DEN-STL-DEN Towing a 5x8 Trailer-- MPG Questions

Conan

Veteran Member
Joined
Dec 2, 2010
Location
Denver
TDI
2003 GLS TDI
I needed to jam over to St Louis over Memorial Day Weekend to get some furniture I was tired of storing there. U-Haul quoted over $400 to rent a trailer one-way (STL-DEN), but only $19/ day local. So I dragged an empty trailer out there, and drove back loaded. The trailer pulled fine, and I felt like I could have easily cruised at 75MPH all day. I set the cruise on 74MPH indicated, which I figure is pretty close to 70MPH. The drive is mostly pretty flat, with a few rolling hills, but no mountains to worry about.

I was freaked by the way the Jetta drank fuel! I'm used to getting 600 miles out of a tank of mostly-city driving. I was getting fuel lights in the 300 mile range! One time I pulled into a station with less than 400 miles on the trip meter, and it took 16.5 gallons! Yikes-- that's WAY worse than my worst mileage. I was in the 20s for the whole trip. I have PP520 nozzles and a custom Kerma tune, which is a little on the smoky side now, but the car runs fantastic. The worst mileage I've ever seen (w/o trailer) was 32, and the best all-highway tank was 48.

Afraid of even worse mileage, I went slower on the return (laden) trip. I packed about 1000# of hardwood furniture in the trailer, and drove back with minimal stopping. It would get down to half-tank at about 200 miles, which is amazingly bad. I set the cruise for an indicated 67MPH for almost all of the trip, and think I averaged about 29MPG. Evidently, air resistance is super important to FE-- I bet it would have been a lot better if I could stand to go 60 for long periods of time. That is a freaking brutal trip, though. I can't drone on at 15MPH under the speed limit for 16 hours plus-- just can't stand it.

I will say, though-- that Jetta pulled like a tractor. The brakes aren't really up to towing that much weight, but the ALH barely felt it. I would cruise up every hill in 5th, and never even had to think of downshifting. Rolled some pretty serious coal, but I never got any indications that I was getting hot or running bad EGTs. I didn't log anything, and I haven't scanned for codes yet, but the little diesel towed 2000+# around like it was nothing. Very impressed with the performance, even if I was very underwhelmed by the fuel economy.
 

schwarze Käfer

Veteran Member
Joined
Oct 21, 2010
Location
Texas (panhandle)
TDI
2003 New Beetle GLS 5spd
Towing 2000lbs? Yikes! That's alot of weight. Was it one of the square box enclosed UHaul trailers? Lots of drag if it was...

BTW... My F150 would've only gotten around 15mpg towing that! (at best)

What kind of clutch do you have?
 
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scurvy

Good Ol' Boy
Joined
Feb 21, 2006
Location
Chicago IL USA
TDI
2006 Golf
Air resistance is paramount to fuel economy, you're absolutely right.

I towed the slightly smaller 4x6' UHaul trailer from Baltimore to Chicago at about 65 - 70 mph indicated (actually 105 -110 kph as I've got a Canadien cluster face, but that's another story) and got about 32 mpg for the entire trip. Not bad, but my brother in the NB following me got nearly 50 mpg! Even the 4x6' trailer sticks up over the roofline of the Golf significantly.

Later I hauled an assembled bed frame back to Ikea on an open 4x7' UHaul trailer, with it standing up sideways. That had a significant impact on fuel economy as well, sticking several feet over the roofline of the Golf like a particleboard kite.
 

Conan

Veteran Member
Joined
Dec 2, 2010
Location
Denver
TDI
2003 GLS TDI
What kind of clutch do you have?
Still on the stocker. I was VERY careful when leaving lights. It never slipped on hills. Maybe I was subconsciously hoping to fry the stock clutch so I could upgrade, which will open the door to a 17/22, 11mm pump, lift pump, bigger intercooler... :cool:
 

schwarze Käfer

Veteran Member
Joined
Oct 21, 2010
Location
Texas (panhandle)
TDI
2003 New Beetle GLS 5spd
Wow, good to know, Conan. I'm itching to get a tune, but figured I should wait till I could afford a new clutch & SMF setup, too ... maybe I should just go for it.
 

Conan

Veteran Member
Joined
Dec 2, 2010
Location
Denver
TDI
2003 GLS TDI
I wouldn't wait. The difference is AMAZING. I think my bad mileage is a symptom of incomplete tuning. My guru installed the Kerma tune last year, and tweaked a few things. When I told him it was pretty smoky, he offered to "tune the smoke down", but I passed, since it was running so well. I'm guessing it is overfuelling, and hopefully we can get the smoke turned down and get some better mileage, without losing any power. When I ordered the tune, I asked for "as much power as I can get without having to upgrade the clutch", and that's exactly what I got. This is a very strong running little car now. My OEM DMF doesn't rattle, and slips predictably on engagement. It has never slipped when fully engaged, just on launch.

I definitely wouldn't pull a heavy trailer like that in stop and go freeway traffic (not enough brakes!), or up too many hills, but it did great on the trip. No ill effects noticed on the way to work today.
 

Lightflyer1

Top Post Dawg
Joined
Sep 13, 2005
Location
Round Rock, Texas
TDI
2015 Beetle tdi dsg
I just bought a small 4x6 myself for towing. Although not the weight you were towing! Small stuff. It has the pointed nose though so I thought it should help some.



I really wanted one of these for a luggage trailer, but the seller couldn't stay at one price long enough to buy it.


 
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