BTW I am going to weld these flanges together to make one wall
of the intake plenum. The rest of the plenum can be bent up from
sheet aluminum riveted or welded together and then bolted to
these flanges with small machine screws. With Tracy's EFI system,
that does not use a mass air flow sensor, or a throttle position
sensor, air leaks in this area are of no consequence.

Also BTW  use as large a throttle body as you can fit in as aircraft

engines

run WOT the vast majority of the time. The idea is to minimize
the pressure drop through the throttle body. If at all  possible
use just one butterfly as that minimizes the pressure drop
for a given throttle body intake area. I think the Ford V8 has
a single 80 mm (3.2 inch) but I notice there are some 100 mm (3.9

inch)

throttle bodies on the market now. Chuck Dunlap has about a five
incher on his :)


Paul Lamar

 Paul,  I found air leaks in the intake plenum (even fairly small ones)

will

effect your minimum idle speed, it will of course have no impact when

even

at partial open throttle.

Ed Anderson

Yes of course. Did you reprogram Tracy EFI to accommodate the leak? :)

Paul Lamar

The EC2 doesn't care where the air comes from, leak or throttle body, it's
all the same.  If the throttle body falls off the engine the EC2 would
assume the pilot was at full throttle and the engine would go WFO!  : )

Tracy

I wanted to see what Ed would say :) Now you have gone and spoiled it :)
What I was really thinking was perhaps Ed could lean the ROM map (not 
manifold pressure map) at real low air levels to the point the HP was affected 
and consequently the  idle RPM slowed. Of course this is not a good idea
in general as I think the engine would have trouble idling when cold.
Do you you have a cold idle switch Tracy? Equivalent to a choke knob?

Paul Lamar 
 
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