Dougnuts
Well-known member
Huh. I never knew about the +91 octane boosting HP / Torque numbers. Most stations around here carry 87, 89 then it jumps to +93/+94. I'll have to try filing up with +93/+94 next time I'm headed out towing our trailer and see if I can notice any difference in torque when towing.
Low (engine) speed, high load, is where the differences are really felt. Lots of people don't know that is where pre-ignition is the hardest to control. Everyone focuses on peak power output, but low and mid-range torque increases are what you will feel, and the areas where timing is often pulled the most.
In my 2018 3.5TT, the difference in low RPM throttle tip-in between 87 and 93 felt nearly as big as eco mode vs. normal mode. I ran premium in it probably 90% of the time. I'd have to go back and check to verify, but I'm pretty sure I got about 5% better fuel economy too.
For my new '23 (also a 3.5TT w/ 3.55 gears), I may not run premium in the winter or spring, but in the warmer months and when laden, I will certainly run 91+.
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