses because the pistons will create more vacuum which slows them down and chokes the,. And how did they end up saving fuel? Like what did they modify? You didn't post that.

[pissonNOS]

Originally Posted by '72customdeluxe

restricting air increases pumping losses because the pistons will create more vacuum which slows them down and chokes the,. And how did they end up saving fuel? Like what did they modify? You didn't post that.

are you refering to my post?? if so i just copy and pasted that from a guy that does ecm tuning

['72customdeluxe]

Yeah. I still don't understand because when (on an efi vehicle) you have a dirt filter, you lose performance and mileage. And he didn't mention what they did to get better mileage

[big_al_71]

I dont know much of anything but i do know that if you go too big you will create a lean condition and if you do go too small you will create a rich condition. However what i have always done in the past has been to tune the motor on a dyno and adjust the air fuel mixture the best possible to the conditions and go from there. I know that all of this has been mentioned but right or wrong it has always worked out good for me...Here is what I am using
K&N oval style filter on an HP650 Holley Carb..

[fdbdw]

Id like to see what you powdercoated on the Fire Truck if you got any pics, my department would never let us do that, thats cool id like to see

[pmpski_1]

[Tx Firefighter]

Originally Posted by fdbdw

Id like to see what you powdercoated on the Fire Truck if you got any pics, my department would never let us do that, thats cool id like to see

Each of our engines has a different color for marking tools so we can keep them separate when picking up after a fire. My engine, everything is blue. So I coated the spanners first and I am working on doing the brass now. I have a pretty big assortment in my pump compartment that we're trying to get done. Each item I take home we do have to borrow a spare off of a reserve truck to have while I am working on an item.

[Shaky]

Here's my ultra-rare factory hi-po air cleaner for the 292. Adds like 20 hp and 5 mpg!

[ll____b0t____ll]

heres what Im running.

['72customdeluxe]

Originally Posted by Shaky

Here's my ultra-rare factory hi-po air cleaner for the 292. Adds like 20 hp and 5 mpg!

Hey, the air cleaner might not be the greatest but the motor's nice. If fuel goes back up i'll have to line up a trade with one of you 292 inline 6 guys for a nice but leaky 350 Just get some milled heads for compression and it should get some mileage

[Tx Firefighter]

Originally Posted by '72customdeluxe

Hey, the air cleaner might not be the greatest but the motor's nice. If fuel goes back up i'll have to line up a trade with one of you 292 inline 6 guys for a nice but leaky 350 Just get some milled heads for compression and it should get some mileage

I don't know. I have had 292s and small blocks. The 292 always pull harder than a small block, but the mileage is wretched. It's kind of famous for bad mileage at the expense of torque.

['72customdeluxe]

Yeah, but i've heard a big part of that is the 8:1 compression. Maybe not. That's why I mentioned milled heads. I've always had a fascination with the sixers though.
Gotta love that 4 3/8's or so stroke though

[eightbanger]

OK! since you pointed it out shorty.