PLease help me get up to date/speed

[Jonathan R. Lusky]

robert dingli writes:
> 
> > 3.  Oxygens sensors:  Several years ago there were wide A/F range sensors 
> >     available for about $750 each.  Clearly,  the slick solution is to use 
> >     something like that.  Has the price come down enough so they are being used?
> >     A bolt on aftermarket that could build it's own table would make things 
> >     so much easier.
> >From what I've gatherd, there are at least two types of wide A/F EGO sensors.
> The NTK sensor which is useful for AFRs from 10 to 30:1 which costs close
> to Aus$900 and the wide band Bosch unit which is wide band only in the lean
> region and cost around Aus$250.  The Bosch unit operates as a voltage source
> as do normal EGO sensors.  I'm not sure how the NTK unit (nor the Japanese 
> UEGO sensors fitted to production cars) work.

I'm not familiar with the sensors that the Jap lean-burn stuff use.
I have used the NGK UEGO (it was US$1000 back then) though.  The useful
range is actually a Lambda range, the AFR range will depend on the fuel
you are using.  I was using the sensor with a Horiba MEXA-101L and it
worked GREAT for tuning!  It has two problems that I can think of for
feedback control use, though.  First, it's useful life is somewhere
around 200 hrs.  The second is that has to go through a 30 second
burnoff cycle each time you turn it on, so you can't just turn it on
when you get near WOT (I'm going by the Horiba owner's manual on this
one, someone please correct me if this isnt really necessary).  I have
heard of at least one person doing closed loop under transients with
the NGK's on marine race motors.

-- 
Jonathan R. Lusky                        lusky at knuth.mtsu.edu
http://www.mtsu.edu/~lusky/                 (615) 726-8700
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68 Camaro Convertible - 350 / TH350  \_/ 80 Toyota Celica - 20R / 5spd