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

[Adam Wade]

--- Erik Jacobs <emj14 at columbia.edu> wrote:

> a) how much is a four gas analyzer?

A tremendous amount of money.  The O2 sensor is truly
more than enough for most people.

> b) is they a diy_fga list or something?

Well, if you want to put it that way, this isn't the
diy_wb list, either.  I was simply replying to a
comment that the WBO2 was "fooled" into seeing rich or
lean based on changes in ignition timing.

> c) why do most tuning places seem to use wbo2 over
> fga?

Couldn't tell you.  I can tell you that in my
experience, the ones that use inertial dynos and O2
sensors for highly-responsive motors always get worse
results than places that use eddy current dynos and
four-gas analyzers (having worked with and for both at
the racetrack, and retuned bikes going both
directions).

> price? ease of use??

An eddy current with a four-gas is as easy to use as
an inertial with an O2 sensor, so price may be a
factor, although the price difference is pretty small
as a ratio to the overall investment in hardware.

> Can't you figure out if timing is optimal by EGT to
> a certain degree? (i havent been following the
> thread)

Not as far as I have been able to determine.  In fact,
inertial dynos don't have the precision to see small
changes in timing or fueling, but lap times tell no
lies...  And they match the results I've gotten with
an eddy current and a four-gas.

In any case, I was merely pointing out that with a
four-gas, you can tune for optimal timing based on
exhaust gases, and all you need to do is hold the
vehicle steady-state at a given load to do so.  An
eddy current dyno happens to be the easiest way I have
found to obtain that.

=====
| 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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