Well, I believe that we've all expressed and discussed our thoughts and experiences with different octanes for the 6.2L V8s.
What's REALLY important here, we discussed and shared our differences in opinions in an open and RESPECTFUL manner.
No harassing, no name calling, no personal insults, no Facebook/X BS nonsense.
That's just another reason why this Forum ROCKS!
I RESPECTFULLY beg to differ. The above is unfinished.
If one person says it's raining, and another says it ain't, eventually, somebody PLEASE go and check outside!
The respectful discussion is a worthy end in and of itself - but the truth is another equally worthy end.
I don't think those old computers had the ability to do that. We've only recently seen Toyota and Ram if memory serves do that with some of their vehicles.
I'm aware of the tables, sort of, I thought there was one for gas and one for E85 on the GMT900s.
To my way of thinking, there would have to be some kind of sensor to detect the octane rating of the fuel and then run the appropriate table.
Maybe they could've written a program to permanently pull timing if there was so much knock retard under such and such conditions and not reset until a refueling event was detected?
I would think that all that work would slow down the responsiveness of the system and possibly the engine's reaction to such changing conditions.
Just speculating, I'm no automotive software engineer ...
Since GMT800 - and I very strongly suspect since the '97 LS1, but have not personally witnessed-
those old pcms already had separate Low Octane & High Octane Spark Timing tables.
And I know the pcm interpolates between the two; I noticed the differences between copying
the Low Octane Table into the High VS the High Octane Table into the Low
A separate TEMPORARY knock compensation function disables use of the High Octane table,
and applies only to the Low Octane table, but it does not get 'learned' like a fuel trim.
Then there is another SEPARATE ethanol variable compensation table (which I saw but did NOT touch),
which requires a Flex Fuel Concentration / Composition sensor to operate properly.
As
@swathdiver stated above,
"Love my 6.2Ls, they put a smile on my face every time we get behind the wheel!".
That is exactly the way that I feel about my 6.2L.
I feel similarly about GM 6.2L V8s. Too bad so many of them have been damaged by GM's shortsighted 'goals' ...
