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Old 12-20-2017, 05:30 PM   #1 (permalink)
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Roof rack better or worse than a small trailer?



For fuel economy. What do you think?

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1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
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Old 12-20-2017, 06:01 PM   #2 (permalink)
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I think I can't see it.

Why not both?

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Old 12-20-2017, 07:32 PM   #3 (permalink)
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Trailer, I've had a few record trips towing various trailers.

I think especially with a Prius where the roof shape is critical to drag, you'll see a big hit if anything is ruining airflow attachment.

On a big boxy vehicle it wouldn't matter as much, but again the boxier shapes mean the trailer follows in the vehicle's wake.

We know that it's at least possible to make a trailer that improves economy- I've never seen that with any roof mounted accessory.

Plus, I never feel 100% safe with a load on the roof.
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Old 12-20-2017, 08:38 PM   #4 (permalink)
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Quote:
We know that it's at least possible to make a trailer that improves economy- I've never seen that with any roof mounted accessory.
Lest we forget:

http://ecomodder.com/forum/showthrea...ted-26915.html

In 2013 HHOTDI moved his CVT from the rooftop to a hitch mount, and confounding all expectation excepting mine, he gained mpg over a slick top.

Quote:
I just returned home from a 770 mile round trip to Portland, lake Oswego and home! I returned home late last night and checked the hard mileage and found 770 miles, 15.6 gallons netted 49.3MPG! So as Freebeard suggested, what will we do if the mileage goes up?!?
Beetle w/o any attachments/slick top= ave 48mpg :{)
Beetle with factory VW Roof racks and CVT tent= 38mpg :/
Beetle with new areo-hitch mounted rack/CVT tent= 49.3MPG WhoooRah!
That is a gain of 11.3 mpg boys and girls!
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Old 12-20-2017, 08:57 PM   #5 (permalink)
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Mounting an accessory to fill the wake of one of the least aero economy cars in decades doesn't count. Besides, hitch mounting makes it a trailer

It's more akin to how when I load an open vehicle I try to distribute the load so it forms a kamm back.
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Old 12-20-2017, 09:04 PM   #6 (permalink)
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Doesn't count?



I agree the New Beetle shares the old Beetles biggest problem. The old Beetle used the inward falling vortexes to gain engine cooling.
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Old 12-20-2017, 10:53 PM   #7 (permalink)
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While going through a toll road where the additional axle(s) in a trailer would mean a higher cost, I'd try a roof rack with an air deflector (similar to the ones fitted on the rooftop of certain trucks with a box van body) in front of it to smooth out the air flow.
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Old 12-20-2017, 11:45 PM   #8 (permalink)
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Quote:
Besides, hitch mounting makes it a trailer
Here's a single-wheel trailer that folds and folds up against the tailgate of a pickup truck:



Plus a half-tonneau and Coanda nozzles on the twin stacks.
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Old 12-21-2017, 07:49 AM   #9 (permalink)
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It depends on the load.
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Quote:
Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

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Old 12-22-2017, 10:47 PM   #10 (permalink)
It's all about Diesel
 
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Quote:
Originally Posted by Fat Charlie View Post
It depends on the load.
It's also worth to remind that certain loads which could be safely moved with a trailer might exceed the payload rating when a roof rack is used instead.

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