MPG on 89 Octane

[a2jack]

Most of the stations in our area have replaced mid-grade 91 with 89 oc.. The next choice is 93 with a 30 cent increase. Our choices now are. 84-89-93.

So far only CITGO runs 91 as a mid-grade.

A2Jack.

[randyzimmer]

Finally went on a trip w/ the smart and did a couple tests.
I filled up with 94 Sunoco and watched the ignition timing readout on the scangauge.
At 70-80 it was usually 23-24 degrees and went up a couple hitting a hill or opening the throttle and then it dipped to 22 soon afterward.
Coming home I filled at a station I had never heard of (off-off brand) and bought their cheapest brew.
I saw no difference in the readings, it seemed for a while the timing was a degree higher(!) but that is not for sure. The timing with cheap gas should have dialed back not ahead and if anything it increased.
I started at 600 miles and ended at 1100.
I saw very few 40+mpg reads on the way out and many more on the return. I'm not claiming the gas had anything to do with that, I just figure the "break-in mileage improvement" has occurred.

So, if the knock sensor is doing anything to prevent pre-ignition with crap gas, I haven't witnessed it. (I drive fast but very rarely use full throttle on any car - full throttle figures are thereby, not reported here).

[SmartDigger]

The only way to find out which grade is best is to test tank by tank and see which gives you the best results. Every driver is differant and every car is differant.

[rrrucke]

Thanks for everyone sharing their gas info (especially with the math already calculated). For me, I happily put in premium because it's recommended and it's still half the price to fill up than my Acura TL. I'm still all smiles when I pass gas stations and when I fill up!

[Fredvon4]

Hummmm

Most are willing to pay MSRP for a car that nets the dealer 9%, the importer PAG some undisclosed XX%, the smart producer XX%, and parent company Mercedes XX%..... so we can assume the entire product caries at least a 15% profit in the consumer stream

and no one dares refer to PAG or Mercedes as evil thieving BIG CAR!

But have a legitimate energy business make an honest 6% profit on a commodity we all need, and they sure do get bashed and hated... hummmmm?

BIG OIL does not own the oil ...they buy it at market prices... normal speculators and investors own the oil... almost every body who has some mutual fund, 401, or other investments with some mix of commodities have a vested interest in energy costs... and PROFITS

[Big Panda]

Originally Posted by Orphan-Beggar

The consumer choices we make can have an impact-
I avoid Exxon/Mobil

....AND lets not forget "Citgo"!!

"BP" is pretty much the only station i use. have had no issues with the gas and it's convenient too. ;)

[race911]

As I posted over on a Porsche forum........you price your own businesses product or service (or your own labor) at below market prices?

Interesting to hear about all the capped wells being brought back into production (Wall Street Journal article specifically reported on Oil City PA) now that it's worth it to go back in an extract what's left. When it's no longer economically viable to produce, guess what, capped off again.

[canon1753]

I almost wonder if there isn't a lot of fuel quality stuff (oil, natural gas, coal liquifying processes, alcohols and so on) out there, which in the past was discounted by the amount of money it would take to get it out of the ground or where ever, and now that energy prices are up much higher it is economically feasible to use it.

But also alt energy is a good growth industry too. (also owned by energy and oil cos too- they always have a seat when the music stops...)

Sorry way OT

I suspect I'll keep it on 92-93-94 octane to keep the motor happy.

[Smartcarracer]

Originally Posted by stan1174

No disrespect to Smartcarracer but I decided to see how much one would save…

assuming one has a commute of 20 miles each way a day, so 40miles X 5days =200miles a week
+ 40miles for sun and 40miles for sat
total miles a week=280
at 35mpg, fuel used per week is 8 gallons

in los angeles, 91 octane is generally 10 cents more than 89 octane which is 10 cents more than regular 87 octane.

so assuming one uses 87 instead if 91, one saves $1.60 a week(20 cents X 8 gallons) so in a year, one saves $83($1.60 X 52 weeks)
if one uses 89 octane instead of 91 octane, one saves half that or $41.50

Personally saving $40 or $80 is not worth it for me to go against what is recommended by the manufacturer. I not a rich person but can't feel saving $80 per year. It’s a non issue.

Stan, I didn't take offense. Thanks for sharing your math.

Over in the Washington D.C. area I normally have the octane options of
87 for ($3.40)
, 89 for ($3.57)
, 93 for ($3.89)
(prices as of 4/8/2008)

For me .32 cents is the difference.

I use approximently ten gallons a week.

(10 * .32) = $3.20 a week saved

Per month = $12.80 (almost a half of tank)
Per year = $153.6 (three rounds of golf)

I will use 93 octane during the hot summer months but not until then.

Thanks for everyone's input.

[saronian]

Northern California seem to max out at 91.

Only choices I've found so far are 87-89-91.

Originally Posted by a2jack

Most of the stations in our area have replaced mid-grade 91 with 89 oc.. The next choice is 93 with a 30 cent increase. Our choices now are. 84-89-93.

So far only CITGO runs 91 as a mid-grade.

A2Jack.