Greetings, a newbies first post @ greenhybrid.... I suppose it could be coincidence but..... I accidentally put mid-grade (91 R/M octane at my station) in for the first time instead of my normal 89 octane. Only have 20-some miles on this tank but my mpg has gone from 38ish to 43ish over the same daily route! Still in the 'break-in' period on my '08 HCH (yes, I know modern vehicles generally don't require a true break in). Slightly warmer weather today (Wisconsin) could also have helped. Anyhoo, has anyone else had a similar experience? Will be interesting if I finish this tank at the higher mpg. Thanks much for your attention.

 

It probably was due to the weather more than the octane. I have very large swings in mpg's in differing weather conditions. People are going to say the higher octane doesn't make a difference but I have noticed myself the car is a little smoother with the higher octane but have not noticed more than like a 1mpg increase. Thus the ratio of price to benefit is not there (stick to a quality 87 octane) I don't post much but I have logged about 40k miles on my hybrid (purchased Aug 06) and I drive it more like a regular car. I have a lifetime mpg of 47.2.

 

I agree with bajer... It's more likely the unseasonally warm weather giving you the boost than the different gas. I typically feed mine 89, since that's what's in the pumps at the office, but when I'm on the road, I have seen no appreciable difference when I buy commercial 87 instead.

 

Interesting that your mid-grade at 91 octane is the best stuff we can get in the SF Bay Area. Our "cheap" stuff is 87 octane and the mid grade is 89. Sounds like you can't even get 87 where you live.

This raises another question, when national gas price surveys are conducted, are they comparing apples to apples when it comes to octance or is California gas even more over-priced then surveys indicate? If the least common octance demonimator across the country is 89, then that rasies the gas price by another .10/gal here.

-dan

 

Gas stations in Singapore offers 92, 95, 98 and some claimed to have octane close to 100. Crazy!!!

"WINTER" in Singapore is like 27 degrees C ( 81 degrees F ).

My first tank clocks 20.21 km /l ( 47.53 mpg ). 2nd tank at 20.64 km/l ( 48.54 mpg ). And I have been using the cheapest grade of them all as HONDA indicated that the engine could take 91 Octane or better.

I too agree with bager that ambient temperature has effects on mileage.

Now trying all kinds of HYPERMILING tricks to try to get better mileage.

 

http://en.wikipedia.org/wiki/Octane_...nal_variations

87 octane (N.America) = 91 RON (elsewhere)

 

The selling of mid grade gas and the octane rating (89 vs 91) has to do with the average altitude of the area.

 

I know the hybrid has a high compression motor. Does anyone know if the ECU is self learning? I know there are other high compression motors that Honda makes that require 91 octane. I am to cheap to try it out and I am sure the savings will be minimal if any based on today's price for a gallon of gas.

 

Higher octane gas in the HCH II 1.3 engine is just money wasted.
If you have enough money to spend an extra 10 or 20 cents a gallon on gas, give that money to charity, not the big oil companies.

Temperature makes most of the MPG differences, not octane. last wek it was in the 60's here last week - got 47 MPG. it is in the teens this week - 36 MPG.

FYI - your engine takes longer to warm up with higher octane gas as it has less energy ( that why it does not ping in higher compression engines ) - less energy - longer to heat up = poorer gas mileage. It is slightly better going up hills, if all you are going to do is go uphill for 400 straight miles ( where in the world can you find a road like that that has no downhill sections???), it would be better but only going uphill. Maybe 1% better. look up the BTU's for each grade of gas - interesting isn't it that the higher octane has less BTU's. But you can compress it more to get more useful energy conversion - less heat - more power = poorer MPG.

 

Maybe your 87 fuel has ethonal in it. H