Originally Posted by seanbeckaroo
Not true; I tow on a 87 performance tune, and simply run 89 octane while towing. I've even towed on 93 performance tune with no knocking.
Well first off an 87 tune is more of a regular tune, not a performance tune. And if you are using 89 octane with an 87 tune you are essentially counter acting the problem with higher octane gas. Which makes sense, that's the right thing to do.
There's also more that plays into it though. What kind of weight are you towing? Is it only on flat land or are there hills/mountains? That significantly changes the load on your truck and the amount of potential knock at different tune levels with different octane fuels.