Re: Chirping

[jlandry@domain.elided (John A. Landry)]

The aliens commander decided jmbrodsky@domain.elided would make a
perfect specimen for dissection, and he yelled...

>        My hypothesis:
[snip]

Sounds good to me! <grin>

>     Next I put a K&N in, 
>     and WOW, it makes the truck louder to the perception of the driver.  
>     Super load on acceleration, louder on cruise, lower fuel economy with 
>     K&N.  What should I do about jetting?

Hmmmm... I wonder if the K&N causes a *more* or *less* restricted flow for
the incoming air.  I would assume it would be less.  This would cause a
less vacuum above the venturi (in the air cleaner), so potentially with the
K&N you'd have a bigger pressure differential in the vacuum measured above
the venturi and below it, verses with the stock paper element.  Possibly
this could cause more fuel to be drawn into the carburetor and thus a
richer mixture.

I have one of those chrome Edelbrock 10" diameter round open style air
cleaners which uses paper elements.  I use it sometimes during the summer
months, but I prefer the stock air cleaner with the manifold heat diverter
valve for winter driving.  Anyway, I find that when I install it, my air /
fuel mixture gets slightly *leaner* rather than richer.

I think it's time for you to get an air / fuel mixture gauge Joel!

>     BTW are the exhaust ports different between your truck 392 and your 
>     scout 345?  oval/round/etc like a chevy?  Just curious, since the 392s 
>     are usually rear dump, and 345 center, do you have an extra set of 
>     rear dump kicking around now?  Please let me know.

The exhaust ports are identical in shape and size (more or less).  In fact,
the one remaining exhaust manifold that was left with the donor 72 pickup
(where the 392 came from) had the same exact part number as my Scout
exhaust manifold (center dump).  That was a 2wd pickup.  I have no spare
manifolds left.  All I had at one time were center dump and they all went
with the 345's I sold.

Thanks for the reply,

John L.
-------------------------------------------------------------------------- 
jlandry AT halcyon DOT com      | 
Conservative Libertarian        |  "The road to  tyranny, we must never
Life Member of the NRA          |   forget, begins with the destruction
WA Arms Collectors              |   of the truth."
Commercial Helicopter - Inst.   |                     William J. Clinton
http://www.halcyon.com/jlandry/ |    10-15-95, speech at the Univ. of CT