They’re just one sample... since I’m not measuring on a dyno it’s hard to measure without breaking the law... it’s hard to catch the numbers in 2nd gear

 

The ignition timing may be hard coded into the engine computer in which case raising the octane might make no difference unless there were already performance issues. What I mean by that is that if the designers at GM coded the maximum timing advance for 87 octane fuel then running a higher octane will have no difference. If however the timing was being dynamically retarded due to excessive knock (as sensed by the knock sensor) then a switch to higher octane fuel could allow the system to return to the maximum programmed timing advance.

If instead the maximum timing advance was programmed for 93 octane (or higher) then there will indeed be a difference switching from 87 to a higher octane fuel.
Someone must know which situation we have here and bone's experiment could lead us to the answer.

 

Hopefully after about 30 gallons of 87 I can have our answer... given how mild the timing curve is I would wager a guess it’s tuned, conservatively, for 87 octane... I guess that’s why a stock L61 only makes 140bhp lol

im betting that with upgraded manifolds (LE5 intake/ LSJ exhaust) and a good aggressive tune you could approach 200bhp...

its been told told that the Ecotec has heads that flow near what a Honda K series can, but thanks to GM’s restrictive manifolds and conservative tuning we ended up with an underperforming engine...

 

I would bet with more timing they would have to use egr to control nox. That is a trade I can live without, egr and all the cooler issues are one of my major issues at work. I had a big truck go into limp mode and barely make it back to the yard because an intake manifold pressure sensor was plugged with exhaust soot at 50k miles. These are on the newer twin turbo Maxforce 10 Diesels we have in our medium duty powerline construction trucks..

 

That’s a solid point about emissions, I’d now bet anything that’s why the timing curve sucks... given that I’m not concerned in the least about emissions I’d rather be able to advance the timing a few degrees... I do get 36* at cruise but at full throttle I want more

 

Wait

So the guy ecomodding the crap out of his Ion to use less gas doesn't give a crap about emissions?

That's not very nice to the environment overall, is it?

 

My never ending quest for better mileage has nothing to do with the environment, but rather the cost to operate the car...

 

Oh well
Goodbye
Although
I'll cry
Ain't that a shame
My tears fell like rain
Ain't that a shame
You're the one to blame......

 

So after running 87 for a while, the only thing I’ve noticed so far (other than cheaper fuel) is that engine load at idle has gone up around 1%, and it fluctuates more now... not sure why?