Crappy Winter Mileage

HRC-E.B.

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Dec 22, 2011
Location
Montreal, Canada
TDI
2012 Golf TDI, 6MT
Pretty new car (2,600 km or 1,600 miles). On a mix of about 60% highway @ approx 75 mph and 40% city driving with about 10 cold starts (10-15 degrees F), I am averaging 7.2 l/100 km or 34 mpg.

34 mpg is not disastrous, but several small gas-powered cars do a bit better (newer Civics, newer Hyundais, etc.).

How bad does it get for you guys in the winter? More importantly, how much better performance can I expect with summer fuel and warmer temps?

Also, how long before I see an improvement related to better break-in and how much does that typically represent?
 

MikeMars

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UK
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Vento 1.9 TDi (retired), A4 1.9 TDi (rear end collision), VW Passat 1.9 TDi (retired), Audi A2 1.4 TDi
Well, you've already seen an improvement of 13mpg on the figures you posted last time, presumably since you're doing more highway mileage since that initial post.

How long is your average trip (still 8km each way)? When it's cold, short trips have a particularly big MPG impact. You live in Montreal, the effects of your winter climate will be severe.

I'm about 6mpg under my peak mpg (68-70 vs. 74-75), but that's with a much longer daily journey, and less harsh climate.

Have you got a mains-powered block heater? They're a good idea if you live in Canada/Finland/Sweden/Alaska/etc.

Here is a sample from a recent journey of mine - zero C (I think that's about 30F?), webasto turned off, MPGs are imperial not US.

Without webasto:
1 mile - 30c 29mpg
2 miles - 41c 36mpg
3 miles - 48c 37mpg <-- Double fuel consumption here
4 miles - 52c 40mpg
5 miles - 60c 44mpg <-- Joined the highway here
10 miles - 79c 52mpg
15 miles - 85c 62mpg <-- Nearly up to temp here (at 15 miles!)
25 miles - 90c 66mpg
60 miles - --- circa 73mpg


Note how long it takes for the engine to heat up, and how long it takes for fuel consumption to settle down - mpg still has some way to go after 25miles. Additionally, keep in mind that my climate is much more moderate than yours.
 
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Jim W

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Jun 23, 2011
Location
Oswego Il
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2011 Jetta TDI
There are several factors that affect fuel mileage.
Winter fuel is less energy dense, so your mileage will be down. Driving style will also affect your fuel mileage, so slow down to 55MPH. This will provide you with the best fuel mileage at any time of the year. Another item; is when will a diesel engine provide the best fuel economy after certain break in period?
Since this is my first TDI VW, I cannot provide a break in target for you, others might.
On my Dodge pick-up truck equipped with a Cummins diesel, I did not see a real improvement until 20,000 miles and now at 52,000 miles my engine is finally broken in. I should see my best fuel mileage from now on.
Jim W.
 

HRC-E.B.

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Montreal, Canada
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2012 Golf TDI, 6MT
Obviously, the short trips from cold starts are the worse. On the other hand, I'm surprised that the highway mileage, cruising between 65 mph and 75 mph depending on trafic, wind direction, etc. doesn't yield better mileage. I had read so many reports of people being solidly in the mid-fourties mpg on the highway cruising 70-75 with newer CRs, whereas my highway mileage seems to be around 37-38, which I find at odds with reports from other drivers.
 

HRC-E.B.

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Location
Montreal, Canada
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2012 Golf TDI, 6MT
Still a bit puzzled by all of this. Despite car getting broken in and the temps ever slightly warmer than a couple of months ago, my mileage seems to be the same, or even slightly worse.

City driving, even with the car fully warmed up seems to bring consistent 23-22 mpg, driving quite reasonably. That's GTI mileage, not TDi mileage... Highway mileage is about 37-38. My combined mileage (with about 60% highway) still doesn't reach the 34 mpg mark EPA rating, whereas everybody reports that their TDi consistently beats EPA ratings.

What gives?
 

MikeMars

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quadrun1

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Sep 3, 2010
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Fairfield County, CT
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past: 2013 Passat TDI SE 6M, 2010 Jetta TDI DSG
How long are your highway trips?

In the winter your engine won't be achieving its best fuel economy until you've been driving at least 20 minutes or so.

Inflating your tires to 40 psi helps too.

Jason
 

an60an

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Aug 1, 2009
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SLC/Utah
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2002 Golf TDI 5 speed 2003 Golf TDI 5 speed
Still a bit puzzled by all of this. Despite car getting broken in and the temps ever slightly warmer than a couple of months ago, my mileage seems to be the same, or even slightly worse.

City driving, even with the car fully warmed up seems to bring consistent 23-22 mpg, driving quite reasonably. That's GTI mileage, not TDi mileage... Highway mileage is about 37-38. My combined mileage (with about 60% highway) still doesn't reach the 34 mpg mark EPA rating, whereas everybody reports that their TDi consistently beats EPA ratings.

What gives?

What gives??? THE CAR, your car is still under 2000 miles, what do you expect?
Get yourself a cup of coffee and have a read:
http://forums.tdiclub.com/showpost.p...67&postcount=1

My car started with 24 MPG, now...I never seen anything under 45MPG...this is 164000 miles later of course.
 

MikeMars

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UK
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Check that brakes are not dragging.
...
My car went in for a service yesterday, and I was very surprised to discover that the right/rear drum brake pads had been dragging, and in fact the pads had split in half due to the heat. I do feel the temperature of the hubs every few months just to see if any are unexpectedly hot, but it has been a while since I checked last.

It'll be interesting to see whether my MPG increases (although on Sunday I also changed my rims from being 185/50R16 to 175/65R15 with low-rolling-resistance tyres, which is an increase of 2.6% on the wheel circumference, so I am also expecting an improvement due to that).
 

bvencil

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May 12, 2011
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Virginia
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2011 JSW TDI (6MT)
Obviously, the short trips from cold starts are the worse. On the other hand, I'm surprised that the highway mileage, cruising between 65 mph and 75 mph depending on trafic, wind direction, etc. doesn't yield better mileage. I had read so many reports of people being solidly in the mid-fourties mpg on the highway cruising 70-75 with newer CRs, whereas my highway mileage seems to be around 37-38, which I find at odds with reports from other drivers.
Well, you do mention a highway trip in which you got mid-40s:

http://forums.tdiclub.com/showthread.php?t=341247&page=2

That's the kind of scenario that will return solid 40s over and over again. Long enough for the car to warm up completely.
 

bvencil

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Virginia
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2011 JSW TDI (6MT)
Also, I find measuring mileage on a trip by trip basis does not give a realistic picture of overall fuel consumption. While it is helpful to look at the MFD results, it is more helpful (IMO) to calculate tank averages ala fuelly.com.
 

Padrino

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Western US
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2002 / Golf 1.9 TDI 5-speed
Starting thread after thread asking the same question would NOT help. As many have suggested already, your car is very, VERY new (under 2000 miles) you are driving in -20C on a VERY short trips (8km = 4.7miles) According to your own posting from 01/16/2012 you car was just under 1000 miles, next time you asked the same question on 02/14/2012 you car was 1600 miles, so for the whole month you covered only 600 miles..... In whole honesty, you bought the wrong car for your needs.
Diesel is a car for miles and miles of driving. As someone have written already in your earlier thread you better get the bus to work.
I am sorry if I sound a bit harsh, but following your frustration and unhappiness with the performance of your car (MPG) perhaps you should consider alternatives.
All the stories about 45/50 or even 60 MPG are all true, but they all are after at least 60000 miles on the engine, after the owner have learned HOW to drive diesel properly, under almost ideal weather conditions etc... If you bought your VW expecting to see 50 MPG from the first tank you are mistaken.
Just my $0.02
 

MikeMars

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UK
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...
under almost ideal weather conditions etc...
And mostly highway miles. The people who are unlucky enough to be in the middle of a city have an uphill task to get decent MPG out of a diesel engine due to the warmup time.
 

Engineers<3Diesel

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Oct 7, 2011
Location
North Carolina
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2012 VW Jetta TDI
Just to add to the break in period, my Jetta has only 7K miles on it. I've kept very detailed records of the fuel mileage for each fillup and am seeing an increase as the miles pile on. I didn't see my first 40 MPG run until 2500 miles were on the motor.

I have all my data in a control chart and if I run split limits at the 4000K mark there is an average increase of over 1.5 MPG between the two data sets. With that being said, I only had 3 fill ups by the time I hit 1600 miles. 3 data points is not nearly enough data to start making claims of poor fuel mileage. Just sit back, relax and report back at 20K miles to let everyone know what you are really getting as your MPGs.
 

HRC-E.B.

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Joined
Dec 22, 2011
Location
Montreal, Canada
TDI
2012 Golf TDI, 6MT
To answer a few questions:

To those that suggest wrong car for me, you are entitled to your opinions. As it turns out, my mix of city and highway mileage would be minimum 50-50%, more like 60% highway 40% city most of the time. As far as I know, it I am not venting frustration but, rather, trying to understand how to get my car to perform as advertised (i.e., EPA-rated mileage).

Temperatures were around -10 degrees celsium (20 F) and are now overing around 30-35 F nowadays.

Brakes appear not to be dragging.

As far as checking mileage, I do it by measuring the number of liters put in when filling up completely vs mileage. This would tend to confirm that the MFD is optimistic by 0.2 to 0.4 liter (1.5 to 2 mpg).

Understanding that highway mileage is where the car shines and warm-up costs fuel, my questions are fairly simple:

1) at what approximate mileage can I expect break-in to be sufficient to get to the EPA-rated fuel mileage?

2) is the car supposed to be a gas hog in the city all the time? Because even when warm, I find that it uses a lot of fuel (around 22 mpg) driving normally in the city (i.e., using the engine's torque, shifting around 2750 rpm or so), whereas the EPA says 30 mpg city.
 

MikeMars

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UK
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... trying to understand how to get my car to perform as advertised (i.e., EPA-rated mileage).
To equal or improve on the EPA rated mileage, your conditions need to match the EPA test's model journey.
* Highway speed of 60mph max, average 48mph (much slower than in real life)
* Accelerating at 3.3 mph per second (much less than in real life)
* Between 68 and 86 degrees Fahrenheit (less will cause higher fuel consumption)
* No aircon or heating
* Urban drive of 7.5 miles assuming free-flowing traffic (less will cause higher fuel consumption, traffic congestion will also cause higher fuel consumption)

The details are in this post:
http://www.cleanmpg.com/forums/showthread.php?t=1510

There is no way you can get anywhere near EPA until winter is over.
 
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Padrino

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Western US
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Mike, I don't think that he is aware of the way how diesels work. It doesn't matter what we say, the question stays the same.
The link that an60an have posted on 8 and reposted on 17 from Drivbiwire is explaining everything in details about break-in and how long it would take, however he is still asking:
"1) at what approximate mileage can I expect break-in to be sufficient to get to the EPA-rated fuel mileage?"
Some times one need to learn on their own. Some times even our best intentions and desire to help is not good enough. You could only help a person who would like to be helped.
 

HRC-E.B.

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Location
Montreal, Canada
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2012 Golf TDI, 6MT
Mike, I don't think that he is aware of the way how diesels work. It doesn't matter what we say, the question stays the same.
The link that an60an have posted on 8 and reposted on 17 from Drivbiwire is explaining everything in details about break-in and how long it would take, however he is still asking:
"1) at what approximate mileage can I expect break-in to be sufficient to get to the EPA-rated fuel mileage?"
Some times one need to learn on their own. Some times even our best intentions and desire to help is not good enough. You could only help a person who would like to be helped.
Forget my other questions! A more appropriate, and certainly more interesting question is: how could someone like you pull off the feat of being THAT condescending without getting punched in the face all the time if it were not for internet forums?

You have all my sympathy, as it must truly be awful to be you.
 

HRC-E.B.

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Joined
Dec 22, 2011
Location
Montreal, Canada
TDI
2012 Golf TDI, 6MT
Sorry. I MUST ask: do you not know how to read???

To be clear: I did NOT ask "how should I break-in my TDi engine". I've read that post. Several times. Thank you.

My questions were fairly simple: 1) at what point during this break-in process should I see a difference in mileage sufficient to get close to the EPA ratings and the type of mileage that most others report here? And 2) Is it normal for this car to yield 22 mpg driving in the city even when warm, as this seems high for a small 4-cyl engine. In other words, are diesels that much worse for fuel in city driving than similarly-sized gassers?

Are these not simple enough questions?
 

Padrino

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Forget my other questions! A more appropriate, and certainly more interesting question is: how could someone like you pull off the feat of being THAT condescending without getting punched in the face all the time if it were not for internet forums?

You have all my sympathy, as it must truly be awful to be you.
Are you sure you are Canadian? Every Canadian I ever met was very pleasant and nice, but once again every rule have an exception.
 

HRC-E.B.

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Montreal, Canada
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2012 Golf TDI, 6MT
Are you sure you are Canadian? Every Canadian I ever met was very pleasant and nice, but once again every rule have an exception.
If "nice" means "spineless", then no I am not nice. Your post was deeply condescending, to the point of being disrespectful, and I felt obliged to point it out.
 

an60an

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SLC/Utah
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2002 Golf TDI 5 speed 2003 Golf TDI 5 speed
Sorry. I MUST ask: do you not know how to read???

To be clear: I did NOT ask "how should I break-in my TDi engine". I've read that post. Several times. Thank you.

My questions were fairly simple: 1) at what point during this break-in process should I see a difference in mileage sufficient to get close to the EPA ratings and the type of mileage that most others report here? And 2) Is it normal for this car to yield 22 mpg driving in the city even when warm, as this seems high for a small 4-cyl engine. In other words, are diesels that much worse for fuel in city driving than similarly-sized gassers?

Are these not simple enough questions?

If I can read your repeated posting this is enough of a proof that I can read. What you fail to recognise is the fact that PROPER brake-in procedure is very important for the performance of any TDI engine...but to understand this you need something more than just ability to read..... intelligence would help.
However now is my turn to ask you: Can YOU read?
The answer to your question 1 is in posting from Engineers<3Diesel (this was posting 18) but once again you should be able to read.....
 

Padrino

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If "nice" means "spineless", then no I am not nice. Your post was deeply condescending, to the point of being disrespectful, and I felt obliged to point it out.
Whatever....:cool: I hope you sleep better tonight.
 

HRC-E.B.

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Location
Montreal, Canada
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2012 Golf TDI, 6MT
If I can read your repeated posting this is enough of a proof that I can read. What you fail to recognise is the fact that PROPER brake-in procedure is very important for the performance of any TDI engine...but to understand this you need something more than just ability to read..... intelligence would help.
However now is my turn to ask you: Can YOU read?
The answer to your question 1 is in posting from Engineers<3Diesel (this was posting 18) but once again you should be able to read.....
Ok. I get it now. Any effort to seek clarifications on anything here will cause the resident jackasses to belittle the poster. I see. Shame on me for asking a damn question on the internet. I should have known...
 

an60an

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Aug 1, 2009
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SLC/Utah
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2002 Golf TDI 5 speed 2003 Golf TDI 5 speed
Ok. I get it now. Any effort to seek clarifications on anything here will cause the resident jackasses to belittle the poster. I see. Shame on me for asking a damn question on the internet. I should have known...
No, no...you got it wrong, shame on you for asking the same question over and over again and expecting different answer....hey you know what?
This was saying from Albert Einstein, no actually it was a definition of insanity by him:
"Insanity: doing the same thing over and over again and expecting different results." :D


 

fs2k2k

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Feb 4, 2011
Location
Toronto
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2010 Golf Wagon TDI
Finally someone who talks real fuel milage numbers, 7.1L/100 in the winter. Sounds a lot like what I get, I never get the 4.7L/100 that a lot of people are talking about, not even in the summer on the highway. Then they say that its because I have a new TDI, the old ones get MUCH BETTER milage. I cant see that as the new ones are precisions injection, accurate injection volumes, etc. I guess you have to take what you get.
 

Blinkinbanana

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Aug 8, 2011
Location
Long Pond, PA
TDI
2010 Jetta TDI
Pretty new car (2,600 km or 1,600 miles). On a mix of about 60% highway @ approx 75 mph and 40% city driving with about 10 cold starts (10-15 degrees F), I am averaging 7.2 l/100 km or 34 mpg.

34 mpg is not disastrous, but several small gas-powered cars do a bit better (newer Civics, newer Hyundais, etc.).

How bad does it get for you guys in the winter? More importantly, how much better performance can I expect with summer fuel and warmer temps?

Also, how long before I see an improvement related to better break-in and how much does that typically represent?
I've been getting 33-35 mpg per tank and closer to 50/50 highway vs around town miles. I've done much better in the fall. Best I've seen is high 30s- low 40s. Per tank.
 

Jim W

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Jun 23, 2011
Location
Oswego Il
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2011 Jetta TDI
Finally someone who talks real fuel milage numbers, 7.1L/100 in the winter. Sounds a lot like what I get, I never get the 4.7L/100 that a lot of people are talking about, not even in the summer on the highway. Then they say that its because I have a new TDI, the old ones get MUCH BETTER milage. I cant see that as the new ones are precisions injection, accurate injection volumes, etc. I guess you have to take what you get.

This is a known fact that the pre-emission diesel engines have better fuel mileage than engines built after 2010 for most diesel engine builders. You can thank the EPA for this.

There are several design elements that were used to meet the 2010 emission rules that affect fuel mileage. One cause is the EGR the other is the DPF that is on most diesel engines built after 2010.

The EGR is cooled and routed back into the combustion chambers of the engine, this displace the oxygen that would be in the combustion chamber. Thus you are not getting a clean burn of diesel fuel and not getting all of the potential energy that is in the fuel for use.
The other is the DPF with a lot of city driving you will be loading up the DPF with more diesel particulates that need to be burned off too prevent plugging of the DPF. The regeneration of the DPF uses diesel fuel in the exhaust to burn the diesel particulates and to clean the DPF. This burning of diesel fuel is none useful work and fuel mileage will suffer.

As an example of this my son has two pre-emission, Cummins equipped pick-up trucks. One is a 98, 24V which gets 22 to 24 MPG on the highway (work truck). His other is a 06, this truck is equipped with 90HP over stock injectors with a dual CP3 pump and programmer. This truck also gets 20+ MPG on the highway.
Now my truck is a 08, 6.7L 24V Cummins that is 2010 emission compliant this truck on a good day will only get 16 to 17 MPG. I have fours of data to back this up.
Jim W.
 
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