Seeking feedback on two separate matters:
Matter the FIRST: I am taking a long road trip (approx. 1100 miles one way so 2200 miles total) from Houston, TX, to Tucson, AZ, and back.
I would like to get good MPGs. What do you recommend for my tire pressure given the hot weather and the long highway hours (I will drive it in two days one way - 500 miles/day with the only stops being fuel and restroom)??

A) Keep them at the recommended 33psi?
B) Inflate to 34, 35, or 36 psi? Higher than this and I'm afraid of blowouts.
C) Any other recommended pressures?
D) Recommended speed? Cruise control or not?

Matter the SECOND:
My current tank is premium gas (Shell V-power) - I know that I should just use regular unleaded, but I did this solely as an experiment to see if there is a difference. I only have about 30 miles on the tank, but I've noticed two things so far: 1) The MPGs seems to be about 3-4mpgs lower than usual (at least from the reading on the gauge), and 2) the MPG number is much more volatile than usual - changes of 1mpg or more in a matter of a few minutes - it never behaved like this prior to this tank.
Any explanations as to why this is happening, especially from those who understand the physics of this better?? Should I expect it to behave as before once I start putting regular unleaded again, or have I ruined my Fit??
Thanks

 

Regarding the tire pressure, I prefer not to run more than 35 psi, because I think it makes the ride harsher. No need to worry about blowouts going higher, though, at least up to the 44 psi sidewall rating. It's dramatic underinflation that causes blowouts.

Regarding recommended speed, your mileage will tend to be higher the slower you drive, within reason. If you're on the interstate, though, even 65 mph will be slower than 90% of the other drivers. There are still trucks driving 65, though, to save fuel, so you won't be alone. IMO using the cruise is the way to go. Not using the cruise and letting your speed vary a lot going up and down hills may or may not save fuel, but it's certainly annoying to other drivers around you. To say nothing of the safety aspect of using the cruise, let's you give your attention to the road instead of the speedometer.

Hard to imagine why premium fuel would reduce your mileage. But 30 miles is not much time to understand it, maybe you had a headwind on that leg. You need to at least run through 1 or more complete tanks to get a handle on it. No worries about doing any damage to your Fit by using premium, only damage to your wallet!

 

Very good advice. The only thing I would add is that you might want to hit the Cancel button on cruise control going up long steep hills, if you come across any. Depending on traffic - and that's the important thing - you can let your speed drop a bit. Cruise control can be overly enthusiastic maintaining speed up a hill - lots of high revs. When you see a hill in the distance, pick up some speed on the downhill that usually comes before it.

Steady driving will give you high MPG, but high speed will cut into that. Your Fit is getting better mileage than 90% of the cars on the road, so don't take chances to get one or two more MPG.

Let us know how you do on this trip.

 

So I just hit 2,000 miles on the odometer so I thought I'd weigh in with my mileage estimates so far. I usually reset the trip meter and run a quick MPG hand calculation to compare with the computer. My hand calc typically indicates ~1 MPG lower than the computer. I realize the tank is small and there are various factors that skew the data but we're talking about averages over time and that is close enough for me. I just returned from a 400 mile trip where I averaged just under 42 MPG (mostly state highways at 60-65 mph with a fair number of small towns slowing me down to 35 mph).

 

41.6 mpg in 800 miles.

 

Hello all, from Malaysia. Just got my Jazz V-spec CVT a bit more than a week ago. Features wise it seems to be similar to the USDM Fit EX minus the sunroof and a few other features.

On my second tankful of gas so far, about 700+ km only of almost 95% city driving of 10km or less with the AC on 100% of the time, but my fuel consumption is a dismal 11-11.5km/l (~27mpg US). I'm a bit envious of the much better mileage people are getting from their Fits here but I'm hoping that the mileage will be better when the engine loosens up and I get around to driving a bit further outside.

 

i think a lot of us who get the higher gas mileage have experience driving hybrid cars. i've been driving hybrids for the past 2 years and it completely changed the way that i drive. You get used to driving and accelerating slower, not necessairly because you want to, but because even if you tried, the hybrid doesn't accelerate fast enough to be satisfying anyways lol.

42.2 average for 1,000 miles.

 

The above quote says it all in my opinion. Those are really short trips, and the engine probably barely reaches operating temperature, and then you have to consider the continuous AC load. I think your mileage is fine under those conditions, and don't realistically expect you'll do much better after more miles are on the car. And I would be surprised if hybrids would do much better, but at least there you recover the braking energy between stoplights. Most other non-hybrid cars wouldn't even do as well as you're doing.

 

Stop-and-Go and hills are MPG killers. Keep using the A/C. It's not going to hurt mileage very much, but it will keep you comfortable.

 

Please correct me if I'm wrong, but I think the engine for the Malaysian Jazz (Fit) is different than the US and Canadian one. I don't think it's a direct injection engine outside of the US and Canada. This would probably explain part of the MPG differences.
If someone knows this for sure, please let us know.

 

Yes you're correct, the Jazz GK I have is using a SOHC 1.5l engine without direct injection. I know it's less efficient, just wasn't sure how much less efficient it is. Will try a few longer runs over the next few weeks!

 

I did go through the route which my wife takes in a bit more detail. The primary one is 8km (~5 miles) which takes roughly 25 minutes altogether, including the traffic lights, stops, speed bumps. That's about 20km/h (12mph) average speed after all the stop/go, she does this 5-6 times throughout the day which definitely kills the fuel consumption.

I've done a few longer runs, getting up to 16.5km/l (~39mpg) average which is more in line with what the car's capable of

 

That sounds great, your car appears to be doing what it should do! Maybe your wife would be interested in a bicycle for those short trips, but also perhaps too dangerous where you live.

 

The numbers from the 1st leg of the trip. Each leg began from a full tank based on when the pump had its first click. Tires were at 34 PSI on 07-03-2015:

Houston, TX, to Ozona, TX (07-04-15):
353.7 MILES
8.635 GALLONS from a Stripes Gas Station in Ozona, TX. The gas for the leg was from a Shell Gas Station in Houston, TX, just prior to the trip.
353.7/8.635 = 40.96 MPG
Mostly highway with with the cruise set between 70-75mph for a while, then around 70mph. Hill Country so up and down hills. Some minor slowdowns here and there due to other traffic, especially in San Antonio, TX.

Ozona, TX to El Paso, TX (07-04-2015):
371.5 MILES
8.528 GALLONS from a Shell Gas Station in El Paso, TX. I filled with Plus (88octane) since for some reason the regular was labeled 86 octane.
371.5/8.528 = 43.56 MPG
Highway driving with the cruise set around 68-69mph. Uphill and downhill.

El Paso, TX, to Tucson, AZ (07-05-2015):
346.0 MILES
7.645 GALLONS from a Shell Gas Station in Tucson, AZ.
346.0/7.645 = 45.46 MPG
Highway driving with the cruise set between 65-68mph. Some lengthy downhill segments.

We'll see how the Fit does on the return trip a few weeks from now.

 

Thanks for the detail posting of your trip, 2015FIT, I always find those things interesting. Nice numbers, and hopefully the winds are predominantly out of the West/Southwest so your return numbers are even better.

 

GoBucky, your Fuelly numbers truly impress, especially considering (and assuming) you started recording in winter! I think you must be #1 on Fuelly. There is supposedly somebody with an average of 75 mpg, but that has to be a one tank anomaly.

 

Thanks John. Yeah, I don't look forward to what those winter numbers do to your average. It definitely would make a big difference to have an engine block heater, but I don't want to go that route again. We can only dream of getting 75mpg, but that would only be possible with a hybrid version and some VERY serious hypermiling.

 

Im only getting good high 30s/ low 40s on the freeway.

My city driving is seriously lacking in the high 20s.

 

Compare that to what you would get driving a pickup with a V8.

The higher the speed, the higher the fuel usage.

 

This is definitely an outlier, but I scored my all-time-single-trip high MPG today: 64.1 mpg!



This was over about 25 miles at an average speed of around 40 in light traffic with minimal stops and a warm engine.

The bottom number is more in line with what I've getting driving back and forth to work on rural 55mph farm roads.

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