What does ECU remapping do?

Electronic ignition allows the manufacturer to fine tune economy at popular road speeds such as 30mph, 56mph and 70mph where most cars spend a large proportion of their time. (Some manufacturers in the 2016 cheat software scandal have even created code to detect test conditions and run super lean to pass emissions limits.)

It is now possible to advance the timing if the throttle is wide open to give greater power or back off the timing when cruising at constant speed for improved economy.

Manufacturers do not want people breaking down, suffering premature parts failure or to get a reputation for uneconomical cars so they build in a wide margin of tolerance. Different countries use different grades of fuel and have varying degrees of extreme weather conditions, all these factors add to the fudge that has to be done to keep all the cars working well across the globe.

Each car that leaves the production line is also unique, some achieve 20bhp less and others can be 20bhp up on standard specs, depending on how well the components are machined and put together. So rather than put each car through a unique assessment and get a bespoke timing map, they adopt a standard one map fits all philosophy.

It is also a fact that manufacturers use the remap to produce different power versions of the same engine and get lower insurance cover ratings and better fuel consumption. You start to see the fantastic scope for improvement, when you add into the mix the fact that the average TorqueCars reader will be adding better performing components to the car, you have a really strong case for a remap.

Other things that the manufacturer builds in to their map equation is the possibility of user neglect i.e. infrequent servicing with items struggling like dirty plugs, bad leads, clogged air filter, partially blocked injectors etc... The list goes on.

" When a manufacturer creates a timing map they build into it a big margin of error to cope with: adverse temperature ranges, minor faults & bad conditions. In some countries emissions targets vary as measured by CO2, HC, NOx and these usually require a fudging of the one setup for all approach. "