Fuel Econ and Hiway Mode

[Len Sabatine]

>  Detonation , Lean Mixtures and N Ox   are all part of an undesirable 
> fuel , ignition
     EVENT.
   Disconnect the EGR on a  "On the Fence" tune combination , Part throttle 
cruise
   detonation and NO x ramp up substantially. Maybe,  GM didn't teach this 
in school,
   however that fact has been born out many times in real world operation.
   " Not having proper EGR can cause "Ping" , but it's purpose is NOT ping 
Supression."
  OK then , Define " Ping". Would you say it's  Uncontrolled Combustion" ? 
Can we agree
that the "Ping" is the mechanical "noise" as a result of the combustion of 
the low octane
portion of the chamber mix  igniting prematurely ?  Lastly ,  Factory 
School Instructors
don't always present this information in the same manner, so indicate many 
Top Gun
  Dealership Mechanics I've spoken with.  EGR feed is a mechanism to LOWER
Combustion Temperatures, So Does Higher Octane Fuel , for One Fix. Space  here
  doesn't afford a proper discussion of all the complexities of the subject.
  Len


><<  Exhaust Gas Recirculation is proportionately induced into the Intake
>  charge
>       to Reduce Detonation and Oxides of Nitrogen Emission levels. The key is
>       Supression of Detonation . Detonation is a great way to trim 15% power
>       output , damage cylinder walls , pistons , rings and rod bearings, to
>name
>       a few of the problems that are associated. EGR is kin to artificial
>Octane
>       in a pollution controlled combustion engine.
>       Len
>   >>
>I never knew that. I was instructed in GM school that EGR's sole purpose was
>to LOWER CC temps below 2500*. At that temp NOx is formed. Not having proper
>EGR can CAUSE ping, but its purpose is NOT ping suppression.
>
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Jim  (FA) Testa                                             TType86 on
>#BuickGN
>ASE Master Technician                                buick.fiendish.net:6667
>L1 Advanced Engine Performance                    NJ Lic MV Inspector
>jtesta1966 at aol.com                           NJ Lic Emission Repair Tech
>http://members.aol.com/jtesta1966/buick.htm
>Associate Sponsor, Buicks at Bristol (RCA/JTP)
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