Date: Mon, 01 Feb 1999 20:47:40 -0800
From: Paul <rotaryeng@earthlink.net>
To: z <rotaryeng@earthlink.net>
Subject: Dynamic Chamber Intake manifolds & E-shaft ignition trigger.
Tracy Crook wrote:
Paul Yaw wrote:
snip
I AGREE with all of your statements about the
importance of velocity, and was quite happy to see you state that.
My
belief is that inlet velocity is THE MOST CRITICAL factor in
determining
the power output of an engine
snip
OK, I'm happy. Sounds like everyone is bored with this stuff so I'll
let
it go. I did think it was important to get consensus on the
significance of
intake velocity. If there is no agreement on this point then all
discussion about intake tuning is futile.
On the Eshaft trigger : It looks good Paul. Only suggestion now
is to
shift the 30 degree rotation holes so they don't line up with the
TDC
(actually 30 degrees before TDC) holes. The rotation holes don't need
to
be referenced to anything and the processor is happier when it doesn't
have
to handle the events at the same instant.
Tracy Crook rws@altavista.net
Just a couple of questions. Do you interrupt the processor once per
hole or are the thirty dgree holes pulseing a counter? Sounds like it.
That's a lot of interrupts at 6000 RPM 100 RPS 1200 interrupts
per second or once every 833 microseconds.. did I do that right?
That's a lot of interrupts. That's a lot of overhead.
I imagine the 30 degree holes are for determining RPM... is that
correct?
We can specify more if that would help. The interrupter ring on the
fifth wheel for the road test equipment had 50 holes per foot traveled.
We chemicaly machined it out of hard stainless steel. We used an edge
discriminator to get 100..two microsecond wide pulses per foot.
We used an external counter to determine RPM and read it when the
numbers came out right. (I.E. RPM) This scheme required minimal
processor overhead and gave much better resolution on RPM.
BTW I have been meaning to ask you this for quite some time.
Can your computer advance the ignition up to 50 degrees BTDC.....
at altitude and at low power? I think Klause is running his
up around there. One of his little go-fast secrets :-).
Sounds like not... if the the trigger holes are only 30 degrees
BTDC. Here is an opportunity to have more advance if needed.
I would not try it without a knock sensor however. Maybe on
the test stand.
Paul Lamar
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