A tank without Hypermiling

[chuckm]

I'm not sure how to react here. Here's the story. The fillup prior to this one was MUCH lower than I expected. My scangauge, which had been +/- 0.2mpg for the last several tanks, was showing ~46.5mpg. I had been busting it on my hypermiling techniques, including maintaining 55mph in a 65. I fill up at the same pump I had been using and recorded 44.8mpg. A bit frustrated (and not thinking that I may have just gotten my first taste of winter gas). I spent this last tank driving without using any hypermiling techniques at all. I was even driving 60 in the 55mph zones a good bit. So was did this tank come in at this morning? 42.5mpg. What the hell? Does that mean my hypermiling, on average, has only provided 2.5mpg?

In one sense, I feel good that my aeromods have provided me some very good improvements . On the other hand, I worked my butt off and only got 44.8mpg .

[Matt Herring]

Hey Chuck...I wouldn't get frustrated too much about your recent tank as there are many factors that can throw off a tank or result in lower than expected results. The thing you have to remember is while you don't think you were hypermiling on your last tank you probably actually were a little bit...enough to affect mpg compared to 3, 6 or 12 months ago tanks. You are programmed to hypermile and as much as you think you're driving like a bat out of hell compared to when you really try to hypermile...you're probably still hypermiling at some level.

As far as variables, winter gas is one for sure but small changes in driving style or road conditions could also do it. Lower ambient temps could also be a factor in final tank averages. Pump and fill error could also be the culprit.

I recently had four highway runs of 400 miles each and all without much hypermiling and got in the 53-56 mpg range. I did the same runs back in May and got about 50-52 mpg while hypermiling. While I'm sure my driving has improved in a new car since May I also chalk the improved numbers up to higher temps and better road conditions. Even though I was not "hypermiling" like I usually do I would expect I am also programmed to hypermile even when I think I'm not.

Hang in there...the good news is you are pulling close to 50% over EPA in your car!

[KJSatz]

Well, what did the scangauge say for this second tank?

It's conceivable that the first fill was an "overfill" and the second one was a correct fill or even an "underfill," which could throw off all kinds of numbers. Of course, if your scangauge value for the second tank was around 44-45mpg, then that seems less likely.

Further, I would guess that you did not in fact drive with no hypermiling techniques...even if you drove faster (and 60mph isn't really that fast in the scheme of things) and accelerated harder. You probably weren't on the gas and brakes all the time; you probably coasted a lot...that sort of thing.

[chuckm]

Hmm... You may be right. On this tank, my scanguage was showing 41.7mpg.

Regarding coasting, I consciously did not coast in the few places where I normally would. Certainly no coasting in neutral (auto tranny, so no EOC ).

[Matt Herring]

Potential disaster averted Chuck...numbers and stats are funny things with many variables that can skew them...come down off the roof my friend!

[chuckm]

Damn... Looking at my tanks, I must have gotten about 0.3 gallons into my tank two fills ago... then my numbers come in pretty close to the SC. Now I've got to readjust my scangauge!

[Sulfuric]

Even when I try not to hypermile, I usually end up coasting much further than I used to. If I see a red light I let off the accelerator, because in my head I know it's just wasted gas.