Knock Control reading high? Read on.

[gtman]

I started out running Hondata and now KTuner. With Hondata, K. Control was almost always at .54 (the lowest Hondata goes) running 93 octane Sunoco Ultra. If I did multiple WOT runs it might have shot up to as high as .70 but quickly came back down.

Fast forward 6 months later to KTuner. Using the same 93 octane Sunoco Ultra, from the same station, I struggled to keep it at .49 (KTuner's lowest). I couldn't understand it. Even a light jab of the throttle would send it to the .60 range and a single WOT run would have it in the low to high .70's. And it would take forever to drop down. I didn't understand why.

Then I read an article about gas stations and posted octane ratings. And that sometimes for a variety of reasons, the pump marked 93 might actually have a lower octane rating. Maybe this station I've been using has been fudging the numbers in recent times? So, I tried an experiment. I went to a different Sunoco station and filled up with 93 octane there. Hooked up my KTuner and kept my eye on K. Control. Almost the entire 45 minute test drive, it hovered around .49! I tried my best to push it. I went up a very long, steep hill and gave it 2/3 throttle. It went up to .55 and quickly dropped back to .49; merged onto the highway going WOT and K. Control quickly stabilized back down to .49.

It's pretty clear the station I had been going to was either knowingly lying about the octane or they've had shit batches of gas for months. I guess the moral of this post is to change stations if your K. Control seems higher than it should be for the posted octane.

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[dc2turbo]

you want to use a gas station that has high traffic. Sheetz/Wawa are good examples as they refill their tanks a lot.

 

[Micah]

Costco has never let me down for fuel quality. Wawa in NJ considers 92 as premium so I only go there for regular for my wifes SUV.

 

[kytos]

Heatsoaked intercooler and high ECT will cause higher knock control also, I'm get readings from 0.49 to 0.53 on hard pulls using 95RON (91AKI) and with mishimoto intercooler at 47ºF ambient temperature. Tho if I change gear at very high RPM knock control spikes to 0.65 sometimes.

 

[caspar21]

ktuner 23.5 and then tsp stage 1 tune.
winter here. iat 25C.
costco 91 octane.
knock control stays .49- .55 no matter how hard i push it.

make of that what you will.

 

[gtman]

I just finished reading an ABC news investigation of gas station scams. This part in particular was kind of upsetting...

But that's nothing compared to what the inspection team found in February. A laboratory test of gasoline taken from a local station as part of its annual inspection, showed that the 93 octane gas turned out to be 89 octane. Gardner said that maybe the station was scamming customers or maybe the gas supplier was scamming both the station and the customers. Either way, customers weren't getting what they were paying for.

This took place in NY where apparently they actually do have inspectors checking out gas stations. I wish all States would do that. Sort of like the way health inspectors do random checks of restaurants.

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