Perry, just wondering if you know fuel burn at full throttle. If
the engine
is tuned well (good Ve), it can burn double the fuel rate you
mentioned at
5000 - 5300 at full throttle. I'm assuming that you are well below
WOT at
5300?
Tracy Crook
No I don't, I guess that's where a fuel flow monitor be a nice thing
to
have. No, not well below WOT at 5300.
WOT was 5500 before the recent mods, down to about 5400 now. The mods
are going well to shorten the runners, so we'll see if I can get some
of
that back. I mainly want the power back for climb. Climb RPM at 90
knots decreased from 5200 to 5100 and it is noticable.
--
Perry Mick
Tracy I might add that Perry is using the stock computer and mass
airflow
sensor so he has no direct control over the mixture in case you were
thinking
of an conventional aircraft system. Is that still correct Perry?
Paul Lamar
Yes it's true, I have a fake FADEC. Also, if the engine was capable of
large fuel consumption, wouldn't that also indicate it would be capable
of high HP output? My engine just isn't putting out that much HP. If I
did the calcs right 6.5 gph is 87 HP and 7.5 gph is 100 HP. If my
engine is capable of 120 HP max, that would be a max burn rate of 9 gph
- consistent with observations.
If it was actually burning double-rate WOT, 15 gph --> 200 HP, that's
not what I'm experiencing!
Perry Mick
I think your BSFC estimates are optomistic at best power mixture but you do
see where I'm going with this.
I think that either the Mazda ECU is giving you a much leaner mixture than
best power or you are not getting good volumetric efficiency due to manifold
or maybe both conditions are true. A mixture monitor would tell you a lot.
Have one? It should work OK on your existing O2 sensor. Sounds like the
ECU is giving you best economy mixture all the time.
I suspect the 28" intake runners are killing you. Can't wait to hear the
results of trying a shorter one (16 - 17" sounds right to me).
Tracy Crook
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