I am just wondering if it is recmended to use a higher octane fuel in hyrbids or not.
What is available here is either 90 or 95 octain, any recommendation?

 

to run on lower octane. I doubt you would see any difference except in your pocket when running higher octane. on the other hand if you retuned you engine you could get 20 to 30 extra hp but then your mileage and warranty would suffer. remember we have a total of 492 hp available and 160 hp is INSTANT (electric) learning the best throttle position for max acceleration (if thats your goal) is easy...and its not floored buy the way.

 

Thanks jet,
what octane do you use for your hybrid?
Does retunoig the engine have anything to do with the octane percentage, or you mean the 95 should give more hp output than 90?

 

What does your owners manual recommend?

Typically, the only reason to go to higher octane is if it's recommended by the manufacturer, and typically that would be necessary due to a higher compression ratio being used, where regular octane would cause pre-ignition.

Higher octane gasoline's main characteristic is that it is harder to ignite, more resistant to pre-ignition, ie: being ignited by glowing embers in the compression chamber in advance of the spark plug(s) firing. Higher compression engines are more prone to pre-ignition, temperatures get higher, the environment is more volatile/explosive, thus the need the higher octane, "colder" gas.

IMHO, gas stations have a wildly disproportionate quantity of higher octane pumps, considering the percentage of cars that actually require it. And an equivalant amount of nebulous hype surrounding the high octane offerings, to hint at (but not come out and state, because that would be dishonest) higher performance, better mileage, "cleaner" engines, etc.

 

Depending on the combustion chamber design and in chamber flow characteristics, higher octane can actually reduce your fuel economy. In chamber flow is a spinning or recirculation much like the figure scater on the ice spinning. The spinning is intended to mix any left over exhaust (internal EGR) and the incoming reactants of fuel and air.

As the piston compresses this spinning motion the angular momentum of the spinning trapped mass is almost conserved.

In more simple terms the spin RPM increases as the piston compresses the fuel, air, and internal EGR.

This increasing spin is just like blowing high velocity air on a fire. It greatly speeds up combustion and the heat release rate. Therefore any knock retarding higher octane may slow the heat release at the desired crankshaft angle for peak pressure. PV=nRT

So re-tuning your engine will now involve intake runner, port, chamber shape, piston top shape, valve angles, cam, and exhaust designs and timing.

You can still do it but it's more work.

 

Regular unleaded fuel is what is called for. 87 octane is pretty much standard in the States.

 

Thank you all for your input.
So I should go for the 90 octane in my case since it is lowest we have in Jordan.

Marty, does a lower octane means a lower quality gas for the engine where it would have more impurities compared to higher octane, which could harm the injectors?
I heard that Sometimes the engine check light lights up in regular tahoes due to gas quality is that possible?

 

in the U.S. we only have 85 octane in regular grade. mine runs just fine on that. BTW i ONLY use CHEVRON gas in all my cars as it has an injector cleaner that keeps everything happy. I have had NO fuel delivery problems for many years since I started using it.
Octane has nothing to do with quality its a thermal rating, any gas could have contaminates in it. I once strained jet fuel through cheese cloth in one of the former soviet states to strain out the excess dirt, twigs, rust and other contaminates.

 

Thanks jet for your feedback
much appreciated.

 

0arty and Jet thanks for your comments first class.