Hi Lars-ss:

___You are fooling yourself. Have you wife start filling every tank from darn near empty with a back and forth mix and you will find out the truth. And since you are not using the A/C down in Phoenix at all this time of the year vs. every month previous …

Phoenix, AZ. – Monthly averages

Phoenix, AZ. Average monthly temperatures

October: Day time high: 86 Night time low: 63
November: Day time high: 73 Night time low: 50
December: Day time high: 65 Night time low: 44
January: Day time high: 65 Night time low: 43
February: Day time high: 69 Night time low: 47
March: Day time high: 74 Night time low: 51

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net

 

Okay, so I've had a chance to try out the car in the closest thing that I have to a semi-controlled comparison of running with 87 octane gas versus 89 octane.

December, 87 octane:
Highway, 65mph, sunny, mid-50s temperature: 49.2 mpg
January, 89 octane:
Highway, 65mph, foggy, mid-40s temperature: 52.2 mpg

Both trips were over 250 miles of roughly level terrain, averaging about 65 mph, minding my own business in the right lane unless passing a slower truck or car. No difference in trying to draft or whatever. I also don't think that my driving style (to try to maximize mileage while maintaining speed) is any different, but that may be hard to judge. Traffic was basically the same, without any real congestion at any point in the trip.

The 87 octane was allegedly "good" Chevron gas, the 89 octane was our local cheap Safeway gas. I have not adjusted my tire pressure in the month, so presumably my current pressure (with 89 octane) is equal to or lower than the previous trip.

Like I said, this is just anecdotal and unscientific, so consider it only with a large grain of salt. However, I thought I'd post the update in case anyone is interested and following this thread. I myself don't really know what to make of it, but it seems interesting to me nonetheless.

 

I'm due for a fill up too. I'll try the 89 and report back. I've always gotten poor mileage (i'm still trying to learn how to drive more efficiently) but it is pretty consistant.

 

... and you should be proud! You have probably increased your mileage by 25-33% with the hybrid, over a similar non-hybrid. Undoubtedly your mileage will also improve when spring rolls around.

My colleague at work has now also purchased a hybrid, and we never cease to be amazed at how we sometimes get disappointed with our mileage, when in fact, with our old cars, if we had ever achieved anything *close* to that mileage, we would have been jumping for joy!

 

Yup. I used to own a metro manual. I only got the hybrid because I wanted a new car that I only had to fill up twice a month like I did with my metro. So basicly as long as it does that I'm happy with it. Like you said, this time of year is not the time to expect awsome milage living in chicago.

Also, I comit the mortal sin of having had remote start added to my civic. I can feel you hypermilers cringing as you read this.


I figure I will fill up on Wed. or Thurs with 89 and see what happens. Does cold have any affect on cars knocking? Maybe sometimes 89 is good and maybe sometimes 87. Only way to realy find out is test.

update: well, I did in fact fill up with 89 when I predicted. The tank emptied today. I got about 34mpg which is typical for me. I did drive it a bit harder than normal but since I achived my average mpg I can only deduce that mpg gains by higher octane can be achieved without the added expense by using good driving habits.

update: If one or two mpg is achived that would only mean about 13 to 26 miles extra per tank which to me seems pretty negligable.

 

Hi Tbaleno:

___Cringe? I darn near threw up breakfast

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net

 

Actually, Wayne, I ditched that Wasteful Wife in Summer 2003 !!!

No, I'm not fooling anyone at this point. I'm just running a test based on the type of octane.

My commute for this current tank has not changed since my last two tanks using this commute, and the weather has not changed either. It's still 40-50 for the morning commute and 55-70 in the afternoon commute.

So comparing this tank to my last two Phoenix tanks will be a very accurate test, as much as "tank to tank" comparsions can be accurate.

As of this morning I have 303 miles on the 91 Octane tank and am sitting at 56.3 MPG for the tank. That's higher "so far" than even my Late Fall tank last year when it was still warm (85-95F) enough to get good tanks and still cool enough to run without the A/C. The best tank I had in that time frame was 53.8 MPG with 87 octane.

One thing I have noticed that is CERTAINLY attributable to the 91 octane is that at higher RPMS, the car is more efficient. I had two short (7 miles and 5 miles) highway jaunts, and both times, I GAINED MPG on the hwy, once from 56.7 to 57.1 and the other time from 56.0 to 56.3. I have never before GAINED MPG on a highway run of 55-65 MPH as I did with these two events.

So nothing is yet proven - I have 300+ more miles on this tank, and it well might drop back down into the low 50s or the upper 40s - only time will tell. But I have shown to myself that at high rpms the 91 octane does a better job, which is good to know for my next long hwy trip.

 

Hi Lars-ss:

___First off, you are not even approaching the top hypermilers yet. Second, you are grasping at straws … Higher FE at higher RPM’s etc.? The reason higher Octane fuel can achieve higher performance is that the KS does not pull timing back because it does not detect knock. If you are running anything below this threshold (all hypermilers do) there is no retardation of timing thus nothing changes in Performance or FE. In some cases, higher octane fuel has less BTU/Lb then lower Octane because of the added Oxygenates to slow down the flame front. When you start hitting 65 - 70 mpg tanks tank after tank and then switch, your experiment might mean something but right now, it means zip.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___Waynegerdes@earthlink.net

 

I realize I am not approaching the top hypermilers yet, and I will NEVER be able to, because of my short commute and the fact that I almost always have myself and two kids in my car, and because I refuse to overinflate my tires to hypermiler levels. I will be happy with low to mid 50s.

All I do know for sure is that I am on tank number 14, and I have been on the highway a good number of times before this tank. And NEVER BEFORE NOW has my tank MPG RISEN during a hwy jaunt. So that is attributable to SOMETHING, right? The only variable right now at this moment with this tank is the 91 Octane gas.

And I have concluded nothing about the affects of 91 Octane yet except for that odd reaction to higher RPMs.

Whether or not the 91 Octane has any bearing at all on my current tank of 56.3 is not yet proven nor disproven - I am in the second half of an experiment which will span 4 tanks. The next tank will be 87 Octane again and I will compare that tank versus the 91 Octane tank and the two 87 octane tanks prior. That way, I will have FOUR TANKS, one of which is 91 Octane, and the other three with 87 Octane, and I will be able then to determine in my own mind whether the 91 Octane helped at all.

If the 91 Octane turns out to be helpful to MY car with MY commute in MY environment, then I will use it. If it's a waste of money, I will not bother. I am not under controlled environment and thus cannot declare my results "scientific", but they will be good enough for ME because I will have 2400 miles of almost identical driving with which to compare four tanks.

It's all I can do - I'm just passing on MY data, and whoever wants to can do their own experiments - I am not declaring myself the "Mad Dr. Frankenstein" of GreenHybrid.com..........

 

I've noticed a slight difference in mpg switching from Chevron to Shell. (87) I might've simply been psyched by the more expensive Shell. When you THINK it's better you tend to drive better.