Fuel Economy

[marcus]

Originally Posted by stuffy

hey marcus, i also noticed an improvement in fuel economy when using a tank of premium gas.

i made the same 600 km round trip on two weekends, one with premium gas and one with regular.

the premium tank was 41 mpg with poor traffic conditions, the regular tank was 36 mpg with better driving conditions.

i know they say it doesn't make a difference, but that has not been my experience.

you got it. the question is is it worth the extra money for premium gas to get the extra mileage? also i put premium only because the engine runs quiter on it specially during acceleration....but be ready once other sees this we gonna get jumped.. with "oh premium dont give us better mileage and stuff" hehehe good luck!

[BailOut]

Well, it looks like the premium gas worked for a few of you but my MPG actually decreased by 9% on 93 Octane vs. 87 Octane.

Perhaps it's because my driving style is so different.

[marcus]

try 89 instead of 93 thats too high of an octane for our car.. maybe u may notice the diff... again i only do it for the engine running slightly quieter on premium..89 ofcourse.

[BailOut]

I've done that. 89 Octane = a loss of 5% MPG, 93 Octane = a 9% loss.

I tried 2 tanks in a row of each to get a more accurate test (and the low numbers hurt my running tank average). Without a doubt I consistently get the highest MPG with 87 Octane.

Aside from my much calmer driving style two other things that may make a difference for me are that we're always on 10% Ethanol here and I'm at a higher altitude than most folks (my home is at 4,500ft., my office is a 6,350ft., and I traverse an 8,900ft. summit to get there).

[jmharn]

Does anybody notice that the 2008 yaris mpg ratings are lowered from 34/39 to
29/35? (mpg, that is)

I asked my dealer, and he mentioned that it has something todo with the government's policy to conduct the test has changed in 08...anyone second that?

[ern-diz]

Originally Posted by BailOut

I've done that. 89 Octane = a loss of 5% MPG, 93 Octane = a 9% loss.

I tried 2 tanks in a row of each to get a more accurate test (and the low numbers hurt my running tank average). Without a doubt I consistently get the highest MPG with 87 Octane.

Aside from my much calmer driving style two other things that may make a difference for me are that we're always on 10% Ethanol here and I'm at a higher altitude than most folks (my home is at 4,500ft., my office is a 6,350ft., and I traverse an 8,900ft. summit to get there).

facinating...i just filled up with my first tank of 91...have been running 89 and it appears as though to start i'm getting a bit better mpg with the 91 than i have with the few tanks of 89...as far as conditions go, i'm in socal and its been warm (besides today lol)...trying to figure out what would be the best octane to run for engine life vs. FE...87, 89 or 91...

[BailOut]

Originally Posted by jmharn

Does anybody notice that the 2008 yaris mpg ratings are lowered from 34/39 to
29/35? (mpg, that is)

I asked my dealer, and he mentioned that it has something todo with the government's policy to conduct the test has changed in 08...anyone second that?

The EPA changed the way they do the test to reflect the way people are actually driving rather than how they are supposed to be driving, starting with the 2008 model year.

http://fueleconomy.gov/feg/ratings2008.shtml

[swng]

Originally Posted by Lafiro

Hey thank you.

I will follow this. Would it also make a difference that I have two nice amps still connected to the battery? I would assume all extra demand on the alternator would then mean less miles per gallon? Specifically since I removed the two sub's the 2600watt amp is still connected. The 4 speakers then are connected to a 1200watt 4channel amp which is always on and I always listen to music. Maybe this is affecting it as well? But I cant assume this will affect it any at all?????

Once again thanks for the communication and your interest in the subject of this thread.
I am no expert but I know that amplifiers do not run with 100% efficiency. Some amps (for that matter, sound systems) can have a higher efficiency then the others. When an amp is switched on, a certain power, which has to come from the gas you buy, is lost i.e. not producing sound. Say if the amps' average efficiency is x %. Then each time an amp is on, (100 - x)% of power is simply lost. At the same overall sound level (deep bass requires a lot of power anyway), the greater is the amp's list power, the more power, hence your fuel, is likely lost. A distant analogy is that at the same speed and carrying the same driver, an SUV uses more fuel than our Yari. Most amps consume a certain power whenever turned on, whether the volume is turned up or music is played at all or not. A visible circumstantial evidence of the power lost I am talking about can be found in the big heat sinks (the multiple heat dissipation fins) that are built into the high power amplifiers. Apart from whether they are electrically safe to touch, those things are very warm or even hot to touch after the amplifiers have been switched on for some time. Even when we are not talking about amplifier efficiency, generally, using the sound system consumes power. Again, some systems are more efficient than the others, but no sound system can run without using power. As a rule of thumb, heavy bass consumes the most power.
I submit that for comfort (e.g. masking the noise), pleasure, safety and convenience (i.e. traffic and weather reports etc) and alertness (that is keeping you from falling asleep whilst driving), there are certain advantages of turning on the sound system, so the fuel is not consumed for nothing. However, bigger sound systems usually mean bigger fuel bills.
Just a further note about http://www.howtoadvice.com/SavingGas, there are some links to a few very useful articles at the bottom of the page. If you have time, I recommend that you go through them, at least cursorily. As a disclaimer, I wish to point out that some gas saving tips may contradict with some others and they are to be adopted (or otherwise) with good sense, with reference to the local laws and driving environment, and at one's own risk.
Just my humble opinions. Correct me if I am wrong. Please post here often.

[voodoo22]

Originally Posted by marcus

you got it. the question is is it worth the extra money for premium gas to get the extra mileage? also i put premium only because the engine runs quiter on it specially during acceleration....but be ready once other sees this we gonna get jumped.. with "oh premium dont give us better mileage and stuff" hehehe good luck!

Do you use Shell gas? Shell puts no ethanol in their premium, but up to 10% in their 87 octane, so you should see an increase in mileage with Shell premium even if there is no performance difference for our cars when going with a higher octane.

I can't stand this 10% ethanol crap. Keep the corn for popping.

[voodoo22]

Originally Posted by BailOut

I've done that. 89 Octane = a loss of 5% MPG, 93 Octane = a 9% loss.

I tried 2 tanks in a row of each to get a more accurate test (and the low numbers hurt my running tank average). Without a doubt I consistently get the highest MPG with 87 Octane.

Aside from my much calmer driving style two other things that may make a difference for me are that we're always on 10% Ethanol here and I'm at a higher altitude than most folks (my home is at 4,500ft., my office is a 6,350ft., and I traverse an 8,900ft. summit to get there).

Do you have Shell gas around there which put 0% ethanol in their V-power? I wonder how that would result. I can't see you gaining over 9% based on no ethanol. I only use regular and can't justify spening over 10% more for gas when the car doesn't need it. After years of buying premium, spending less than $30 on gas at the end of the week is something I don't want to give up

[BailOut]

Originally Posted by voodoo22

Do you have Shell gas around there which put 0% ethanol in their V-power? I wonder how that would result. I can't see you gaining over 9% based on no ethanol. I only use regular and can't justify spening over 10% more for gas when the car doesn't need it. After years of buying premium, spending less than $30 on gas at the end of the week is something I don't want to give up

I only use Shell gas and E10 is a mandate. Regardless of the Octane level, if you buy it in Nevada or California it's 10% Ethanol. In the cold months it gets worse as our Winter fuel - by mandate - is E10 RFG (reformulated gasoline).

This helps the lead-footers produce much less emissions, which is a good thing, but by proxy it robs the proper drivers of lots of mileage.

[eTiMaGo]

Wahoo! just got 30MPG today

Minimal use of aircond, DFCO to the max, and rarely revved over 3000RPM. And not a whole lot of highway driving as well which surprises me...

[jdium]

Originally Posted by eTiMaGo

Wahoo! just got 30MPG today

Minimal use of aircond, DFCO to the max, and rarely revved over 3000RPM. And not a whole lot of highway driving as well which surprises me...

I've never had a tank below 34 empeegees in 5,000 miles...you driving in 110% humidity, 125 degrees?

[eTiMaGo]

Originally Posted by jdium

I've never had a tank below 34 empeegees in 5,000 miles...you driving in 110% humidity, 125 degrees?

Something like that... but also very very short trips usually, which does not help at all. Previous best tank was 26MPG, so this was a nice little jump!

[Lafiro]

Ok, just put has and noticed Ive been running on low PSI on my front two tires the whole tank. BUT!
Previous tank was 32mpg, this tank was 33.1 MPG!!!!!!!

Now Im going to inflate the tires to like 43PSI instead of there maybe 26 there at now. And then I will see what happens this tank.

[swng]

I am preparing to find some time to read all these articles. I know I may not agree to everything that they say, but I know I am going to enjoy every article immensely. I also know that I may be surprised by something that they say as I read on:

http://www.edmunds.com/advice/fuelec...les/index.html

These articles touch on many subjects that are frequently asked about by members interested in fuel economy.

[SuperFunBall]

wow after reading 115 pgs, i'm tired

[briman]

Originally Posted by jdium

I've never had a tank below 34 empeegees in 5,000 miles...you driving in 110% humidity, 125 degrees?

I'm routinely 26 mpg in the city. I do not drive the car hard. My last tank was 23 mpg, all city. I'm more than a bit disappointed. I'm beginning to wish I had just bought a corolla or camery.