Adding a chip to a 2015 Passat TDI better mileage

I had a 2013 which went through the buy back. Now I have a 2015 Passat TDI with 45,000 miles on it, already had the fix. Is there a chip I can add to it that would give me better mileage? I've never chipped a car so I don't know what is involved. But in Reading, I see that some talk about 10% or 20% better fuel mileage. Is that true and which one would I use? I do 20 miles on the highway twice each day and then driving around town. Thanks for any advice.

VW already has maximized MPG. Your best solution is to slow down and accelerate slowly. Wind resistance is proportional to the square of the speed, so a small increase in speed has a larger drop in MPG.

I get 50 MPG in my Touareg TDI at steady 40 MPH on flat land. Nowhere near that at highway speeds.

Look up on Malone tuning for better MPG but you having NMS Passat... cant promise you for better MPG because Passats are known for long gears on highway speed. Mines stock and averages 47-52 mpg all highway.


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10-20% is probably exaggerated; there is probably some gain with a chip but I'd wager it to be minimal. You'll get more effective fuel economy gains by using the "foot mod".

Yup he is right. For golf and JSW, yes nice improvements with the tunes but for Passat probably slightly better but do the “foot mod”, its gonna be your best friend.


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Is another 1-3 mpg worth losing the 11/162K warranty for? Not to me.

My new longest tank (741 miles) hand calculated at 46.0 mpg. My overall average since buying the car is ~41 mpg. I live in the mountains and run up the grades at 80 mph, all flat ground my mileage would average much better.

The stock tune for a fixed '15 is probably the best you're going to do for FE. Keep it stock, keep your warranty.

Any "chip" or tune without deleting emissions hardware won't get you much of any MPG improvements.

+1 for the foot mod and for BroncoAZ's post above. Driving smart will get you the best all around deal on FE.

What am I doing wrong. I barely get 34 avg. 2012 auto

Depends on how you drive it. Some people here are reporting MPG in the high 20s with 1st gen CR cars in city driving and short trips. I find that kind of amazing but I guess it happens.

AaronB said:

What am I doing wrong. I barely get 34 avg. 2012 auto

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Are you accelerating fast off the line? I don’t accelerate faster than traffic most of the time. I think I annoy some other drivers because I don’t floor it off the line, people are very impatient these days. I drive 79-80 mph on the highway including up long mountain grades without slowing down, otherwise I’d probably be averaging 45 mpg instead of 41 mpg.

Besides changing driving style, going to slightly narrower, low rolling resistance tires at a firm 40 psi will get you a few mpg or better.

short drives less than 5 miles will have more of an effect on MPG as that emissions stuff will never get up to temp.

740GLE said:

short drives less than 5 miles will have more of an effect on MPG as that emissions stuff will never get up to temp.

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I think this is where the newer cars really take a hit compared to the older cars. My '02 ALH rarely dips below 45 MPG, traffic or no, short trips or not, winter or summer. My '15 GSW has averaged 42 MPG so far, but I don't use it for short trips. I also think, despite what the EPA figures said, it appears DSG cars get significantly worse FE in town/traffic than manual cars.

I think Indigo is right. My '15 takes a while (as in a longer trip) to start racking up mpg

AaronB said:

What am I doing wrong. I barely get 34 avg. 2012 auto

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That's about where I am with my 2012 DSG model - I was able to hit 40 consistently when I had a 50 mile highway commute but now that I'm doing less than 15 each way I'm always in the mid-30's.

My 97 Passat would return 45+ no matter the commute or weather but it had a straight-through exhaust, an MT, and a lot less weight to haul around.

I have only had my 2015 Passat TDI for a few months now so do not have a solid baseline of MPG, but overall it is just over 41mpg with driving patterns all over the place. When I get to feeling down on getting <40mpg around town, I just drive my 2004 Passat 1.8T gasser and see how good I have it now.

I've been cruising lately to see if I can get the MPGs up. Went to Tulsa from OKC and back at 80 cruise set car said 38. But fuel up showed 34. Hardly get 500 miles before light comes on. 2012 DSG. With the fix. I drive 25 miles to work daily. Just not really what I thought it should be. I run my tires at 33 psi per the door. But I'll bump to 40 psi. Also have 255/40/18s on it not sure if that Is a factor

18s are a factor. 80 MPH is a bigger factor. Slow down to 70 and I'll bet you'll get over 40.

I don't know how the Gen 2 cars (yours) are doing post-fix. The Gen 3 cars are getting great FE by most reports. Gens 1 & 2 seem to take more of a hit, especially in traffic and suburban driving.

I'm about to take it to Florida Next week so I'll see how that goes with strictly highway driving

Yeah, fuel efficiency drops off pretty fast past 70 mph. 255 tires are also incredibly wide for this class of vehicle- I wonder if that's a typo. I think stock would have been more like 225. 205's would reduce road friction losses quite a bit.

Stock 18s for the NMS are 235/45s. I actually moved the ones from my son's car from my guru's to my house today. Big and heavy. I took my B4 15" wheel and tire up there to get a slow leak fixed, and the difference in size and weight is pretty significant. If the poster's car has 255s on it, not only are they creating more drag because of the extra width, but they're also probably causing the speedometer and odometer to read wrong.

We swapped the 18s on my son's NMS to 16s from a '16 1.8T NMS. Width went from 235 to 215. Also much lighter. Their impact on FE remains to be seen.

I just happened to get 255/40/18s for free when I was in desperate need of tires when I bought this car. But I'm due for tires so I'll go back to OEM size. Just found OEM size is 235/45/18. Here is a tire comparison I found between the two.

I just googled, but can't find any info... what is the "foot mod?" Is that the removal of the torque limiter via VCDS?

saucer said:

I just googled, but can't find any info... what is the "foot mod?" Is that the removal of the torque limiter via VCDS?

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“Foot mod” or “driver mod” means take it easy like grandpa driving style.


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Yeah, it means "control your foot".

Yes between the tires and speed (i also avg 80 on the highway) i get 34-36. You will not crack 40 driving 70... more like 37-38 if youre lucky. To me i would much rather have a wide tire and enjoy the many two lane roads around here for the sake of a couple mile per gallon.

Yup! "Stomp and release" driving kills MPG . . . On my Gen-2 going from TX to MI (a lot of which isn75 to 80 MPH or get blown off the road) I can still do my first day 750 mile freeway leg with no issues, and typically see high 40's to sometimes cresting 50 MPG on the slower 2 lanes up north. I don't typically bother checking for in town driving, but open road, mine seems pretty much unchanged (and has had the first fix, and then the fix for the fix as well . . .)

Drive it like ther ]e is an egg between your foot and the pedal (or use cruise) and mileage will come up. Frankly, I don't feel like I am doing anything out of my norm - it's just how I drive. I was taught that driving should be smooth, and any sudden move/accel/decel is an error (especially in snow!) and it really helps on all my vehicles (I get just about 20 MPG on my diesel 2011 RAM 2500 on the same trip, at 8500 lbs empty . . .).

It works . . . and my wife (more of a stomp and relrase driver) can't even get close on the same road in the same car . . .

Lex Tdi said:

Yes between the tires and speed (i also avg 80 on the highway) i get 34-36. You will not crack 40 driving 70... more like 37-38 if youre lucky. To me i would much rather have a wide tire and enjoy the many two lane roads around here for the sake of a couple mile per gallon.

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I beat 40 mpg all day at 80 mph on stock 215/55R17. My flat highway trips are 44-46 mpg. I live in AZ with 75 mph limits.