[Diy_efi] RE: Diy_efi digest, Vol 1 #413 - 12 msgs

[Adam Wade]

--- Dave Dahlgren <ddahlgren at snet.net> wrote:

> Most of the tuning I do is on pretty conventional
> water brake dyno and they are computer controlled so
> will hold any programed speed until the engine
> breaks or runs out of fuel LOL..

A water brake dyno should be controllable in much the
same way an eddy current dyno is...  I would think,
based on my understanding, that a water brake would be
a better choice for larger, higher-horsepower
machines, and eddy current for the opposite (just in
terms of space required, ease of construction, power
handled, etc.).

> What is the analyzer of choice

You know, I am not entirely certain where the
analyzers are sourced from (4- or 5-gas are available
from the manufacturer for which I used to work, but a
4-gas is used by them for their development work), but
I could probably find out if you wanted one, or they
could supply one (I'm not sure I could definitely pry
the info out of them!  :D  ).

> and where is there some good reading on what it will
> do and what readings indicate what conditions? I.E.
> timing retarded or over advanced etc..

Actually, I've never seen it documented.  :(  One
thing I can tell you is that there will be variations
in what "ideal" is based on cam profile, tract
lengths, combustion chamber shape, atomization, and on
and on...  My experience has been that there are
TRENDS you can see in how things change based on
changes you make, so you can tell what direction you
are going in, and once you play around a little bit
and find "ideal" gas output for a given engine, then
you can use that information as a target on other
load/speed sites.  It won't be exact on every
load/speed site, of course, but will get you very
close...  Much like a WBO2 sensor will, but it will
allow you to see things like even fueling of
multi-cylinder engines and ignition timing, as well as
straight mixture.  Again, thus is my own experience,
and not etched in stone for all applications.

I can give you a few people to talk to if you want to
get some ideas about trenads and what to look for in
terms of diagnosing particular issues.  I *wish* they
would write it all down.  Once I am done with the
three books I have in the pipeline, I may sit down
with them and ghost-write a book on that subject
(although beyond this mailing list, I'm not sure how
many sales I could expect!  ;)

> other question I do a fair amount of tuning on the
> road.. how big is it becomes the next question a
> well. Not an argument for or against but size does
> matter.

How big is the analyzer?  The acutal unit is smaller
than a micro-ATX board in a matching case.  There are
a few pumps and so forth, filters, that would make a
package that could comfortably sit about a foot tall
in the passenger seat of a standard car.  For best
effect, you'd need to route the probe through a hole
in the firewall and get exhaust gas readings right
after the manifold (via an exhaust port).

=====
| Adam Wade                       1990 Kwak Zephyr 550 (Daphne) |
|   http://y42.photos.yahoo.com/bc/espresso_doppio/lst?.dir=/   |
| "It was like an emergency ward after a great catastrophe; it  |
|   didn't matter what race or class the victims belonged to.   |
|  They were all given the same miracle drug, which was coffee. |
|   The catastrophe in this case, of course, was that the sun   |
|     had come up again."                    -Kurt Vonnegut     |

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