Springfield Flyer.

[floydjer]

Like so

[tauruck]

Jerry it doesn't go completely through the interior of the body.

When I raced the F2 Mazda Rotary March my race engineer Norman Thersby
came up with a way to improve airflow on a Weber 48 IDA carb.

Simply put we drilled and tapped the shaft as close to the wall as possible on both sides
and then cut the centre section away. There were two stubs that were radiused and housed
counter sunk screws, naturally fitted using Loktite. The Brass butterfly had the original holes brazed shut
and the leading and trailing edges were smoothed for better airflow.

The only drawback was the throttle stop. If you never had it set up right the butterfly would be twisted like a candy cane.

That's why I'm using that multi layer Carbon Plate. No twisting involved. I can laminate you a piece and post it for you to test.
I've been working with the stuff for 30 years and this blade (butterfly) is right up there.


The mod did show improvement on the back to back Dyno tests. Norman is sharper than I'll ever be and he calculated the increase in volume
by removing most of the shaft. Like you said the original system did restrict.

Another thing worth looking at is using mesh over an airbox to keep FOD out. You know this already but if you measure the thickness of the wire strands
both on the weft and warp you'll find you might be getting 60% flow.

[floydjer]

Weft???  where is my dictionary??

[Stainless1]

Weft???  where is my dictionary??

On the next google page... I had to look it up
weft
noun
(in weaving) the crosswise threads on a loom over and under which other threads (the warp) are passed to make cloth.
Like Mike said.... ya learn something new every day on this site 

[tauruck]

 

I finally contributed something.🤓🤓

[Elmo Rodge]

Weft is often referred to as fill. 
Wayno

[floydjer]

....I thought it was Elmer Fudd giving directions...............

[tauruck]

When you meet me Jerry you'll get the picture.
Weft and wight!!!!!

Thanks Wayno.

[Lemming Motors]

Coincidental throttle body content; my engine head builder person recomended (from experience) AT Power ITBs for my engine. He is based in California (unfortunately). The ITBs however are made in the UK which has a sourcing advantage as so am I.

I have just placed my order so it was coincidental that a butterfly spindle discussion popped up here - AT Power ITBs have no spindle - they pivot on what I would descibe as a shoulder joint at the edges of the butterfly.

.... link to the AT Power blurb ...  https://www.atpower.com/why-shaftless

[tauruck]

So Norman Thersby from Sheffield, England was 30 years ahead of his time.

[wobblywalrus]

Good intake flow bench numbers were obtained on the Triumph with the cylinder head and manifold.  Butterfly carbs were added and there was a significant drop in flow.  Best performance is had with flat slide carbs where the only obstruction in the intake tracts are the needles at wide open throttle.  Minimal obstruction to intake flow.  The Triumph uses two 45mm dia Mikunis.     

[tauruck]

Bo, on the karts I raced we had Tilotsen slide carbs.
The good one's of which I still have two here revved to 20,000RPM.

Building a slide type throttle body for a twin turbo application is overkill.
The amount of pressure produced won't be affected by a small variation
in flow, so I'm told.

[tauruck]

Hey Pete, I just found out for the umpteenth time that the same ID doesn't go into the same size OD!!!!!!

I never learn.
Not too tough of a fix but a lathe would have been nice.

[tauruck]

Got it. Eventually.

The perceived gap at top right is the masking tape peeling away.

[tauruck]

One more for my Canadian mate Peter Jack. Thanks for always inspiring and advising me.
Canadians raised me and Americans adopted me. God Bless all of you.