ECU RE-map. Do they really save on fuel?

andy8442

Well the questions in the title, but I'm seriously thinking about a re-map, and just wondered if there is anyone out there with experiences of these.

I am purely interested in increasing MPG, I already drive in an economical as possible manner, but would like to hear from anyone who has a re-map and can honestly say which way the fuel economy has gone.

Strider590

Yes it can sometimes save on fuel, in order to increase power without altering the engine, you must increase efficiency...... And that is what a remap does.

BUT, typically a high performance remap will have the effect of placing the engine's usable power into a much tighter RPM range, thus decreasing efficiency outside that range.
Realistically this behaviour doesn't work well in a normal road car, because you loose the flexibility of having a wide even torque band.

On the other hand most cars have some room for improvement, the manufacturer has to meet EU regs as well as their own set specifications and they often detune the ECU in order to meet these standards.

Additional..... The govt plans to outlaw such modifications and unless your mate runs an MOT station, you could find your car failing it's MOT in the not too distant future.

fivetide

As above, short answer, yes.

Each engine is slightly different so tuning the ecu to the motor rahter than one size fits all from the manufacturer can help but you need to make sure it is a good map and prefereably, a 'live map' with the car driven on the road not just reprogrammed, offered a piggy back chip or done on a rolling road (although the last one is better than the other two).

It'll probably come in at around £500 but trhe biggest performance boost will be to a turbo engine. On a non-turbo car you are unlikely to see much improvement in terms of power and will only save one or two mpg so unless you do big miles it might not be worth it.

5t.

TrickyWicky

Strider590 wrote: »

Additional..... The govt plans to outlaw such modifications and unless your mate runs an MOT station, you could find your car failing it's MOT in the not too distant future.

When I first heard about that a while back I found myself wondering how many cars will fail their MOTs next year. Also there still isn't any clear guidance on how they're actually going to check ECUs yet. If its been chipped they're going to break the no dismantling rule are they by taking your ECU apart? - What happens if they break the ECU and its no longer available?

Gloomendoom

TrickyWicky wrote: »

When I first heard about that a while back I found myself wondering how many cars will fail their MOTs next year. Also there still isn't any clear guidance on how they're actually going to check ECUs yet. If its been chipped they're going to break the no dismantling rule are they by taking your ECU apart? - What happens if they break the ECU and its no longer available?

There won't be any problem at all because it won't be part of the MoT test next year.

Edit: I have a remapped car. If you do get it done be aware that the remap can screw up your trip computer. The only way to get a reliable mpg figure is to brim the tank and check the fuel used over several hundred or preferably thousands of miles.

CompuCall

My experience of driving remapped cars is overall they do not increase mpg.
There are different levels of remaps but despite the claims you will not see an increase.
Save your money and check the usuals ie tyre pressures, reversing in when parking, gentle throttle control, slowing up to red traffic lights, roundabouts, stationery traffic so you do not have to stop, not using premium petrol/diesel, block gear changing up as well as down, emptying the boot etc etc.
I am sure there are many more to add to these.

forgotmyname

Depends on your car. Recent non turbo petrol cars, Very little to be had from a remap.


Petrol turbo and diesel turbo cars can be tweaked a fair amount. But its unlikely to pay for itself.


You may find the extra overtaking power useful and when you do use it the economy will suffer.


Dont carry fat passengers will benefit you more.

atrixblue.-MFR-.

stainless exhaust, replacement re useable panel filter from the likes of k&n piper and other places, replace old fuel filter, dont use air con (climate control etc), warm car up in the mornings (let it idle to temp),keep eye on tyre pressures, make sure tracking and balancing is spot on, use the recommended fuel for the car. usually 95RON in most vehicles, add an injector cleaner once a or twice a year, you cant go wrong to save few MPG's.

rodenal

My experience of remapped turbo petrol cars is that the map does indeed increase your maximum possible mpg.....but you'll never, ever see it as you'll use the extra performance on offer (even if you don't notice you are doing it).

My experience of decent remaps (not a one size fits all map i should add) is that they will generally give a wider/smoother power band, usually aiming to produce better power curves and so making it feel more muscular all over - in that respect i disagree with striders' information.

It is possible to get a live map that will be an economy not power map, so you may only achieve say a 5-10% power increase but the car is mapped to be in a better tune for achieving higher mpg for your driving. As already stated it's highly unlikely you'll ever do enough miles to pay for the map so not really going to be worth it as you'll need someone to at least put your car on a rolling road if not physically drive it.

As noted your trip computer will be affected - though most can be ammended to compensate for the new map, you'll just need to figure out what adjustment factor you need to add/subtract & be able to access that menu (not always easy even with an obd2 cable & software)

andy8442

Thanks for the advice, but what if I don't use the extra power available, will I see any improvements?

leosayer

When working out the cost/benefit don't forget to add in whatever extra your insurance company will charge you for the modification.