Just curious as to what H3 owners habits are regarding fuel and what your thoughts are on how the different fuel grades affect the performance /mpg's of your ride. This isn't scientific just your opinion is fine. Go ahead and comment on a specific brand of gas that you may prefer but lets not get into a discussion on my brand is better then your brand. Thanks

I have heard some different methods like alternating between high and low octane, or using octane boosters once a month while using regular octane gas, etc..

Here in California we have watered downpee for gas:

Premium Octace 93
Special Octane 89
Regular Octane 87

So if you live in another state the octane level may be different so just go by the name.

 

Octane levels here in BC are simliar 87, 89, 92-94

 

This is tired old topic covered on many auto forums..but I always like to endulge this topic whenever it comes up..


For reference, the basic four stroke (4 Cycle engine works on this basic revolutionary principle..

Intake
Compression
Power
Exhaust

aka ..Suck, Squeeze, Bang, Blow


Octane is in simple terms..the ability of gasoline to burn...High octane is for High compression engines and of those that are timed with spark Advance well before Top Dead Center (TDC)...Hence, the need for slower burning fuel so as to not predetonate under the higher compression and then it will burn longer to follow through into the power stroke.

Low octane fuel is for modest to low compression engines with timing set closer to TDC..

Having said that..If you use High octane fuel in engines that are not tuned for it, is pissing away money for no more bang for the buck..In fact, it will become detrimental to your engine with continued use..as it burns too slow and eventually will carbon up the combustion chambers and increase the need for Higher octane as the compression ratio increases proportionately with carbon build up..

So if 87 Octane is what the engine was designed or tuned for as is the H3..then save your money and use that octane only...If you have your PCM retuned, then that means Alvin can adjust your octane tables and timing via a program interface....I had mine tuned for 89 octane.

 

Name me a topic that is not tired in an auto forum. LOL

I agree with most of your post on engines calling for or being tuned for a certain octane, I have also heard from people that when they use high octane (on occasion) they notice a marked difference in the way the engine runs, smoother idle, quicker acceleration. Is this just a placebo effect? or is the engine responding to the higher octance level?

 

I believe with all my heart and soul..those that think they've seen or felt a performance increase by using higher octane than needed,is experiencing the Placebo effect...

However, the PCM can adjust somewhat for lower octanes if you should run accross some camel **** that is watered down...but it cannot adjust for Higher octanes...The PCM is watching for predetonation (via sensors) as a result of lower octanes and retards the timing even more than optimum settings to compensate...That is the simple explaination...Perhaps Alvin or somebody that can look at the full spectrum of the performance range of the combustion process can go deeper with ambient intake air temps, MAF readings and a bunch of other inputted data from the engine, but that is just more confusing...and exceeds the needs for this discussion.


I haven't heard about peeps driving around naked too much..that topic ain't tired out yet...

 

Sometimes on high altitude trips I'll put in a tankpremium hoping for a little more boost from the higher octane gas.

It may just be a waste of $$ though?

 

Premium, since day one. Except, twice I tried the regular unleaded.

 

My PCM is tuned for all levels, but optimized for 93 Octane. There is a very noticable difference in performance using 93 over 87 when tuned properly for it, therefore I use 93. The engine is smoother, quieter, faster and idles smoother. To me it is worth the extra $100 a year it is for me to use 93 over 87.

 

Sounds like you like it a little rough there too Denny!

 

[:@]You people already