Premium fuel a benefit?

[Ars Gladius]

The owners manual (for my 2004) says:

Octane rating: Volvo engines are designed for optimum performance on unleaded premium gasoline with an octane rating AKI of 91, or above. AKI (ANTI KNOCK INDEX) is an average of the Research Octane Number, RON, and the Motor Octane Number, MON. (RON + MON/2). The minimum octane requirement is AKI 87 (RON 91).

So optimum performance with 91 or above but anything from 87 up is fine, is how I read that.

http://www.volvoxc.com/forums/showpo...84&postcount=4

[wsp310]

I've found that if I use non-ethanol mixed fuel my mileage increases and shows a net savings in cost per mile. We have 87 octaine with 10% ethanol mix here and in my 2002 suburban I averaged 12.5 mph over the year based on a mix of city/highway driving. It was driving me nuts. I started using non-ethanol blended fuel in either 89 or 91 octaine and found mileage increased a few mpg. From everything I've read, and I'm no scientist, ethanol blended fuels have less energy than non blended fuels. So it's safe to assume that with more energy, less is needed to go same distance. I found that I paid more and the initial cost is daunting ($138.00 at last fill) but when the higher mileage was figured in, my cost per mile decreased between $.03 and $.05 per mile using non blended fuels. I am still able to purchase either 89 or 93 octaine at the same place nearby. Only their 87 is blended at 10%.

I don't buy into the whole ethanol blended sales pitch since it's pushed so hard by those who have created a market for it and some strong lobying on the part of the market.

We have started using non blended fuel on our 2002 XC too with a noticible increase in power and smoothness while starting out. Checking on the mileage still since with the XC we have so many varibles such as how many kids, stuff in the back and what's on the roof. I think there will be an increase but not as dramatic a percentage as I saw with my Suburban. The only real changes in the Suburban was if I had the dog in the back and which way the wind was blowing I guess.

As far as blended fuels, I wish they would have allowed the market to set the standard rather than have it driven by legislation. I don't think it's the same as when we switched from regular to unleaded. Seems that with less energy available to the engine, less mpg, I use more gas and create more exhaust, sending more to the tail pipe. Can't say I've sniffed the back since the change.