Monday, Oct 20, 2014 at 11:59
The problem of excessive fuel consumption is one that's thorny for most people.
It pays to remember the following points.
1. If you want a vehicle that's economical, you buy one that is light. If you drive a 2.5 tonne 4WD, expect fuel consumption to match a 2.5 tonne truck. You can't have your cake and eat it too, as the old saying goes.
2. Petrol engines love drinking fuel. They need quantities of petrol to cool the combustion process. Lean your mixture right off and your exhaust gas temperature goes through the roof, and you'll end up with burnt valves or valve seats in short order.
3. You can minimise fuel consumption by not carrying around large amounts of excessive junk in the vehicle. Carrying spares, hi-lift jacks, de-bogging equipment, unnecessary
tools and all the other junk we tend to cart around, when we don't really need it for that particular trip, all eats up fuel.
4. Keep your tyres inflated to correct pressures and even a little above recommended pressures if you're on good roads and travelling at speed.
5.
Check wheel alignment and axle alignment and make sure that they fall within the precise manufacturers specs. If I had a dollar for every 4WD I've seen crabbing up the road, due to loose spring hanger U-bolts, or bent chassis, or bent axles - I'd have enough for a decent all-expenses paid holiday.
It's not the first time I've measured the wheelbase precisely on each side of a vehicle and found it was a different measurement each side.
A mate was restoring an old Chev and he couldn't get things to fit properly. He got in an old fella who had been a chassis aligner in his working career.
The old fella found the Chev chassis was 50mm out of alignment diagonally, probably because of a smash - and it had never been corrected or properly repaired.
Misalignment of wheels and axles will increase fuel consumption.
6.
Check wheel bearing tightness and ease of wheel rotation. Wheel bearings should have zero clearance or just a very slight preload for the least rotational resistance.
You can easily get brake calipers that are not releasing properly because of rust on the caliper pistons. I've got a ute right now, suffering from this problem - badly. This creates unnecessary drag.
7. Tune the engine. That means ensuring the valve clearances are also regularly adjusted. You'll often be surprised at how adjusting valve clearances to specs can improve engine performance.
8. Use low-friction additives in your transmission and axles. These do help in reducing friction losses. Molybdenum disulphide (Molybond) and Moreys products all help in reducing friction. It's not a huge gain, but everything helps.
A bloke in
Sydney used to sell MoS2 in the old Modern Motor magazines, he called it "Krause". It was great stuff for stopping whining diffs and gearboxes. Of course, he made a motza out of selling us a simple low-friction lubricant at exorbitant prices.
I've seen a bloke use Nulon in an International
farm tractor transmission and before he used the Nulon you could fry an egg on the tranny in 30 seconds when it was working. After he put the Nulon in, you could hold your hand on the tranny when it had been working.
9. Don't EVER believe the BS fuel consumption figures posted by manufacturers. They bear no relationship to the real world. They are "adjusted" by pulling all kinds of stunts to get the figures to look good on paper. Tens of millions in sales profits rely on those figures, they HAVE to look good.
Talk to people who own the vehicles and ask about real world fuel consumption. It's always a lot worse than the advertised figures.
10. Finally, practise good driving techniques.
Gunning it at the lights and then braking hard is just plain wasteful. Keep speeds down on the highway. Every 10 kmh increase in speed increases fuel consumption exponentially.
In conclusion, if the fuel consumption is still grating on you, buy a 1.5L runaround hatchback. I've got an 81 model $300 Laser Ghia that is superb for a city runabout. It runs for a week on a sniff of petrol, it goes like a train, nothing ever goes wrong with it, you can fit an unbelievable amount of stuff in the hatchback with the seats down - and if someone runs into it, I've only lost $300!
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