Tuning for economy

I have never owned a car that I have been happy with its economy

"John" gurgled happily, sounding much like they were saying:

Very unlikely.

If the mixture was not right - either way - it'd fail the MOT.

Most likely cause - assuming tyre pressures etc are all correct - is that she's just not driving economically. Is she doing mainly short journeys from cold, urban mileage? If so, then it's no wonder it drinks.

Get some actual consumption figures; fill the tank, zero the trip, use it until it's nearly empty, then re-fill it ideally at the same pump.

Use the data you have to actually know what mileage it's getting.

No.

If its service history is unknown, you need to get that done first.

Dirty air filter, worn out plugs, binding brakes, under-inflated tyres, slipping clutch, even tracking way out, will all contribute to poor consumption.

Of course, the biggest waster of fuel is always the driver!

Chris

that is the problem, cheap cars using outdated designs will be unlikely to be as economical as something bang up to date and more expensive to buy. What you save by buying the sort of car you have may be (will be) outweighed by its lack of economy and rapid depreciation.

Almost nothing (in practical terms) is adjustable in the way of ignition and mixture on modern cars.

I would expect something like that to do somewhere between 30 and 35 mpg for reasonable length journeys

As to whether it is uneconomical, mostly that will be down to the way it is driven and maintained: engine wise: oil and plugs are the most critical, the engine management will accomodate a dirty air filter for a long time. Good quality tyres that are correctly inflated are a good way to improve economy, but driving habits and journey type and length will probably outweigh everything else.

No. It needs to go to a place dedicated to doing remapping.

A far better bet would be to service it as required, make sure tyres are at the correct pressure on a weekly basis, take all the s**te out of the boot and PUT YOU AND YOUR WIFE THROUGH A DEFENSIVE AND ECONOMICAL DRIVING COURSE.

Thanks - you have all confirmed what I thought - Yes it is used for short urban runs. Tyres kept at correct pressure.

I think she uses a lot of petrol reversing off the drive! She hasn't mastered driving it on so that it will come back off without needing to move the steering wheel!

Its official combined consumption is 37.7mpg, and the urban is only

Chris

Sounds about right then.

At the expense of a reduction of volumetric efficiency.

but unless you have your foot right down there will be no or very little difference economy wise

Remove / by-pass any hot start enrichment device. Only really needed for tropics or very hottest of summer days.

Put a resistor on a switch in parallel with ECU temp sensor so it responds as though it's warmer than it really is while warming up. It will lean it out. Leaving it switched on when engine is up to temp will make it over fuel to cool engine.

Don't use it till the weather is warmer. I think during the cold spell I've taken a 2mpg hit.

Buy a bicycle & stop driving it for 2mile trips.

In article , John writes

Driving style makes a huge difference. For example, those people who accelerate up to a red light or a stationary car then brake hard. Why? Just coast up and save the fuel.