Can somene tell me how well a stock fresh air intake system works .I'am thinking it would be better than open air element fiter,because it will be cooler and somewhat forced air.

 

Forced air? On a stock set up? Hardly.

Like all performance upgrades, there is a compromise involved.

Open element air cleaners are less restrictive than the factory air cleaner housings. They can alse be subject to slightly higher inlet temperatures but its' not like the front end of these rigs is as well sealed as newer vehicles. I wouldn't be concerned about the tad higher intake air temp with an open element. it's still better than not getting as much with the OEM housing.

Mustang Monthly (magazine) did a test a couple of years ago and an open element air cleaner housing (and K&N filter) was worth 12 HP over the stock system. That comes out to about $65 for the entire conversion. Howz that for cheap horsepower?

 

The purpose of the original fresh air intake system is to prevent the carburetor from icing over. The air cleaner is closed with the exception of the snorkel that extends past the engine. The bottom of the snorkel runs to a heat riser that surrounds the passenger exhaust manifold.

Inside the snorkel is a vacuum-controlled door. With the engine is COLD, vacuum is supplied to the vacuum motor fixed to the door and SHUTS the door. The engine pulls in warm air that is wafted from the ehxaust manifold. After the under-hood temperature reaches a certain point, vacuum is cut off from the door and it springs open, allowing the engine to draw in air from the front of the snorkel. The snorkel is supposed to be connected to the radiator support through a fresh air hose that pulls in fresh outside air through the front of the vehicle.

This system has nothing to do with performance. Tehnically an open-element filter draws in air from 360 degrees and lets the engine breath more, but part of the gain is offset by the fact that you only draw in warm underhood air. However, few people here have offered any scientific data to prove any actual gains or losses between either system. One disadvantage to an open element is that the carb can ice over; this is typically less of an issue in warmer climates. I agree with HIO in that the stock system is in no way "forced" air. The original setup simply directs where the air is pulled from.

 

Well we're on the topic has anybody ever had there carb freeze up? I live up here in Saskatchewan and it gets pretty cold and I've never had a problem with my open element although the truck mainly gets used for short runs. Hope I'm not hijacking your thread.

 

Well I think with the air intake at the front of the radiator support with movement your going to push air into the air cleaner,how much who knows wouid like to see real scientific data.

 

The air inlet is not positioned in such a way that forces air down the throat of the carburetor as you move forward. If you have ever seen one (most have been removed by a previous owner), it's quite obvious.

And even if it were, the path between the inlet and the throat of the carburetor is not direct because of the curvature of the snorkel hose. Furthermore, many air cleaners have a baffle directly behind the snorkel - air must come in through the snorkel, then go around the baffle to hit the sides of the air filter.

As I mentioned before, the fresh air intake system simply directs where air comes from. It does not add momentum in any way. You have to spend big money to make that happen.

 

The aftermarket at Summit Racing are selling fresh air closed single or dual snorkel air cleaner systems,couple hunderd bucks .The old 64 fairlane thunderbolt had the dual snorkel with hose going from snorkel to deleted head light openings not so much big money

 

All right then; buy it, install it, put it on the dyno and let us know what you find out. Your question was how the original system works, which I've answered in full.

 

Yes I have had one freeze up, on my 66 F100 with a 390 engine with open air cleaner, but I was following a semi truck for about a 100 miles in a snow storm.

 

Yes on a dyno I'am sure an open air cleaner will out flow a close air cleaner .But on the hiway at 70 with close air cleaner and the fresh air intake tube i'am not so sure.