<VV> Single Carburetor

[jvhroberts at aol.com]

 Exactly, Bill! The only HO engines I am aware of with long runners like this are air cooled single carb VWs and carb'd Subarus. There may be others, but every flat 6 I'm aware of for automotive use has carbs on each bank, for those with carbs! 

And yeah, modern engines and carbs??? Didn't they really start to die out on new cars about 30 years ago?

 

John Roberts
 

 

-----Original Message-----
From: Bill Hubbell <whubbell at verizon.net>
To: Mike McCrae <mmccrae6 at cox.net>
Cc: <virtualvairs at corvair.org> <virtualvairs at corvair.org>
Sent: Tue, Apr 23, 2013 5:18 pm
Subject: Re: <VV> Single Carburetor


Sorry, you lost me when you said,
"All modern engines compensate for this phenomenon by locating the 
carburetors...."

Funny, I thought all MODERN engines were now using Fuel Injection!

Bill Hubbell

On Apr 22, 2013, at 10:26 PM, "Mike McCrae" <mmccrae6 at cox.net> wrote:

> This was my letter to “Corsa “ RE: use of single carbs....perhaps there are 
some words in there that may help with your problem....
> Regards, Mike McCrae
> 
> 09/08/2010
> 
> 
> 
> Dear Larry,
> 
> I found the four barrel manifold article interesting, but what always gets me 
is that no one, VW, GM, etc. has ever made a remote carb work well without 
applying heat to the manifold. Remember the Grand National....they had to plumb 
the turbo intake manifold to accept heated water from the radiator. There is a 
very simple answer which I provide, and solves these problems. The bottom of the 
four barrel intake manifold is machined away, and an aluminum box is fabricated 
and tig welded in place to carry engine oil. The oil comes from the oil filter 
log which I machine off....A remote filter is then used on the return line from 
the heater box. This system not only heats the plenum, it cools the oil as well. 
The oil leaving the manifold is generally 10-12* cooler.
> 
> Exhaust could be used for heat if one wants to replumb an AIR exhaust 
manifold. The perfect example is the single carburetor V W engine. 
> 
> All carburetors become refrigeration systems, due to the Fuel/Air (F/A) 
compression in the venturi and idle systems and later expansion in the plenum. 
All modern engines compensate for this phenomenon by locating the carburetors 
over the oil valley in a V-8-6, or over an exhaust manifold in inline engines. 
Corvair engineers wisely mated the intake manifolds directly to the head, 
keeping the F/A mixture warm, and in suspension.  The lack of heat to the remote 
4-barrel manifolds we use allows the F/A mixture to condense on the sides of the 
frozen plenum, creating a very lean situation, and resultant hesitation (lean 
skips). Winter operation becomes almost impossible due to carburetor ice 
formation with resultant frozen idle circuits. Most folks compensate for the 
problem by using the 50 cc accelerator pump and fire-hose nozzles. The result 
being poor gas mileage and extreme dilution of the oil at the top compression 
ring. With my system, one can use the stock Holley accelerator pump and normal 
nozzles.
> 
> My suggestion for initial carburetor settings in the Holley 390, 4160 series 
is as follows:
> 
> 
> 
> Stock accelerator pump (NOT the 50cc)
> 
> .031 Accelerator pump nozzles
> 
> .057 primary jets
> 
> .059 Secondary plate jets
> 
> 75 power valve
> 
> Electric choke
> 
> Purple secondary diaphragm springs
> 
> 
> 
> 
> 
> Best wishes, Mike McCrae
> 
> 619-466-0014
> 
> 
> 
> 
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