Date:         Fri, 14 Mar 2003 11:25:31 -0800
Reply-To:     Mark Keller <kelphoto@SHAW.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Mark Keller <kelphoto@SHAW.CA>
Subject:      Re: Maximum engine power and Performance Chip disscussion
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David Brodbeck wrote:

> On Fri, 14 Mar 2003, Mark Keller wrote:
>
>
>
>> The Digifant Fuel system works largley by monitoring  input from the O2
>> sensor.  By monitoring the O2 sensor with an averaging multimeter you
>> can see the average fuel mixture theengine is actually getting. Because
>> the engine is constantly getting a little less and a little more than
>> this average, it probably isn't even producing the same power it could
>> if it got a constant mixture.
>>
>
>
>
> Another issue that you only lightly touched on is emissions.  Best
> emissions in a catalyst-equipped engine are obtained with a mixture that
> alternates between slightly rich and slightly lean, hovering around the
> mixture where the available fuel exactly matches the available oxygen.
>
> Best *power*, on the other hand, occurs with a mixture that is richer
> than that value.  Unfortunately, that results in a lot of unburned fuel
> (hydrocarbons) going out the exhaust, which is a no-no from a pollution
> standpoint.


Dave,

For  purposes of  theory, all mixtures above  O volts indicate unburnt
gas.  Real world value were  50 ppm unburnt hydrocarbons present at .5
volts were the readings on a 4 gas analyzer..  The .84 volts range is
150-200 ppm.  The Catalytic is in effect always burning off some fuel,
good for emissons.

Mark