Tonight I conducted a test to see what kind of fuel efficiency I got at different speeds.

I accelerated to target speed, set cruise down the hill (<1% grade), cleared my scangauge current trip at a specific road sign on a straight 1.5 mile stretch of road, noted the mpg at another specific road marker, turned around, accelerated, then resumed cruise up the hill, cleared the trip at the same road marker, noted the mpg at the original road sign. Headlights were on, driver's window cracked 1", temperature: 33F/1C, some light snow, no traffic.

Test 1.1: 30 MPH, 6th gear, 1430 rpm: 52.3 MPG
Test 1.2: 30 MPH, 6th gear, 1430 rpm: 41.5 MPG
Test 2.1: 40 MPH, 6th gear, 1900 rpm: 48.5 MPG
Test 2.2: 40 MPH, 6th gear, 1900 rpm: 38.7 MPG
Test 3.1: 50 MPH, 6th gear, 2380 rpm: 53.3 MPG
Test 3.2: 50 MPH, 6th gear, 2380 rpm: 43.4 MPG

I must admit I am shocked that 40 MPH is somehow less efficient than either 30 or 50 MPH. This requires further investigation to determine which speed yields the best results. And possibly whether different choice of gear helps or hinders efficiency

 

i think alot has to do with RPM , the fit likes to see 3000 on the tack

 

You might want to find out how the software calculates mpg. It is not always the same, and when you reset the mpg indicator, the accuracy is not there immediately. I found it interesting that when I refill the tank (I always top it off to assure myself that amount of gas used is correct between fill up-please don't tell me it's not good idea), it takes the mpg gage a while to become believable. Then, it is not accurate when compared to my hand mpg calculation.

Maybe try same tests but in a different order. You may still scratch your head to figure out the unexpected results.

 

My Scangauge-E is calibrated and verified accurate after each fill up. I'm not sure how it calculates average trip MPG, but however it's doing it, it's accurate enough for my satisfaction. Also I would think that 1.5 miles would be enough to yield semi-accurate and realistic results. I could be wrong of course, but that's why I plan to do more tests at my convenience. I'm not attacking you, (the text might come across that way) just trying to share what I know.

 

Judging by my previous post, I think the Fit's 1.5L motor likes 2400-2500 rpm more than 3000. More tests are on the way as I have free time.

 

for the last few weeks with every refill , i only zero out the B mileage , i let the A accumulate , i figure the average mileage number would be a little more accurate over a few weeks
time . it stays between 34.4 - 34.7 mixed driving