Poor MPG, is there a concensus?

leicaman

Top Post Dawg
Joined
Dec 24, 2004
Location
Sheboygan, Wisconsin
TDI
2015 Golf TDI SE, 2005 TDI GLS, RIP
That looks like a knock off. Just buy the right thing. Buy the legit version and be done with it. You know it took talent and great effort to invent this thing, why try to cheap out and get something that isn't real.
 

thebaz67

Veteran Member
Joined
Sep 14, 2006
Location
Louisa, Virginia
TDI
2015 Audi A7
All I can say is the Ross-Tech stuff I purchased paid for itself the first time I did not have to take the car in.

Well worth it!
 

JungleDeath

Veteran Member
Joined
Aug 27, 2005
Location
Reno, NV, USA
TDI
00 Golf_11 JSW
...You're right Truman - it's a piece of cake!

Thanks to all who shared their wisdom, especially Dr. Oilhammer...
It is very easy. Easier than doing an ALH motor. My car was at -.5. It is at zero now. I will take a spin in a little while and report back.

Thanks again for the insight and info.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
This seems to be going well.

On a different note: another Passat fell victim to a broken tensioner, luckily it made it in under its own power. 101k miles. :(
 

Smokerr

Veteran Member
Joined
Sep 3, 2005
Location
Alaska
TDI
Passat Wagon GL,2005,Silver
Well, I do not know of any that are getting poor MPGs, but I know if you drive them too easy the mileage will drop down some, but not as low as yours.

I would check all the data blocks for things that are off, like temp values, timing (torsion), boost, etc.

I just got an even 40 MPGs on mine up to Chicago, running 70 to 75 with the A/C on the whole time (I have RC1).

FWIW, I service a LOT of these cars for the upgrade, many come in after driving great distances, and it is very rare to see an MFA display of less than 38... many have 42+ displayed (I know that is not necessarily 100% acurate, but as a general rule pretty close and good for comparison).
Oilhammer: Kind of missing seeing you post regularly. I know its a real time consumer, a lot of comfort knowing you are out there.

As you stated, 38 mpg on the MFD is about the lowest I have ever seen on the road. Typically 40 is more the normal minimum (for any distance over 20-30 miles if its open road and good traffic flow). 42 is about the norm for ours long distance, and some trips 44 (keeping in mind this is AK 55 is common, 65 is max in some stretches and A/C is not needed often)

When I have done good actual gallons put in to the top and actual miles driven, the MFD is withing tenths. Topping off is a bit of a variable, but it averages .2 to .5 low (never higher though).

All in town at is consistently about 1.5 mpg lower actual that what the MFD shows.
 

JungleDeath

Veteran Member
Joined
Aug 27, 2005
Location
Reno, NV, USA
TDI
00 Golf_11 JSW
Here's my little concensus...

I did a little test on my car to see if fe would change when changing torsion values.

My car: 2005 GL Sedan, B20, Big O Euro Tour 205-65-15 tires, a/c on, oe balance shaft and chain, 48,000 miles, vnt rod adjusted 1/2 turn shorter, cruise set on 70mph out and 65 on the way back.

Quick trip: 94 miles round trip to Doyle, CA from Reno, NV repeated 3 times, 92*-96*F, rolling hills, straight-ish highway.

Since my glow plug recall I have noticed a drop in fe. I know this has nothing to do with BS upgrade or TB replacement but something was up. Even with RC2, I was getting better fe. So after stumbling on this thread...

Car warmed to norm op temp,
My torsion was originally set at -.5*kw as per VCDS 10.6.

I set torsion to 0*kw and went for a drive. I reset both 1 and 2 on the mfa when I left the driveway. Drove to Doyle via 395 north at 70 mph, turned around and came back to Reno at 65 mph.
MFA when pulling in the driveway: 38.3 mpg

Set torsion to .5*kw, repeat but only setting 1 on mfa.
40.5 mpg

Set torsion to 1*kw, reset 1 on mfa,
39.2 mpg.

This is not really all that scientific but told me to put the torsion back to .5*kw and see what happens. I will be getting more B20 tomorrow and will do a 3 tank avg and see what happens.

Again, thanks for your thoughts and input. My wife thinks I'm an idiot for spending so much time on the Club, but she has no idea what a value this place is. :)
 

aja8888

Top Post Dawg
Joined
Dec 25, 2007
Location
Texas..RETIRED 12/31/17
TDI
Out of TDI's
Trip stats and comments

Trip summary: Houston, TX to Tomahawk, WI and back between July 10 and July 18.

Car: 2005 Passat wagon TDI, unchained, RC1+, torsion value @ 0.0, 97K miles at trip start. Fresh oil change, new fuel, air and cabin filters. Recent new outer CV joints, new motor mounts.

Tires: 17” Bridgestone 225 45R 17 on Bistar wheels @ 38 PSI.

Loading: 5 adults (one 16 yr old and mother, step daughter, wife, self). @ 750 lbs total.

Luggage: about 200 lbs; entire rear hatch full to top of seat

Miles traveled: 3,224.

Average speed: 67 MPH (from MFC and GPS). This is from highway runs only. Hwy was 90% of miles.

Fuel economy: 34.5 MPG over entire trip (hand calculated). Best tank; 36 MPG, worst: 33.3 MPG.

Fuel: D2 from available retail stations when needed (Shell, BP, FINA, Phillips 66, Mobil and some unbranded station.

Additive: one quart of Biodiesel (100%) per fill up.

A/C on 100% of time.

Comments

1. This is not a car for traveling with 5 full size people. The center of the rear seat is like a prison cell. It has no comfort factor and your butt will be sore in 10 minutes.

2. With this loading, and the stock suspension, the rear mud flaps scrape the road on dips and bumps. I wore 1/16” off the two flaps!

3. Overall, the car ran fine with the cruise set at 75 – 80 MPH most of the way. RPM was at 2,200 – 2,300 at those settings.

4. I believe fuel efficiency would be increased 2 -3 MPG with 15 or 16 inch wheels. A/C also adds to less MPG.

5. The usual complaints on lack of cup holders, poor front cup holders (only dumped two drinks from those). The rear cup holders could not be used due to the use of the center seat.

6. On a trip like this, a larger vehicle is desired, even with less efficiency.
 
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traubenberg

Veteran Member
Joined
Dec 29, 2009
Location
Ville of Liberty
TDI
B5.5 Passat (wagon)
Having taken a break from the site for a bit, I'm getting to be more frustrated than ever. What am I doing wrong ...?

From purchase (12/09) through May 10, I was averaging only 32.25 mpg. Hand calc'd, several trips to the same 1 or 2 stations, 70% highway miles, stock program (no chiptune), driven well - but not abused. This summer (through last fill up 8/29/10) I'm down to 28.93 mpg. I got about that out of my first B5.5 (1.8t sedan, 5MT). (And I know that my MFA is off between 6 - 10%.)

No major changes in May. (MAF in early, early April, though.)
Best MPG was March 2010 - 35.5.
Last oil change was 7k miles ago and I'm down 4.1% since then, but I might attribute most of that to running the AC this summer.
Running 225/45-17 Nokian WR tires (came with the car), PSI closer to 40 than 35.

Lifetime average since owning the car (9 mo now) is 31.5 mpg. To me, that's depressing. I love the car, but damn ...can't I get better? Shouldn't I expect better out of this vehicle?

Trying to think if there's anything that would be gunking it up, but I've done air/fuel/oil filters on time and with quality products. Good synth oil. Etc. Seafoam it? Not sure it would do a damned thing. Give it to someone to go over with a fine-toothed comb? I'm broke as hell right now (but would love to give it to OH for kicks). Chip it? That bumped my MPG in the 1.8t when I did it, but I'd rather know that there are NO issues before I go messing with stuff.

Should I be happy with what I have, or is there *something* I'm missing?
 

traubenberg

Veteran Member
Joined
Dec 29, 2009
Location
Ville of Liberty
TDI
B5.5 Passat (wagon)
Well, did you check your torsion setting like the others have?
No, because I'm a goon and TL;DR'd pages 3-6 of the thread before I posted.

That said, I went back and read through everything posted herein. I now know to log torsion value (Group 004 - block 4) at hot idle (operating temp) and that said value should be 0.0.

I also know to pull the top timing cover, loosen 3x 13mm bolts, turn 18mm *VERY* slightly counter-clockwise and reassemble. That step, of course, is assuming the torsion value is other than 0.0.

I'll report back after I find a VAGCOM to borrow. It's Chicago, someone's got to have one.

: off to PassatWorld to find a VCDS:
 
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BadgerFan

Well-known member
Joined
Aug 14, 2005
Location
Grafton, WI
TDI
2012 Touareg TDI Executive, White
I just got back from ST. Louis to see OH for brakes, shocks, blower fan, oile change, fuel filter, etc. and the best I could do was 35 mpg with A/C on (there and back). The temp outside was mid 70's and low humidity. I have noticed it is difficult to get mileage (38 to 40 mpg) I had before BSM upgrade and my new CAM. I do have RC1+ with EGR disconnected. I run performance 17" Bridgestones in the summer at 50 PSI so i am sure the additonal rolling resistance has something to do with the mileage drop. I do notice an increase in mileage with my 16" winter tires at full pressure and I do use an engine block heater in the winter. I am woindering if fuel(low sulfur) and use of diesel kleen have any effect on this issue?

Just my $.02

badgerfan
 

traubenberg

Veteran Member
Joined
Dec 29, 2009
Location
Ville of Liberty
TDI
B5.5 Passat (wagon)
For the record, I'm logging my data this Sunday (9/12/10). I'm sincerely hoping for soemthing like +1.5 and that resetting to 0.0 will slingshot my piss-poor mileage to the respectable numbers everyone here is seeing.

Of course, I will record and report for posterity.
 

spiceredwagon

Veteran Member
Joined
Apr 2, 2007
Location
Edmonton
TDI
06 wagon
I changed my BHW to 0.0 today from -2.9. It sounded better once out of the negative numbers. I will report the economy after three tanks, each tank seems to come in a little different. It was nerve wracking messing with the timing freehand after having it all pinned with special tools. It took three attempts to land on 0.0.

Interesting the BEW reads 1.0 with the factory belt.
 
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leicaman

Top Post Dawg
Joined
Dec 24, 2004
Location
Sheboygan, Wisconsin
TDI
2015 Golf TDI SE, 2005 TDI GLS, RIP
Today I took a nice drive in the passat and I got 39mpg out of it. I am hoping once the Michelins are installed (gettin' new tires) I hope to pick up a touch. The GY tires are a gettin' square.
 

aja8888

Top Post Dawg
Joined
Dec 25, 2007
Location
Texas..RETIRED 12/31/17
TDI
Out of TDI's
Traubenberg:

My lifetime MPG with the Passat and 17" heavy Bistar wheels and Bridgestone Potenza/Yokohama tires is 33.3 MPG. This is over 52,000 miles and well over 100 fill ups. I have to believe the heavy 17"s play a lot in the drop of a few MPG.

Once I wear out this set of Potenza's, I am getting some lighter 16" wheels.
 

leicaman

Top Post Dawg
Joined
Dec 24, 2004
Location
Sheboygan, Wisconsin
TDI
2015 Golf TDI SE, 2005 TDI GLS, RIP
Traubenberg:
My lifetime MPG with the Passat and 17" heavy Bistar wheels and Bridgestone Potenza/Yokohama tires is 33.3 MPG. This is over 52,000 miles and well over 100 fill ups. I have to believe the heavy 17"s play a lot in the drop of a few MPG.
Once I wear out this set of Potenza's, I am getting some lighter 16" wheels.
To think I almost ordered 17 inchers with mine. What cinched it for me was the replacement cost of the 17 inch tires at the time. Whenever I buy a car, I look at tire replacement costs because you almost always buy new tires for any given car. At the time I was a little peturbed that one could not get 15 inchers at the time. I saw the pricing on older passats for tires and that is something I wished I could have had on a GLS. I know I can still do that, but I'd prefer not to buy rims. The 16 inch size is okay iin my view for econ.
 

s4phillips

Veteran Member
Joined
Jul 3, 2005
Location
Live in d/FW, TX. Transplanted from the Pacific
TDI
2002 Beetle, 2005 Passat Variant-DOA blunt force trama, 2014 Beetle-went home
Traubenberg:

My lifetime MPG with the Passat and 17" heavy Bistar wheels and Bridgestone Potenza/Yokohama tires is 33.3 MPG. This is over 52,000 miles and well over 100 fill ups. I have to believe the heavy 17"s play a lot in the drop of a few MPG.

Once I wear out this set of Potenza's, I am getting some lighter 16" wheels.
Tony - I am not so convinced the 17" wheels cost that much in fuel mileage. We have 16" wheels wearing Michelin tires and our average after 82 tanks is 33.6 MPG as reported on Fuelly.com. However, our mileage is slightly understated because of the 215/55-16 tires. It should really be about 34.6 MPG. And no, didn't see a measurable difference in mileage when we switched to the 215's.

I think driving style, loads carried and air conditioning plays as much or more a factor in the achieved MPG. It is only anecdotal, but I am starting to think even the air conditioner run on the higher fan settings has a greater effect on mileage than the lower fan settings. Since we both live in neighborhoods where you need the AC on 10 to 11 months of the year it may be taking it's toll on mileage.

...and our timing is at -0.5 at the moment.
 
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aja8888

Top Post Dawg
Joined
Dec 25, 2007
Location
Texas..RETIRED 12/31/17
TDI
Out of TDI's
Tony - I am not so convinced the 17" wheels cost that much in fuel mileage. We have 16" wheels wearing Michelin tires and our average after 82 tanks is 33.6 MPG as reported on Fuelly.com. However, our mileage is slightly understated because of the 215/55-16 tires. It should really be about 34.6 MPG. And no, didn't see a measurable difference in mileage when we switched to the 215's.

I think driving style, loads carried and air conditioning plays as much or more a factor in the achieved MPG. It is only anecdotal, but I am starting to think even the air conditioner run on the higher fan settings has a greater effect on mileage than the lower fan settings. Since we both live in neighborhoods where you need the AC on 10 to 11 months of the year it may be taking it's toll on mileage.

...and our timing is at -0.5 at the moment.

S4: you may have a good point about A/C use as we seem to always keep it on in the Great Swamp south of you. We may be suffering from a combination of ills; heavy rims/tires, A/C on 90% of the time, higher freeway speeds as we have more of them, etc.

But the only thing I can control (comfortably) is a switch to lighter 16's. If that gets me 2 MPG more, it may be justifiable, cost wise. I'll have to put a pencil to it when I need tires again.
 

traubenberg

Veteran Member
Joined
Dec 29, 2009
Location
Ville of Liberty
TDI
B5.5 Passat (wagon)
Also cleaned the MAF and changed my oil today. Anxious to get some results, but I'm only doing 30-40 miles a day. Even with crap mileage, that's still 10-12 days between fillups. If not more.
 

truman

Top Post Dawg
Joined
May 18, 2000
Location
columbia,MO,usa
TDI
'05 Passat Variant, Still miss the 03JW
I just returned from a 700mi RT and averaged 34.5mpg. Average speed via MFA was 58mph. MFA on mine tends to read .5mpg high vs P&P. Mostly drove 75(actual) on the interstate.
On my daily 60mi RT commute, I drive a bit slower- 65-70 and average the same- warm up subtracts from the lower speed.
205/60/16 non LRR tires and torsion at 0.0.
If my previous experience w/ an ALH holds true, I could probably recapture 2-3mpg w/ LRR tires.
 
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mech644

Veteran Member
Joined
Feb 7, 2007
Location
Blue Hill, Maine
TDI
'00 Golf, '14 Touareg
Not a Passat owner, but as far as wheels/weights and mpg go...
Winters of '08/'09 and '09/'10 I've run 15" steelies/Blizzaks and average 50 mpg as long as roads are clear,
spring/summer/fall of '09 16" Montreal II's/Michelin MXV4's, averaged 47 mpg
Spring of '10 mounted 15" Jaramas/GY Triple treads, averaging 50mpg.
I run always maintain 38psi tire pressure.
As soon as i have $1700 to blow I'm getting some 15" SSR rims, 11lbs each!
 

thundershorts

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Joined
Jul 15, 2010
Location
west chester pa
TDI
2015 passat tdi sel premium 2015 golf s tdi gls tdi b5.5, 2002 eurovan,Peugeot 505 td,Citroen cx25 prestige
if there is a consensus on this issue, torsion value set to zero, could be that a/c compressor running acounts for 3-5mpg.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
if there is a consensus on this issue, torsion value set to zero, could be that a/c compressor running acounts for 3-5mpg.
These cars use a variable discplacement compressor, so you cannot account specifically for compressor drag, because it can vary a great deal. Once the cabin is cooled down, however, the drag should be pretty low. You do not notice the A/C much on TDIs since the engine has ample power. You do notice it quite a bit on the gasoline 4 cyl VAG cars when first started, as that is when the compressor load is greatest.
 

truman

Top Post Dawg
Joined
May 18, 2000
Location
columbia,MO,usa
TDI
'05 Passat Variant, Still miss the 03JW
Speed, stop and go, and short trips seem to effect my mpgs the most. Engaging AC at highway speed deducts about 1-2mpg, as far as I can tell.
 

sirpuddingfoot

Veteran Member
Joined
May 14, 2010
Location
Seattle, WA
TDI
05 Passat, 05 Jetta
Well, we have noticed a significant downturn in mileage recently. Our mileage dropped from a consistent 38-40 to 33-35 in the middle of August. At our local G2G I checked the torsion value +1.2. No adjustment was or has been made at the time. 2.5 weeks ago I changed the oil and replaced the air filter. The air filter was literally oily in the inner rear corner. After replacing the oil filter, we saw a minimal improvement, and I'm able to hit the 40MPG on the computer cruising at 60 (mostly with help coasting into towns and no AC). I now have some MAF cleaner at home and will be cleaning it tonight.
 

traubenberg

Veteran Member
Joined
Dec 29, 2009
Location
Ville of Liberty
TDI
B5.5 Passat (wagon)
The downward spiral continues. Since July 1, my calculated MPGs are ...

7/01 - 30.66
7/10 - 30.24
8/01 - 27.50
8/29 - 27.05
9/12 - 28.11
9/26 - 26.83

And in seeing this, my jaw has literally hit the floor. The change from July to August is readily visible and thereafter, it's pretty steady. In fact, if I measure my average from March through July, I'm at 31.93. In Aug-Sept, the average drops to 27.36. That's a 14.3% decrease. What happened between the July 10 fill up and the Aug 1 fill up that could have had that sort of impact on my mileage? I had no maintenance done. Didn't run the A/C more or less than previous. Didn't begin revving at every stoplight.

I moved.

July 27, I moved and started using a new filling station exclusively. That's the biggest thing I can think of. Knowing someone in the fuel industry, I find it hard to believe that one station could have that kind of impact (because it's a limited number of refiners/distributors selling to all of the stations in the area) ...but what if?

Unless someone can tell me 100% for certain that this cannot be the case, I'm going to run out the tank that I have right now and switch to a different station (and a different brand). Now I've got myself really, really curious.

Thoughts?
 
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