My thoughts, exactly!!

 

the overall diameter is different too. it should account for a 1% change in mpg.

 

Only if I drive short trips with lots of stops do I get low MPG.

On a 3/4 mile trip to lunch which includes three stop signs and speeds of 25-40 MPH I get about 21 MPG on that trip.

But if I extend the return trip from lunch to also include going to the ATM at the bank I get around 35 MPG.

On a longer trip of 15 miles for dinner with speeds averaging 40 MPH I recently got 50.1 MPG on that trip.

 

You are correct about the overall diameter, but decrease of 4-6 mpg is quite a bit more than 1% (more like 12-13%!!) ... something else going on. I have the steel wheels back on and a full tank so will be able to compare in a week or two

 

I drive a 2009 Fit Sport 5MT. I was having poor fuel economy (could hardly get 400 km with a full tank, even driving moderately), until I started filling with Shell fuel — which doesn't contain ethanol. I've read ethanol is not recommended for small engines like the Fit's. Since I started using gas that doesn't contain ethanol, I can easily do 600 km with a tank, city/road combined.

Where I live (Montréal, Québec) gas can contain up to 10% of ethanol. Shell gas doesn't contain any. BTW, I only fill with Super since it makes the engine run smoother.

Soyeux

 

I'm averaging 42 mpg (actual/measured) and here's my 2019 LX (stock) with CVT history on every fill up. YMMV. 87 pump octane - mostly Speedway (non-TopTier), with 3K oil 0W20 syn change interval with Honda filter, tire P at 35 psig, stock tires, ECON on, Techron added right before oil change, 89% highway miles to date.

 

Wow! Impressive. Thanks for sharing the graph.

Soyeux

 

Just realized this is an old thread. I get about 33.5 mpg overall (calculated) in summer with a/c on, a little less if I push it hard, a lot more on long hwy roadtrips (40+). I'm happy with the performance vs the fuel economy, it's fine....and pretty fun, as far as econoboxes go

 

I drive normal - but make up the mpg on slowing down using engine braking and pacing on the highway. I still drive let's say +10 over the limit but I leave a large gap in front to engine brake while others run right up on people and gas it and brake heavy just to be close. I've done that and in the LX CVT, that's the difference of averaging 39 vs 42 mpg. Since I bought new - I'm trying to get my money's worth on days that I have 50 or 100 mi round trips (depending on heading to the office or factory). [I make up for that by driving a absolute fun Mazda RX that only gets 15-18 mpg].

 

I wonder if your front O2 sensor is "aging". Your car determines the fuel:air ratio by examining the exhaust O2 sensor (front) signal and adjusts accordingly. I wonder if it's having an issue reading ethanol-based fuels that require more fuel ratio to burn at stoichiometric conditions vs. pure gas. You will lose about 3% mpg by using E10 (10% ethanol) so if you normally get 42 on pure gas you'll see 40 on E10.

If I ever get back up to Montréal in my Mazda RX - we'll have to meet up. I have a few RX friends up there that we've gone on road trips - most recently in 2018 - staying in Bromont overnight.

 

60% highway / 40% city

 

This is a good thread to bring back.

Gas mileage all depends on what kind of driving you do. Most of the time I drive short trips of 3-5 miles, all within Washington, DC, which is constant stop and go. Top speed is usually 30 or 35 mph. It's rough, but recently I've been averaging between 24.9 and 26 mpg. That's mostly with the AC on and driving in a fairly tame manner. It should be noted that I have a manual transmission. The best I've done with only in-city driving as described is about 28 mpg. Long stretches on the highway result in about 44 mpg, so quite the contrast there! (2019 EX)

 

Thanks for your reply! Does gas with ethanol alter your MPG ?

Soyeux

 

Thanks for your reply! Yes, maybe the aforementioned sensor is aging. A scan would tell it, right?

Yes, Bromont is not far, let me know when you come to Mtl

Soyeux