[LJF]

This is a kind of philosophical questions - what kind of gas do you buy?

In a PM discussion, we were comparing mpg, and it turns out that one local brand of gas gives lower mpg. Turns out that is because it is very low-sulfur/oxygenated, and is being touted as a better environmental choice.

From the gas website: "Reduces emissions by 10-20 percent...Use of Blue Planet® earth friendly gasoline is equivalent to removing 60,000 cars from the Twin Cities."

Well, that's good, and I expect quite a few of us are driving Insights because we are Treehuggers . But if that same gas is costing us mpg, what is the tradeoff?

And of course, being in the Midwest, we have 10% ethanol in all the gas. Good for emissions, local farmers, and foreign policy, bad for mpg. Another tradeoff. :?

And then there's the 89 versus 87 octane question. My Insight runs smoother on 89, and maybe gets a couple mpg better on it. But it is a more-refined product, so what are the upstream energy costs associated with making it? :?:

 

[Insightful Trekker]

Hi LJF seems you nead to read-up on gasoline and the differences there are several common misconceptions in your post.

Been extensively discussed is several older threads.

See:

any thoughts about Sunoco's 100 octane fuel?
http://www.insightcentral.net/forum/vie ... 10&start=0

and:

LAF questions
http://www.insightcentral.net/forum/vie ... php?t=4232

there are many others too.

Better MPG vs. lower economy and the overall balance of emissions is a very complex issue. I suspect it could fall either way depending on many specifics.

However, the politics of better MPG is too far removed from the purpose of this forum and almost always deteroiates into a purely political "debate". There are other forums on the Internet more approprate for such.

HTH!

 

[kapps]

Remember, higher octane fuel actually has less BTU's. For a car tuned to run on 87 octane, you won't see any benefit from increasing to 89 or 93. You might even loose mileage. You have to increase timing (or CR) in order to see the benefits of high octane.

 

[Insightful Trekker]

You have to increase timing <snip> in order to see the benefits of high octane.

Your right kapps. And the Insight does just this with its knock sensor.

But as the other 2 links I referenced above expand upon you won't see enough of an MPG increase to offest the cost difference.

Still, 93 is the gas for me.

 

[Kevin]

Octane aside, in Minnesota (and I'm sure in other states as well), we do get to deal with a triple whammy this time of year:

• 
  10% ethanol
  winter blend gas
  low sulfur/oxygenated brand at certain stations

All of these conspire together to reduce BTU's and overall MPG.

Only with the latter, can I make a decision as a consumer whether to buy it or not -- the rest is goverment mandated. Personally, I choose to buy higher sulfur blends of gasonline to get more bang for the buck; however, I would support a decision from above which forces me (along with everyone else) to buy only the low-sulfur stuff. OK, I can see how this could deteriorate into a political debate now

 

[Insightful Trekker]

Personally, I choose to buy higher sulfur blends of gasonline to get more bang for the buck; however, I would support a decision from above which forces me (along with everyone else) to buy only the low-sulfur stuff. OK, I can see how this could deteriorate into a political debate now

:?
Keep reading Kevin. Hi sulfur is not good for MPG nor LAF's (the Insight's primary O2 sensor $200+) or CAT's (exhaust system cataylist $1000+)

Ethanol has less bang for the buck (contains less heat energy so it _will_ yield lower MPG) but other than that no harm or damage can result. Added to a base octane gasoline it can be an octane enhancer, but AFAIK its usually blended in lower grade fuels to boost octane to the minimum standards.

 

[Kevin]

:?
Keep reading Kevin. Hi sulfur is not good for MPG nor LAF's (the Insight's primary O2 sensor $200+) or CAT's (exhaust system cataylist $1000+)

Very true... I didn't mean to imply that what made the stuff good was the *sulfur*. It just so happens the blend which is higher in sulfur is also less oxygenated, which to me translates to more choking (cough, cough) but better MPG.

 

[james]

Seems you're all leaving one thing out of your figuring: the extra gas burned (and time spent) driving out of your way to a particular gas station.

I generally fill up at the no-name station at the grocery story I go to: it's at the low end of the price range, and I don't need to drive more than about 50 feet to get to it.

 

[ElectricTroy]

Low-sulfur gasoline doesn't result in lower MPGs.

It's the *oxgenated* gasoline which results in lower MPGs (and poisoning out water with MTBE).

Low-sulfur == good for our air.

Oxygenated == bad for our water.

 

[trunkout]

I generally fill up at the no-name station at the grocery story I go to: it's at the low end of the price range, and I don't need to drive more than about 50 feet to get to it.

I could push the Insight to the Casey's gas station near my house, that sells 89 Ethanol, and I've used it since day one (16k) until today (110k).

No probs to report.