Setting mixture with Nitrous

[Matthew Lamari]

Problem here is in OZ you can still get high octane leaded at the pump,
whereas the same octane rating unleaded is unattainable.  Also, Australia
switched to unleaded much later, and one of the problems with using unleaded
in the older cars (Besides compression and timing) is valve lubrication.
Unless they had hardened alloy valve seats, a car built for leaded (up to
1985-ish) just cannot run on unleaded.

And, in Australia, buick GN sensors aren't really that common.  For sensors,
you'd probably want to stick to one type of heated sensor (to fit it to
exhaust easily).  For example, if you wanted to use, say, a Falcon sensor,
you'd either have to keep paying FoMoCo $100 Aus a pop, or find a plethora
of trashed EAs.

The lead situation is a real bummer for any sort of
emissions/no-leanout-self-destruction feedback, either for hand or computer
calibration.

Anyone who knows a way to get a decent mixture feedback with leaded petrol,
please let me know as well.


Matthew.

Matthew.


At 01:17 PM 8/15/96 PDT, you wrote:
>  <<<
>  From: David Crocombe <david at abc.GOV.AU> Date: Thu, 15 Aug 1996 16:43:49
+1000 
>  Subject: Setting Mixture with Nitrous
>  ***
>  What I've heard so far is that the oxygen sensors get ruined by the lead in 
>  leaded petrol; that maximum power (objective) is at a mixture of about
18:1 I 
>  think rather than the 14.7:1 for least emmissions.
>  >>>
>  
>  Yes, lead will ruin them after a period of time. Max power is obtained
>  around the 12.5:1 range (rich), at least for forced induction.
>  
>  <<<
>  All sensors I've heard mentioned work around this 14.7 mark. Are there
sensors 
>  for those of us who require maximum power regardless of emissions?
>  >>>
>  
>  Granted, the typical sensor is intended primarily for a "binary" (high/low)
>  type of application; but many people have demostrated that the sensor is
still
>  useful for setting WOT A/F. Most people shoot for a reading of 800-850mv at
>  WOT, assuming the sensor is ready to go (warm, operating OK, etc.) Of
>  course you must back up the readings with a best e.t. analysis as a drag
>  racer... and this is from the Buick GN (ie turbocharged) camp; N20 or
normally
>  apirated might deviate a bit.
>  
>  <<< Any information or ideas would be most welcome. >>>
>  
>  I would suggest using the sensor with a) tanks of high octane unleaded for
>  testing or b) go ahead and accept the loss of a few sensors and test with
>  the leaded fuel. They aren't really that costly (Buick GN sensors are about
>  $25 ea these days) and again, yes, I believe the EGO sensors can be very
>  useful for setting your best power mixture. Read them with a circuit that 
>  has high input impedance.
>  
>  Todd  Todd_King at ccm.co.intel.com
>
>