Jerry Hey wrote:

Paul,  how about designing the pp intake system for me and all the
other guys who are thinking about it.   I think we should come very
close to Power Sport's design.   Could we  use   your intake parts
for the cold side stuff?  They  are 1.5o.d. which is what I was
thinking of for the i.d. port size which I got from your drawing on
the ACRE site.  If we can match these (or do they need to be
matched?) that would make it a lot easier.   And look good, too.

Maybe we can find a throttle body that was used on a production car.
New, high performance throttle bodies that I have looked at on the
internet are expensive.

I will commit myself right now to providing housing machining and the
inserts unless someone else wants to do it.

  Jerry

p.s.  The first structural change to the Tailwind caused by rotary
performance  is a thicker windshield.

If I were doing it I would copy the Leman engine porting exactly
except put the butterflies next to the rotor housing.
240 HP at 6000 RPM and a lot more at 7500 with a 2.85:1 PSRU.
You don't need a throttle body. Just a couple of home made
butterflies. You also don't need my castings as everything is
too simple and can be made from tubing. Scale up this
drawing for the same size tubing Mazda used on the Leman
engine.

Thicker Windshields are a good idea anyway. That reminds me
I need to get one for the KIS.

Paul Lamar

What do you think of this cautionary note found on the TWM Induction web site:

Why are the injectors positioned in the TWM throttle bodies and not in the manifolds, like
original equipment EFI systems?

Original equipment EFI systems are configured to meet very stringent emission regulations and to
provide "soft" driveability characteristics. Positioning the injector as close to the inlet valve
is beneficial in this respect. Maximum power however, is usually obtained by moving the injector
away from the inlet valve, some racing engine manufacturers going as far as to mount the injector
high in the velocity stack and others installing two injectors, designed to operate at different
RPM. When TWM designed the throttle bodies our engineers were not in favor of having high pressure
fuel on the atmosphere side of the throttle plate, although this could have resulted in some power
increase. We compromised by mounting the injector as far from the cylinder head as possible while
still maintaining the safety afforded by keeping the fuel downstream of the butterfly.

The amount of fuel injected is a function of the air flow.
So when the throttles are closed there is very little fuel.
This does not seem to bother Power Sport. Unlike cars we run at 
high power the vast majority of the time anyway.
If you are concerned you can seal the plenum and use a 
excess fuel drain tube overboard.

In the case of TWM it is cheaper to mount the injectors in
the throttle bodies. 

Paul Lamar
 
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