Failed Califoria smog test.

But Bill, if one _needs_ high octane gas, they have a high performance engine. They need the octane to boost performance in a motor that can actually produce said performance.

High octane in a motor that does not need it is wasteful. Mostly, it wastes money. Indeed, there is a strong argument that high octane gas might actually boost the emissions because it hasn't been burned completely. I am not sure I buy into that particular argument, but it's out there. The bottom line, boosting octane is of little value when the motor does not demand the higher octane.

In my `62 Econoline? Hahahahoooo. That thing would slow down from 60MPH downhill, with the clutch in.

Seriously, why should a higher octane fuel have any positive effect on tailpipe emissions?

From Bill's response to your below answer Jeff, it's apparent he is still believing an Old Wive's Tale on what octane really does. From him having owned a gas station, I would have thought he would have had a good understanding of what octane does... apparently not.

Jerry

Jeff Strickland wrote:

In article , snipped-for-privacy@cox.net says... LW> That's the difference, it's a slower, more consistent, clean burn. Thats always been my thinking as well.

The higher the octane rating (octane is a unit of measurement, not a physical material) the less volatile the gas is. One reason to use a higher octane fuel is to reduce detonation ("knock") if your engine isn't running right.

I would tend to agree with the hypothesis that it may increase the emissions on an engine that was designed for a lower octane rating due to the slower and cooler burn.

-D