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I agree with the trailer module and the towing settings. Never did I feel like the system was not optimized and working properly and only on descents did I feel that I wanted to shift manually to engine brake.
The trip from east to west and return over all types of roads and mountains was comfortable and the Touareg never set a foot wrong during the entire 8000 mile trip.
Probably a lot better than many pickup trucks.
Trying to outguess the transmission (other than a steep descent) is probably more of an exercise in ego than an improvement in towing
 

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The downside with diesels is they dont really offer engine braking. Its super minimal.
 

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Yep, there's no choking effect from a throttle body or carburetor, which is what supplies most engine braking. But that's not a problem.
 

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I wrote that poorly - it isn't a 'problem'... its a downside. I'll edit that. These things have nasty brake systems on them... just use em.
 

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its still effective for mountain travel, w/my rig any grade 8% or less I can find a gear to maintain speed in w/out needing to use brakes, over 8% I use brakes sparingly.. Teton pass (10% grade) had my brakes a lil spongy but that had more to do w/Eclipse Traffic made it stop and go most of the way down.

That was with the original pre-fix TCM.
 

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We averaged 14 mpg last summer/fall over 12k miles. Through the Rockies twice, around Lake Superior and lots of headwinds through the Prairies. Used a pile of DEF!! All in all, very happy pulling a 5500lb brick!
 

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On a recent trip here in Oz, travelled 3,885 km (2,414 miles) at an average of 15.03 l/100km (15.65 US MPG) while towing a caravan (travel trailer) weighing in at 3,460 kg (7,627 lb). We don't have really high mountains here, but this did include crossing our Great Dividing Range in both directions. Given the size and weight of the van I considered this pretty damned good. Figures calculated from fuel fills, not the computer.
 

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I've found that by not using cruise control especially on hilly trips, economy goes up big-time. You can keep a super-light foot on the go-pedal and drive to the conditions, consumption-wise, rather than driving to the vehicle's capability. It's a test of self-restraint not to use all that lovely torque to power up a hill at the speed limit towing a big weight just because you can, and to let others pass you.
 

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Someone else put it in an earlier post, but FUEL is probably the biggest contributor to your current economy. I saw in one of your posts that you are in the snow belt (I think I saw Grand Haven MI). Winter fuel has a lot less energy in it to prevent it from gelling up. And it's still winter blend time in the north.

I'd say if you make that exact same trip in June, your economy will be better. I have a Polaris Ranger that I pulled with my TDI (on a 12' single axle aluminum trailer - Aluma 7712 HSLR). I would get ~17mpg on highway trips with it during the warm months. I have a roof and half windshield on the machine for extra aero drag too. Even unladen my economy is noticable worse when it's winter blend time.

Hope that helps! I sure miss my TDI.....
 

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Discussion Starter #31
Thanks to everyone for the great posts sharing your towing experiences. I'm just amazed at how efficient the Reg is at towing, especially the heavy stuff. After running the Power Service additive (double dose), I'm not seeing any of the "yellow dust" on the back window, so it must have done the trick. I recently filled the tank with a 1.5 dose of additive and reset the trip meter. I've driven 50 local miles w/o towing and driving conservatively to improve mpg, and the fuel gauge needle has barely moved from the full mark. Most of my local driving is fairly flat with a couple 5 mile highway stretches and lots of 35-45 mph driving with stops every 1/2 mile to mile. I'm really enjoying this vehicle the more I drive it. The 275/45-20 tires do transfer a fair amount of bumps, but they look great and I'm sure improve handling.
 

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Hey I really appreciate the feedback and sharing your own MPG experiences with your TDI machines. Just today I drove it about 20 miles, and during that time, I observed about 35 mpg on a straight and level stretch at 58 mph, which is something I hadn't seen before. I'm hoping it's the fresh fuel and Power Service additive working its magic. Once I get down to 1/4 tank and fill with fuel, I'll reset the trip odometer and drive it "normally" without a trailer. Once I'm below half a tank I'll refill again, document the fuel used and mileage, calculate the mpg and post the results on this thread. Note that right now here in MI the diesel is "winter blend", and I'm told that this formulation can negatively affect mpg around 5% compared to the "warm climate blend" that is available once the weather warms up.
What your missing is what rpm are you cruising at? Any engine, diesel or petrol, exceeding 2000 rpm kills mpg. Did you have your tires at max pressure as listed on the sidewall? Many people neglect this idea.... Tire pressure is a huge factor in towing and max mpg.
 

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I've found that by not using cruise control especially on hilly trips, economy goes up big-time. You can keep a super-light foot on the go-pedal and drive to the conditions, consumption-wise, rather than driving to the vehicle's capability. It's a test of self-restraint not to use all that lovely torque to power up a hill at the speed limit towing a big weight just because you can, and to let others pass you.
This! I remember driving my dad's 41' RV (with a toad) back from Florida a few times and he would use the cruise control while he was driving and I would just park in the right lane and drive to the conditions and not use cruise. Guess who got 2mpg better mileage? It makes a difference when you're in single digit mpgs. I've found the same pulling our camper behind the Touareg. I try not to use the cruise control and just adapt to the road and I got way better mileage.
 

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I'm a new Touareg owner -- 2012 TDI Executive with 77K miles. I just finished a 200 mile round trip towing a load, which is my Can Am Maverick Trail 1000 side by side on a single axle 14 ft aluminum trailer. I'm estimating the total weight to be 2800 lb with about 300 lb tongue weight. The trip is maybe 40% flat and the rest hills and a total of 30 stop signs/lights. Speeds ranged from 30 to 70 mph. According to the vehicle computer, I averaged about 15 mpg. On the freeway flat straights, the real time computer showed 14.5 mpg at 65 mph. I've read many posts from other TDI owners claiming close to 20 mpg on the highway towing more than 5000 lbs. Something is amiss here. Prior to the trip I ran the "original unknown type and age" fuel down and put in 22 gallons of Marathon diesel with 16 ounces of Power Service Diesel Kleen with Cetane Boost per my local VW service manager's suggestion, and I was "getting on it" sometimes going through the gears manually to get over 3000 rpm while upshifting. Something I did notice is that in 8th gear and 65 mph, when I'm going up a hill, I can sense a very slight surging -- almost feels like a gas engine that's got an ignition issue or bad gas. That's the only time I notice this, but it can be repeated consistently. This is my first diesel vehicle so I'm a complete newbie when it comes to how they're supposed to run. Any suggestions would be appreciated.
Hello
I'm a new Touareg owner -- 2012 TDI Executive with 77K miles. I just finished a 200 mile round trip towing a load, which is my Can Am Maverick Trail 1000 side by side on a single axle 14 ft aluminum trailer. I'm estimating the total weight to be 2800 lb with about 300 lb tongue weight. The trip is maybe 40% flat and the rest hills and a total of 30 stop signs/lights. Speeds ranged from 30 to 70 mph. According to the vehicle computer, I averaged about 15 mpg. On the freeway flat straights, the real time computer showed 14.5 mpg at 65 mph. I've read many posts from other TDI owners claiming close to 20 mpg on the highway towing more than 5000 lbs. Something is amiss here. Prior to the trip I ran the "original unknown type and age" fuel down and put in 22 gallons of Marathon diesel with 16 ounces of Power Service Diesel Kleen with Cetane Boost per my local VW service manager's suggestion, and I was "getting on it" sometimes going through the gears manually to get over 3000 rpm while upshifting. Something I did notice is that in 8th gear and 65 mph, when I'm going up a hill, I can sense a very slight surging -- almost feels like a gas engine that's got an ignition issue or bad gas. That's the only time I notice this, but it can be repeated consistently. This is my first diesel vehicle so I'm a complete newbie when it comes to how they're supposed to run. Any suggestions would be appreciated.
Hello sidecraft i have a 2016/17 Wolfsburg version and tow a heavy camper (about 1800 kilo’s and Ball weight of around 180-200 kilo’s) and I average around 10-11 ltrs per 100klms I think That is about 27mpg.
 

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145miles... ~1500lb trailer... 80 mph average... 16.5 mpg


Sent from my iPhone using Tapatalk
 

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That's pretty amazing that doubling the trailer weight doesn't make much mpg difference -- I suppose that's a key advantage to diesel engine physics vs gasoline.
It's got nothing to do with diesel vs gas. Aerodynamic drag increases as the square of velocity, so each additional 1 mph consumes more fuel per mile the faster you go. When I set cruise control at 65 MPH, the trip computer reports 36 MPG. If I increase to 70 MPH, it drops to about 33 MPG. If I increase to 75 MPH, it drops to about 29 MPG. If you're towing something with a large frontal cross-section (like a travel trailer) or with lots of uneven surfaces (like a Maverick Trail), aerodynamic drag will be disproportionately large.

The reason diesels get better mileage towing is because the torque peak and hp peak are closer in RPM. Torque peak is where the engine operates most efficiently (uses the least fuel per work done), hp peak is where the engine delivers the most power (can tow the biggest load). So a diesel towing (closer to its hp peak due to the higher load) is still relatively close to its torque peak. A gas engine has to rev up higher to generate the power needed to tow, which puts it further from its torque peak and thus makes it operate less efficiently.
Towing a 1500kg caravan at the 60mph UK towing speed limit, I average 22 mpg Imperial but headwind/tailwind can give silly figures above and below that.
Note that Imperial gallons are bigger than U.S. gallons. 22 MPG imperial is 18.3 MPG US.

Someone else put it in an earlier post, but FUEL is probably the biggest contributor to your current economy. I saw in one of your posts that you are in the snow belt (I think I saw Grand Haven MI). Winter fuel has a lot less energy in it to prevent it from gelling up. And it's still winter blend time in the north.
Winter blend only has about 1.5%-2% less energy than summer blend. Edit: Strike that, I was thinking of gasoline. Ethanol fuel also makes a difference. It's got less 30% energy per gallon, so E10 fuel (10% ethanol) will have about 3% less energy. Bear that in mind if you ever guy E85. In addition to possibly ruining the gaskets and seals in your engine, 12 gallons of E85 is only going to move you as far as 9 gallons of pure gasoline.

I've found that by not using cruise control especially on hilly trips, economy goes up big-time. You can keep a super-light foot on the go-pedal and drive to the conditions, consumption-wise, rather than driving to the vehicle's capability. It's a test of self-restraint not to use all that lovely torque to power up a hill at the speed limit towing a big weight just because you can, and to let others pass you.
This one is a bit tricky. For relatively flat but hilly terrain that you traverse at high speed (like a highway which goes up and down), yes maintaining constant engine RPM will give better mileage than maintaining constant speed. If you go up a hill at a certain speed, then go down the same hill at the same speed, the energy used isn't the same as traveling the same distance on a flat road. Due to having to run the engine harder going uphill, you're operating less efficiently. So the extra fuel you burn going uphill is more than the fuel you save going down the same hill.

At slower speeds however, the hotel load of the engine (how much fuel it needs to burn to keep running regardless of speed) starts to become a factor. It's proportional to how long the engine is running. It's why your MPG is worse at 35 MPH than at 45 MPH, even though the aerodynamic drag is less. The engine is on for a longer time covering a mile at 35 MPH than at 45 MPH, so it burns more fuel just keeping itself running, more than enough to offset the savings from less aero drag. If you try to maintain constant engine RPM like in the above paragraph while going at a slower speed, the decrease in your speed while going uphill will greatly extend your travel time, and you will wind up burning more fuel simply due to the needing to run the car longer to get to your destination.

The Touareg TDI also shuts off fuel to the engine when coasting or going downhill. The last half mile to my house is a slight downhill grade and I was annoyed that my Touareg insisted on engine braking since it forced me to tap the accelerator a bit to make it home. I tested it coasting the distance and occasionally tapping the accelerator to maintain speed, versus putting it in neutral and just coasting the entire distance (I didn't need to tap the accelerator to maintain speed). To my surprise, it used more fuel in neutral. The engine is constantly getting fuel if it's in neutral. Whereas if it's in gear the computer cuts off fuel and relies on the downhill grade to keep the engine turning.

So the Touareg would actually benefit from hypermiling like Prius drivers do. I don't do it (most of the time) because it's annoying for people behind me. But on long empty stretches I've hypermiled (accelerated to speed up to about 75 MPH, then let off the accelerator to coast down to about 55 MPH, then speed up again and repeat). I managed to push it from about 36 MPG at 65 MPH, to about 38 MPG. Basically, when fuel is cut off to the engine, the hotel load drops to zero, resulting in a small fuel savings.

All that said, the difference probably isn't worth it. Unfortunately, the U.S. uses MPG to measure fuel economy. MPG is actually the inverse of fuel economy, so it's not a linear measure. The bigger MPG gets, the less fuel you're saving per 1 MPG increase. In other words, going from 15 to 16 MPG, actually represents a much larger fuel savings (nearly 4x) as going from 30 to 31 MPG, and 2x the fuel savings of going from 30 to 32 MPG. So my increase from 36 to 38 MPG from hypermiling for 10 miles the highway, can be completely offset by being stopped at one red light.

The rest of the world uses liters per 100 km to avoid this problem. That measure is linear with respect to fuel efficiency. If you don't believe me, imagine a 100 mile trip on a 20 or 25 MPG sedan, vs a 40 or 50 MPG economy car.

20 MPG = 5 gallons used
25 MPG = 4 gallons used, 1 gallon saved for a 5 MPG increase.

40 MPG = 2.5 gallons used
50 MPG = 2 gallons used, 0.5 gallons saved despite a 10 MPG increase.

If it helps, you can think of this as diminishing returns, although that's not entirely accurate. It's only diminishing because you're inverting the fuel consumption graph (which is linear).

FWIW, I get about 14 MPG on the highway towing a 7500 lb boat with a large frontal cross section at 55 MPH. But if I'm forced to stop a couple times at red lights, that'll quickly drop to 11-12 MPG.
 

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That's a great post. I am coming back to read it all again later - and that's probably a first given that when it comes to Touareg MPG threads I'd normally be thinking - "You've bought a two ton, 4x4 brick. If your'e asking about MPG then you should have bought a Prius!"!
 

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The only thing I'd like to add to Solandri's wonderful post is, while winter diesel has (according to him) only 1.5-2% less energy than summer blend diesel, winter blend diesel has regularly gotten ~10% less economy in every diesel I've owned.
 

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The only thing I'd like to add to Solandri's wonderful post is, while winter diesel has (according to him) only 1.5-2% less energy than summer blend diesel, winter blend diesel has regularly gotten ~10% less economy in every diesel I've owned.
Let me rescind that statement. I was thinking about winter and summer gasoline. I don't know the difference in energy content between winter and summer diesel offhand. Thanks for pointing out my error.
 

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Although winter blend diesel does have slightly less energy per gallon I believe a big part of the drop in fuel efficiency is the fact that any internal combustion engine is not very efficient until it gets fully warmed up... and a diesel engine will take longer to warm up vs a gasoline engine. Diesels typically have a bigger heavier engine and often almost twice as much oil that needs to heat up.
 
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