Vehicle Mileage And Gasoline Grade

[Castuserraticus]

Last November I did a road trip with a business partner from Calgary to Bonnyville for work. I got 18-21mpg with my '99 4runner. Last week I did the same trip alone and got 26+ mpg. The main difference is I filled up with premium (91 octane) for the latest trip. I'd heard burning premium on a long trip was like giving your engine a tune-up. I was astounded at the increased fuel economy (+25%) and there was noticeable power improvement. The premium is ~10% more expensive but the trip was still cheaper. The 4runner is rated for 21mpg hiway.

 

Has anyone else ever experimented like this?

[maxwell]

yup it works for me too.. talked too my mechanic about it tho and he siad over long periods of time teh overcombustion can damage ur engine and gaskets..... not sure if he was trying too save me money or talkin teh truth but i stopped...... my drivers manual also says dotn burn premium.. conpsiracy maybe..........

[Guest 420FLYFISHIN]

Under regular city driving conditions you will build up a lot of carbons an crap inside your combustion camber. With the Premium being 10 octain higher you clean out all the crap. This stops small imperfections from hindering the full burn of the gas air mix bettering the efficiency of the vehicle.

 

The higher temp shoudnt damage anything uless your adding an octain booster aswell.

[birchy]

Haven't tried it myself, but I was able to do a few other 'do it yourself' maintenance tricks to get the 4Runner back up to 20.5 (mixed city/highway) from like 17 when I first got it.

 

Interesting. I'll give it a go on the next road trip.

[Castuserraticus]

yup it works for me too.. talked too my mechanic about it tho and he siad over long periods of time teh overcombustion can damage ur engine and gaskets..... not sure if he was trying too save me money or talkin teh truth but i stopped...... my drivers manual also says dotn burn premium.. conpsiracy maybe..........

 

?? overcombustion = running too hot??

 

I did not notice anything - still cooler than when I'm pulling the tent trailer.

[Weedy1]

Do you mind me asking what your business partner weighs?

[Tungsten]

Do you mind me asking what your business partner weighs?

Thats funny .......................................wind can also make a big difference

[maxwell]

?? overcombustion = running too hot??

 

I did not notice anything - still cooler than when I'm pulling the tent trailer.

im not too sure dude. im far from a mechanic... i didnt notice any problems shortterm...

[AndyW]

I notice no difference running regular compared to premium. I have noticed that I get 10% worse mileage running ethanol blended gas from Husky. Ethanol seems to be bad news, net energy loser to produce and then it gives crappy mileage.

[orvisonly]

Thats funny .......................................wind can also make a big difference

 

Wind is probably the most responsible. Tires can also have a major effect, especially if you had large tires with aggeressive tread. Finally speed combined with wind will make huge difference. Driving at 120 km into a 30 wind will yield up to 35-40 percent lower mileage than travelling at 110 with a 30 km wind tailwind.

 

As for mileage, or anything else, premium does not make a difference for engines designed to run on regular octane fuel. Higher Octane does not mean more heat energy, it simply means that the fuel requires higher compression before it will ignite. For high compression engines, premium may help to ensure that the fuel does not ingite before spark is present. Most independent engineers agree that engine manufacturers have to work really hard to make an engine that won't run well on regular fuel. This is so that the person who spends 100 thousand on a vehicle doesn't have to buy the same fuel as the common folk. Marketing works. Add premium to anything and people will gladly pay more. Sometimes the premium version is better, many times it is not.

 

The rest of the info about premium burning cleaner etc is incorrect.

 

And for your info - the premium gas costs refiners nothing more to make, but they nearly double their profit when selling to retailers. Retailers also make more than double the profit. Of course, this also helps auto makers charge you more for vehicles because they have intentially designed it not to run well on regular octane fuel (this takes some effort and most engines designed for premium will run perfectly well on regular).

 

The beauty of this marketing is that consumers, who are most often too lazy to do 20 minutes of research, not only fall for this fantasy, they perpetuate the myths by drawing a causal relationship between premium fuel and any number of outcomes, for which only some degree of correlation exists.

[Castuserraticus]

I talked with a friend who used to race one of the amateur circuits. According to the car junkies, there are big differences between different refiners. Porsche mechanics recommend Esso and PetroCanada and discourage using Shell. They really dislike Husky's ethanol blends and any of the independent refineries/sellers. Canadian gasoline is better than US gasoline. BC gas has higher sulphur content than Alberta gas so produces more emissions. The lotus land people blame the smell on eating too much granola while chanting to statues of David Suzuki.

 

My friend figures I fluked out that my motor had an affinity to premium or it may have had the chip changed. He gets noticeably better power in his porsche with mid grade over regular but doesn't track mileage.

 

Wind wasn't noticeably different on the 2 trips and cruise control was set the same. The tire pressure was good on both trips. The mileage I got on the first trip was within the rated range of the vehicle.

 

Since the historical refining profit margins are in the order of 6% or less I don't see any marketing windfall there. I don't mind paying 10% more for a 20+% increase in fuel economy unless it's going to hurt the engine.

[dube]

I have a new Toyota and in the manual it only states a min octane (87 I think - regular).

My mechanic there said use regular and toss the odd tank of premium from time to time.

I'll only fill with premium if I know I'm going to burn it all in one trip, I don't notice any difference in mileage and maybe a slight increase in power.

 

For what it's worth I try to use only petro or esso fuel and I'll run out and walk before I'll use husky or mohawk. I've heard bad things about ethanol.