This MPG is crazy

DasTeknoViking

Veteran Member
Joined
Nov 7, 2010
Location
Palatine IL
TDI
B4 TDi, A4 R32
Cruise control is not good for mpgs. My Golf SportWagen is coming up on 100k so it's well broken in by now.



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Miss_Athanatos

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Joined
Oct 21, 2015
Location
Kansas
TDI
2015 Golf SportWagen 6-speed manual; 2016 3500 Ram Tradesman 4X4 6.7L Cummins 6-Speed manual
That's great! Is that a hand calculated value? What % highway driving?
Yes, that's what I calculated.

The percentage of highway driving is about at 85%.
 

sloinker

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Joined
Jun 27, 2015
Location
Casper, Wyoming
TDI
'15 Sportwagen '15 Golf Hatch
These engines/cars like hot weather and 50 mph speeds for max MPG. The dropoff on MPG from 60 to 80mph is stupid. About 20mpg. I get 45 mpg@80mph in the summertime. I get 50mpg@70mph and 57mpg@60mph it reaches its peak near 50mph in the mid 60's mpg. I do hand calculations so these numbers are relatively accurate. Other drivers on the freeway don't appreciate my experiments so I now go 80mph all the time and screw the fuel mileage.
 

Lightflyer1

Top Post Dawg
Joined
Sep 13, 2005
Location
Round Rock, Texas
TDI
2015 Beetle tdi dsg
Some of you folks are interestingly touchy about mpg reports. It seems that now my engine is seated, I'm getting better fuel economy than ever with a 54 mpg average over the last year.
Because short distances and without accurately measured amounts of fuel and being able to manipulate things in these scenarios, makes them really not worth anything. It also fails to represent what the average driver can expect to get when driving. There are many ways to inflate your mileage when doing short trips. Much, much harder to do in published tank after tank after tank averages. Who would you believe when the stories are told. The one tank wonder with 60 miles or the person who consistently tracks their fuel economy online with tank after tank after tank of averages?
 

740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
That and you catch 2-3 regens per tank it'll throw the calcs off pretty good.

Our Passat showed 54-55 MPG on the dash over 350 mile road trip this past weekend, I'll be shocked if the tank gets above 48MPG but won't find out as the wife needs to put on 200 more miles before it needs fuel, should hit 750-800 miles on the tank easy.
 

Miss_Athanatos

Veteran Member
Joined
Oct 21, 2015
Location
Kansas
TDI
2015 Golf SportWagen 6-speed manual; 2016 3500 Ram Tradesman 4X4 6.7L Cummins 6-Speed manual
Because short distances and without accurately measured amounts of fuel and being able to manipulate things in these scenarios, makes them really not worth anything. It also fails to represent what the average driver can expect to get when driving. There are many ways to inflate your mileage when doing short trips. Much, much harder to do in published tank after tank after tank averages. Who would you believe when the stories are told. The one tank wonder with 60 miles or the person who consistently tracks their fuel economy online with tank after tank after tank of averages?
You say it as if there is no way to cheat fuelly and other online fuel economy trackers. So...maybe one-tank-wonder-60 is in reality getting 55, so what? What other i.c.e. car on the road in the USA gets above 40 mpg?

I believe that VW marketed this vehicle for all-around driving economy, not just economy on 700-1500 mile cross-country trips or solely on full tank use bases.

I'm a conservative driver, sure, but I'm not coasting everywhere in neutral, so, I think for other folks who make between 30 and 240 mile daily commutes, there would be an interest on what one such as myself is seeing per trip. It's a real joy to see 60+ mpg on the display trip after trip.
 

Grigg3

Veteran Member
Joined
Aug 5, 2006
Location
Lexington, VA
TDI
05 Jetta wagon, 15 Golf wagon
I believe the point is you can drive differently or on the right stretch of road and or for a short enough distance to achieve whatever mileage number you want.

Or look at data from longer more varied driving which much better represents overall mileage, the big picture.
This is most useful for comparison.

Again it seems much more accurate or consistent to calculate mileage a full tank at a time filled to the brim each time, doing the math on miles traveled over gallons used.
Also more useful for comparison than what the car thinks the mileage is.

I like to see high per tank mileage figures and try a little to better that if conditions are favorable, realizing these per tank mileage numbers aren’t same as what the car gets month after month year after year. Still fun to try.
 

bigb

Veteran Member
Joined
Dec 15, 2018
Location
Arizona
TDI
2015 Sportwagon S
Sure you can but I know my calcs are pretty accurate, same pump and I fill till I see it in the top of the neck. Takes a lot of time waiting for the foam to dissipate and yes I use my Surefire pocket flashlight to see it. I totally understand the average thing but I don't drive strictly on the highway with each tank so I like to see what it can do when I have the chance. Notice on my last 10 fillups the three that were mostly highway average out to 47.2 which makes me a happy camper. If you were used to driving an F-350 before this you would be as excited as I am about this MPG. I am having fun with this, no intentions of starting any arguments or pissing matches :)
 
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Lightflyer1

Top Post Dawg
Joined
Sep 13, 2005
Location
Round Rock, Texas
TDI
2015 Beetle tdi dsg
One person getting 60 mpg on a 20 or 30 mile trip does not compare to the thousands of people on Fuelly that list full tanks on all their drives over long periods of time. Sure the cars do extremely well on the nonstop long distance travels. They will do less well but still exceptional in urban and city driving as well. My beetle averages about 35 mpg since I bought it but it has never been on a long trip. I am fixing to make a round trip from Austin to Wichita and back and that will be my first highway trip and we'll see how it does on that. I'm sure it will gain probably 10 mpg on doing that kind of trip versus the shorter 30 mile trips I do commuting to and from work every day. If the only thing you post is 60 mpg at a 20 or 30 mile trip some people think that is the mileage they should get. If you look at Fuelly with all of the cars listed there you can see the graph of the percentage of people that get outliers way towards the high end of the scale and outliers way towards the low end of the scale and see in the median or average where people fall in the middle. That is most useful information. You're one time trip of some short distance doesn't mean anything to anybody but you. I am not trying to be rude but that's just the way it is. My Excursions I have owned have gotten in the low twenties on the highway. I thought that was exceptional for a great big tank of a vehicle. my all-time high for any of the 10 or 11 TDI's that I have owned is about 53 mpg which was strictly an interstate non stop trip on cruise.
 
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bigb

Veteran Member
Joined
Dec 15, 2018
Location
Arizona
TDI
2015 Sportwagon S
. You're one time trip of some short distance doesn't mean anything to anybody but you.
Not sure who you are talking to but I don't consider 3 trips of 300-500 miles each, averaged out, a one time short trip:confused:
 

Beeah

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Joined
Dec 19, 2006
Location
Plymouth, MI
TDI
15 GSWs 6MT | 02 Jetta TDI(Sold)
Took a 4 hour drive from Detroit Metro to Indianapolis. Thule roof rack, 3 people and camping gear for 4 days. Averaged 49mpg indicated. I don't car how far the car math is off, very happy.
 

dubStrom

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Joined
Aug 6, 2007
Location
Kansas City Missouri
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2003 A4 Jetta (sold), 2010 JSW (sold), 2013 Passat 6MT traded for 2014 JSW with 6MT-TOTALED in November 2016, 2003 ALH 5MT conversion (sold), wheezing 2015 GSW/DSG and a new 2021 Tacoma Access Cab 4x4 p'up
fuel usage monitoring adjustment- VCDS???

Can the mpg calculation (calibration of measured fuel usage) be adjusted with VCDS?

Mine is way off. It is showing maybe half of what I am actually getting.

I just did a Kerma 1+ tune (after phase 2) which is really excellent, and even with some "spirited" driving mixed in, I am still getting about 40-45 mpg (hand calculated), but the instantaneous MFD readout is showing maybe half of that, and range (miles left on tank), and average consumption are also way low.

There must be a way to adjust this FE calibration using VCDS. Does anyone know how?
 

The Tortoise

Veteran Member
Joined
Apr 24, 2017
Location
Ottawa
TDI
2015 GSW Trendline - White
There is a way. I adjusted mine to +7% and now it's pretty accurate.

I don't think it had that much range though. Maybe +/-10%.
 

dubStrom

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Joined
Aug 6, 2007
Location
Kansas City Missouri
TDI
2003 A4 Jetta (sold), 2010 JSW (sold), 2013 Passat 6MT traded for 2014 JSW with 6MT-TOTALED in November 2016, 2003 ALH 5MT conversion (sold), wheezing 2015 GSW/DSG and a new 2021 Tacoma Access Cab 4x4 p'up
There is a way. I adjusted mine to +7% and now it's pretty accurate.

I don't think it had that much range though. Maybe +/-10%.
Have you got a link to instructions, or a guide?
 

adjat84th

Veteran Member
Joined
Dec 13, 2008
Location
Virginia Beach, VA
TDI
'01 Jetta TDI/'15 Golf TDI
I took 10 tanks and calculated an average of how far off it was. For me on the stock turbo, it was optimistic by 9% (adjustment was put at 109%). It can adjust +/- 15% so you can set it at 85% or 115%. In VCDS, go to Instruments and then Adaptation. I believe it's something like "fuel consumption"
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT, '01 Golf GLS 5MT, '96 Passat variant
Correcting FE display

There isn't enough correction range to solve your problem, though. I've read that tuners can tweak the tune to allow the display error to fall within the available adjustment range. Contact Kerma.
 
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dubStrom

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Aug 6, 2007
Location
Kansas City Missouri
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2003 A4 Jetta (sold), 2010 JSW (sold), 2013 Passat 6MT traded for 2014 JSW with 6MT-TOTALED in November 2016, 2003 ALH 5MT conversion (sold), wheezing 2015 GSW/DSG and a new 2021 Tacoma Access Cab 4x4 p'up
I took 10 tanks and calculated an average of how far off it was. For me on the stock turbo, it was optimistic by 9% (adjustment was put at 109%). It can adjust +/- 15% so you can set it at 85% or 115%. In VCDS, go to Instruments and then Adaptation. I believe it's something like "fuel consumption"
Thanks,

One other complication is that I have much taller wheels on there. 17" OEM was 225/45 Conti ProContacts (25" tall, 831 revs per mile). I installed 215/60 True Contacts, which increase height to 27.2" and dropped revs per mile to 765.

I use 6th as an overdrive now, for extended flat driving and slight downhill runs (like driving across Oklahoma or Kansas from West to East). The odometer has about a 9% error (speedometer is about the same). I calibrated by using mile markers on long drives, and verified more than once.

Obviously, the actual number of miles is higher than recorded, and it affects the mpg calculations for the MFD. I would like to get it closer to real, at least. I will test this longer term and get back to Kerma when I have a good averaged mpg error. If Jason can get me within 10% on his tune, maybe I can re-adjust it using VCDS. Thanks!
 

dubStrom

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Aug 6, 2007
Location
Kansas City Missouri
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2003 A4 Jetta (sold), 2010 JSW (sold), 2013 Passat 6MT traded for 2014 JSW with 6MT-TOTALED in November 2016, 2003 ALH 5MT conversion (sold), wheezing 2015 GSW/DSG and a new 2021 Tacoma Access Cab 4x4 p'up
adaption?

After tanking up a second time and a few errands, the mpg is behaving normally. I think it needed to adapt to the tune or something.

Based on this, I think I will have to wait at least a few tanks to see how close the average mpg (MFD) is to my calculated values. Then I can look into the % correction in VCDS.

The Kerma tune is nice. This is 1+ tune on a completed phase 2.
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT, '01 Golf GLS 5MT, '96 Passat variant
Based on this, I think I will have to wait at least a few tanks to see how close the average mpg (MFD) is to my calculated values. Then I can look into the % correction in VCDS.
Correct the impulse distance (odo/speedo) error before correcting MPG error.
 

dubStrom

Veteran Member
Joined
Aug 6, 2007
Location
Kansas City Missouri
TDI
2003 A4 Jetta (sold), 2010 JSW (sold), 2013 Passat 6MT traded for 2014 JSW with 6MT-TOTALED in November 2016, 2003 ALH 5MT conversion (sold), wheezing 2015 GSW/DSG and a new 2021 Tacoma Access Cab 4x4 p'up
Correct the impulse distance (odo/speedo) error before correcting MPG error.
Oh, That is a great idea. But it is by tire size rather than diameter, isn't it? Well, I can at least get it close to accurate in measuring distance (and therefore, speed).

I was going to do that a while back, got distracted. Yes, I should fix that first.
 

dubStrom

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Joined
Aug 6, 2007
Location
Kansas City Missouri
TDI
2003 A4 Jetta (sold), 2010 JSW (sold), 2013 Passat 6MT traded for 2014 JSW with 6MT-TOTALED in November 2016, 2003 ALH 5MT conversion (sold), wheezing 2015 GSW/DSG and a new 2021 Tacoma Access Cab 4x4 p'up
I took 10 tanks and calculated an average of how far off it was. For me on the stock turbo, it was optimistic by 9% (adjustment was put at 109%). It can adjust +/- 15% so you can set it at 85% or 115%. In VCDS, go to Instruments and then Adaptation. I believe it's something like "fuel consumption"

Thanks very much
 
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