I needed a throttle for my turbo intake system. The pipe from
the turbo to the intercooler would be the place to put a throttle.
The stock Mazda turbo setup uses a 1-3/4 inch tube for this purpose.
1-3/4 inch is a bit on the small side for a butterfly throttle
as it obstructs any pipe it is installed in when wide open.

Ever since I got interested in furrin cars around the age of
19 I have been fascinated with slide throttles used on some
exotic furrin race cars. The advantage of a slide throttle
is you get a nice smooth tube when the throttle is completely
open. The downside is there is a huge pressure load on the throttle
plate that causes them to stick. The historical fix for this has
been some sort of very expensive linear motion ball bearings.

I was looking through the McMaster Carr catalog this morning
for linear ball bearings and I came across low cost cam follower
bearings. I then had the bright idea of using four of those
and making the throttle plate into a sort of miniature four wheel
car that runs in tracks. Been racking my brain off and on for
forty years on how to solve this problem at low cost. I think I
have hit upon a solution.

Here it is. It is half in the cockpit and half in the engine
compartment for the world's most simple and direct throttle linkage.
A very simple push pull rod with a knob on the end of it.

Paul Lamar

Bill Freeman wrote:

  And, like those incredibly cool Ferrari F1 slide throttles of
yesteryear,  all it takes is one piece of sand and you have a
fixed throttle setting.  Neat idea, not practical in the real world
IMHO.  Not that much deltaP from a butterfly, esp if you
oversize the area at the butterfly above what you "woulda"
made it otherwise.

As to the belts - I'd go for separate belts with a substantial
divider to try to keep a single failure from dumping the other.
Is it possible to drive the alt from the prop end and leave
the water pump all alone so it can't be "killed" by a failed
alt bearing or belt dumping the alt belt or pieces of it into
the water pump belt?

Bill

Hopefully the grain of sand will not get through the compressor.
This design should be more resistant to a grain of sand
than the classic zillions of tinny re circulating ball bearings.

A smooth transition to a larger tube and back down again is too
hard for me to make. Also more bulky and consequently hard to fit
in to the turbo air plumbing. This is a fine fit and its location,
just in front of the classic throttle position on the instrument 
panel, is ideal.

"Is it possible to drive the alt from the prop end and leave
the water pump all alone so it can't be "killed" by a failed
alt bearing or belt dumping the alt belt or pieces of it into
the water pump belt?"

Possible but not too practical.

Paul Lamar
 
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