Paul Yaw wrote:
Tracy Crook wrote:
snips
I have measured the saturation time on the Mazda coils and verified
that they can maintain full energy up to about 7000 rpm which is why I think
they work fine for aircraft use.
No kidding! Learn something new every day. I found out just recently
in my daily driver that with an MSD to direct fire, I get better results
with the stock coil than with anything else. That is really pretty
impressive. Is that due to the electronics involved, or is that due to
the coil itself? I noticed that the primary resistance was only .3
ohms. The lowest that I have measured.
snips
Keep in mind that my reply was addressed to someone thinking that a magneto
would be an improvement. I would take an MSD system over a mag ANY day.
I don't know ANYTHING about magnetos aside from the fact that nobody
uses them on a racing engine.
I have not seen any reason not to believe you Paul. I'm sure there is a
measurable difference and I would be very interested to hear what that
difference is. I have not personally tried the MSD system so of course I
can't say for a fact but I'm guessing that if that is the ONLY change
(compared to the stock 86 - 92 system) there would not be a "world of
difference" at 6500 rpm.
I guess that is a relative term. For instance, the increase in
horsepower that you feel in your car between the heat of the day, and a
cool night FEELS like a world of difference. In fact, it is only 2 to
3% tops.
> BUT, my point is that the average airplane builder assumes
that Mazda didn't know what they were doing in way too many things. Case in
point -- replacing the stock coils on the 86 - 92 13B with mags. Pardon
the expression, but trust me on this Paul, your knowledge of the Mazda
rotary (and engines in general) is NOT represenative of the average airplane
builder. It's OK to change something the factory did, I'm just saying that
we need to understand the relavent facts before doing so.
Good point.
Just repeating a number thrown about here on this newsletter. I really know
nothing about the Racing Beat engine.
I was curious about that and a few other things so I called Mederer and
wasted some of his time. He said it was not going to spin over 7500.
That is VERY impressive, and he uses the same data acquisition system
that I do, so I believe his quotes. Most are not believable.
snips
Again, I was addressing the "average airplane builder". I know because I
once went on that quest (in a previous airplane, not rotary powered) and
busted myself up so bad I can no longer walk straight. A total of 6
different systems were tried. The CD system I installed (piece of shit (to
borrow a phrase) Delta Mark 10B) failed and I crashed. I did get a few
more static rpm using the CD system but the effect on aircraft performance
was not noticible (until it died anyway). A Dyno is a fine place to go on
that quest, an airplane is not.
Have I ever mentioned that airplanes scare me?
snips.
I also agree that boost places much higher
demands on ignition systems. BTW, I assume that direct fire inductive
system was the stock 86 - 92 system? I do not have much confidence in the
earlier system.
It was the system that SDS supplies with their unit. It uses stock GM
dual tower coils which I now realize are HORRIBLE. They actually fire
the plugs in series. No kidding! So much for proper coil polarity.
Only GM could come up with something like that. I'll bet that same GM
engineer did some moonlighting for Mazda, and added "That GM jingle" to
the second gen. RX-7
I forgot to take a floppy to work, and I was too lazy to drive and get
one. I will try to get to it tomorrow.
PY
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