Servicing and fuel economy - Greg Parker
I have been interested in comments that good fuel economy comes from good servicing and responsible driving.

However, when coming to servicing, what is important to have changed or looked at to maintain economy. Coming to mind may be air filter changes and cleaned, oil change (pistons and rings), changing timing belt on time.

What other items need to be taken up at service to maintain economy in the long run. Just a SH is not enough, and knowing what items need inspecting means I can probably check the servicing quality myself to some extent.

Also, what driving techniques are important to maintain good fuel economy e.g. quick gearchanges, low revs etc

Any comments would be really helpful.

Also, where can I get information about old cars e.g. max torque, max speed, MPG, (the official stuff).
Servicing and fuel economy - matt35 {P}

Also, what driving techniques are important to maintain good fuel economy e.g. quick gearchanges, low revs etc


Servicing and fuel economy - peterb
Revs shouldn't be TOO low. There's normally an omptimum band in which to keep the revs - the techie experts can probably tell you what it is for different types of engine.

Just a small word of caution. I have known some drivers become so obsessed with economy* that they forget about safety! Sometimes brisk, high revs acceleration is the order of the day.


* For example, Honda removed the "economy" light from the Civic after some drivers became obsessed with it.
Servicing and fuel economy - RogerL
In intermediate gears, the optimum revs, for economy, are around the revs at which maximum torque occurs. In top gear, the slowest acceptable speed will give the best economy.

All service items should be changed at the manufacturers' recommended intervals.
Servicing and fuel economy - madf
I find the obvious things are often ignored.. brakes not rubbing, tracking and tyre pressures to name but 3.

Servicing and fuel economy - TrevP
as others have said, the primary aims when driving are safety and smoothness (then speed).

Decent economy actually "falls out" of that philosophy.

(p.s "quick gearchanges and low revs" are not part of the smooth style)
Servicing and fuel economy - sean
Hiya greg,

Basics are:

Spark plugs, points if your old car has them, air filter, thinner oil to reduce friction, turn your air intake nozzle to face fresh air in summer, exhaust manifold in winter, oil filter, run with minimal volume of fuel to minimise weight, empty your boot likewise, check brakes aren't binding, air filter nice and clean, tyre pressures high as possible, route selection to maximise time in top gear, minimise delays, select time of (night) likewise, set off on your journey as soon as you start your car, no cup of tea while it warms,correct thermostat,selection of economical marque in the first place,no extra electrical loads ie fogs, spots, heated rear window, etc

Advanced stuff comes down to anticipation. Every energy conversion results in wasted heat. Touch your brakes... Turn your aircon on... Turn your electrics on...

Are you awake still? Not easy is it?

That's why you're here. Brilliant people are here, now. One will come by shortly.

I dare not tell you about coasting downhill in neutral.

Someone will, if you're lucky. Warning. Danger if not carried out correctly......
Servicing and fuel economy - OldOiler
Belive coasting used to be standard in Saab's ?? - least you could hear the radio!!
Servicing and fuel economy - Chad.R
"turn your air intake nozzle to face fresh air in summer, exhaust manifold in winter"

I'm no expert but wouldn't the colder (and therefore more dense) air provide more energy during combustion and hence better fuel economy??

Or am I the one being dense....?

Servicing and fuel economy - sean

Chad, the fuel burns in air.

The oxygen in the air SUPPORTS combustion.

To enable combustion of petrol (gas) what you need is warm surfaces and hence warm air.

Keep the air temp warm in winter, cold in summer, and guess what you get?
Servicing and fuel economy - Chad.R
Then why have "intercoolers"?

Servicing and fuel economy - TrevP
"I dare not tell you about coasting downhill in neutral.

Someone will, if you're lucky. Warning. Danger if not carried out correctly."

No such thing as "correct coasting". Only Dangerous coasting.
Servicing and fuel economy - Tony N
Intercoolers don't chill the air, they just remove the excess heat caused by compression to allow the air to become more dense, hence increasing the content of oxygen per unit volume. The air post intercooling will still be fairly warm.
Servicing and fuel economy - RichardW
Colder air = denser = more oxygen = more fuel can be burnt = more power out of engine. Up to a point, modern petrol engines want the air as cold as possible - obviously in the middle of winter you want warmer air to help get the engine warmed up so it stops running rich, but once warmed up cold will be OK.

Original reason for taking warm air off the exhaust manifold was to stop the water in the air going below its freezing point in the carb venturi, thus preventing carb icing. Modern engines do not have venturis, so don't need warm air, and can use cold air to get the most power.

Unfortunately this usually leads to the air intake being positioned under the radiator, where it is ready to swallow large chunks of green water, and ruin your engine....

Intercooled TDs go much better on cold damp mornings when inlet temp is low and intercooler efficiency is high - some high performance (petrol!) motors also have water sprays onto the I/Cs to get the charge as cold as possible.


Is it illogical? It must be Citroen....
Servicing and fuel economy - 007

The best article I have ever read on this subject can be found at:

Servicing and fuel economy - Vin {P}

The relevant passage is:

"Mark Dougherty of the School of Transportation and Society at Borlange, Sweden, which supervised the project, said: "They think to accelerate gently will get a better fuel consumption. That's basically wrong." The key to fuel-efficient driving is to accelerate hard without over-revving the engine and to move through the gears briskly so that the car reaches its cruising speed quickly."

Basically, accelerate at around peak torque revs (most efficient) until at the speed you wish to be travelling. It's much greater acceleration than you would expect, and experiment shows it's more efficient overall than accelerating gently.

Servicing and fuel economy - TrevP
"Basically, accelerate at around peak torque revs (most efficient)"


Value my car