Brow'ing Down

[Brian L Massey]

On Sat, 23 Oct 1999 10:45:26 -0400 "Bruce" <nacelp at bright.net> writes:
> 
> What sort of display are you using to see this *noise*.

Oscilloscope. It shows on my LED bar graph, but it's easier to pick out
on a scope trace. I can get rid of most of it with additional filtering
capacitance in the circuit, so it isn't much of a worry.

> Also, what state of tune is the car your looking at?.
> Race gas?.
> I'm working on some theories about gas, and any comments about it 
> are welcome, in ref to WBs.

No, just high oct unleaded for now. Recently converted engine from carb
to efi. Same effect noticed in carb, before converted, which was one
purpose for having two sensors. What I mean is, in Heywood and other
books, they talk about the cyl-to-cyl variations in combustion *and also*
firing-to-firing in each cyl . So I was hoping with the collector sensor
to also see the greater fueling variations due to the carb & wet
induction vrs. the improved port injection setup. You know, different
jugs seeing diff AFR. So I spent a lot of time the last month looking at
the AFR signal with the carb before conversion to efi. You can certainly
see the differences, but I'm also real sure someone could write a big
book on interpretation of afr signals. I notice that the highend Bosch
meters have a dial-in filtering capability, so you can choose just how
much filtering you want to do before you datalog. I might try doing this
with a bunch of filter caps and a rotary switch.

I would like to get to the point where I can be confident I'm seeing the
combustion variations and not just some artifact in the signal. BTW I
moved my injectors around to see if I could get any variation from them,
but they are matched pretty good. You *can* pick out the cylinder clear
as day, if you try swapping out a 24# inj for a 19# on one cyl (don't try
this under load, of course), if you trigger your scope on cyl #1 ignition
so the trace gets synced up properly. I did these tests at 2500rpm. I
resorted to using the scope instead of the logger, to make sure I wasn't
getting the noise from the logger itself, since it is also new. Next
thing I would like to try is a sensor per cyl, close by each exh port.
Maybe the 'noise' I'm seeing is an effect of the collector. Good thing
this is a 4-banger, otherwise I would need a second mortgage for all
these sensors. :)

Thanks again to the whole diy-WB team for such a great tool; we having
fun now! I am looking forward to more people sharing their results and
learning more about how to use it, and what more to learn about engines
and tuning from it.

[now, about the brow-beating :o]
> So it really wasn't a compliment?.
> Trouble with this international stuff, things can get lost in the
> translation.  You'd have thought this being a USA list of origin, 
> subers
> from other countries would at least try to present info., in a way, 
> that
> partipants would understand.   And here I thought it had something 
> to do
> with his site being copyrighted, and his disreguard for the WB 
> Users
> agreement.   So your saying that he doesn't like to have such 
> matters
> pointed out?

Dang, no Bruce, it wasn't really a compliment, unless you are using
high-brow-talk. Then the best insults are the ones you can't be called
on. :)  Yes, it had something to do with you calling him on the hypocrisy
of copyright notice on his own site, while him intentionally breaching
the WB EULA. Good one. High-brows hate to be found out and especially
called on their hyprocrisy. It's an assault against their main moral
crutch: denial. Notice the General responding to my ridicule by
pretending to take it as a joke. More denial. Perfectly consistent with
his MO.

He's too far away to be soundly trounced, so I guess we'll just have to
settle for ridicule.

BLM
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