Fuel Efficiency and the Yaris

[tooter]

Originally Posted by b20vteg

anyone notice lower mpg now that it's colder? why is that? :S

I get exactly the same effect on my Yaris as with my motorcycle. The bike averages 66 in Winter and 70+ in the Summer.

I got my Yaris at the end of April which was mild Spring into hot summer weather and it's 2,000 mile average was 36.5 mpg.

Then I installed the tooter manifold and the next 1,100 hot Summer weather into milder Fall average was 38.3.

Now the latest 800 mile cold weather Winter average (also with the tooter) is 37.2.

So I can't wait for more than a year to pass so that I can get comparative mileage averages under similar seasonal weather conditions.

[Amdkt7]

There are a lot of factors relating to poor economy in cold weather. Much of it is increased friction from lubricants, plus winter blend gas, and often colder operating engine temps. A hotter engine is usually more fuel efficient (not if the ECU is backing off timing to prevent knock).

[screenprintr]

What happens when you turn on the Air conditioning? My car barely moved once I turned on the Air today. Yikes!

[Amdkt7]

Huber Optic film, all the way around the glass. Did not need air today, I know in the past I would have! I did use air on a trip with a load of people (full car) because of the humidity. It did not hurt my mileage much. 38 mpg, 70 mph much of the trip.

[peewee1]

I got tired of hypermiling, tired of the hard ride,tired of coasting down hills. So I lowered the air in my tires to 30 lbs, nolonger do any coasting. I just driver smarter and slower ( under 58 mph). No jack-rabbits and feather the gas pedal,and my mpg has gone from 36 to 41 mpg. The real answer to good mpg is TAKE IT EASY.

[TLyttle]

Bump. My Yaris is 6 years old now, so I thought I would do a FE check, pleasantly surprised at 5.1L/100km, city and highway. Even now, that is a nice number, and the fact that I have been getting that for all this time makes this a very efficient vehicle!

[Amdkt7]

Some short trips, or trips with to many stop signs kills my mileage to the low 40's (mpg). Often get over 50 mpg on my trips to and from work. I sometimes can eek out 60 mpg. I use pulse and glide a lot. I have been experimenting with staying in lower gears while accelerating (up to 4k RPM), my trip average does not seem to suffer. Once I reach my target speed I'm in 5th, or coasting as soon as possible. So, it does not seem to matter much how you pulse, low rpm, or mid rpm, the overall mpg does not seem to be effected. The higher rpms gets you up to speed much faster even though the instant mpg is worse, the overall mpg is about the same. Otherwise, highest gear possible is the way to cruise.

When I bought the car I was only hoping for high 30's. What a great car!

[charles nelson]

Most modern cars get better mileage using AC with the windows closed at typical highway speeds. Slower...better mpg with the windows open and the AC off. At higher speeds, the open windows cause increased drag. Usually your car's velocity varies quite a lot at lower speeds...urban stop and go type. And the engine has to rev higher to speed up and run the A/C. So for best mpg, open windows at slower speeds and A/C when cruising down a highway.
At highway speeds and the windows open, I get a very loud low frequency thumping from air pulsing into the vehicle. With the windows closed, there is very little air noise. Noise is wasted energy. Some new cars now have air speed controlled louvers in front of the radiator to deflect and smooth the air flow over the front.

[Amdkt7]

A lot of hyper-millers have found that AC on anytime is worse then having the windows down.

I coast down the same hill every day and have not been able to detect any difference in the coast with the windows up or down (though I usually only roll down one).

It may vary from car to car. Some cars may have a less efficient unit that really hogs the power.

[bigdoglover]

just filled up yesterday and i manually check my mpg every tank. with the hot weather and using a/c the last week my yaris only got 34 mpg. i normally get 38 mpg without even trying so using the a/c really sucks the mpg in my yaris. i need a more fuel efficient car but this one is paid for. it just was too hot not to use the a/c

[Amdkt7]

Originally Posted by bigdoglover

just filled up yesterday and i manually check my mpg every tank. with the hot weather and using a/c the last week my yaris only got 34 mpg. i normally get 38 mpg without even trying so using the a/c really sucks the mpg in my yaris. i need a more fuel efficient car but this one is paid for. it just was too hot not to use the a/c

I guess you do a lot of city driving? Only a hybrid is going to do better I think. Are you driving an automatic? With a stickshift you can pulse and glide, even in traffic to some extent. Very short pulses in lower gears, then coast a little, pulse again.. one can maintain pretty much the same speed as the traffic.

However, on trips to go pick up my kids on that side of town I seldom can wring out 40 MPG, even doing all of that. The rest of the time I usually get over 50 mpg on any trip over 10 miles. Short trips always suck.

[JimKellyfan]

Good post, nice read. I got 38 mpg (new owner/one month-ish) while doing 80-85 down to st pete and 36 mpg / uphill on way back. Coming off a caprice wagon with an LT1 engine, I am lovin the 38 @ 80-85 mph. I am going to put a TRD high flow filter in, for the increased flow potential, HP gain potential and improved performance/response. However, it is a myth that any high flow or even just new air filters provide better fuel mileage in anything that doesn't have a carburetor. FYI. New air filter will protect your engine and if it is fuel injected, will provide better response, not mileage. This is average user, hyper-miler, well, they get good mileage anyway. Good job, 50 plus, cool. I am also against the start stop feature, as every time you use your starter is one less time you can use it again. If doing this, just get a Prius and enjoy the drive instead. Me, I was afraid of the many Prius failures, and know these cars to be good and dependable. (The Yarii). everything else in the read great, make sure to read the tire sidewall before bumping to 50 psi, as the majority of the market on tires is 44 psi max or some less 35 psi, and some at 51 psi, but more rare. Michelin has a mileage tire for us, but up a size or to a 16 inch and get the handler for performance hounds, the Pilot Sport AS3's.

[frog13]

Folks get way too hung-up on MPG,they drive themselves "crazy".From the first page: Turning off your engine at all of those intervals is ridiculous,keep your engine in a good state of tune and be done with it.

[Shroomster]

How are people getting 38mpg?
are you guys looking at instant mpg, looking at your scan gauge, or are you calculating your per tank mpg?
Somehow skewing the numbers?

38 psi in the tires
a/c on most of the time
I drive on average 25 miles one way to work
70-80mph
I only see 32-33 mpg per tank
Average 326 miles on 10 gallons
I fill the tank completely every time




This is summary of every fill up (partial and full) since owning my '14


Sent from my metallic purple honami

[nookandcrannycar]

Originally Posted by Shroomster

70-80mph

I would guess that this is the biggest issue. I usually drive 55-62 MPH in the slow lane. My last tank = just over 42.5 MPG, and the current tank will surpass that rate.

[Rigaud]

Best economy is 50mph and below.

[Shroomster]

Originally Posted by nookandcrannycar

I would guess that this is the biggest issue. I usually drive 55-62 MPH in the slow lane. My last tank = just over 42.5 MPG, and the current tank will surpass that rate.

That's what I thought too, but looking through the thread, all these people who claim to red line the car or drive faster than that, are getting better mpg than me...

Sent from my metallic purple honami

[nookandcrannycar]

Originally Posted by Shroomster

That's what I thought too, but looking through the thread, all these people who claim to red line the car or drive faster than that, are getting better mpg than me...

Sent from my metallic purple honami

The ones I saw that mention your lowest speed or above :

Page 3 -- member lgcharlot: 37 MPG at 70 MPH for a couple of California to British Columbia road trips (member = a 4 post wonder)

Page 4 -- member Maypo mentions peak fuel economy was 39 MPG at 75 MPH -- closer attention reveals he is talking about a Fiat X1/9 (who knows why he is mentioning an X 1/9 (member = a 1 post wonder))

page 12 -- member Bilstein mentions 39 MPG at 75-80 MPH...but his tire pressure is at 50 PSI.

page 13 -- member Amdkt7 mentions 38 MPG at 70 MPH with a full load of people. The nature of all of his posts....overall, the hills probably help a bit, but I think he just has a stellar focus re his driving habits.

page 14 -- JimKellyfan -- 38 MPG at 80-85 MPH....aided (I imagine) by the downhill part of the trek (he uses 'uphill' in reference to the return)

side note: Page 2 -- Keesue's reply to Nigal -- set tires to 32 PSI and MPG improved....same thing happened to me when I did same (down from 38 PSI for me) sometime after last summer. In the past, PSI increase = MPG increase in my experience.