<VV> stock air cleaners

[Jim Davis]

Well the venturi is actually 1" in diameter and there is a venturi 
cluster blocking 1/6 of that.  So the effective hole is about 0.88" in 
diameter.  The HVs flow 87.5 cfm @ 1.5 inches of water.   My aero is 
rusty as shown in a couple recent post but the divergent nozzle slows 
down the air flow before it enters the aircleaner element.  Slow air is 
less turbulent and passes through the filter medium easier.   The 
nozzles are there for sound and also, to help prevent carb icing when 
the winter air plate is removed.   Due the airflow above the fan, the 
nozzles are placed where there is the least turbulence in the engine 
compartment to distort the airflow.   Believe me, if a cheaper 
alternative could be found that was almost as good Chevy would have used it.
Jim Davis



On 7/19/2012 11:28 AM, Mark Durham wrote:
> Paul, Bob is correct, if you want to spend many more $ and provide
> unrestricted airflow. Those air cleaner sets look geat, too. California
> Corvairs sells individual air cleaners at a much smaller price. But lets
> take a look at the parts you have and see if they will work for you.
>
> First, remember that the carb top opening is way bigger than the actual
> size of the opening in the head, or carb throat, both of which are 1.25
> inches. The venturi is much smaller than that. What is needed at each carb
> is the amount of air each venturi will flow on each intake stroke of each
> piston. Since each piston works at a different time than any of the others,
> you only need to supply enough air and exhaust enough air for one cylinder
> at a time. So, those two inlets only need to supply enough air drawn in
> through a venturi. If you measure the area of the two air filter
> inlets (3.1416 x diameter of one x 2) and compare that to the inlet area of
> 1.25 inches(3.1416 x 1.25 is 3.927), the area needs to be larger than that.
>
> Your valve job and angled exhaust will simply help get a bit more air in to
> the cylinders faster, and allow it to exit as hot expanded exhaust more
> quickly, which in turn allows it to draw in more, so it makes the system
> more efficient. But as long as the area of the two filter inlets are larger
> than the amount of air that can be drawn thru the 1.25 inch round hole in
> the carb and in the intake runner, the stock filter housing should work
> fine. And yes, if you want a bit more air capability there, you can drill a
> few holes in the bottoms of the snouts, but I would do it fairly close to
> the opening so the air stays relatively the same temperature as what it
> gets from the snouts.
>
> My two cents. Mark Durham
>
> On Thu, Jul 19, 2012 at 10:50 AM, Vairtec Corporation <Vairtec at optonline.net
>> wrote:
>> Paul, as to "what was the General thinking," the general was thinking
>> "low cost street driven economy car."
>>
>> As for the comparison to the marathon runner, I'd say it is more like
>> asking the runner to breathe through a drink straw.
>>
>> As for a suitable upgrade for an engine with the modifications you have
>> made, take a look at the air cleaner assemblies in Clark's "OTTO"
>> catalog.  From what I have seen, they are quite popular among those with
>> high-performance 140s.
>>
>> --Bob
>>
>> On 7/19/2012 1:35 PM, Paul wrote:
>>> Okay, tell me how this works: I spent a lot of money on the performance
>> carburetor modifications done by our friend Mr. Young to improve airflow, I
>> spent more money on the custom three angle grind on the valve seats to
>> improve airflow, I installed, at great expense, the "slant" exhaust tubes
>> and custom equal length headers to improve airflow. Now, I'm looking at the
>> intake system and I find two small "snorkel" intakes on the stock air
>> cleaner. The cross-section of these intakes appears to be less than half of
>> the total area of even the stock carburetors. It seems to me that this
>> would be kind of like a marathon runner trying to breathe only through his
>> nose. What was the General thinking when he came up with such an apparently
>> restrictive air intake?. Would I be better off replacing the stock (but
>> attractive looking) air cleaner? How about just removing the "snorkels" and
>> perhaps putting some more holes around the perimeter of the stock filter?
>> Is there a recommendation for
>>    a
>>>     low restrictive air cleaner on a 140? Thanks for your help, I am
>> always amazed at the depth of knowledge on this site.
>>> Paul Michalczyk
>>> 65 Corsa Convertible, just completing a 10 year restoration project
>> (that's two years working on it, eight years thinking about it and saving
>> up the money)