Individual Cylinder AF Adjust, was: NTK wb-sensor price

[Greg Hermann]

>
>Option #1 would be enought for idle-testing.
>Option #2 wouldn't give me far more results than option 1 but
>at twice the price :(
>Option #3 is the best one. Full range readings, but at astronomical
>costs.
>
>So I'll take option #1.
>
>Thanx a lot,
>
>Marc
>
Marc--

For setting individual cylinder A/F ratio with Webers (DCOE's or IDA's)
there is a wonderfully accurate instrument which has been used for the
purpose for decades for doing the full range of the idle circuits.

It is known as the human ear.

It works incredibly well in conjunction with the idle mixture screws and a
screwdriver, all the way up to where the main circuits begin to cut in
(3500 to 4K rpm at no load if you are running reasonably large chokes). Of
course,, this assumes that the "tuner" understands how to phase the
position of the throttle blades with the transition ports.

For getting a handle on the main circuit mixture with such Webers, I would
suggest using a WBO2. Put a bung for the sensor in EACH header tube, and
work on the cylinders one at a time. Best not to lose track of the fact
that float level, the emulsion tube, the auxiliary venturi,, and the pump
jet are integrally important  to the shape of the mixture curve given by
the main circuit--in addition to the usual simple minded reliance on choke,
main jet and main air corrector jet.

If you have a properly built engine--consistent porting, equal length
headers, and accurately ground cams, etc., I doubt that you will find any
significant variation in A/F ratio from one cylinder to another. To quote
John Passini, "There are three secrets to Mssrs. Webers' success:
precision, precision, and precision!"

Greg



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