Regular vs Mid Grade vs High Test

Dengine said:

It is the minimum octane recommended. But the fact is the engine pulls less timing and makes more power on 93 vs 87, even on the stock tune.

Click to expand...

Everything I have ever read contradicts this. Where are you finding tests that show higher octane in a standard, non-tuned engine, increases output?

I know the opposite is true, in that an engine designed for premium will retard timing slightly to prevent knock when standard grades of fuel are used ... but not the other way around. I'm curious to see which tests you found to support your point.

fzr100098 said:

Well documented, believe it was Hondata

Click to expand...

I couldn’t find anything there that referred to a standard tune engine. Here's an interesting comment on Quora that basically mirrors everything else I've read.

fzr100098 said:

There are several dyno threads that prove the case e.g.

2.0 MT 87-91 octane test dyno

As promised: We ran down the 87 in our first tank of fuel and filled with 91. There was a little mixing, so it was not 100% 91, but it was a lot better than before. Roughly, you are looking at 9 HP and 11 lb-ft torque above 4000 rpm. But there is another way to measure what the computer is...

www.driveaccord.net

Click to expand...

That's interesting. Not sure why every other test I have read comes up with completely different conclusions. My own “seat of the pants” testing shows no improvement that I can feel, but not sure a 3-4% measured improvement could be felt.