[Diy_efi] WB free air calibration

[Mark Williams]

Dammit man... you need to take a chill pill.
Ive only been on this list for a month or so, and im already tired of reading your "i-know-all" attitude replies.
I would HATE to work with you... always criticizing everyone.

This is a DIY list... poeple dont come here to get attacked by you for making mistakes.

I think you need to get off the EFI-DIY list and get on the EFI-I-KNOW-ALL list.

> >From you testing of many diy-WB circuits, what has been your observed AFR
> >error rate?  You quote percentages, but I am wondering how much is
> >conjecture compared with scientific experimentation?
> 
> OK, since you asked (thank you thank you), I'll tell ya. We have two
> 'dweeb-WB' circuits here we use for demos for those customers that have heard
> of it, and ask questions. Yeah, I guess we 'violated the so-called user
> agreement' to built them, so...umm, sue me. :)  One using the original board
> we got from Bob V. & kit from Steve C., and one from Peter G. in Oz which we
> bought assembled, again to avoid suggestions that one or t'other weren't
> built correctly. Friends on this very list handled the buying of them for us,
> so we could do our research quietly. 
> 
> They BOTH function exactly the same, since they're essentially carbons of
> each other. Of course, neither works properly until you get up to ALT output
> voltages, so they both expose the sensor to late warmup, and from sensor to
> sensor, they each may take from 30secs to a couple minutes to NEVER, for the
> sensor's heater to warm up properly, once the ALT is turning. Depends on the
> sensor. The heater resistances especially vary alot, the heater control in
> the dweeb-O2 is also just simply WRONG.  Wrong method for ramping up the
> temps, not ever recommended by NTK, and wrong/no method for maintaining a
> controlled temperature. Consult the original SAE article by NTK or just
> observe with a scope how any NTK or Horiba box heats up the sensor, if you
> want to see how it's supposed to be done. These dweeb-O2 guys apparently
> didn't even bother to look to see how it was done correctly by everyone else.
> 
> I've run around 60+ different sensors now thru BOTH of these devices since
> they were built/obtained, on our full-sweep gas calibration bench and in
> client & test vehicles, mainly to avoid suggestions that something 'just must
> be broken' with one or the other. On our main test vehicles, the exhaust
> systems have MANY O2 and EGT bungs in every imaginable location.
> 
> The errors with these two 'dweebs' using this large a spread of sensors are
> HUGE. Sometimes as much as 1.5AFR, and that's ignoring EBP errors.  Partly
> due to the fact that the Cal R circuitry is just plain WRONG in the design
> (which is why the free-air values are all over the place), and partly due to
> the fact that the pump control circuitry used causes a hysteresis effect
> whenever you quickly go rich or lean across stoich, which throws the
> transient results especially off by as much as 1AFR.  Yes, one whole AFR. I
> have it on good authority that the dweed-O2 Cal R circuitry was
> 'reverse-engineered' based on measuring just TWO sensors.  Yuh, good plan. I
> could quote the person involved, who didn't know he was communicating with us
> at the time, but I wouldn't want to embarrass him. :)  I even have drawings
> and explanatory notes; we do our intel homework.
> 
> Oh, and if anyone questions the use of our gas calibration bench, let me just
> tell you that we have a Horiba and two NTK blue-boxs here also, that we run
> along side in our test chamber with EVERY calibration, just in case. Next
> month we spend the big bucks for a Bosch LA-3, just for the purpose of
> demonstrating to clients that we know how to measure AFRs correctly along
> with the big high$$ boys.
> 
> Our full-sweep calibration bench allows us to sweep the full range of mixture
> sample gas concentrations from less than 10AFR all the way to free air. This
> way, we can measure & compare entire calibration CURVES for each sensor, not
> just a few selected points. During this sweep, we can also vary the exhaust
> back pressure by as much as 5 ATM if needed (tho we normally only go up to 3
> ATM absolute, unless you're one of those crazy tractor drivers). This is how
> we can offer a full-gas calibration and EBP calibration on our sensors.
> Consider the expense we've gone to, in order to offer this level of QA.
> AFAIK, only Bosch and Horiba offer this level of support, and then only to
> select customers.
> 
> >Oh and please don't use my questions or comments as a springboard for
> >personal attacks on others.
> 
> Gee Rob, no, wouldn't think of it. I'm not attacking the person, just their
> trash. Yeah, attacking the person spreading their trash would be, umm, un-PC.
> 
> Gar
> 
> BTW, to illustrate a simple contrast, here's some specs for you data hogs:
> our EGORmeters will operate on power down to 8V, FJO 12V, ECMs & NTKs require
> 11V or better (same design), Horiba's 10V, and the Bosch LA-3 big daddy ($$$)
> will actually run OK all the way down to 6V power!  'Dweeb-O2' requires 14+V
> to operate, and will NOT operate on even a fully charged +Batt w/o the ALT
> running, so it won't even begin to warm up the sensor until the exhaust is
> already flowing. What's wrong with this picture?
> 
> 
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> Diy_efi at diy-efi.org http://www.diy-efi.org/mailman/listinfo/diy_efi

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