Fuel Efficiency and the Yaris

[marcus]

Originally Posted by TT75

Thanks for your comments. I think it may be possible to run 800 km with 37 liters (37/8=4.6 lt/100km) if the car is Yaris D-4D (Diesel engine) and if it is going on highway. Beacuse, D-4D has a theoretical value of 4.5 lt/100km on highway. However, it is nearly impossible to get 4.6 lt/100km with 1.3 VVTi engine (gasoline).

The record on Dec 11th 2008 is for a long trip on highway. You are right that my speed was around 150-180 km/h for whole the trip. Actually, board computer says it is 7.9, but the calculation says it is 8.1 which is even higher :).

i understand d-4d engine but that mpg is on 1.5 liter ..its someone in canada and we dont get 1.3 or d-4d engine in here so go figure...i dont get it..

[BailOut]

Originally Posted by marcus

i understand d-4d engine but that mpg is on 1.5 liter ..its someone in canada and we dont get 1.3 or d-4d engine in here so go figure...i dont get it..

marcus,

That is 497 miles on 9.774 gallons for 50.85 MPG. While it is certainly impressive it by far not the only 50+ MPG tank that Yaris owners with the 1.5L have achieved. I alone have 16 50+ tanks - some even after gaining carpoolers and having the crappier route that comes with them - as does voodoo22, and he even has the auto transmission!

As has been explained time and again, it all comes down to self discipline and attention to detail. If you want it it is yours for the taking.

[Woody_Woodchuck]

I also can see 50+ mpg US with the 1.5L gas Yaris. Mine just made its first “break-in jump” at 7,000miles and is getting about 2mpg better mileage with no driving adjustments. I look forward to spring/summer when I can hopefully join the 50+ club. Best winter tank so far was 47.77 mpg US for 281 miles driven.

I think terrain has as much to do with achievable MPG as driver ability or techniques. Someone with a flat or low rolling drive will get better mileage than someone in mountains or smaller steep hills. Also driving speed, I have had some fantastic mpg segments going 45 mph but can not do it regularly due to traffic. And then comes the driver. Getting over 45 mpg (at least for me) takes some work and dedication.

EDIT
The actual increase I have is:

First 19 tanks average 43.73 mpg US
Last 4 tanks average 46.47 mpg US
A 2.74 mpg increase.

The previous 4 tank average (before the sudden increase) was 44.79 mpg which gives a 1.68 mpg increase.

[TT75]

it is really interesting to have 50+ mpg with 1.5 L Yaris. Is it running with LPG? :)
I guess your roads are always flat, they are in good condition with less friction. Also i think you dont have any hills. You must also be very patient in hypermilling :)

My Yaris is 1.3 VVTi gasoline engine. Manufacturer's specification for FE is 5.3 lt/100km which is minimum value. If am not wrong it corresponds to 48 MPG. What is the MPG value of the manufacturer for 1.5 L Yaris?

[Woody_Woodchuck]

For my 2008 LB w/5-speed: 29 mpg US city, 36 mpg US highway or a combined average of 32 mpg US.

I do have hills which is why I mentioned it. Not mountains, small hills. Maybe ¼ mile to 1 mile between peaks and only one hundred or two hundred feet of elevation. Lots of gaining momentum on the down slopes and losing it on the uphill sections. If it was flat here I could see getting mid 50’s for MPG on the highway.

And yes, I do work hard at trying to get that kind of mileage out of my Yaris. No tailgating trucks or turning the engine off (except at long lights) just driving with a light pedal and at or under the speed limit. I’m still learning and hope to do better as I progress.

I can also see where folks are getting in the low 30’s for mpg. They are driving for fun, I am driving for economy.

[daf62757]

Just curious....when some of you get +50 MPG in your 1.5 Yaris, do you do anything special? What is your speed? Oil? Air Filter? Spark plugs? Tire pressure?

[BailOut]

Originally Posted by TT75

it is really interesting to have 50+ mpg with 1.5 L Yaris. Is it running with LPG? :)
I guess your roads are always flat, they are in good condition with less friction. Also i think you dont have any hills. You must also be very patient in hypermilling :)

I climb 4,500 feet (1500m) of elevation 5-7 days per week in an area that sees 300-400 inches (750-1000cm) of snow each year. That's not what I would call flat, and while the roads themselves are in good shape that all goes away as soon as the plows start running during snow storms, and each summer one alternating half of the road must be resurfaced.

Yes, hypermiling does take patience and attention to detail, but that's what makes it fun. Each tank of fuel is a personal challenge and an opportunity to best yourself while lessening your oil usage and saving some money at the same time.

Originally Posted by daf62757

Just curious....when some of you get +50 MPG in your 1.5 Yaris, do you do anything special? What is your speed? Oil? Air Filter? Spark plugs? Tire pressure?

Every one of us that breaches the 50 MPG barrier uses several hypermiling techniques. You can read all about them in the first few posts of this thread and select some things that are relevant to your driving circumstances to experiment with.

Out of the "mods" you listed the only two that matter much are your speed and tire pressure. Changing to synthetic oils will gain a small amount of MPG, as will ensuring that the air intake can breathe and that your spark plugs aren't fouled, but those gains are small.

As for speed I never drive over 55 MPH (sometimes 60 MPH for short distances if I'm in a tight spot) unless I don't have to use fuel to do it and I run my tires at 60 PSI year round.

[knowmercy]

Thanks for replying to my comments. I appreciate the wealth of knowledge that you provide here. :) I've rebuilt many engines and I think we're going to have to agree to disagree on a few points, but that's ok. For what it's worth, I got about 31mpg on my first tank and I'm up to about 36 now with approximately 1100 miles logged now.

[vancouveryaris]

would changing to synthetic oil help with fuel efficiency?

[BailOut]

Originally Posted by vancouveryaris

would changing to synthetic oil help with fuel efficiency?

Hello there,

Yes, it does help with efficiency, but only by a small amount. That amount is often too small to break even with the higher cost of synthetics.

To get around the cost issue I run an extended performance synthetic with a 15k mile drain interval.

In the big picture there are many other benefits to running synthetic motor oil such as better protection during cold starts, better resistance to thermal breakdown, etc. In the end each of us needs to make our own decision and decide on our own price point.

[voodoo22]

I just eked out my first 50 US mpg tank of the year at 50.3 US mpg over 837kms. Hopefully this is the beginning of another streak, but colder weather and powerful winds over the next couple days might prevent that. At least the real winter is over. This was my most successful winter MPG wise as I didn't dip below 47 US mpg.

837 kms
39.099 litres of gas
4.67 l/100km
50.35 US mpg

[BailOut]

Well done, voodoo22! Pulling 50+ MPG in Winter is no easy feat at all.

[voodoo22]

Originally Posted by BailOut

Well done, voodoo22! Pulling 50+ MPG in Winter is no easy feat at all.

Thanks Bailout, but I can't take credit for doing that under real winter conditions like you drive in or like I used to live in when I was in central Canada. It rarely goes below -20 Celsius here, but with the AT anything below 0 Celsius makes it exceedingly hard to break 50.

[regal]

I have basically been hypermilling since 1990 when I was driving a 350ci Cutlass on a student budget. I think the OPer is not understanding the concept. The whole idea is not to accelerate more than you need to. Yes some of the techniques are not practical but gunning the car between lights is not practical either, or speeding up +20 mph 30 seconds before your exit. The idea behind hypermilling is to use common sense, something that probably 95% of the US drivers have none of. I drove a 50 mpg 85 Jetta for a few years and the 50 hp engine had no choice but to hypermill. It takes much less fuel to go from 0 to 60 mph in 25 seconds than to do it in 7 seconds.

The other thing about hypermilling people don't understand is that it isn't always about driving as slow as possible. 5th gear is always more efficient than 3rd. Puttering around at 30 mph in 3rd gear will give terrible milage vs 55 mph in 5th.

[Naya]

Hello,

I'm kinda new to this whole car thing, so forgive me if any of my questions seem a little noobish.

I have a 2007 Yaris with about 30,000km on it. I've taken it for all it's scheduled oil changes and haven't had any issues until recently.

I noticed my fuel economy getting worse and worse over time. At first I just attributed it to the cold winter (it gets pretty frosty in Ottawa) but even now that it's coming to spring, it's getting worse. When I was doing mostly highway driving I was getting about 400km to a tank (this was up until Janurary). I am now getting about 350km to a tank, running it almost to dry. Most of my commute now is city driving, not going above 85km/h.

I took it to my local dealership and they said nothing was wrong. Most of these issues seem to have started happening after my last oil change, but that might just be a coincidence. I also noticed that when the engine is cold, the transmission is really sticky. If not warmed up for at least 15 minutes, it will sit at about 4000rpm doing 80km/h and refuses to shift until brought up to 90km/h (4500rpm).

Sorry if it seems like I'm just spewing out information, but I really have no idea what would and wouldn't be relevant. I'm hoping someone might be able to give me some ideas. My dealership has been no help at all.

[BailOut]

Hello Naya,

The high RPM/no Drive gear change is normal while warming up. It is the same for all owners that have the automatic transmission (AT).

As for your drop in mileage I an going to ask you a seemingly stupid question:

Are you sure you have the shifter in the D position rather than the 3 position when you drive off?

Many AT owners get confused by the D placement and drive around in 3rd all the time, causing a huge hit to their fuel efficiency.

[firemachine69]

It's normal. Had my Yaris for over a year, and even with some insane hypermiling, never broke 35mpg (about 98% city driving, very short trips).

[Naya]

Hi Bailout,

Thanks for the quick reply! It's not a stupid question at all (since I have made that mistake once before). I always use D and not 3.

Just as an example of the change in fuel economy, in the first year I had the car I was doing city driving (the same as I am doing now) and was getting 600-700km per tank (run almost completely dry). My fuel economy was insanely good. I don't expect it to ever get that good again, since I don't know what I did to luck out on that, but as it stands I'm getting about the same fuel economy as my friend who has a Dodge Avenger R/T. He's really getting a kick out of that.

Oh and FireMachine, I just found a quick calculator online and I'm currently getting about 26mpg.