Quote:
Originally Posted by Gecko
Next update:
Out of curiosity, right before I got my baseline dyno, I started running premium gas. Of course, it takes 4-5 tanks before you'll see any difference - if there is one - but I've been on two road trips this month and am 15+ tanks of premium (91) into my experiment at this point. So...
My commute is 90% city, and I drive fairly aggressively.
Stock (combined) with BFG KO2s on 87 octane : 14.5 MPG
Stock (combined) with Yoko Geolandar G015 A/Ts on 87 octane: 15.5 MPG
Stock (combined) with Yoko Geolandar on 91 octane: 16.8 MPG
Stock highway with Yoko Geolandar G015 A/TS on 87 octane: 18.6 MPG
Stock highway with Yoko Geolandar G015 on 91 octane: 19.4 MPG
So, there is some real, measured improvement to MPG when you run premium. I've been keeping notes over the last 4 weeks, and the results above are represented to the best of my ability.
The butt-o-meter says there is a little extra oomph at the top end on premium, most notably for passing power.
|
Kudos to you for taking the time to log this data and share it with us.
I'd be curious to see this run again as I feel like this might be counter-intuitive.
Premise: the engine is tuned for 87-octane
Octane rating is directly related to its ability to resist detonation (pre-ignition or pinging).
So, unless the engine management system is intricate enough to advance timing to compensate for higher octane, I'd like to see the test ran again.
During your driving sessions, did you take note of the climate and elevation changes or were your routes more or less the same?
Based on your results, it would imply that running fuel with an even higher octane rating would produce more power. In normal boosted applications, this is ONLY true when coupled with increasing PSI because the fuel can now sustain increased pressures. However, simply running race gas without any other changes to compensate for the fuel would have non-beneficial results.
BTW - I'm merely striking up a conversation to get some heads thinking.