[Cortina-list] We're getting sloppy around here

Mister Lou enfohead at yahoo.com
Sat Jan 14 15:35:31 UTC 2012


This is good off-topic fodder. Not sure why so many smart folks are into Cortinas?

lou weinert 
415.601.6744
www.misterlou.com

On Jan 14, 2012, at 6:29 AM, "Peter Pentz" <peter.pentz at gmail.com> wrote:

> Norm,
> Bryan beat me to it - you are dead wrong on this !  Octane rating is a measure of the fuels point of detonation at certain pressures and temperatures, and has absolutely nothing to do with the calorific value of the fuel, or the flame spread speed. The latter is based on the mix of hydrocarbons in the fuel.
> Peter
> 
> -----Original Message----- From: Bryan Engquist
> Sent: Friday, January 13, 2012 2:46 PM
> To: cortina-list at lotus-cortina.com
> Subject: Re: [Cortina-list] We're getting sloppy around here
> 
> I think we have discovered "Team Blitz's" Blitz on Engine terms and
> terminology!
> 
> I was going to write up a "Lesson in Octane Ratings", but I decided to just
> say, No Blitz, you are wrong, do your homework, go here for a quick
> reference and lesson:
> http://en.wikipedia.org/wiki/Octane_rating#Effects_of_octane_rating
> 
> If you have any questions, I can answer for you. But in short, as you will
> hopefully read and understand, the higher the Octane number (Octane only
> goes to 100, high than that has other additives) the less an engine is
> likely to knock, or pre-combust which is why it is important for race
> engines / engines with high compression. The higher your compression etc ,
> the more likely you are to have pre-combustion which is a knock. You can
> fix that with timing....but there is a point at which that is bad..
> 
> A snippet in case you don't go read the whole lesson so you know the
> correct answer: "A common misconception is that power output or fuel
> efficiency can be improved by burning fuel of higher octane than that
> specified by the engine manufacturer. The power output of an engine depends
> in part on the energy density of the fuel being burnt. Fuels of different
> octane ratings may have similar densities, but because switching to a
> higher octane fuel does not add more hydrocarbon content or oxygen, the
> engine cannot develop more power."
> 
> "Higher octane ratings correlate to higher activation
> energies<http://en.wikipedia.org/wiki/Activation_energy>:
> This being the amount of applied energy required to initiate combustion.
> Since higher octane fuels have higher activation energy requirements, it is
> less likely that a given compression will cause uncontrolled ignition,
> otherwise known as autoignition or detonation.
> 
> *It might seem odd that fuels with higher octane ratings are used in more
> powerful engines, since such fuels ignite less easily. However, detonation
> is undesirable in a spark ignition engine, and is signified by audible
> "pinging" or in more extreme cases "knock"."*
> 
> 
> I suppose it could be worse, talking about Football or Nascrap or something
> 
> 
>> Message: 5
>> Date: Fri, 13 Jan 2012 13:04:24 -0500
>> From: "Team Blitz" <blitz at teamblitz.com>
>> Subject: Re: [Cortina-list] We're getting sloppy around here
>> To: cortina-list at lotus-cortina.com
>> Message-ID:
>>       <901880563c8afcc12490314d160fd8c4.squirrel at host155.hostmonster.com>
>> Content-Type: text/plain;charset=iso-8859-1
>> 
>> Bryan, exactly wrong.
>> 
>> 
>> 
>> 
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