Al Gietzen wrote:

We've done the first runs on my NA 20B on the dynamometer, and overall
the results so far are good.  In any case it is exciting.  You may
recall my custom induction and Tracy's EC2.

The engine starts right up; 3-4 seconds of cranking when cold; and
almost instantly when warm.  Runs so far have gotten up to 5000 rpm and
maximum MAP of 24.5".  EGT's are very close; max range of 45 F,
sometimes as close as 10F.  Runs smooth and seemingly strong, however we
have not yet done any higher power operation.  That is planned for
tomorrow.  Before we go do that I'm looking for input on a couple of
mysteries and haven't been able to reach Tracy

First is that the engine runs better on trailing plugs only than it does
on leading only.  Timing is right on according to Tracy's recommended
setting of 20 btdc at 5000 and <24".  Using the unshrouded NGK B9EGV
plugs at .025 gap.  Something not right about this, and it is probably
not good for optimum power.  Haven't played with timing yet, but would
guess it means it's too early.  One suggestion I've gotten is that
Tracy's system is setup for second generation, and that the plug
placement is different on the third generation housings - spaced further
and leading plug placed lower (later).  The implication is that the
timing is too early, and that firing them both at the same time is not
the best approach.  Is this true and would one of you experts care to
comment.

How about plug gap?  Could the unshrouded leading plug have trouble
igniting because of the amount of turbulence encountered in the rotary?

Anybody using the EC2 find that the staging may occur at more like 17"
rather than 15".  My primary and secondary injectors are not the same
flow rate so I expected some anomaly right at the 15" point, but it
seems smooth right through there, but at light loads and rpm over 3000 I
get some surging right at 17" MAP that I can't seem to adjust out.  I'll
put a voltmeter on the relay tomorrow to verify staging.

Oil and coolant flow rates look good.  Graphs of this and more later.

All Gietzen

Some pictures for the new people.

Paul Lamar
 
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