Fuel Efficiency and the Yaris

[mchllp925]

Thanks! I read your earlier posts and will definitely impliment many of those points. Up here in Winnipeg our winters are harsh ( 2-3 months of -20 to -40 celsuis temps) so I will need to idle for at least 30 secs to ensure oil movement to the heads before moving.
Taking out the spare will help save gas? I will try that ( only thing in there)I was not aware of the DFCO so I will be looking for that.

So I will respond later with hopefully a better mpg.
Thank you again for the tips!
Darrin

[mchllp925]

Hi, me again, Just went to get the morning paper and I tried to keep the acceleration 2,000 rpm or lower. WOW I really am a lead foot. It took a little concentration to do that, usually got to the speed limit as quick as I could.
Ho boy can I see the fuel savings.
Darrin

[mchllp925]

All I drive is less then 10 kms. I live out in Transcona and drive to Palliser on Kernaghan. I have definitely found my driving habits are bad. So far in 1 day I have mastered taking off slowly from a stop and not going over 2,000 rpm.
I am still concentrating on coasting to stops. 26 years of bad driving habits wont change overnight, but I'm giving my best. LOL
At least I can't fault my Yaris.

[orheen]

For the fuel consumtion of yaris 1.0 your speed must be at 65 km/h when only driver in the car. When you 5 people your speed must be 100 km/h

yaris 1.3 best fuel comsumption speed 78 km/h

yaris 1.4 d-4d manuel 78 km/h

yaris 1.4 d-4d multimode 68 km/h

I will put the diagrams here that show speed - strenght. And fuel consumptions.

[marcus]

wow......great lookin graph.. good job..atleast ur stats are more realistic..very close to mine...i just dont get how people getting 800km on a 37 liters...i think ill get bored hypermilling the whole time..

your dec 11th 2008 was a little weird seems not possible unless you kept ur engine running in neutral for a very long time.. plus it shows hwy.. you going 180km/hr the whole time??

[knowmercy]

You know, this article is an absolutely great resource! I'd like to offer some, hopefully insightful information to it. Some of these suggestions do make your car use less gasoline, however they can substantially wear on other parts of the vehicle. For instance, shifting at 2k rpms will almost certainly lug the motor and the risk of detonation is considerably higher at rpms that low. The second thing about that is you actually burn less fuel depending on the engine load at the time. So shifting at 2500 or 3k under light load burns about the same amount of fuel as shifting at 2k under moderate load or heavy load. You press on the gas harder, more air comes in and the engine puts more fuel in there. Also, turning off the engine at lights is horrible for it. Every time you restart the engine it takes a short period of time to rebuild a "safe" amount of oil pressure in the engine. This is not achieved if you start the engine and drive off. Not to mention the wear on the starter, relays, and fuel pump. Not trying to be a downer on any of the resources that have been made available. Making a car use less fuel doesn't equate into the best health for the car. Also, always running your car at low rpms actually creates a TON more carbon build up inside the engine. I hope this is helpful to folks who are trying to not only save fuel, but keep their car running for a long time. :)

[BailOut]

Welcome to the forum, knowmercy. I know you meant well with your post and I appreciate that, but I disagree with most of what you presented.

Originally Posted by knowmercy

For instance, shifting at 2k rpms will almost certainly lug the motor and the risk of detonation is considerably higher at rpms that low.

The ECU adjusts for this by retarding the ignition timing by quite a bit. I have never heard any audible indicators of pre-detonation.

Originally Posted by knowmercy

The second thing about that is you actually burn less fuel depending on the engine load at the time. So shifting at 2500 or 3k under light load burns about the same amount of fuel as shifting at 2k under moderate load or heavy load. You press on the gas harder, more air comes in and the engine puts more fuel in there.

The fuel/air map in modern engines is anything but linear, and using a simple tool like a ScanGauge shows that what you say here is just not the case. The loads do not always occur where you think they do.

Originally Posted by knowmercy

Also, turning off the engine at lights is horrible for it. Every time you restart the engine it takes a short period of time to rebuild a "safe" amount of oil pressure in the engine. This is not achieved if you start the engine and drive off.

While it is easy to believe statements like this they simply are not true. Oil pressure has nothing at all to do with the current coverage of oil on any part of the engine. Pressure only lifts oil from the pan to the top of the block where it begins a gravity-fed trip back to the pan. Oil does not magically disappear from all internals the second you turn off the ignition.

Originally Posted by knowmercy

Not to mention the wear on the starter, relays, and fuel pump.

As is mentioned in the first posts in this thread, the break even time for idling versus all wear and tear on a modern vehicle is just 7 seconds. If you can't wrap your head around that number then allow me to show you a real world example:

Even with the carpoolers, equipment, snow, elevation and climbs I deal with I still average about 46 MPG. I think we can all agree that the median MPG for all Yaris owners is 32 MPG. I drive roughly 17,000 miles per year. At 46 MPG I use 370 gallons of fuel. Someone at 32 MPG uses 531 gallons to go the same distance. With fuel at $2.50/gallon I will spend $925 on fuel for the year while the 32 MPG-er will spend $1,328. This means I save $403 per year in fuel costs.

To put that into perspective a starter replacement costs about $180 and comes with a lifetime warranty (I am at 37k miles and still on the OEM starter despite using it more than a dozen times per day). A replacement fuel pump costs about the same (I am still on the OEM). Relays are all less than $20 (I am still on the OEM).

In other words, even if I had to replace one of those items every year I would still come out way ahead.

Originally Posted by knowmercy

Also, always running your car at low rpms actually creates a TON more carbon build up inside the engine.

This is inaccurate. Carbon buildup occurs due to incomplete combustion and exhaust processes. This condition is rare in the Yaris due to the tight control the ECU exerts, and from posts in the tuner forums I would say that it is far more likely to occur at high RPM than low. It's not like I have torn down my engine but I see no signs of carbon or sludge anywhere that is easily accessible (none under the oil cap area, nothing in the throttle body, no fouled O2 sensors, etc.).


Again, I know you meant well, but spreading disinformation helps no one. In the future please be sure to research any information you have before sharing it, and never, ever be afraid to perform your own research.

[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.

[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.

[BailOut]

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

[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.