Thanks
It does.
I don't use HPTuners, but I'm acquainted with it because the guy who does all my cal work sometimes uses it and sometimes uses other software which allows him to access tables HPT doesn't display. While he's done my HHR, I wasn't present when he did it so I don't know which app. he used. I just mailed him the controller and he programmed it. The last car we did together was an '01 Camaro. Initially we used HPT but after he was able to defeat the double-check summing, we switched to his other application that allowed access to additional tables. As I recall, that ECM simply used either the high-oct. or low-oct. spark tables. It did not "interpolate" between them.

I'd agree with that.
I've found that if the controller dials out a bunch of spark on the initial onset of detonation, you can "feel" a "hesitation" or a "jerkiness". Also, you run consistently with a lot of KR, coolant temp will rise a bit.

 

Many "botique" and medium-sized oil refiners, and even a few major refiners, will not be on that list.
It is because the testing necessary for that certification is very costly. Small refiners, like Red Line, choose not to certify because 1) the price is too high and 2) being certified makes regular changes in oil formulation to keep up with the latest technology in base stocks or additive pacakges impossible because, even big oil companies can't afford to recertify every time they change and oil blend.

Admittedly, this gives the appearance of risk to the consumer but really, the reputable small and "botique" refiners can be counted-upon to meet or exceed GM's standard. Red Line has been in business a long time. It wouldn't have remained sucessfull over the long haul, if it's products didn't meet or exceed those requirement.

That's a very brief explanation. A much more lengthy one was published a few years ago by Amszoil. It's located at http://www.performancemotoroil.com/A...Licensing.html
There are others, but in my experience, none has proven superior to Red Line, so...no...I can recommend any.
What you need to remember about 5W30s in relation to GM vehicles is: 1) The "mandate" to use 5W30 in engines subjected to most duty cycles is driven by fleet fuel economy numbers and 2) if your duty cycle includes frequent operation in temperatures below zero, then you may want to use a 5W30.

You're welcome. Glad to be of service.

 

It', my contention that the elevation where you drive should have a lot to do with engine knock and what fuel grade you choose.

Some of you drive at very high elevations ... and should be able to run on low octane?

I'm in the valley where the Yukon River is 2100 feet so that's the lowest I can be. I'll try low octane for just low power around town driving on the next fill up.

Bottom line is that if you drive near sea level you should probably use high octane - all just my thoughts.