Setting mixture with Nitrous

[Todd King]

  <<<
  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