How to improve MPG in my 2002

Redex the fuel system and use premium gas . IMHO

 

Do you actually calculate your MPGs, or just accept what the MFD reads? In my experience, 56 MPG is a highly suspect number! The best my '02 ever got was 55 MPG on a measured course when the car was practically brand new. It's now 20 years old and averages in the 40s (it does better in the warm seasons than in fall and winter). Premium gas would be a waste of money, IMO.

 

Your choice. I found premium gives much better economy than regular. Each to their own. Can’t be bothered with calculation so I just take the readout. Sounds like your 02 (20 year old) needs a de-coke.

 

I was mainly responding to the OP. You're driving a 2019 model, quite different from the Classic. Owner's Manual clearly states regular gas. However, it is important to use top tier gas for maximum effect. It would be interesting to see whether premium would make a difference in MPG. My guess is it wouldn't, but there's one way to find out for sure!

 

I can get mid-50s mpg in my '03 if a) I specifically drive to max out on mpg (not hypermiling, but driving habits consistent with that; b) I stay off of interstate driving and stick to rural backroads and around town.

Other than that I'm also suspicious of a mid-50s mpg report. In mixed driving (meaning some interstate miles mixed in) I get mid-40s in the warmer months and low 40s in the winter (though that's also with winter tires which seems to matter).

"Premium" gas is meaningless. It's not "cleaner" or "better" or whatever. It just has a higher octane rating which means it resists combustion a bit more than lower octanes. Its relevance is solely related to engine compression. Higher compression engines need it so that the compression doesn't cause pre-ignition. Prius engines are not high compression so the only thing higher octane does is drain your pocket faster.

 

1000% agree.

If higher octane gas does make a real measured provable difference, rather than a perceived difference (that is, "I feel it gives me better economy,") there is something wrong with the engine that should be addressed. Using higher octane gas to fix knocking is just a panacea that won't last long term. Fix the root cause of the problem.

 

sadly no. E5 premium 97 RON gives 5mpg better performance over E10 95 RON
Here.

 

This has more to do with the energy content of the ethanol blends, which is less than gasoline. Generally the higher the E number the lower the cost, but also lower gas mileage.

Fuel Ethanol: Hero or Villain?

 

<Facepalm>

 

Totally true.

 

I always thought (and still do) that ethanol was a dumb idea for a myriad of reasons. The biggest reason it became a thing was industrialized agriculture. Corn producers could make more corn than there was market for, so a new market was fabricated. The lower energy content is only ONE of the reasons that it remains a dumb idea. (Some of the others can be found in small engine carbs / fuel systems everywhere).

Given that corn surpluses became so common, they should have gone into making more whiskey instead!!


(U.S. Energy Information Administration - EIA - Independent Statistics and Analysis)

 

Excellent graphs, thanks for posting!

 

Ah, yes the old ethanol blend chestnut. I guess I should qualify my information as I had E0 RON 95 vs E0 RON 98 or greater in mind so comparing apples with apples and so the information given is true for that.

As mentioned above, adding ethanol to the mix lowers the energy density which in turn lowers MPG. Additionally, adding ethanol to gasoline has a similar effect as adding octane with regards to the RON/MON/AKI octane values (AKI being RON+MON/2)).

Comparing E5 RON 97 with E10 RON 95 is comparing apples with oranges. The ethanol content comes more into play as far as fuel economy goes than the actual RON rating. But, if you do the maths and the price differential between the cost of those two blends to get 1.1 more miles per litre (or 49.5 miles per tank) works out cheaper for the miles driven, then go for it.

I did a similar exercise with cheaper RON 91 vs 8c more expensive RON 95. It worked out significantly cheaper per kilometre to buy the more expensive RON 95. Conversely, it worked out more expensive per kilometre to use RON 98 vs RON 95. These were all E0.

For the American readers,

• RON 91 equates roughly to 87 R+M/2
• RON 95 equates roughly to 89 R+M/2
• RON 97 equates roughly to 91 R+M/2

 

Interesting maths. My point was better fuel economy from
“Super unleaded” over “unleaded” here in the uk.E0 not available unless you go to a racetrack. The point was “Premium” is better than “Regular”

 

I do understand your Premium vs Regular observation, but it is more to do with the fact that ethanol is blended into each of the fuel grades at different ratios, not because of the difference in octane rating per se. While it may be true in the UK with these two particular blends it still does not translate across the board that Premium is better than Regular. In your specific instance, it just happens to be that 97 has less ethanol than the 95 so that is what gives the slight increase in MPG. Given all that, it would be interesting to know whether that actually translates to 97 being cheaper when calculated in pence per mile vs the 95.

 

>How can I improve the mpg? It has to be more than tire pressure and driving technique.

clean air filter, MAF sensor, throttle plate
fully charged 12V battery

 

You'll have to drive the car over the same routes at the same speeds under identical conditions in order to obtain valid results!