>>> Paul
>>>
>>> Thanks for the info. Something Fred said last year got me thinking
>>> that if
>>> the slide throttle hole in the throttle plate was designed correctly
>>> (sort
>>> of like a 'comma' mark on its side,  only the top corner of the hole
>>> could
>>> be exposed during idle.  This might possibly eliminate port overlap
>>> during
>>> low rpms.
>>
>> Doug,
>> I doubt if it will eliminate overlap as this is the physical state in
>> regard
>> to the position of the ports.
>> What it may do is stage the inlet, something like the Mazda
>> carbies whereby the idle inlet (and manifold tube) is much smaller.
>> This may
>> increases inlet speed and improve idle, and throttle response at low
>> speeds,
>> but only if the manifold sized matched the inlet size.
>> A hard one to visualise!
>> George (down under)
>>
>
> George
>
> Yes you are right.  So much for late night ponderings.  I just
> realized that
> the location of where the slide throttle opens first may not be so
> relevant.
> For example on the side or top.  Air will still travel to the lower
> part of
> the intake p-port or said another way gases will seek the path of least
> resistance.
>
>
> Doug

Hi George/Doug;

One thing you might consider is a staged sideport/PPport intake/throttle.
I've been meaning to get around to building one to test the idea but
haven't had the time.
The premise is to have a staged Pport slide throttle combination along
Paul's design for wide open throttle operation; and
a separate runner/butterfly for low speed/power operation using the
center iron side ports/injectors.

The plan was to have a single, small diameter (say 1") intake runner
supply air to the center iron intakes and fuel by the stock
center iron injectors.  I can't remember the intake velocity
calculations but a smaller diameter could be tailored to provide
velocities for a stable idle and low power operation.  Staging of the
PPort could take place around 3000rpm or so.
Why?
I believe Tracy Crook could run in this manner with his original carb
setup at reduced power.
The side port is supposed to be more efficient at lower power setting
according to Kenichi Yamamto's? book.
I am sure running on the center irons alone is not quite as good - how

much?

With a single runner, an idle air controller would also be an easy

addition.

Cheers
Cary

Cary/Doug,
To my mind that would be the perfect solution, however some might consider
that it takes away from the simplicity of the single runner in the P-port.
It would be an interesting project!

What we really need is a variable length, variable diameter inlet tube and a
butterfly like a camera shutter- however no chance of that!
George (down under)

----------------------------------------------------

Naw you don't need all that. An aircraft engine runs WOT 99%
of the time. We built some of that stuff and never tested it.
If you pay shipping and you guarantee you will test it soon
on a dyno I'll send it to you.