What's your most efficient speed for max MPG?

kassel

Active member
Joined
Jul 6, 2005
Location
SC
TDI
(2) 2011 Jetta TDI - DSG / 06.5 JETTA SE DSG
My 2011 Jetta TDI seems to like 60 MPH for max MPG. I routinely get 50 MPG+ at 60 MPH. At higher speeds (65/70) the mileage drops to 45/46 MPG. What are others seeing?
 

deucelee

Veteran Member
Joined
Jul 8, 2011
Location
Central WI
TDI
'11 Jetta TDI 6MT ___ Plat Gray on Black
My last fill up was 47.6mpg going 70mpg with 85% highway.

I bet I'd hit 50mpg easy with 60'ish to 65'ish.
 
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Jack Frost

Veteran Member
Joined
Nov 30, 2007
Location
Rural Manitoba
TDI
2009 Clean Diesel
I have a Scanguage. My instantaneous mileage for my 2011 DSG is best at 80 kph or 50 mph. At that speed it is about 65 mpg but that drops off to about 50 at 60 mph. My combined city/highway/gravel road mileage over a tank is about 43 mpg.
 

kassel

Active member
Joined
Jul 6, 2005
Location
SC
TDI
(2) 2011 Jetta TDI - DSG / 06.5 JETTA SE DSG
I have a Scanguage. My instantaneous mileage for my 2011 DSG is best at 80 kph or 50 mph. At that speed it is about 65 mpg but that drops off to about 50 at 60 mph. My combined city/highway/gravel road mileage over a tank is about 43 mpg.
I am curious about a scangauge and where is connects in the car (2011) and where I can get the gauge as well. I was under the impression the VWs were unique in their protocol and were readable using VAG COM only. Is this not the case anymore?
 

philip_g

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Apr 18, 2009
Location
none
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jetta
I am curious about a scangauge and where is connects in the car (2011) and where I can get the gauge as well. I was under the impression the VWs were unique in their protocol and were readable using VAG COM only. Is this not the case anymore?
Its never been the case in regards to using a scangauge. Scangauge gets data from the obd2 port.
 

Mundgyver

Member
Joined
Aug 27, 2011
Location
Sherwood, Oregon
TDI
2011 Jetta TDI Sedan, 2001 Dodge 6 speed Cummins 5.9 L
To get the best fuel economey you need to know at what rpm, peak engine torque is developed. Once you know that then it is just a matter of setting speed with rpm selected to the gear you are in.

I have not seen a torque chart for these TDI yet. Does anyone know where we can look at one?

On my Dodge Cummins, I set the engin at 1750 rpm in 6th gear and will get around 23 mpg, and this is a 1 ton truck.
 

Savageman69

Top Post Dawg
Joined
Aug 3, 2007
Location
ontario
TDI
2012 Highline Touareg TDI
i seem to get best mpg at 90km/hr by the speedo on the car..thats scangauge confirmed and 51 mpg on a entire 1233km tank
 
Joined
Sep 1, 2011
Location
CA
TDI
None Yet
Differences in F E

What must be consider is the big differences in RPMs between the DSGs and the manual 6 MTs per mile!

There is no way that the DSGs can obtain the F E of the late manual 6 MTs.
 

Savageman69

Top Post Dawg
Joined
Aug 3, 2007
Location
ontario
TDI
2012 Highline Touareg TDI
i think the dsg is almost spot on with rpm of the manual. I do agree that manual will put out better mpg IF the manual driver can drive it right.
 
Joined
Sep 1, 2011
Location
CA
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None Yet
Not So

i think the dsg is almost spot on with rpm of the manual. I do agree that [the]
manual will put out better mpg IF the manual driver can drive it right.
DSGs have a ratio of 2.31

6 MTs have a ratio of 1.98

At 96 KPH, the DSG is turning 1933

At 96 KPH, the 6 MT is turning only 1657

A difference is favour of the 6 MT by 275 revs

Because of the gearing, the 6 MT will do better

The 2009 gearing of the 6 MT was different, and they were closer to equal.

The '09 6 MTs were geared 2.23, and yes they would still do slightly better F E wise.
 

RLWSNOOK

Well-known member
Joined
Aug 26, 2011
Location
Ohio
TDI
2011 Jetta TDI
My read out says something like 74 mpg at 40 mph, but not sure if that's right.. nor would I want to drive around at 40 mph all the time... My car is still not really broken in so I've only once tried to see what fuel economy I could get out of it. I'm waiting until my break in allows me to drive the way I want to drive to get the fuel economy. Happy with the 36-45 mpg I'm getting now...

Edit: mind you this was an instant read out, and on a flat road with no ac, but I did maintain the mpg for a few mins...
 
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Joined
Sep 1, 2011
Location
CA
TDI
None Yet
My read out says something like 74 mpg at 40 mph, but not sure if that's right.. nor would I want to drive around at 40 mph all the time... My car is still not really broken in so I've only once tried to see what fuel economy I could get out of it. I'm waiting until my break in
allows me to drive the way I want to drive to get the fuel economy.
Happy with the 36-45 mpg I'm getting now...

Edit: mind you this was an instant read out, and on a flat road with no ac,
but I did maintain the mpg for a few mins...
You do not say, but I think you have the 6 MT?
 

RLWSNOOK

Well-known member
Joined
Aug 26, 2011
Location
Ohio
TDI
2011 Jetta TDI
You do not say, but I think you have the 6 MT?
Nope I have DSG. Like I said I wasn't sure if it was right, and it is only the instant computer and for a few minutes as I got to the end of the road... but I was getting pretty good fuel economy for the few mins I was on that road.
 

Surrylic

Well-known member
Joined
May 1, 2011
Location
Winchester, VA
TDI
White 2011 VW Jetta TDI, Manual
Mine is around 35-40mph. The reason everyone gets better mileage at 50ish is simply because they arent hitting in town traffic and traffic lights. Overall i get far better mileage on long highway trips where i average 60mph or so, but for that instant the best mpg will always be at 35-40mph.
 

> Luke <

Veteran Member
Joined
Jun 16, 2011
Location
West Los Angeles
TDI
Golf 2011 TDi DSG
Fm > Kassel
My 2011 Jetta TDI seems to like 60 MPH for max MPG. I routinely get 50 MPG+ at 60 MPH. At higher speeds (65/70) the mileage drops to 45/46 MPG.​
And would '2nd' that observation, as that is what I'm getting with my Golf DSG

Fm > Jack Frost
What is your rpm at your best mileage speed?​
1,900 rpms
 

highender

Veteran Member
Joined
Oct 8, 2006
Location
Northern California
TDI
2012 Jetta TDI
I have 2012 Jetta DSG auto ( i know, redundant, but for other reader's sake) . Just wanted to see what other people are getting iin terms of MPG. I remember one of VW's partners, Porsche , making the point that even though each engine is built with the same tools, same engine parts, and same engine mechanic, there will still be differences in output and fuel efficiencies.

I think MPG can only reliably be calculated over at least a tankful of fuel. The trip computer gives only instantaneous readouts, and any momentum gained from previous acceleration or downhill roads, will give one an unrealistic albeit fun figure of 200 mpg ( max of VW computer). My Scangauge sometimes gives me a figure of 2999 mpg on long down hills. :p

I achieve normally 45 mpg with lots of local drivinig with my 2002 Jetta .
Still on our first tank of gas with the new 2012 DSG. I am hoping for a high of 38 combined..... and maybe all highway of 48 to 50, driving at 60 mph.

Ok.... look forward to hearinig from all the TDI members...
 

JThiessen

Veteran Member
Joined
Apr 25, 2011
Location
Edmonds, WA
TDI
2011 Sedan LE, DSG
I was actually wondering how people's average speed compared to the fuel mileage. I was scrolling through my readout this afternoon and it says an average of 42.x mph. My mileage average so far is just about 40 (its in my signature..)
 
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740GLE

Top Post Dawg
Joined
Aug 19, 2009
Location
NH
TDI
2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
my average speed per MFD is always way low, but 90% of my time I'm either doing 65-70 or 35. For best tank over tank MPG's I'd need to drive at 50-55 mph. Speed kills.
 

Plus 3 Golfer

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Oct 29, 2008
Location
ARIZONA
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Und tschüss! 2009 Jetta 12/23/2012
Guys if you want to see the affect on mpg vs speed look at this thread.

Rockwater (2010 6M JSW) and I (2009 DSG Sedan) ran tests at constant speed to see the affects on mpg. Derrell H Green (2010 JSW, DSG) also ran similar tests with oversize tires.

Also note these curves. You will always get the highest mpg in the tallest gear at the lowest speed that does not lug the engine.
 
Joined
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Location
CA
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None Yet
Derrel H Green (2010 JSW, DSG) also ran similar tests with oversize tires.
Since he changed the GY LRR 205/65-16s to even larger LRR 215/65-16 Continentals,
he 'thinks' F E may not be as good as it was with the GY LRRs!

More 'tests' will need to be done to find out for sure.
 

JThiessen

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Joined
Apr 25, 2011
Location
Edmonds, WA
TDI
2011 Sedan LE, DSG
my average speed per MFD is always way low, but 90% of my time I'm either doing 65-70 or 35. For best tank over tank MPG's I'd need to drive at 50-55 mph. Speed kills.
Its low because that's the average speed you drive at.

I'm curious because the average mileage seems to be all over the place. Guys who drive mostly highway would probably have higher averages than those of us who drive more of an even combo, or all city, and thus have lower average speed.

Just another data point.

Plus 3's info is nice and well done, but nothing we can really compare to. With 3 of the cars not being stock config, all I can do is a SWAG comparison with my stock DSG. But - why do I need to......I am thrilled with my 40mpg.....
 

Jack Frost

Veteran Member
Joined
Nov 30, 2007
Location
Rural Manitoba
TDI
2009 Clean Diesel
I think MPG can only reliably be calculated over at least a tankful of fuel. The trip computer gives only instantaneous readouts, and any momentum gained from previous acceleration or downhill roads, will give one an unrealistic albeit fun figure of 200 mpg ( max of VW computer). My Scangauge sometimes gives me a figure of 2999 mpg on long down hills. :p

QUOTE]

Whether MPG can be reliably calculated depends on many things. The only difference between MPG calculated over a tank or that read from a ScanGuage (what you call instantaneous readout) is the time interval the MPG reading is estimated over. The tank method is done over the time it takes to use a tank of fuel (which could be a day or a week or a month or more). The instantaneous is not instantaneous but done the same way as the tank method but over a smaller quantity of fuel (typically the amount of fuel consumed in a single second).

Most of us cannot use a tank of fuel entirely on the highway on the same road, with the same weather condstions such as wind. One tank may produce quite a different MPG than another tank. The instantaeous method can be very accurate if one wants to know what the MPG is under very specific and controlled conditions. For instance, I have seen many times that there is a 5% difference in MPG between an older concrete highway and a freshly ashphalted section of it. That could never be realized using the tank method.

The tank method is a better method for estimating your overall fuel costs. Generally I found that the law of averages is very powerful. MY commuting mileage is always withing a few MPG on consectutive tanksfuls. There is about a 2 or 3% difference between summer and winter mileage. However without the instantaneous method, I had no idea of how much fuel that freshly asphaulted highway helped me.
 

Plus 3 Golfer

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Joined
Oct 29, 2008
Location
ARIZONA
TDI
Und tschüss! 2009 Jetta 12/23/2012
To get the best fuel economey you need to know at what rpm, peak engine torque is developed. Once you know that then it is just a matter of setting speed with rpm selected to the gear you are in.

I have not seen a torque chart for these TDI yet. Does anyone know where we can look at one?
...
Not quite true. Engine efficiency and peak torque is not the same as fuel economy. I think the charts you really want to see is the BFSC and it's in the thread I posted the link to.
 
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