Turbo Rx8

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.

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

I hate to be so blunt about it but some of the things Tracy did
were down right dangerous. Using those four stroke coils was one of
them. He was an electrical engineer so he should have known better.
Every auto mechanic in the world knows that a four stroke engine
fires every OTHER revolution. A rotary fires EVERY revolution. If
you use those coils your going to heat the hell out of them!!! PLEASE
don't kill your self in a rotary.

Paul Lamar

I'm building a Tango in Flordia and live in Canada. Same as Alex M.

The ls2 truck coils are actually used in the rx8 car world
extensively. 2 race companies actually sell conversation kits to
change rx8 coils (which seem to have a history of failing after
25k-30k miles) to ls2 truck coils.

Setting a dwell of 3.5ms - 4.0ms seems to be key for the ls2 truck
coils. I can't confirm but I've read the stock ecu for stock rx8
coils is 3ms.

Anyways. At 9000rpm we have 150hz which is 6.66ms a revolution we
have an spark event per coil. Enough time for ls2 truck coils.

I'm not sure if tracey used ls1 coils back in the day? The ls2 truck
coils are far superior and have a heatsink for blast tubes.

I do have an oscilloscope, but I can't run the engine up to higher
rpm until I have a "load" upfront. And throttle lever. And radiator
hooked up.

- Matt Boiteau

That was the early RX8 coils. I had a set and they overheated.
That was way back in 2004. The RX8 coils sold now are 2nd generation.
There have been amazing advances in electronic switches in
just the last 5 years. The technology was steadily improving
since 2004 and is still improving.

Most mechanics, racing or otherwise, don't have the foggiest notion
of how coils really work. Yes you have 6.66 ms per revolution and
the coil dwell is only 4 ms.

BUT the time for a FOUR stroke for one revolution is 13.32 ms !!!!!

That is a duty cycle of only 30% for a 4 stroke engine.

You put them on an RX8 engine and the duty cycle is now
60% or double the duty cycle. The RX8 coils ARE designed
for that duty cycle. They only cost $26 dollars US the last time
I checked. Rock Auto

As far as I am concerned the rule still applies now and into
the future. Use a CD ignition system on Wankel and 2 strokes
and any damn coils you damn well want to.

Tracy failed some of the early GM coils and switched to the truck
versions with heat sinks. The heat sinks are a clue about the problem.

I discussed it then on the news letter. Tracy built a CD system
of his own design (I think) a while back years before then.

It failed on 2 stroke ultra light he was flying and it crashed
permanently injuring one of his legs. He would not even consider
a CD system at the time. Since then MSD has sold millions of CD systems.

There have probably been a billion motor bikes and out
board motors with CD systems built and sold. They are super simple and
would work great on a Wankel.

You don't need the stater on the e-shaft. A 12 volt battery and alternator work just as well.

Think it over.

Paul Lamar

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