Decided to tune for 91 as it's just easier to come by. I knew shell's 91 was the best to go with as they still claim there's no ethanol in it. I was running since I got my MS6. Did one long trip and was very surprised, like very surprised I was able to match my Mazda 3's fuel economy on a long highway trip. This car weighs around 500lbs more and have the drag of the awd system.
Anyway, shell was good to me. Ran well on my 91 tune (just a tweaked OTS map). I wanted to clean up my afr's as I saw they weren't as steady as I'd like. So I decided to just do a maf cal and check to see what my ltft was doing. They were out very slightly. So I made the corrections. Then I went to go do my WOT checks to check OL operation and adjust for OL. I had gotten gas the day before doing some logs, at shell.
Knock all over. Every one of my logs I did. Knock a low rpm. Then tons at around 5k. Was registering over 5. Ugh! (Wasn't a 'lean' condition to provoke it)
So after seeing those I went in and started reducing timing in those areas. Thought that might help at least enough to get a decent log. But even just gently driving around I'm getting knock up to about 3.
So today I decided to go to petro and get some 94. I've used 94 once or twice in past but saw that fuel consumption went up. I had to see if this would remove/reduce my knock. So as I'm leaving gas station I'm just watching KR on my AP going about 15km/h I hit over 1KR. Then after like 2 min of driving. Nothing.
So on my way home I do a quick 2nd gear pull and log it. Then another one just not up to redline. Come home and check both logs,,,, 0KR. Not one point of KR anywhere on either log.
I thought shell gas was good and have heard other people praise it. I'm actually thinking that maybe the particular station I get it from is just shit. Sucks for me because there's only 1 petro in town that sells 94 and it's on the other side of town.