She runs!!!!!

https://youtu.be/yqRx-hH8xsk

https://youtu.be/PGN509s67oU

Is anybody running the slide throttle? I'm finding it hard to slide
with engine running due to the suction. Now mind you, I don't have
any mechanical advantage or throttle cable setup yet. I'm using a
threaded bolt to test with.  Can someone share their setup with the
slide throttle / lever quadrant used?

With the engine on the test bench, what safe rpm would be good
without any load on the crank? I'm aiming between 2000-3000 right
now. Not sure if it matters without a load on engine?

- Matt Boiteau

You will have to put a 2 to 1 lever on it.  That will reduce the
force by half. The travel will be 4 inches at the top of lever. The
lever can be six inches long.

With the 5 square inch area throttle nearly closed and 15 psi
(atmospheric pressure at sea level ) across it the force is 76
pounds. Assuming you did the Teflon liner properly  and used the
right kind of Teflon the coef. of friction for  Teflon is below 0.1
so that is 7.6 pounds of force on the cable.

As you open the throttle the pressure drop across the throttle
becomes less and that number will drop.

Historically slide throttles have used linear ball bearings but they
are very expensive and subject to jamming with just a little bit of
dirt. They usually cost over a thousand dollars US. The Teflon liner
will tolerate dirt and embed it in the soft Teflon. Many small slide
carbs have the slide coated with Teflon. The SU is a well known
example.

The e-shaft is absolutely  the last thing you need to worry about
since we are using a stock e shaft and we are getting 650 HP. The
part of the e-shaft next to the flywheel is the most highly stressed
part and that has held up with over a 1000 HP on a turbo 4 rotor.
Stock e-shaft and stock diameter. The stock e-shaft is atomic bomb
proof :-) After all It was built in Hiroshima. Sorry! politically
incorrect joke.

IT MATTERS! BE VERY VERY CAREFUL. The engine will run up to very HIGH
RPM's with no load and then seize. I don't know how high WITH oil
pressure but WITH OUT oil pressure it seizes around 10,000 RPM very
roughly speaking. It has been done so don't try it again :-)

Of course there is a rev limiter in the stock RX8.


Paul Lamar


Does anyone have any pictures of their slide throttle / lever /
quadrants? Just wondering what setups people have so far. I'll go to
Aircraft spruce tomorrow and look for parts.

I forgot to post my setup before.

ECM: MegaSquirt MS3 Injectors: 4 x RX8 yellow (moddifed to flow
820cc/min each) Fuel Pump: 2 x Walbro GSL392 255LPH (primary and
backup) Coils: 4 x LS2 GM Yukon truck with heatsink Spark: NGK RE7C-L
& RE9B-T


Just need a nice PSRU on the front :)

- Matt Boiteau

Matt, get some RX8 coils those piston engine coils where designed to
spark half as often despite the heat sink.

Hang in there. Neil is working as fast as he can on the PSRU.

You might have to make a throttle lever. What kind of tools do you
have? Do the home/hardware  stores sell aluminum bar stock in Oz?

Go to Aircraft Spruce? I thought you were in Oz.

Paul Lamar


OR, If your cramped for space and don't have enough room for the slide
and related cable hardware this "Barrel Throttle" looks like it would
very effective. Its a very compact design the bearings wont bind during
high vacuum or high boost.

https://www.youtube.com/watch?v=LFHD57V7bRQ

Erik Wahlstrom

Keep it close to the rotor housing and the P-port will idle better.

Paul Lamar

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