fuel prices...

[damian]

[woodhutt]

It was my wife's birthday recently and I suggested we go for a meal.
She said she wanted to go somewhere really expensive so I took her for a pie at the local filling station.
Pete

[Handyjack]

Sticker that was seen in the 1980's

The Cars Paid For, the Petrol is on Credit!

[woodPixel]

275771028_708885586807766_662251561098058411_n.jpg

[BobL]

Yesterday I finally removed the 4 old school roof racks from my Hiace van which I've had on there since I got the vehicle in 2010.
At most I have used these racks about 3-4 times a year. They are not difficult to remove/replace so they can sit inside the van so I can get at them quickly when I need to.

Estimates of what this does to fuel consumption are interesting and depends on a bunch of factors like rack design and vehicle speed. Most of kms I do in this vehicle are going up and down the freeway outside of high traffic times so higher speeds for which additional consumptions of 10 -12% have been measured. I will be keeping an eye on this to see what happens.

The other way to save a bit on fuel are
- make sure your tyre pressures are correct or even a touch over.
- remove heavy crap from you boot to reduce vehicle weight

[chambezio]

It was my wife's birthday recently and I suggested we go for a meal.
She said she wanted to go somewhere really expensive so I took her for a pie at the local filling station.
Pete

That is how I got this black eye.

[damian]

Rules of thumb on fuel consumption:


In town, mostly below 80kmh/50mph


Rapid acceleration and hard braking, Heavy vehicle increase fuel consumption.


Highway driving, over 80/50


Aerodynamics is the killer. Vehicle shape and appendages like roof racks etc. The exponential increase in drag is one of the biggest reasons fuel consumption goes up so much at say 110 compared to 100 compared to 90.


The roof racks are quite disruptive of airflow but something people don't seem to realise is managing the airflow at the rear of the vehicle is more important than the front. A flat back is literally like towing a parachute. Caravan manufacturers seriously don't understand this, or maybe they don't care. In extreme cases it can destableise the whole rig.


2c

[woodPixel]

My ancient HSV (2001 VX) has a monster donk.

It barely turns over, even at 110 its only 1800rpm.

Fuel consumption drops off a cliff at 106, which is interesting. It goes from 8.0 to 6.1L/100km.

Driving to/from Sydney from Canberra is a good measure as its mostly good flat highway (except for the few "fun bits" that are left).

Putting the cruise control at 106km/h does nothing to trip time but saves a fortune.

I'm a bit lucky as the old beast has a you-beaut computer that gives me real time feedback and dynamically tunes itself. One can select several modes for the engine... sedate to enthusiast. The engine is feral at the last setting...

Its interesting that there isn't an active community of re-tuning companies for ordinary engines that will put a dash mounted fuel monitoring system in as part of a widely-installed upgrade. Its not hard and a good rechip/tune/remap on any engine can save a FORTUNE.


Petrol was $2.55 the other day in North Sydney. Yikes.

[BobL]

The roof racks are quite disruptive of airflow but something people don't seem to realise is managing the airflow at the rear of the vehicle is more important than the front. A flat back is literally like towing a parachute. Caravan manufacturers seriously don't understand this, or maybe they don't care. In extreme cases it can destableise the whole rig.

There's probably not much that is flatter than the back(and front) of a Hiace van.
The manufacturers fuel consumption for that model vehicle (2008 3L diesel) is 8.6 L/100km.
Our Isuzu DMax 3L diesel supposedly gets 7.9 L/100 km - OK its not what you would call aerodynamic but its got to be better than than Van.
In practice the best we get with the Max around town is about 9.2 which was about the same as the van around town before I put the roof racks on.
However the DMax does do more short trips than the van.

[damian]

When you get to analysing specific vehicles the driving factors also become specific.


If you holden has aerodynamic foils they may be designed for looks and be an aerodynamic disaster, or they may be optimised for rasing speeds and drag terrible at legal speeds. Your experience suggests to me you have an aerodynamic hump at 107 where signifigant airflow detachment is occurring.


Around town aerodynamics should not be significant. Accelerating mass is the killer, but engine efficiency can trump it in extreme circumstances. Car companies can make dreadful mistakes in the design process as it is committee managed now and good engineering can be discarded for marketing or manufacturing expedience. You can't appreciate how chaotic and random the process is until you for for a manufacturing concern.

[ian]

Driving to/from Sydney from Canberra is a good measure as its mostly good flat highway (except for the few "fun bits" that are left).

Curious
where are the "fun bits" ?

I though the last "fun bit" was removed when the highway [north bound] was realigned past Tiyces Lane about 15 years ago.

[AJ.]

No doubt prices are high, but I have seen and paid a lot more than current prices on our travels around Oz.

2008, Rabbit Flat Roadhouse, Tanami Desert.
24.jpg

2016, Ilkurlka Roadhouse, Anne Beadell Highway.
245 Ilkurlka.jpg

2018, Punmu, Telfer Mine Road, NW WA. We actually bypassed fuel at Kunawarritja that was $3.40 as we had to make a 600km detour because of 5kms of flooded and impassible track on the Canning Stock Route.
Ute and canning 022.jpg

Cheers Andrew

[rrich]

OK, Mates

You can save more fuel with common sense than almost anything else.

You are driving in the city at about 65. As you pass through an intersection you see the traffic light about a km away change to red. You have two options. Rush to the red light so that you can go when it changes to green. OR. Relax and coast up to the traffic light.

With the latter option you have to wait about 15 or 20 seconds before the light turns green. But all the fuel you saved is immeasurable. And as a bonus, the distance between brake pad exchanges is significant.

[BobL]

OK, Mates

You can save more fuel with common sense than almost anything else.

You are driving in the city at about 65. As you pass through an intersection you see the traffic light about a km away change to red. You have two options. Rush to the red light so that you can go when it changes to green. OR. Relax and coast up to the traffic light.

With the latter option you have to wait about 15 or 20 seconds before the light turns green. But all the fuel you saved is immeasurable. And as a bonus, the distance between brake pad exchanges is significant.

SWMBO has the lightest feet I know.
When she used to drive a leased Subaru Forester, the lease included a $2500 pa fuel allowance but she rarely exceeded $2000 of fuel PA even though she met the lease milage. The first Forester was a 2 year lease (25k km pa) and the mechanic said the brake pads look like they'd done <20k km. The second Forester was a 2yr/30k km pa lease and it was in such good nick at the end of the lease we ended up buying it out.

[damian]

My driving annoys the boss and was a constant source of amusement.


She is a brilliant driver. So fast and SO smooth. It is a joy to ride in the passenger seat.


I can be fast if I want to but was beaten into submission by endless tickets, several issued despite me being well under the limit.


The funny thing though was whenever we were driving 2 cars to the same destination I'd arrive either at the same time or BEFORE her. She would get every red light, while I would get mostly greens.


My fuel consumption in the same car was always about 10-20% better.


But she was having more fun.