Fuel Economy

[lobo]

I have read that if you keep the RPM as low as possible then you get better mileage. I read 1 article where the guy never had RPM above 2,000 and got around 90 MPG. My 1st 4 tanks on my new wheels were 8.4L/100km, 8.5, 8.2 and the last 8.0. I'm doing an experiment on my current tank ... I'm going to try to never have RPM above 3,000 and see what mileage I get. Max 3,000 RPM means that my top highway speed will be approx 105-110 km/h. I'll update at the end of the tank.

I'm sort of trying something like that. Trying to keep the rpms below 2500 while driving on Highway 7. Funny thing is is that there are times when even doing 2000 rpms the L/100km value can be over 10L/100km. I've noticed this after accelerating from a stop. So this confuses me even more because do I go by rpms or by the mileage indicator?

Lobo

[mazdaagain]

I'm sort of trying something like that. Trying to keep the rpms below 2500 while driving on Highway 7. Funny thing is is that there are times when even doing 2000 rpms the L/100km value can be over 10L/100km. I've noticed this after accelerating from a stop. So this confuses me even more because do I go by rpms or by the mileage indicator?

Lobo

Stops and starts consume more fuel because fuel has to be injected for the acceleration. Thats why highway driving is more fuel efficient because you keep a constant speed.

[Impressive]

Stops and starts consume more fuel because fuel has to be injected for the acceleration. Thats why highway driving is more fuel efficient because you keep a constant speed.

+1

Try driving around in first and second gear at 2500rpm and see how long your tank lasts as opposed to doing it in 5th.

[AHickman]

Should see about 500-550 km per tank no?

[Impressive]

Should see about 500-550 km per tank no?

Driving what model and doing mostly city or highway driving?

That estimate sounds about right regardless.

[kimchisoup]

I'm not that disappointed with my 2.5L fuel economy. I drive on average about 15km over the speed limit. 20-25 over on the major highways. Wish it did a bit better at those speeds...

Avg, 8.9L/100. Best 7.6L

http://www.fuelly.com/driver/rpaton/3

Thats close to mine. Best I avg so far is 32mpg.
http://www.fuelly.com/driver/kimchisoup/3/log

Short trips in winter absolutely killed my fuel economy. I got 14L/100km on one tank in the worst of it (poor traction on snow too, and bumper to bumper).

Gotta say that I'm a bit disappointed with my mileage over the past 3 years of owning a Mazda3. I don't get anywhere near what some of the others post on here and I don't know if there's any other way I can change my driving patterns to help lower it. I seem to be averaging around the 10L/100km so somewhere around the 400-430km/tank range.

Are there any recommendations in terms of trying to get more mileage out of the car? I drive on Hwy7 between Weston Rd & Leslie on a daily basis so there's some stop and go traffic with some stretches of 90km/hr driving. 18km each way. I use Shell regular gas too. Considering the car is 3 years old now, would converting to synthetic be of any benefit? Over inflating the tires from what's on the side of the door? Air filter change?

Thanks.

Lobo

How did you measure 10L/100km. Fill up to full and divide by km done since last fillup? The Trip computer is often wrong by at least 5%.
I haven't done air filter change in ages. Try taking it out and seeing how clogged it it - shaking it out.
30 psi vs 34 psi has very small effect.. maybe 3%. Synthetic vs regular or viscosity also made negligible diff.

By far the biggest factors:
- winter, cold destroys mpg. My mpg skyrocketed from 21 to 29 in March.
- short trips, stop/go, time below 40kph. Should always be using cruise. 100km in city is 9-11L. highway its as low as 6.4L.. and this is 2.3L Auto
- air conditioner/heater on. You can instantly see the economy drop b 1L.

+1
Try driving around in first and second gear at 2500rpm and see how long your tank lasts as opposed to doing it in 5th.

+1. From my experiments doing super slow accel might be actually worse, since you're doing <50kph longer.
And any accel will be >10L. Any hill is often also >10L at any speed.
A reasonable pace is about 10kph per 1.5 - 2sec... about 10 -12 sec to get up to 60kph.

Also noticed that 100kph vs 110kph on highway diff is small.. like 3%.
Over 120kph, fuel economy drops big though, and no surprise since pushing 3000rpm.
Strong wind (headwind) noticed especially on highway.. ie 5L one way, 10L other way.

[kimchisoup]

I have read that if you keep the RPM as low as possible then you get better mileage. I read 1 article where the guy never had RPM above 2,000 and got around 90 MPG. My 1st 4 tanks on my new wheels were 8.4L/100km, 8.5, 8.2 and the last 8.0. I'm doing an experiment on my current tank ... I'm going to try to never have RPM above 3,000 and see what mileage I get. Max 3,000 RPM means that my top highway speed will be approx 105-110 km/h. I'll update at the end of the tank.

For fuel economy, Mazda's lack of tall gear ratios suck.

Notice that the new Altima 2013 gets like 3000rpm at 100 MPH.
If you had some way of replacing the gearbox with a six auto that allows 1800-2000rpm at 110kph, you'd probably see at least 2L better fuel economy.

Mazda is also over-eager to inject lots of fuel on low end to give peppy start. Sure, you do 0-40kph in like 3 sec, but that quick change of moment wastes gas.


Mazda with CVT would be interesting. I was not at all suprised when the new SkyActive massively improved fuel economy, mostly through changest to gearbox.

[MarkWB]

You can do 120 in a gen two with like 2000ish rpm if you don't gas it on the on ramp too much. I try to keep my rpms under 3000 (or even under 2 if possible) daily, and I see about 500 kms to the tank depending on the ratio of city to highway driving (we'll say 50/50 on a 500 km tank) and how much A/C I use.

[sweetadad]

i just did a 400KM highway run and instead of using 87 octane, I used 89 octane and got 6L/100KM. That is by far the best mileage I have ever seen. IN the past past with 87 octane, i have gotten 8~9L/100KM doing 115KMPH. So I guess I'm going to run a few tanks with 89 octane and do my regular driving and update you folks in a few weeks.

[bmxnwrx]

i need to log the mileage of the 3 cuz it seems to fluctuate quite a bit. right now its not doing so well.

[kimchisoup]

Does anyone know why the price of a diesel engine in a car would cost approx $4,000 more then a gas engine? This seems a little excessive and is not justified in my view. Thoughts on this?

Mazda may bring diesel to Canada in 2013.
Problem is always emissions and all the related requirements.
Can not simply bring over European cars here.

Diesel has approx 10% higher energy content, but because of MUCH higher compression ratio and other things, burns more efficiently.


IMHO, all of this is moot, now that Mazda is running up to 13:1 in SKYACTIV with regular 87.

----------------

Only reason why 89 Octane would help that much is if the 87 you were using had lots of ethanol (more than 10% allowed).
Recall higher Octane = more difficult to burn. Its meant primarily for high compression turbo cars to prevent pre-detination.
Theoretically, 91 or 94 should not help much if at all. Even if it did improve fuel efficiency by 2 or even crazy 5%, it would be far less than the added cost.

[kimchisoup]

i just did a 400KM highway run and instead of using 87 octane, I used 89 octane and got 6L/100KM. That is by far the best mileage I have ever seen. IN the past past with 87 octane, i have gotten 8~9L/100KM doing 115KMPH. So I guess I'm going to run a few tanks with 89 octane and do my regular driving and update you folks in a few weeks.

Which car exactly do you have.
Based on your numbers it seems you are pulling them out of the air....

ie, when I report a number: 7.48L/100km 80% hwy. 2.3L 08.
when YOU report: "8~9L/100KM doing 115KPH"
So basically nobody has any idea if its good or bad because we don't know which car, % hwy driving, and you gave a wide range of 26-30mpg.

[sweetadad]

Which car exactly do you have.
Based on your numbers it seems you are pulling them out of the air....

ie, when I report a number: 7.48L/100km 80% hwy. 2.3L 08.
when YOU report: "8~9L/100KM doing 115KPH"
So basically nobody has any idea if its good or bad because we don't know which car, % hwy driving, and you gave a wide range of 26-30mpg.

My bad...this is a 2011 GX (so 2.0L engine, auto) hatchback. I've done that highway run many times and I've always gotten something like 8L/100KM (based on fuelly). This is the first time i got a 6L (fuelly calculation and not mine)

[zoomahh]

For fuel economy, Mazda's lack of tall gear ratios suck.

Notice that the new Altima 2013 gets like 3000rpm at 100 MPH.
If you had some way of replacing the gearbox with a six auto that allows 1800-2000rpm at 110kph, you'd probably see at least 2L better fuel economy.

Mazda is also over-eager to inject lots of fuel on low end to give peppy start. Sure, you do 0-40kph in like 3 sec, but that quick change of moment wastes gas.


Mazda with CVT would be interesting. I was not at all suprised when the new SkyActive massively improved fuel economy, mostly through changest to gearbox.

ahem....
check my fuel stats....my skyactiv gets on av about 6.5L/100 km AND with their 6 speed auto, I DO in fact do about 1900-2000 rpm on 110...so it's being done as you speak...all u gotta do is check in with a few other skyactiv owners and your suspicions will be put to rest.

[sarujo]

I checked your fuelly page and would like to know how you have more than 55L fuel entries (some are over 60) when the standard fuel tank is only 55L (60L for GT with 2.5L).

ahem....
check my fuel stats....my skyactiv gets on av about 6.5L/100 km AND with their 6 speed auto, I DO in fact do about 1900-2000 rpm on 110...so it's being done as you speak...all u gotta do is check in with a few other skyactiv owners and your suspicions will be put to rest.

[bmxnwrx]

what are peoples average fuel consuimption with a 4 speed automatic 2L?

[leungly]

http://www.fuelly.com/car/mazda/3

Click on a Year and then you can see if its GT or GS models.

[DumpInfo]

Don't waste your time get a diesel. This is why I traded my mazda....



This was my tank a couple weeks back strictly highway and still had at least 200kms till it was out. Food for thought!

[MarkWB]

Don't waste your time get a diesel. This is why I traded my mazda....



This was my tank a couple weeks back strictly highway and still had at least 200kms till it was out. Food for thought!

I want this fuel economy! Can't wait to see a skyactiv-d (maybe turbo?) in the Canadian market.

[Honva]

I want this fuel economy! Can't wait to see a skyactiv-d (maybe turbo?) in the Canadian market.

Good for the environment but we don't save money. The car is more expensive and basically we just pay the gas up front. With Toronto traffic, we don't really have "highway". A start-stop type of engine could be more meaningful.

[Jackal]

Not bad for a 2010 GT.

[loosecannon]

Not bad for a 2010 GT.

In winter? That's crazy. Drove like a granny? Lol

[Jackal]

In winter? That's crazy. Drove like a granny? Lol

Actually drove it like a racecar. Average 120km/h. Who needs to get 1000 km if you go only 93km/h? Probably same mileage as mine if it was going 120.

[eSS]

Not bad for a 2010 GT.

Nice, Especially for winter. Ran it completely dry?

[Jackal]

Nice, Especially for winter. Ran it completely dry?

It's great for the 2.5 L engine. Till about 3 squares left.