Mid Grade Gas is Cheaper!
 

Since 1984 I have tested 6 different cars to find out which fuel gives me the best "Miles Per Dollar". In every case I got the best results with mid grade gas by an average of 5 mpg. That's equal to 50 extra miles with a 10 gallon fill-up. Not bad for an extra $0.10 per gallon.

My 2008 Civic Hybrid is still in break-in mode (4000 mi. @ 50 mpg) and have been using 87 octane from the start. This week I have added my first tank of mid grade gas and am averaging 59 mpg! I will have a good average mpg in a few weeks for this higher octane fuel.

Here is a link to an article I posted last year about my 1989 Civic:

Save Money With Mid-Grade Gas

=================================================

This forum demonstrates ongoing mpg results from several Hybrid drivers measuring regular 87 octane vs. mid grade 89 octane.

My final results are in Post #40 on page 4

Re: Mid Grade Gas is Cheaper!
 

Maybe in your area the 87 has 10% ethanol, and the midgrade is 100% gasoline. I think that could explain the increase in mileage since ethanol contains less energy. Otherwise, it doesn't make sense to me how 89 would yield better mileage than 87.

Re: Mid Grade Gas is Cheaper!
 

Maybe it's the weather.

Re: Mid Grade Gas is Cheaper!
 

Agreed. steve1mac, I think you should switch back to low-test for your next tank and see how the mileage looks. I think you will see similar results to mid grade, but I would be curious to see.

Re: Mid Grade Gas is Cheaper!
 

I really can't explain it for your previous cars but there are several factors that could be affecting your HCH. Primarily it is in it's break in period and this car has been known to have a dramatic jump in FE as it gets through this. Even tires are stickier when new and have less rolling resistance after break in. Drivers have a breaking period with hybrids also as the car basically retrains some of the way you drive. My first tank in a HCH was 42.7mpg.

Plus there are the other things people have mentioned, weather, E10, and reformulated fuel for colder climates. In Illinois stations are suppose to label ethanol content but some stations might be sneaking it in there. Weather is a huge factor for FE, both temperature and rain / snow. The Mean High temperature for the first two weeks in May, in Chicago, was 68°F and 74°F for the last two weeks. Six degrees warmer during the day can have a real affect on your mileage.

There are just so many variables to take into consideration that I would not trust it to a single tank of gas. Since you already have the mid-grade fuel in there go for at least 1-2 more tanks of it and then switch back to regular for 2-3 tanks. You should be well into summer by then and the regular gas should have the extra benefit of even warmer weather & break-in period for car & driver even further along. If you still see a drop back to your pre mid-grade fuel usage then I would start to believe that is actually the fuel.

Could be an interesting experiment!

Re: Mid Grade Gas is Cheaper!
 

Yes Hemisync, I agree, there are several factors in play. I am also aware that fuel additives vary throughout the seasons.

With all my previous cars the break in period would last up to 5000 miles. I plan to go through 3 tanks of mid grade and by July I'll return to regular gas for 3 more tanks before I pass judgment.

With 200 miles of commuting I am running steady at 59.5 mpg on mid grade.
Time will tell.

Re: Mid Grade Gas is Cheaper!
 

Kristian,
I think it's best to stay on one fuel for at least 3 tanks to get a good average. Wind, rain, temperature, air conditioning, short trips to the store can all spoil the results of a low mileage measurement.

Re: Mid Grade Gas is Cheaper!
 

Yeah, absolutely. Just so long as you make the switch back to regular in a period of similar weather, A/C usage, etc. to keep things as apples to apples as possible.

I'm intrigued by your results. I found that I got better mileage on 87 (our high altitude mid grade) than 85 in my Contour, but in the days of $1.50 gas it didn't pay for itself for $.10 extra per gallon. Now when regular is $4.00 and mid is $4.10, the equation could be a lot better :). Conventional wisdom around here says that there is nothing to be gained by higher octane, but I would like to see that proven.

Edit: BTW, I have just under 15k miles now and I STILL feel like the car is breaking in based on my summer mileage this year vs. last year.

Re: Mid Grade Gas is Cheaper!
 

Sounds like a plan, please be sure to update this thread when you are done. I will give it a shot myself and let you know what occurs with my 2005 HCH.

Re: Mid Grade Gas is Cheaper!
 

July in Chicago with no A/C??

Re: Mid Grade Gas is Cheaper!
 

I am trying this out....filled up last night with midgrade and will try the next three tanks with this.

Re: Mid Grade Gas is Cheaper!
 

Lawndart,
That's great. It will be interesting to see what our stats are for comparison. Sometime in July I suppose.

Re: Mid Grade Gas is Cheaper!
 

I thought about doing this too, but it would (hopefully) be early September before I would have the third tank finished :).

Re: Mid Grade Gas is Cheaper!
 

I would have to take the skeptical side. The small difference in octane rating between regual and mid-grade (usu 89 oct) is not enough to make that much difference in performance.

As stated in various ways above, there are so many other variables, that is would be difficult to prove any real difference unless you had a "virtual shadow car" that drove exactly as you do with another grade of gas for a reasonable amount of time.

Higher octane gas does actually have higher energy per volume (indirectly, allowing higher pressures and temperatures before autodetonation), hence the reason for the differences. However the differences are not large enough to account for your stated differences.

Re: Mid Grade Gas is Cheaper!
 

A little sweat never hurt anyone! :angel:

Re: Mid Grade Gas is Cheaper!
 

I agree and that is why I suggested the method that I did. When he switches back to regular his mpg will have the added benefits of warmer weather, a car that is further along on it's break-in period, and a driver more used to driving it. As long as he doesn't skew the results with too much A/C usage it should be some interesting results. I personally think his 3 tanks of regular will show about the same mpg, if not better. Just for giggles I am willing to try the same, although I won't need to fuel up for another week or so. Only have 320 miles on this tank and still have over half a tank to go. As for my A/C usage, I rarely if ever use it, so shouldn't be a factor with my car. Where I live in PA is actually further south than Chicago but has lower mean temp in the summer months. Like I said before it should be fun, interesting, and might even prove myself wrong although in this case I don't think it will.

Re: Mid Grade Gas is Cheaper!
 

My first tank of mid grade results are in.
59.9 mpg for 495 miles measured at the pump.

The car computer displayed 57.4 mpg. I noticed this discrepancy during my first 3000 miles and decided to use my calculations at the pump. What's up with that?

I have only found this forum a week ago and am quite pleased with the help and information I receive.

Thanks All!!!

I always use the same pump at the same gas station for each fill up to insure accuracy.

I think the break in period is partly responsible for the higher numbers. I travel about 90 miles round trip per day. Similar conditions each way. This week was hot and windy. A/C for about half the tank.

Re: Mid Grade Gas is Cheaper!
 

The computer will not be as accurate as your calculated results, there are a lot of variables in it's calculations and is only an apprx value. I have found if you keep one of the trips just for lifetime mileage that it all averages out after a while.

Re: Mid Grade Gas is Cheaper!
 

Also, keep in mind that higher octane means more ethanol or a few more additives to suppress engine pre ignition. It has been rumored that increasing the ethanol content to 30% will increase perfomance and FE. This was in a previous thread on mixing your own fuel.....:)

Re: Mid Grade Gas is Cheaper!
 

You mentionthe midgrade gives you the best Miles per dollar, but then provide a MPG results. what was the break down of the MPD by grade? Can you provide those numbers?

Re: Mid Grade Gas is Cheaper!
 

Besides the originator of this topic there are at least a couple others that are going to try it over the next 6 tank, 3 midgrade & 3 regular. At the end of this I am sure we can give you some hard data on that but right now it is going to take a while to burn through those tanks of gas. I am tracking how much gas it takes and what the price is for regular & midgrade at the times of my fillups so I can easily make the comparison. Personally I don't expect a big difference, but that is why I am willing to try it and see.

Re: Mid Grade Gas is Cheaper!
 

It will interesting to see what those results are. My guess, and it's only a guess, is that any improvement in MPG is probably going to be offset by the price increase, such that the MP$ will be close to flat. It will be interesting to see if the results show differently.

Re: Mid Grade Gas is Cheaper!
 

I'd bet the mid does no better. In fact, worse. The ECM is programmed to run 87. The lower the octane, the higher the energy. That's why diesel is more efficient. It is somewhere in the 40's. Higher octane means more volatile, more explosive. Gotta burn quicker. And possibly do some damage to the spark plugs. I have noticed when buying gas that if the fuel is ethanol enriched, fuel mileage suffers also. I'd personally stick with the big bucks Honda engineering has in this thing. I wouldn't mess with the tire pressure either. It is summer, and it isn't hard to have a tire pop when running more than reccomended pressure. Fifty cents or life. I'd choose life.

Re: Mid Grade Gas is Cheaper!
 

I had an old 85 volvo stationwagon and I did the same thing with calculating mileage. I only ever tested it with highway driving because I would drive back and forth between my home in PA and Ohio, and I would test it as I drove the PA and OH turnpikes, which took a little over a whole tank of gas for me. I got 22mpg with regular, 29mpg with premium, and in between for mid-grade. Needless to say, I bought premium from then on.

I have been filling my 2003 HCH with regular and getting 42-47mpg in a mix of city and highway driving (it does better on the highway). I hadn't thought of testing it because the manual said it is fine to use regular grade, but the manual doesn't seem to have any useful info...so...I think I'm going to try mid-grade and see what happens.

Is it worth trying premium too? I read that the old Volvos like mine were actually made to burn high octane fuel. I even noticed a difference between 92 and 93, although I actually got worse mileage when I tried 94 the one time.

I dunno? Thoughts? I'll get back to you too when I try this out.

Re: Mid Grade Gas is Cheaper!
 

Cazort with the HCH if there is going to be any difference for the positive it would be with the mid grade since it is setup to burn regular. Premium has far too many additives, anti-knock, detergent, and who knows what else to really bother with trying at this time. Lots of older vehicles did need higher octane, but that was before computers controlled the process and lots of high performance engines still need it, but I would hardly call the HCH's engine high performance. Before you try it you might want to find a plateau for you mpg with regular. If you are bouncing between 42-47 you really haven't gotten to a steady average yet. I average around 55 mpg pretty steady and that is all back country highway driving at around 45-55 miles per hour. It is creeping up right now but that is because the average temp is climbing. I just filled up with my first tank of mid grade. One of the reasons we proposed trying this little experiment now is because by the time we switch back to regular summer will be at its warmest and regular will have a slight advantage temperature wise. Didn't want it to be the other way around and skew the results in favor of the mid grade.

I gather you just purchased your HCH and it is still teaching you some things about how to drive it and yes most that love their HCH know that it can teach you how to save gas if you let it. Let the 2 or 3 of us spend the extra money to test this theory and you can find your average mpg in the meantime. Then wait and see if you agree or disagree with what we find out over the next 3 months, and you can adjust your fuel purchases accordingly.

I log my mileage here and at cleanmpg, if you click on the part of my signature that has MPGus on it, you will see my mileage along with other notes concerning temps, tire pressures, and whatever maintenance I have done recently. I have expressed this opinion before but I will say it again, I really don't think the increase in mpg, if there is one, will be significant enough to warrant buying mid grade all the time.

Re: Mid Grade Gas is Cheaper!
 

Cazort,
I have tested regular, mid grade, and premium ( 2 tanks of each after 5000 miles break-in) on all my cars since about 1980 and only found premium to be the best bargain on a 1989 Honda Accord. It was a marginal difference above mid grade, but still cost effective.

BTW: The 2008 HCH manual recomends 87 octane or higher.

Re: Mid Grade Gas is Cheaper!
 

That's the problem I have with experiments like this, and ESPECIALLY with this one since it requires a whole tank to test. My mileage is all over the place on a day to day basis, even though I drive the same route at the same time at the same slow speeds. I got a 56mpg yesterday morning and a 63mpg today--probably due to temperature swings. Coming home is even more of a swing because I might be in the mid 70s on a really hot day and mid 50s if it's cold. Throw a week of cold weather into one of the tanks and that could have a significant impact.

Now throw in a couple extra super short trips to the grocery store with one tanks, or a trip on the highway and that tank is either going to have a lower score or higher score because of difference. When a tank gets you between 6 and 7 hundred miles, there can be a lot of variablity in how those miles were driven--even if 75% of the mileage was standard day to day commuting.

I'm not posting this because I'm skeptical about this experiment--I love the fact that people are always out there trying to find the best ways to get high fuel economy! However, I do think it is extremely difficult to get an apples to apples test that would have conclusive results one way or the other...

Re: Mid Grade Gas is Cheaper!
 

The HCH has a 10.8 to 1 compression ratio. Normally, this kind of compression would call for higher octane fuel to prevent knock. The motor has a knock detector that retards timing when knock is detected. So life is good. But what happens when timing is retarded to prevent knock - say in the hot summertime? You lose a bit of power. So now there is a choice of pushing a bit harder on the throttle, or not. If you don't push a little harder, it takes longer to get to your cruising speed and perhaps digging into your battery -and that takes gas to recharge. You do push a little harder on the throttle, and that takes a bit more gas to get to cruising speed. I don't have enough miles on my HCH to draw any conclusions, BUT -

My test car for this was a 2003 Honda Accord with 4 cylinder and many long trips. Mid-grade, (conclusively for me), did two things in warm/hot weather. It stopped my timing from retarding between 2000 and 3000 rpm (that doggy feeling went away!!! happy dance!), and I gained on average 2 mpg. Sometimes 3.
Sitting down with a calculator after a few trips, I determined it was a wash. Higher fuel costs killed savings from better gas mileage.

This Accord is my wife's car now, and when the temps go above 80 degrees, we fill 'er up with premium. My wife hates that doggy car feeling... and I'm smiling cause its not wasted money cause of the slightly better FE.

I suppose I'm saying that it is probably true for some drivers that when temps go up, the HCH is going to benefit from mid-grade. With the usual caveats that YMMV! :omg:

Re: Mid Grade Gas is Cheaper!
 

And I agree with you 100%. But for me I would prefer a real life test instead of just sticking the car on a dynamometer and letting it run for a tank of gas. With three tanks of gas of each I should be able to see if it is making enough of a difference for me to consider continuing buying mid grade fuel. As I have said before I am even giving regular the benefit by being the weather being warmer then and even having more experience with the car. There is nothing scientific about it and I certainly am not trying to claim that. It's only costing me an extra 1.30 a tank so it is not going to break me. It's just something to try. We shall see what we shall see and as always YMMV. ;)

Re: Mid Grade Gas is Cheaper!
 

Finished partial 3rd tank.

Driving was not consistent with my regular trips. I carpooled for 3 round trips to work (275 mi.) with 2 of my lead footed co-workers and about an extra 100lbs. of equipment and tools in the trunk. I even let them drive to work to get the feel of Hybrid driving techniques. I guess they didn't do too bad because my mpg ended up to be around 59mpg.

I am surprised how good the mpg is! Maybe it's the outside temp. I used air conditioning (set to 72 degrees) for half of the miles. I keep my tire pressure at 44psi.

We live on flat land around here. The only bumps in the road are bridges and inclines for rain drainage. But, anyway, I ran this tank short to get back on track with testing.

Re: Mid Grade Gas is Cheaper!
 

If your average temp is 80 then that is helping. Are you recording the true mean average temp or just guessing at it? We have been colder as heck the last two days, for this time of year the mean average temp for the last 3 days has been 54 °F / 12 °C, but I have been off work anyhow so it really hasn't affected my mpg.

For example of your area, for the last seven days the mean temps at Chicago Midway have been 82 °F, 70 °F, 65 °F. High, Avg, Low.

Re: Mid Grade Gas is Cheaper!
 

Hemisync,
The "Add a Tank" screen asks for temps in 10 degree gradients. Since I go through a tank of gas in 5 to 6 days it's a pretty accurate guess. Sometimes I drive home from work late at night where the temp might be 60 or lower, inbound commute is usually mid-day when the daily temp is highest. I just round it out to somewhere in the middle.

Re: Mid Grade Gas is Cheaper!
 

That's why I usually use the average mean temp, but CleanMPG allows you to enter exact temps and graphs them with your mpg so you can see the effect.

As for my first tank of mid-grade, it is not going well, so far I have not seen any increase and am fighting to maintain my 60 mpg that I got on the last tank of regular. We shall see where this goes, but so far it is a rocky start.

Re: Mid Grade Gas is Cheaper!
 

Finished 3 tank test with mid grade.
Last tank got 60.1 mpg for 553.8 miles.

Total mid grade average for 1875 miles was 59.2 mpg.

The tank is now filled with regular 87 octane. This will be the first of 3 tanks for comparison test.

Re: Mid Grade Gas is Cheaper!
 

Hemisync,
I just looked at your stats at Clean MPG.com and was surprised to see the tire pressure (60psi) you are running at! It seems you are raising it a little at a time.

What kind of tires are you using? What is the maximum PSI?
When are you going to explode?!

Re: Mid Grade Gas is Cheaper!
 

I am running OEM Bridgestones with max sidewall rating of 44 psi. I doubt they will ever explode at least not from inflating them to 60 psi. I would never recommend that any individual inflate their tires above the max sidewall. What I have done is a personal choice and if there are any risks they are my own. Now with that said, check out some of the following information:
Driving Under Pressure
What PSI are your tires? (Poll)

Re: Mid Grade Gas is Cheaper!
 

Mid grade seems to be working better for me. My mpg went from approx 46-48 to 52-53 with the 89 octane rating. Driving is mixed freeway/city with some A/C use. I still have about 1/4 tank left with 450mi on the trip odo. I have a 2005 HCH PZEV with the 11 gal tank. Looks like I will get my first 500 mile tank since they changed to reformulated gas here in MA. :shade:

I calculated approx $3 saving per fill-up even with the higher price of mid grade...:) (one gallon saved of regular = $4. Filling up with mid costs $1 more than filling with regular, so I save $3)

Re: Mid Grade Gas is Cheaper!
 

So I finished the first three tanks of mid and my mileage is up roughly 6%. (50 --> 53+).

I put the first of three tanks of regular in and will update when I am done.

I don't know if it is the weather (it has warmed up) or the gas...

Re: Mid Grade Gas is Cheaper!
 

Completed 3 tanks of regular 87 octane gas for a total average of 57.2 mpg. Very similar to results for mid grade test (59.2 mpg). Two miles per gallon doesn't quite justify the extra cost for mid grade.

However, near the beginning of the first 87 octane tank I raised the tire pressure to 45 psi. I think it's only fair to run 2 more tanks of mid grade 89 octane with this same tire pressure (and steady summer temps and weather conditions) to get good comparable results. I should have this completed by the end of July.

Re: Mid Grade Gas is Cheaper!
 

I finished the last 2 tanks of mid grade for an average of 59.45 mpg. My 3 tank average for regular was 57.23 mpg. This is with almost exact weather and driving conditions and 45 psi tire pressure for the past 5 tanks.

So, I guess the mid grade gets a little better mpg over regular.
With a 10 gallon fill-up I will get an extra 22 miles of distance for an extra dollar.

It's almost a wash when you consider the extra cost for mid grade. So let's calculate miles per dollar (mp$):

Regular fuel cost.... $4.259
Mid grade fuel cost. $4.359

Regular gas miles... 1490
Total fuel cost... ÷$111.16
Average mp$......... 13.4

Mid grade gas miles.. 1002
Total fuel cost....... ÷$73.23
Average mp$........... 13.68

Although fuel costs have varied slightly during these tests, the price difference between regular and mid grade has been consistently $0.10 at my filling station. The price per gallon I use in the calculations is an average of these prices. As fuel prices go up in the future, the difference in mp$ will become narrower.

So it looks like mid grade beats regular by a slight margin of .28 mp$. It isn't much - and this test certainly is not scientific - but it's enough for me to decide to stay with mid grade 89 octane for the foreseeable future!

Who else out there has tried this mpg comparison?
It would be great to hear from some Hybrid veterans who can compare their results of mp$ or mpg stats from the same time last year.