Can I modify my car to save fuel?

A local company says it can adjust the fuel use of my Citroen C5 6 spd, 2.0 HDi, upping it 10% without risking any parts. I'm a slowish driver, mostly 2,000 rpm and have the car in eco, whatever that does. She does around 45mpg, maybe less if I'm pushing it along on the motorway. Chipping is another thing which might improve it. Any suggestions, including leave well alone?

Asked on 15 January 2024 by farmideas

Answered by David Ross
We would be sceptical of any claims regarding fuel consumption improvement without risking any parts unless it is an engine remap or 'chipping' process. 45mpg or more for a car of this size is good, and most drivers will get save fuel by careful driving, ensuring their car is well maintained, has the correct tyre pressures and is free from any extraneous weight. A remap may improve fuel economy, but will require a significant financial investment and will also require you to decare the modification to your insurer with a resulting increase in your premium which could easily outweigh any potential fuel savings.
Similar questions
A friend has suggested that I use the above but would welcome your comments. I drive a BMW 420i cabriolet auto and a Toyota Aygo X auto. I rarely use supermarket petrol and mostly use BP or Jet.
My local BP garage is still charging £1.55 per litre for their cheapest diesel, much more than any prices mentioned in the article (although in November 2023 it was 10p more at £1.65). Why would BP be...
Is it better in the long run to top up fuel at half tank on a regular basis or to refuel when almost on reserve?
Related models
Very comfortable. Fantastic refinement. Well equipped from mid-range models upwards.

Value my car

Save £75 on Warranty using code HJ75

with MotorEasy

Get a warranty quote

Save 12% on GAP Insurance

Use HJ21 to save on an ALA policy

See offer