87..91.. Gas which octane do you run?

[Teee-rible]

Just curious how many people run premium gas, does it make that much of a difference?

[az_amsoil]

I run reg...no problems

[Mikeomo]

I know that the owners manual says it's fine to run 87, but I run 91 anyway.

I've heard that there is no performance gain by running the higher octane, and no benefit to the engine or fuel systems, but the Teryx doesn't use much gas so the price difference is minimal. Since I have never heard a definitive answer on whether or not there is any benefit to running the higher octane, I use 91 just incase there is.

[DougS]

Higher octane is usually better when the timing is advanced (aftermarket CDI).

[dieselpowered]

I have always run 91, so I really have nothing to compare.

[Mikeomo]

Well, I have the Dynatek CDI, so I guess it is better that I put 91... Do you know why it is better to put 91 with an aftermarket CDI?

[Hambone]

There is no performance gain in running 91 octane if the engine is stock.

[Mikeomo]

This thread is the perfect example of why I put 91. Some say premium provides some sort of benefit (not necessarily HP) regardless of the makeup of the engine, some say it provides a benefit only under certain qualifications (such as a Teryx w/ an aftermarket CDI, or significant other mods), and some say no benefit at all... But NOBODY says there is harm done by putting 91. So, I'll play it safe and keep putting premium in the tank. I'm far from affulent, but I can afford the extra $1 per tank that it costs

Hopefully someday I will run across the black & white answer to this question!

[Hambone]

High octane gas burns slower than lower octanes.

Why do we need high octane and low octane fuel?

Octane requirements go up when compression is raised or when spark is advanced in order to reduce detonation. This is normally the case with high performance engines

When compression is lowered, the octane requirement goes down too. Your stock Teryx engine is not what would be considered a high performance engine.

In fact, you are wasting your money by using 91 octane and quite possibly reducing power output.

Lastly, the black and white answer is on pages 40 and 41 of your owner's manual.

[Mikeomo]

Well, the owners manual is not a black & white answer. If you listen to the owners manual on everything you will not take the Teryx out to play because it might roll over and kill you, and you won't make any performance mods to the Teryx because it might roll over and kill you, and you won't put seats in the bed and extend the roll cage because the Teryx might roll over and kill all of you... So, I don't consider the manual the black & white answer on much of anything (maintenance not withstanding). And I have read the manual cover to cover.

Thank you for your tutorial on what the differences are between the higher octane levels, and how that may affect performance, that was informative.