Fuel Economy

[enkid]

One thing I've noticed using the SGII and different driving styles and road conditions:

The ECU seems to adjust/tune the performance to the style and conditions of driving over a period of time...for example, if I go from Providence to Boston and back on a warm summer day, and do 70 to 80 MPH, my gas mileage will be in the low 40's that day.....then the next day, same weather, same route, if I semi-hypermile the FE will only be a little better - mid/high 40's....but the following day it'll be back up to 52 - 55 MPG. I've noticed this about a dozen times this summer. The same thing seems to happen when and after rainy weather impacts the FE. The conditions of the previous trip seem to affect the FE performance of the current trip. Could it be that for many drivers, the capability of realizing this really high gas mileage with the Yaris is never noticed because it takes a couple of days of conservative driving under good conditions before it happens?

[Shroomster]

Originally Posted by enkid

One thing I've noticed using the SGII and different driving styles and road conditions:

The ECU seems to adjust/tune the performance to the style and conditions of driving over a period of time...for example, if I go from Providence to Boston and back on a warm summer day, and do 70 to 80 MPH, my gas mileage will be in the low 40's that day.....then the next day, same weather, same route, if I semi-hypermile the FE will only be a little better - mid/high 40's....but the following day it'll be back up to 52 - 55 MPG. I've noticed this about a dozen times this summer. The same thing seems to happen when and after rainy weather impacts the FE. The conditions of the previous trip seem to affect the FE performance of the current trip. Could it be that for many drivers, the capability of realizing this really high gas mileage with the Yaris is never noticed because it takes a couple of days of conservative driving under good conditions before it happens?

most al cars with FI do this. because the computer sends info for how much output from the injectors it wants. thats why if any of you ever go on a trip that first tank is not the best...the second and subsequent tanks are...everything is calculated from how much throttle to o2 temps....

[swng]

Follow up to Post #1523, Page 102:

Fuel Cost
$40 Canadian

Distance travelled
553.6 km
344.01 miles

Fuel Amount
38.32 litres
10.12 US gallons
8.43 Imperial gallons

Cost of Fuel
$1.04 per litre
$3.95 per US gallon
$4.75 per Imperial gallon

Fuel Economy
6.92 litres per 100 km
33.98 miles per US gallon
40.81 miles per Imperial gallon

Mileage Costs
7.2254 ¢ents per km
11.63 ¢ents per mile

No significant change to driving conditions except wife drives more than I do. See Post # 1523 and also: http://www.gassavers.org/garage/viewgaslog/264. Also, we have encountered a lot of road works which created traffic jams. We always drive for maximum safety and comfort but do not waste fuel unnecessarily. In essence, we drive the Yaris like it is a family car and in that sense, the fuel economy numbers should not be too different from those of a typical common Yaris user.
Results have become quite consistent. Fuel calculator used:.http://oee.nrcan.gc.ca/transportatio...ut.cfm?attr=16.
Easy to use. Just copy the result and paste it to the post. Uses up some space though. Fortunately there seems to be no shortage of space here.

[swng]

Originally Posted by enkid

One thing I've noticed using the SGII and different driving styles and road conditions:

The ECU seems to adjust/tune the performance to the style and conditions of driving over a period of time...for example, if I go from Providence to Boston and back on a warm summer day, and do 70 to 80 MPH, my gas mileage will be in the low 40's that day.....then the next day, same weather, same route, if I semi-hypermile the FE will only be a little better - mid/high 40's....but the following day it'll be back up to 52 - 55 MPG. I've noticed this about a dozen times this summer. The same thing seems to happen when and after rainy weather impacts the FE. The conditions of the previous trip seem to affect the FE performance of the current trip. Could it be that for many drivers, the capability of realizing this really high gas mileage with the Yaris is never noticed because it takes a couple of days of conservative driving under good conditions before it happens?

I agree. I do not have a scangauge on my Yaris but I do have something like a trip computer on my other car with which I also get better than EPA fuel economy: http://www.gassavers.org/garage/viewgaslog/266?. I do share your observations. I have been suspecting that I might have been too subjective but now I am more inclined to think that the ECU remembers things.

[bogey mo]

just finished my first tank...630 km on the full tank from the dealer...doing mostly hwy km from oakville to scarborough on .. approx 60 km one way...approx 140 km avg speed with air...im soooo happppy! lol 6.4 L /100km is the shiza!!!

[roxy84]

i think shes gettin broken in. previous 4 tanks:

431.8 mi/10.17 gal=42.4 mpg
424.9 mi/10.016 gal=42.42 mpg
427.3 mi/10.041 gal=42.55 mpg
422.8 mi/9.88 gal=42.79 mpg

my latest tank 406.2 mi/9.16 gal=44.34 mpg--identical driving pattern to the previous 4 tanks. (oops, i just remembered that i changed the tire pressure from 32 psi to 36 psi before this tank, so that may be the reason for the increase)

[YarisPR]

My car has never pass the 250 miles per tank. I don't know if it is my style of driving or the fact that I drive on City 24/7 there is no highway where I live and PR is consider extreme driving conditions due to the constant stop and go (stop lights and traffic jams). And lets not forget the constant hill climbs. I really don't know but its not what I expected from a 30+ MPG car

[death is my gift]

Originally Posted by YarisPR

My car has never pass the 250 miles per tank. I don't know if it is my style of driving or the fact that I drive on City 24/7 there is no highway where I live and PR is consider extreme driving conditions due to the constant stop and go (stop lights and traffic jams). And lets not forget the constant hill climbs. I really don't know but its not what I expected from a 30+ MPG car

I'm pretty much the same. Last tank I got 288 miles. All city, stop and go, red lights. Plus, I drive hard. The gas pedal is my friend.

[nsmitchell]

I did about 50/50 city hwy and got 35MPG.

[BailOut]

Due to my usage of advanced efficiency techniques my mileage in the city is the same as it is on the highway. In the city I have to accelerate many times over short distances due to stop lights and such but that's about the only time my engine is actually running. On the highway the driving is much lighter on the throttle (lots of pulse and glide, never over 55 MPH, etc.) but my engine is running about 98% of the time in order to maintain a speed.

The two sets of techniques end up at the same mileage every time.

[nsmitchell]

Originally Posted by BailOut

Due to my usage of advanced efficiency techniques my mileage in the city is the same as it is on the highway. In the city I have to accelerate many times over short distances due to stop lights and such but that's about the only time my engine is actually running. On the highway the driving is much lighter on the throttle (lots of pulse and glide, never over 55 MPH, etc.) but my engine is running about 98% of the time in order to maintain a speed.

The two sets of techniques end up at the same mileage every time.

You must use the "Little Miss Sunshine" method of taking off. hehe http://www.youtube.com/watch?v=N4O5cTnX8iw
If you haven't seen the movie, you should.

[petesimac]

Originally Posted by BailOut

Due to my usage of advanced efficiency techniques my mileage in the city is the same as it is on the highway. In the city I have to accelerate many times over short distances due to stop lights and such but that's about the only time my engine is actually running. On the highway the driving is much lighter on the throttle (lots of pulse and glide, never over 55 MPH, etc.) but my engine is running about 98% of the time in order to maintain a speed.

The two sets of techniques end up at the same mileage every time.

Okay, Bailout, please to be explaining the techniques for city driving. Now that school has started for my kids, I do a lot of short distance driving with loads of stop signs, traffic, short red lights, etc. Only once with predominantly city driving have I been able to get 34 mpg (note, I've had no problem getting the high 40s for hwy driving), and the current tank looks like it'll end up at around 31 mpg. So, please, tips on how to get this number up. Thanks!

[BailOut]

Originally Posted by petesimac

Okay, Bailout, please to be explaining the techniques for city driving. Now that school has started for my kids, I do a lot of short distance driving with loads of stop signs, traffic, short red lights, etc. Only once with predominantly city driving have I been able to get 34 mpg (note, I've had no problem getting the high 40s for hwy driving), and the current tank looks like it'll end up at around 31 mpg. So, please, tips on how to get this number up. Thanks!

Please see the stickied efficiency thread at http://www.yarisworld.com/forums/showthread.php?t=5979 as it covers everything I do. To be more specific regarding city driving I:

- Make use of my block heater every chance I get, carrying an extension cord to plug in at the homes of friends and family when we visit. I also have the ability to plug it in at work. Between this and errand organization it's a rare day when I do a cold start.

- Never speed.

- Never run the a/c, opting instead for window tint, a sun shade, window deflectors, keeping the windows cracked a bit, and a homemade ice vest for the truly miserable times.

- Never get above 2,000 RPM in the city.

- Use the lowest gear possible to maintain a speed when needed (i.e. 4th gear at 25 MPH).

- FAS a whole lot, basically slowly accelerating to the desired speed between known stops (i.e. stop signs, long lights, etc.) and then cutting the engine ASAP and coasting a great distance to the stop.

- Keep the engine off at stop lights, construction stops, drive-thru windows, etc.

- Park way out in the parking lots so I don't waste fuel looking for a space, and can FAS all the way to a space and park face-out.

- Use the DWB technique in combination with DFCO and P&G or FAS/P&G wherever possible to deal with red lights or lines of traffic.

- Combine all my errands into one trip, starting with the furthest one and ending closest to home.

- Constantly assess the road ahead for several blocks in order to have the time to make any needed lane or speed changes slowly, deliberately, and well ahead of time.

- Use my SGII to help keep myself dialed in.

- Try to stay informed of road work/construction areas and route well around them.


That's about it. Now you know why I say that, in the city, my engine is only running about 30% of the time. I know it sounds like a lot but by adopting and becoming comfortable with just one technique at a time, over a few weeks it all becomes second nature.

[petesimac]

Yeah, but none of what you've written can account for 20 miles per gallon; is it because my car usually has 3 people in it? Can an extra 200lbs take away 20 mpg? Is there a difference between city driving and CITY driving? I must be missing something. I already do DFCO; I don't FAS, though, although I try to DWB, but on a steep hill going down, you either use the brakes or crash, plus, again, that can't account for 20 mpg. Any thoughts?

[bogey mo]

i've found city driving to be similar as well..although I am a manual driver and am able to avoid stopping whenever possible...if people all drove standard cars..we'd all be better drivers!!!

[swng]

Thank you all friends for the discussion about fuel economy in ctiy traffic in the previous posts.

IMHO, as far as fuel economy is concerned, the Yaris is basically designed with city driving in mind without losing sight on the possibility of not infrequent highway trips. I base my opinion on the fact that whilst the Yaris gets practically the best fuel economy in city traffic among cars in the same class, yet on the highway, its F.E. whilst still good, is no better than that of its heavier sibling, the Corolla, with a bigger (1.8 liter) engine. Here are the ratings:

http://www.fueleconomy.gov/feg/calcu...umn=1&id=23548
http://www.fueleconomy.gov/feg/calcu...umn=1&id=22749

My wife and I drive our Yaris not too differently from any ordinary person driving a family car, in the city and on the highway alike, and our mpg numbers are comfortably above the EPA's average rating. Note that the traffic that we drive in is by no means smooth. The car carries two people plus belongings most of the time. The sound system and the AC are also on most of the time. We always drive for maximum safety and comfort, though fuel is not wasted unnecessarily.

I believe fellow members here can all achieve better and better results as they gradually become more and more fuel economy conscious. I wish to encourage those who have not yet been enjoying the good fuel economy that can be expected from a Yaris (in city traffic for the purpose of this discussion) to try harder. Fuel economy conscious driving is not boring and is in fact very additive. Once one starts, one will try to do better on every occasion of driving. There are lots of fuel saving tips here and everywhere on the net (but to state the obvious, please note that there are always risks associated with net surfing). Here is a page of tips that I have casually found, just for an example:

http://www.google.ca/search?q=gas+sa...ient=firefox-a

Safe/save and happy motoring everyone!

[roxy84]

yet on the highway, its F.E. whilst still good, is no better than that of its heavier sibling, the Corolla, with a bigger (1.8 liter) engine. Here are the ratings:

http://www.fueleconomy.gov/feg/calcu...umn=1&id=23548
http://www.fueleconomy.gov/feg/calcu...umn=1&id=22749

swng, i think the data you cited disproves your point. the yaris average from actual drivers is 35.1, while the avg for actual corolla drivers is 31.2, so the yaris is a 12.5% increase over the corolla based on that. looking at the chart from actual yaris drivers, many of the very highest mpg figures come from tanks that were primarily highway. my tanks (5 speed yaris) have been more highway than city lately, and im getting 4-5 mpg's more than i ever achieved with my 5 speed corolla over the same routes.

[swng]

Originally Posted by roxy84

swng, i think the data you cited disproves your point. the yaris average from actual drivers is 35.1, while the avg for actual corolla drivers is 31.2, so the yaris is a 12.5% increase over the corolla based on that. looking at the chart from actual yaris drivers, many of the very highest mpg figures come from tanks that were primarily highway. my tanks (5 speed yaris) have been more highway than city lately, and im getting 4-5 mpg's more than i ever achieved with my 5 speed corolla over the same routes.

Thanks for the response.
I was only referring to the mpg numbers for city/highway driving in the new EPA official ratings and nothing else. The Corolla and the Yaris are both rated at 35 mpg for highway, with the Yaris getting a better number for city traffic. The Corolla is heavier and equipped with a bigger engine. On the other hand I respect the fact that you actually get good mpg numbers with your Yaris on highways. I feel happy for you.
I do not know why on the EPA site, both the Yaris and the Corolla get 35 mpg for highway. Please note however, that the EPA has strict rules about what is "highway driving" as opposed to many individual drivers' own perceptions. Anyhow, I cannot dispute the EPA ratings because I have nothing solid enough to base on. On the other hand, I find that your points are moot and are worthy of further discussion/observation.
Of course the Yaris' fuel economy is good on highway, as I have already pointed out. I was only trying to follow up the discussion in a few previous posts by some fellow members who felt that in city traffic, the Yaris was not performing well enough for them fuel economywise. I was proposing that with its design (I meant characteristics), the Yaris should in fact do well, and be better than other comparable cars, in city traffic.
In a vague attempt to explain why despite both models get 35 highway mpg according to EPA, more Yaris drivers report good highway F.E. to the EPA site than Corolla drivers, as you may have implied (I admit I have not gone through all the data on that site and please forgive me if I understand you wrongly), I would say that it may have something to do with why certain people acquire certain cars. You know, people choose different cars for different purposes and understandably they drive in different styles. As for me, I have bought the Yaris for, inter alia, its good F.E. I tend to believe that Corollas are more likely used as primary family cars (for e.g. taking children to school and groceries shopping etc.) compared with the Yaris, which I believe are more likely used by single/younger people as a commute/pleasure car (but not without significant exceptions on either side). This may give rise to a result that Corollas may on average carry more people and other loads. In the absence of proof that Corolla and Yaris drivers drive with the same/different styles under the same/different conditions, I tend to treat the new official EPA rating (as opposed to the F.E. numbers uploaded by individual drivers to the site) as relatively more objective because at least EPA rate cars under same rules and conditions. I think that the collective results of the individual makes/models' groups of drivers are more appropriate for further but not basic reference. To quote an extreme hypothetical example, I think an expensive big car like a Mercedes S Class is less likely to be reported as more fuel economical than the Yaris on the EPA site when it comes to individual drivers' reports to that site, partly and mainly because it in fact needs more fuel to run but also partly because a typical S Class driver will less likely (but not without exceptions) be a hypermiler, or a very frugal driver. On the other hand, there are obviously some Yaris drivers who are hypermilers or frugal drivers. So when the drivers' results are uploaded to the EPA site, the average mpg numbers for those cars you can see will be affected accordingly by such trends.

In summary, I referred in my previous post only to the new EPA official ratings for the Corolla and the Yaris, both being 35 mpg for highway but the Yaris has better city F.E., as a point of interest. I referred to those EPA ratings to illustrate that in fact the Yaris should be quite good for city driving as far as F.E. is concerned. I may or may not have proven my point successfully though, yet I definitely enjoy the meaningful discussion. For sure, I am not trying to draw a definite conclusion about the two models' F.E. More views from knowledgeable people like you are always welcome.

I apologize for this verbose reply and thank you for contributing your views and sharing your experience, which have high reference values in their own right.