MPG at 75mph

Max Period

Veteran Member
Joined
Dec 30, 2010
Location
Toronto Ontario Canada
TDI
2011 Jetta Comfortline
CR engine
6th gear
GPS speed
2.6 Bar / 38 PSI tires
MFD specific range readouts
no passengers

DSG Data by Plus 3 Golfer:
2009 Jetta @ 8k miles
13-24C / 55-75 F
Powerservice

manual data by Rockwater:
2010 Wagon @ 1-1.5k miles
1-17 C / 33-62 F
Winter fuel

(original thread)


Note: 2 Gallons per 100 miles = 50 MPG (USA). 2.5 Gal / 100 mi = 40 MPG (USA). The very top end of the graph (3 Gal / 100 mi) = 33.3 MPG (USA).

From this graph, to attain a specific range of 50 MPG (USA), cruise at 62.5 MPH for DSG and 66 MPH for manual.
For 50 MPG (Imperial) specific range, cruise at 78.5 MPH for DSG and (about 81 MPH, graph ran out) for manual.
 
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david_594

Top Post Dawg
Joined
Feb 28, 2004
Location
Cheshire, CT
TDI
2000 Jetta GLS Silver
I've found that if I set the cruise at at 68-70mph(actual gps speed) I get a pretty consistent 53-54mpg and thats even with the AC on during the summer. When I experimented with setting the cruise at 60 mph, I was able to pull off a roughly 60 mpg average. I took a small economy hit when i went to 205 width tires.
 

Max Period

Veteran Member
Joined
Dec 30, 2010
Location
Toronto Ontario Canada
TDI
2011 Jetta Comfortline
Hey, our new CR engines burn 14% more fuel (reduced to +7% for SCR Passats) than your 90 hp ALH...

Here I'm tallied the fuelly averages of 2009+ Jettas, 2004-2006 Jettas, 1998-2003 Jettas, and 2012 Passats.

Average L/100 km, weighted on distance driven, fuelly US MPGs for higher precision.
2009+: 6.198
2004-2008: 5.737
1998-2003: 5.440
2012 Passat: 5.837

Fuel consumption difference (compared to 1998-2003 Jetta):

2009+: +13.93%
2004-2008: +5.46%
1998-2003: +0.00%
2012 Passat: +7.28%

Fuel consumption difference (compared to CR Jettas)

2009+: +0.00%
2004-2008: -7.44%
1998-2003: -12.23%
2012 Passat: -5.84%
 
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kennethsime

Veteran Member
Joined
Oct 29, 2010
Location
California
TDI
2004 Jetta Wagon GL TDI 5-Speed Baltic Green
I recently drove to Phoenix @ 75 mph (72 actual speed). My 15-gallon tank lasted about 770 miles, and I got just over 51 mpg.

The only modification I've made is removing the fuel tank vent (ventectomy), making it easier/faster to fill the tank up all the way.

Normally, I average mid-40s.
 

Bob_Fout

Oil Wanker
Joined
Sep 5, 2004
Location
Indiana
TDI
2003 Jetta - Alaska Green (sold) / 2015 GTI 2.0T
I recently drove to Phoenix @ 75 mph (72 actual speed). My 15-gallon tank lasted about 770 miles, and I got just over 51 mpg.

The only modification I've made is removing the fuel tank vent (ventectomy), making it easier/faster to fill the tank up all the way.

Normally, I average mid-40s.
Imagine that, ~70 MPH = ~50 MPG. I see a pattern :D
 

VWBeamer

Veteran Member
Joined
Jan 1, 2009
Location
GA
TDI
2004 Jetta Wagon
This close in my experience. Pretty accurate rule of thumb for MKIVs

The forum's rule of thumb used to be '120 - speed = instantaneous MPG' on the highway, i.e., at 60mph you get 60mpg, at 75mph you would get 45mpg (on the flat, no wind, moderate temperatures, no A/C or heater, & engine already up to full temp).

I don't know if this rule applies to the Mk4. But it should at least give you an idea of the effect of speed on fuel consumption.
 

ksteel8880

Well-known member
Joined
Apr 6, 2012
Location
Charlotte, NC
TDI
91 Eco Wolf
Driving 75 mph ACTUAL (about 79-80 on the speedometer) I can get over 50 mpg.

In the summer in 80* heat, with a stuck thermostat and slipping clutch, I got 57.1 mpg hand calculated on a tank of about ~300 miles. Full tank of gas, no wide open throttle or AC during the trip, traveling at an actual 75 mph. Probably would have gotten over 60 mpg but there was actually about 5 miles of city driving and a shut down in there.

Car is modded with a tune (RC3), full 2.5" turboback exhaust with no cat or muffler, and tires were at about 45 psi. 235,000 miles on the car as well.
I am glad you mentioned this. Why is the speedo off? It reminds me of a motorcyle!
 
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coalminer16

Top Post Dawg
Joined
Dec 11, 2008
Location
Central Wisconsin
TDI
Golf 2004
As with everything, weight matters a little. How you drive with your foot matters a lot. Wind resistance plays some. Elevation. How the engine timing and some other mods are set. I have gotten 59 and 20 with the same car. One was driving from WY to MN with a full car doing 57 the whole way. The other was doing 75 with a very strong headwind, Car top carrier and a trailer with a 4wheeler on with a loaded car.
 

jkornbread

Well-known member
Joined
Oct 17, 2011
Location
Sacramento, CA
TDI
2003 Jetta 5 speed
I'll throw my hat into the ring too I guess......

I commute anywhere from 100-200 miles daily depending on where I might be working...... Longest commute was like 380 or something. That sucked!

I generally keep with traffic, which tends to be 75 ish. Sometimes faster sometimes slower. Mornings usually are 70mph and evenings 75-80. Last tank i got 51.5.
 

Niner

duplicate account, banned
Joined
Jun 3, 2011
So the new guy asks what speed yields 50 mpg, and you say you can get it at 90mph :rolleyes:
Why not take the opportunity posed by his followup question to clarify that you calculated 50 mpg at 90 mph going downhill over a short period of time if that is true? Why answer his original question with some special, rare case that was not clocked over a full tank?

I call BS on anyone claiming 50 mpg @ 75 mph (unless they've modified their final drive ratio)
I've done it a few times, all it takes is some luck having tailwinds both ways based on adiabatic conditions.. From L.A to Phoenix during monsoon season on summer fuel, I've seen 70-75 mph trip most of the way in 95-115F temps with my A/C set on low in an ALH with 130 k miles on a motor with a 5 speed and an 11mm Injector pump.

I've heard that that 11mm pump can make a good sized difference in your MPG due to higher pressure and better atomization of fuel.
 

tikal

Veteran Member
Joined
Apr 18, 2001
Location
Southeast Texas
TDI
2004 Passat Wagon (chainless + 5 MT + GDE tune)
I think the point made earlier about VARIANCE is a good one to keep in mind. I would humbly add that it is also good to review the Central limit theorem in these cases of MPG discussions.
 

blownaway

Veteran Member
Joined
May 20, 2008
Location
Oregon
TDI
2002 TDI (waiting for my 02M conversion) 99.5 TDI(totalled) 2002 gasser wagon, 2012 Golf
My 150hp ALH gets over 50 MPG's every time :D I would slit my wrists if I only got 40mpg's:rolleyes:

Hey, our new CR engines burn 14% more fuel (reduced to +7% for SCR Passats) than your 90 hp ALH...
 

Wksg

Veteran Member
Joined
Aug 2, 2008
Location
Ann Arbor MI
TDI
2003 GLS TDI Wagon
I just made an 900 mile RT trip over the last three days to go to a funeral. Filled up just before I left, mostly highway, drove moderately (70 mph most of the time), except for a ~10 mile stretch at 90-100 mph and another traffic-light laden 6 miles stretch that I had to do twice when the car was cold (30F outside). 910.8 miles on 16.4 gallons, about 55.4 mpg.
 

Rual817

Veteran Member
Joined
Nov 13, 2011
Location
Prosper, Republic of Texas
TDI
2000 Jetta TDI, 2003 Jetta TDI ALH
The forum's rule of thumb used to be '120 - speed = instantaneous MPG' on the highway, i.e., at 60mph you get 60mpg, at 75mph you would get 45mpg (on the flat, no wind, moderate temperatures, no A/C or heater, & engine already up to full temp).

I don't know if this rule applies to the Mk4. But it should at least give you an idea of the effect of speed on fuel consumption.
This does not fit my car. When I first bought it my wife was driving 65-70 and was getting 34-36 mpg. I started a new job that had me going 52mi one way so I took over the car. I started using Lucas. I'm guessing it cleaned the injectors, but improvements only came to 36-38mpg. I started using Power Service and I also started driving 80 to and from work (after learning where to look-out for speed guns), and started getting 37-39mpg. On a trip to my parents, I filled in Vernon Tx on the way back (Hwy 287) and immediatly connected with a bunch of cars cruising 90+. Exited Hwy 82 @ Henrietta Tx and maintained 80-90 and stopped in Gainsville Tx Wallyworld to groceries and top off just to see what it did @ 85+ avg. and was pleased to see that I had registered 40mpg. I started using 5oz of Power Service but switched to 10oz and started getting 41.5 avg. As a test run I quit using Power Service for the last 3 tanks and am recording 37mpg., and I am now only living 5 miles from work and doing more city driving (slower speeds). I put 10oz of PS in this tank now will let you know the results when I get them.
120-speed = mpg (120-85=35) but I got better @ 85+(40) than @ 75+(38) and better yet when I started 75+ and 10oz PS (41.5)
 

ruking

Top Post Dawg
Joined
Mar 27, 2003
Location
San Jose area, CA
TDI
2003 VW Jetta, 5 M, Reflex Silver: 09 Jetta, 6 Sp DSG, Candy White: 12 VW Touareg, 8 Sp A/T, Flint Gray
I just made an 900 mile RT trip over the last three days to go to a funeral. Filled up just before I left, mostly highway, drove moderately (70 mph most of the time), except for a ~10 mile stretch at 90-100 mph and another traffic-light laden 6 miles stretch that I had to do twice when the car was cold (30F outside). 910.8 miles on 16.4 gallons, about 55.4 mpg.
Evidently a lot of cars did not get the "120- speed RULE" FYI. :eek:;) Good shooting ! Sorry about the REASON for your trip.
 
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MikeMars

Veteran Member
Joined
Mar 6, 2008
Location
UK
TDI
Vento 1.9 TDi (retired), A4 1.9 TDi (rear end collision), VW Passat 1.9 TDi (retired), Audi A2 1.4 TDi
Another class that didn't get the FYI !:(
90% of the time the fact that some of these cars are automatics doesn't even occur to me. I've never seen the point in pairing an efficient engine up with an inefficient transmission.
 

ruking

Top Post Dawg
Joined
Mar 27, 2003
Location
San Jose area, CA
TDI
2003 VW Jetta, 5 M, Reflex Silver: 09 Jetta, 6 Sp DSG, Candy White: 12 VW Touareg, 8 Sp A/T, Flint Gray
90% of the time the fact that some of these cars are automatics doesn't even occur to me. I've never seen the point in pairing an efficient engine up with an inefficient transmission.
Evidently VW and the customers that bought them ... DID.

But then,... the jury is still out (need app 200,000 more miles to reach a good verdict), even in light of the DSG, the 8 speed A/T mated to the V6 3.0 L TDI appears to be a good match up. See the FE post for the mpg. Perhaps 406 # ft of torque was a bit much for the DSG.

Just a point of interest, as I know not many people know or more importantly CARE. Also VW T TDI owners are a much smaller group. This 8 spd A/T has a torque capacity of 627 # ft. 54% over capacity. I do wonder what a 6/7/8/ speed M/T on a VW T TDI would fare, as that option is not even offered. Not being offered means defacto 100% are A/T.

In contrast, a normal Jetta/Passat, etc. puts out 236 # ft and has a capacity of 258# ft or 9.3% over capacity for the DSG. Even most 6 speed M/T's will be at the literal edge with barely a nozzle and chip upgrade. This is of course not even to account for the range of normal wear patterns given the driver population. One example so as to be clear, one driver can barely get 75,000 miles vs another that is still spinning alone @ 450,000 miles. The switch to DSG has NOT been "seamless" after 10+ model years of use and constant improvement. One ownership op ed is WE personally like it. It is also well known that it costs more as an option ($1,100) and is WAY more expensive to R/R than a 6 speed M/T. (5,000 vs 1,000)

It is fairly well known in the VW community, that the DSG is a HUGE improvement over both the VW slush box A/T choices and normal slush box A/T's.
 
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rmalone68

Active member
Joined
Apr 7, 2012
Location
michigan
TDI
2012 jetta sportwagen
I agree, VW is trying to sell cars to Americans. Most Americans have no desire, in fact many people I know dont even know how to drive a manual trans. 4 out of 5 people that see my car say "oh my god why would buy a manual, doesnt it come in an auto trans?"
 

ruking

Top Post Dawg
Joined
Mar 27, 2003
Location
San Jose area, CA
TDI
2003 VW Jetta, 5 M, Reflex Silver: 09 Jetta, 6 Sp DSG, Candy White: 12 VW Touareg, 8 Sp A/T, Flint Gray
Manual trans account for 6.5% of vehicles in the US. Probably a bit higher for VW, but I doubt even 15% of new TDIs are manual.
I have also gleaned that app 20% (51.76 M) of the passenger vehicle fleet (2009- 258.8M ) ARE M/T. So in that sense TDI owners with M/T are in an over all sense an extremely small minority group. In THAT minority group there further ever smaller minority groups . But in effect IF it is true that 15% of TDI's ARE M/T, it appears to follow the larger trend (20% of PVF= M/T)
 
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Bigwhitebeast

Veteran Member
Joined
May 1, 2012
Location
New York
TDI
2012 Jetta
I am on my first tank of fuel, I have a 52 mile commute one way to work. Of that 52 miles about ~8 of it is 30-45 mph zone and the rest is 65 mph highway.

I set my cruise control on 74 mph, I haven't used a gps yet to check the accuracy of the speedometer but I think its pretty close. I have a 2012 Jetta with the 6 speed and my readout is indicating 47.9 MPG on a round trip.

I am extremely happy with that mileage and I hope that when I fill up and calculate it out that it is close to that. I had a Honda Accord previously that got 29 mpg and I was filling it up every 3-4 trips, I have 240 miles on this car and it says I have 440 miles left on the tank! :) Sweet
 

npdimonte

Veteran Member
Joined
Jan 17, 2008
Location
Bolingbrook, IL (Chicago area)
TDI
2003 Jetta GLS TDI, 5spd
I have a 2003 Jetta TDI and I drive from Chicago to Tennessee and Alabama at least twice a year. The speed limit is mostly 70 MPH, so I've been able to experiment a little. Here is my MPG at different highway speeds.

At 65 MPH = 62.7 MPG
At 70 MPH = 54.7 MPG
At 75 MPH = 52.3 MPG

I have been able to repeat this on a regular basis.

City driving, Chicago diesel blend,
Winter: between 40-43mpg, some what lead foot :)
Summer: between 45-48mpg, heavy lead foot :D

Nick D.
 
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