Why is my MPG so high??? (HAPPY, but curious)

[StanleyD]

My mpg has been steadily improving over the last couple fills. I know that the last two fills were in lighter than usual 'everyone's on vacation traffic' but I cant explain the last surge. I was stoked to get 542 miles out of a tank when I first started driving slower as a result of joining this site. And now my last tank was 656 miles and thats using about ONE LESS gallon of gas. I know I went from 29 mpg to about 32+mpg from driving technique. The jump to 34mpg was light traffic work week, but the last tank of 36+mpg was an absolute shock. The difference is too much to attribute to tank fill variance.
The only thing I can think of is that maybe my engine was running hotter last tank. I say this because I noticed a small loss of power going uphill yesterday and found out I was REALLY low on oil when I checked dipstick. Maybe my car was running hotter due to low oil and ran more efficiently, although more dangerous to engine. Could this be why? What do you guys think??
Im surprised (not complaining, HAPPILY surprised) to be mpg that much higher than expected. Never thought Id get 650 miles from one tank. I now have to make new goals for this car. 36+ mpg kills the 20/28/23 EPA, even the old 23/30/26 EPA

[brucepick]

Wow - good going!

Lets see - - where are you?
Did local temps change recently? That would have an effect. Especially if they went up. Do you use A/C?

Another odd phenomenon - shore breeze. If you live near a shore you could be driving with a wind assist in both directions. In my case I pretty much have a headwind in both directions in summer. What a drag!

Summer P.M. shore breeze is away from the shore. A.M. shore breeze is towards the shore (most folks pay no attention to that one). So depending on your route this could hurt or help. Spring and fall the phenomenon doesn't occur very strongly, and in winter it would work in reverse, if it does happen: would blow to the shore in p.m. and away from it in a.m. Sorry for the rant.

[CO ZX2]

StanleyD. How low were you on oil? Half quart or so should be a slight help but if your car uses oil, you may not want to do it. Check more often.

You have steadily improved since joining the site. You have logged enough miles and tanks to be sure of that. Your gaslogs show that. Make yourself a list of all the things you have done differently and that will be the why. It may be a bigger list than you think. Good job. Keep working and thinking.

[lovemysan]

Good work

here's a 98 altima thread. I suspect you'll be in the 40s at minimum occasionally.

http://www.gassavers.org/showthread....ghlight=altima

[Rick Rae]

First and most importantly: Congratulations!

One thing to consider is that, being a person without a ScanGauge you don't really know what's been happening until you fill your tank, and that's very coarse granularity.

As you continue to practice and refine your technique, learn the subtleties of your routes, etc., you'll probably have a slow but ongoing improvement. But because of the granularity, you only rarely get to check your progress. So that slow but continual increase can look like a huge jump.

I'd say you and I are in similar territory: My combined EPA is 22. The first tank I registered here (only about six weeks ago) was just over 30MPG. I jumped to about 32 when I started experimenting with P&G. I jumped again to about 34 when I became more "aggressive" with my P&G (more often, or in neutral rather than in gear). I firmly believe I could be turning in 36MPG tanks right now if I hadn't given up "NICE-ON" coasting to see if I could achieve the same numbers in gear. (I'll be verifying that belief soon.)

I'm not saying low oil, higher temps, etc. don't have a bearing, just that our numbers are very similar (and could be even more so if I hadn't pulled back on one of my techniques as a test)... and I'm confident almost all of my improvement to date is from driving style.

Maybe when you get your SG installed some of the changes will make more sense. You'll also likely have another jump as you begin reacting to the real-time data, but at least you'll know where that one's coming from!

Again, congrats; great numbers, no matter what the reason(s)!

Rick

[StanleyD]

Originally Posted by brucepick

Wow - good going!
Lets see - - where are you?
Did local temps change recently? That would have an effect. Especially if they went up. Do you use A/C?
Another odd phenomenon - shore breeze. If you live near a shore you could be driving with a wind assist in both directions..... Sorry for the rant.

NYC metro area, driving from Queens and Long Island area to CT a lot. Logging MANY miles as you can see from gaslogs. No real winds, lots of highway miles although last couple weeks has been noticably lighter than average traffic due to July 4th and many summer vacationers making rush hour sweeter than usual. No real breezes, at least not any changes that would cause change in mpg. Ive learned NOT to use AC. During first gaslog I used AC on occasion and tried to keep it down. Now Ive adjusted myself where I dont even need it. Once in a BLUE moon I might turn on for a few seconds and do a turn on turn off thing, but havent used in last few weeks even with higher temps last month (Only when driving the Mrs).
This weeks fill surprised me because my driving wasnt much different from last weeks and temps were same. Thats why I though that oil may have helped, but I wont be taking that risk anymore. Price of Engine >> price of gas

[omgwtfbyobbq]

If the I4 Camry's are anything like the sixes, you should be well into the forties if you can keep it at ~55mph w/ light traffic.

[StanleyD]

CO: StanleyD. How low were you on oil?
Rick Rae: First and most importantly: Congratulations! ...One thing to consider is that, being a person without a ScanGauge you don't really know what's been happening until you fill your tank, and that's very coarse granularity....Maybe when you get your SG installed some of the changes will make more sense. You'll also likely have another jump as you begin reacting to the real-time data, but at least you'll know where that one's coming from! .....Again, congrats; great numbers, no matter what the reason(s)!

CO, I was about as low as you can get. Barely read anything on the dipstick. I know I have a slight leak that I hadnt checked in a while. Thank goodness for synthetic oil. Will take care of as soon as I have $$$. Debating whether to fix leak or get Scanguage with next check. ByTheWay, congrats on 100mpg

Thanks Rick Even though I have no Scanguage (plan on buying VERY soon, hoping that I can get good deal or maybe group purchase here to get for cheaper) I have somewhat of an idea on how well Im doing. For instance my gas guage does NOT MOVE off Full for at least 60-70 miles after a super-fillup. First time I filled and drove I thought the gas guage was busted. So when that needle makes its first descent at 90-100 miles as oppossed to 80 I know Im doing well. I know what mileage I should be at when I hit every mark on the car and when you drive over 3000 miles month, you pass those markers fairly quickly- maybe not instantaneously but I generally have 'daily progress on how well Im doing. STILL, I cant wait to get Scanguage. Ready to buy very very soon.

[ZugyNA]

Originally Posted by StanleyD

The jump to 34mpg was light traffic work week, but the last tank of 36+mpg was an absolute shock. The difference is too much to attribute to tank fill variance.

You could have gotten a short fill...where the pump shuts off early. This has happened to me 2xs...messes up my testing a lot.

This is why I use a 3 tank avg...reliably filters out this kind of thing.

Also...I once got 47 mpg with a full tank driving with a tailwind all day...normally around 33 mpg or so.

[rGS]

Originally Posted by StanleyD

NYC metro area, driving from Queens and Long Island area to CT a lot. Logging MANY miles as you can see from gaslogs. No real winds, lots of highway miles although last couple weeks has been noticably lighter than average traffic due to July 4th and many summer vacationers making rush hour sweeter than usual.

StanleyD,

That single factor may be quite significant. Based on my own gaslog, prior to 06/16/2007 I was mainly puttering around on local streets and highways. However, by going on a day road trip which is a lot of highway miles going at highway speeds, I was able to achieve the fillup to fillup fuel economy of 28.32 mpg in my non-hybrid gasoline engine car. So maybe that's what is happening to you too?