HC11 and prop

[jb24 at chrysler.com]

Tim,

 It may not be any use to you, but you can get a signal off the tach
output of the ignition ECU.
---------------------- Forwarded by John R Bucknell/JTE/Chrysler on
04/14/98 01:32 PM ---------------------------

        owner-diy_efi @ EFI332.ENG.OHIO-STATE.EDU
        04/10/98 05:04 PM
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Subject: HC11 and prop

Greetings!

I am laying out an HC11 board for use as a datalogger on a motorcycle
initially, and as a programmable ignition at some point down the road.
The ignition will use some sort of Hall effect sensor to determine crank
position.

I wanted to use a simple inductive pickup around a spark plug wire to
pick up an RPM signal. There are a couple of problems here. On our new
GSXR the coils are incorporated in the spark plug caps, so no plug wires
with the big inductive collapse. The coil/cap thing is new to
motorcycles but has been on cars for a while, I understand. Has anybody
figured out how to measure ignition pulses without splicing into an
ignition wire(something known to cause problems, at least with motorbike
digital ignitions), or resorting to building a box to split and amplify
ignition signals.What kind of noise precautions are necessary when
measuring inductive collapse? What effect do the other(three) plugs
have?

I could install a separate Hall effect sensor to read a camshaft bolt,
or use the stock sensor(mounted on the countershaft), but the question
intrigued me.

On an unrelated topic, the use of isopropyl alcohol as a fuel
additive/oxygenator has come to my attention. Does anybody know the
ratio, and what percentage jet increases would be necessary? We are an
endurance team looking for an edge, so any help would be greatly
appreciated.

Thanks in advance,

Tim Gooding
  Army of Darkness Racing
  Smithsonian Institution