Fuel usage with and without a roofrack

Willem

I suppose you would have to do the trip a few times to rule out possible variations, wind - traffic flow, etc but it shows that all the bits and pieces we have on the wagons does have an effect.
I have a roof rack, no deflector but also a 6" waterpipe used to store fishing rods along with odds and sods. As that has a 'blunt' nose it probably adds as much to the consumption as the rack.
As you state 'not much' but over a year would add up.

Banjo (WA)

Um, that's a fair bit - about 9.9% improvement in economy. Think of it this way, how would you like to be paying only $1.16 a litre instead of $1.29?

You're saving $1.55 per 100km - could be a couple of hundred bucks a year.

Gday,

I have a SWB GQ Diesel, running 235/85 16's. have done the trip from yalgoo to Perth (about 550kms) quite a number of times.

With my full lenght roofrack (and tool boxes down one side on roof) on i use a full tank and am empty when i hit perth (so i usually put $20 in along the way to ensure i make it)

However, i went down without the roofrack and toolboxes...and made it all the way and still had quarter of a tank....and on the way back i experienced the same thing...and had over quarter of a tank left.

mine doesnt have the wind deflector..but it made a huge difference to my range and economy..and thats only sitting on 100 - 110 all the way.

Unfortunately...after just finding this out...

i went and bought an imported nissan safari (high roof GQ) with a very high roof...WITH a very big roofrack..and ive put my toolboxes back on top lol

is higher than a troopy and i cant get into any undercover carparks...and my economy is obviously suffering for it.

oh well, thats the cost of extra space and the luxury of rooftop storage

rev

Gday Willem,
My Pajero with Rola Racks and the mesh style basket on top loaded made no difference to economy. However, now with a rack sack I reckon I get about 50km per tank less.
Dean

My roof rack deflector- in side view is shaped like a 6 It is pivoted in the middle of the 'circle' part and (when the rack is empty) actually 'flys' to attract the most efficient angle in relation to speed. It has been tested on a runway (at Camden) with mounted cameras and at 60kph it is at about 15 degrees, up to about 40 degrees at 100kph. The foil is shaped using a wing mould of a Cessna. Also at the leading edge sides of the rack a couple of little wings ala Ferrari F1.
It sounds clumpsy but is very discreet and has cut down drag & noise heaps.
I see some so called deflectors mounted at about 60 to 75 degrees- these must be causing more drag than no deflector.