What you guys think of my air filter idea?

[flatfourfan]

As for the fuel lines....

if you are referring to HP lines as copper or stailess lines.... you need to put in at least one flexible piece of hose to take up vibration and the resulting stresses.
I know, its been done before without the flex hose, but it wasnt right then and it still isnt right now. I have seen a copper fuel pipe (on a ship) crack and leak because of the vibration which caused it to work harden and become brittle.

I was referring to High Pressure fuel hoses like Rui said. Also decent clamps as well.

I know that there are several problems that I have to overcome with diameter of the air filters bases and the carbs calooker and fitting the manifolds from an SP will simplify things, however then I'd have to change the linkage as well. Man nothing in world is easy....

[mevans]

Gary,

I collected bits to do this with my doublecab a while back. Only difference is I planned on using two late split bus canisters mounted to the engine bay(like stock but with additional one on the opposite side) and connected to the carbs with flexible hose.

After flying the idea on a US forum someone suggested that filtration may be compromised due to the canisters being sucked by half the cylinders they were designed for.

Oil bath filters rely on air velocity to smash particles into the oil at the bottom and if it is too low it may not work as intended.

You could probably test this by clamping an oily gauze between the canister and carb and checking how much crap is collected.

Looks lekker though.

[Tony Z]

Gary,

After flying the idea on a US forum someone suggested that filtration may be compromised due to the canisters being sucked by half the cylinders they were designed for.

Oil bath filters rely on air velocity to smash particles into the oil at the bottom and if it is too low it may not work as intended.

Looks lekker though.

I dont know, my logic doesnt follow that thought.
When trying to remove a suspended particle from a gas (oil or water out of air or in this case, dust and other things form air), you want to slow down the velocity of the air to let the heavier particle drop out.

Extreme example... a small fine water mist, no moving air, it just drops to the floor. Now put a hair drier of a big fan next to it... it gets blown all over the place, even moving upwards, then as it slows to a near stop, it drops towards the ground....

look at performance cylinder heads, if they are used on the street, the head porters reccommend going a bit smaller, which keeps the air speed up and prevents the fuel from collecting on the port walls. The air velocity helps with better atomisation by breaking up the fuel into smaller particles and keeping them airborne

Those are my thoughts, but I dont agree with you

[Tony Z]

After flying the idea on a US forum someone suggested that filtration may be compromised due to the canisters being sucked by half the cylinders they were designed for.

Sorry, another thought. No I'm not going "mevans bashing"

Think about that statement carefully. I know it isnt your idea but just follow me here...

2 litre engine... equals 1 litre of air per revolution.
At Idle, 800rpm = 800 litres of air.
Running all day at 3000rpm = 3000 litres air per minute
Flat out = 4200 litres
Everyday driving, ave 2000rpm = 2000 litres

These things will definitely be designed to filter air for all rev ranges.
Your above statement make me assume that I may aswell not have an air filter unless I am driving on the highway, because idling and driving to the shops, doesnt clean the air at all...
4 cylinders or 2 or even 8... if 1000 litres of air per minute is flowing thru the filter, what difference is it how many cylinders are working

[flatfourfan]

Gary,

I collected bits to do this with my doublecab a while back. Only difference is I planned on using two late split bus canisters mounted to the engine bay(like stock but with additional one on the opposite side) and connected to the carbs with flexible hose.

After flying the idea on a US forum someone suggested that filtration may be compromised due to the canisters being sucked by half the cylinders they were designed for.

Oil bath filters rely on air velocity to smash particles into the oil at the bottom and if it is too low it may not work as intended.

You could probably test this by clamping an oily gauze between the canister and carb and checking how much crap is collected.

Looks lekker though.

Hmm, never thought of half the sucking power as it was..........interesting curve ball there..........I have a dew options that I'm trying at the moment, but with the 2.0 type 4 finally coming my way, I may have to put this little project on hold for a while.......

I'm actually thinking of removing the tops (making them removeable and using a K&N style filter for inside and then vent the rear section out behind the motor.....

SO many ideas, so little time.......

So many ideas, so

[flatfourfan]

After flying the idea on a US forum someone suggested that filtration may be compromised due to the canisters being sucked by half the cylinders they were designed for.

Sorry, another thought. No I'm not going "mevans bashing"

Think about that statement carefully. I know it isnt your idea but just follow me here...

2 litre engine... equals 1 litre of air per revolution.
At Idle, 800rpm = 800 litres of air.
Running all day at 3000rpm = 3000 litres air per minute
Flat out = 4200 litres
Everyday driving, ave 2000rpm = 2000 litres

These things will definitely be designed to filter air for all rev ranges.
Your above statement make me assume that I may aswell not have an air filter unless I am driving on the highway, because idling and driving to the shops, doesnt clean the air at all...
4 cylinders or 2 or even 8... if 1000 litres of air per minute is flowing thru the filter, what difference is it how many cylinders are working

Interesting also...........damn you two have given me lots to think about.....

[mevans]

Tony I see your points re filters being designed to be effective at all rev ranges and how particles fall out of the carrier when it slows but the issue with air velocity (as I understand it) is this:

The way the cans are designed has the airflow (with the suspended particles) make a 90 degree turn with the oil bath at the bottom of the turn. Due to the greater inertia of the particles they get 'embedded' in the oil while the air zooms by.

At least in the bus cans there is a mass of oily coir or similar fibre that the air has to get through so maybe it doesn't matter.

I have no idea if this stuff is true and the real reason I never did it is cos I'm bone idle.

A sudden edit thought. The tiddly beetle cans would be for 1100/1200/1300 so a 2l motor would probably come close to sucking twice the air given that that they make at least twice the power.

[flatfourfan]

A sudden edit thought. The tiddly beetle cans would be for 1100/1200/1300 so a 2l motor would probably come close to sucking twice the air given that that they make at least twice the power.

indeed........the plot thickens....

[Tony Z]

A sudden edit thought. The tiddly beetle cans would be for 1100/1200/1300 so a 2l motor would probably come close to sucking twice the air given that that they make at least twice the power.

Yes completely true, but I ised 2 litre because it makes the maths easy. An 1100 at 2000rpm moves the same amount of air as a 2 litre at 1100rpm (in simple maths anyway).

I understand the concept of heavier particles dropping out at high speed because of the turn, but small particles like dust (the things that block jets over time, not over a day), I dont see them dropping out decause of higher speed, I see them staying in suspension.

With lower air speed at the inlet to the filter, less particles would be drawn in as well....

I guess without tests, we will never know and we could debate this till the cows come home.
My opinion remains that the twin filters will do a great job

[eben]

JUst do what I do and pull a lekker thick rugby-sokkie over the ram pipes

[IMPI]

The brazillians had oil bath filters on the 1600 Brazilia with twin carbs I used a set of 1200 filters on my first bug way back in 85. I then replaced them with SP filters Performance was the same but those SP filters made more noise which I liked.
Armand

[RotorBug]

Let the word "inertia" come to mind when you think about particles in air.
The dust is heavier than air and thus have more inertia. Sooooo they can not make sharp turns like air do. Not even fuel vapor can do that. If you want to stop all the dust in your air from entering you motor you'll need a filtration plant twise the size of you bus and you'll need atleast 2 vortex filtration units and an air scrubber using high pressure water(5bar) to clean the air. I think the bus' engine bay is too small.

Yust fit the filters and make yourself feel good that your bus' butt looks as sexy as JLO's

Cheers guys

[RotorBug]

Let the word "inertia" come to mind when you think about particles in air.
The dust is heavier than air and thus have more inertia. Sooooo they can not make sharp turns like air do. Not even fuel vapor can do that. If you want to stop all the dust in your air from entering you motor you'll need a filtration plant twise the size of you bus and you'll need atleast 2 vortex filtration units and an air scrubber using high pressure water(5bar) to clean the air. I think the bus' engine bay is too small.

Yust fit the filters and make yourself feel good that your bus' butt looks as sexy as JLO's

Cheers guys

[flatfourfan]

I found this picture the other day while searching for more info on this idea. It's from a thing.........so I doubt that adding two oil bath filters will create a problem.............interesting.

[fig]

I found this picture the other day while searching for more info on this idea. It's from a thing.........so I doubt that adding two oil bath filters will create a problem.............interesting.

As you can see, that's a factory installation. Double heavy duty oil bath filters were an option on Beetles and Ghias, and could also be service installed. Somewhere I have a VW Service Bulletin with the instructions.