Will a re-map improve fuel economy?

[skiptontweed]

As per title.

I am fairly sure my 200Cup runs rich, and is therefore slightly thirstier than it might be otherwise.

If I have the car re-mapped (rolling road, custom map), by somebody who knows that they are doing, can I expect to see an improvement in mpg?

I used to work at a place that mapped bikes, and to gain power they typically took fuel out of the map (very generally). This made the engine run closer to stoichiometric - had to be careful, but normally picked up power as a result. I appreciate that if you take it too far, you melt things. Richer is safer, to a point.

Finally, can you recommend a suitable tuner, preferably in the north west?

 

[ECG1000]

I've heard it said before the a good map can save on fuel to a point.

I'm getting my car mapped in a week or so at RS Tuning in Leeds

 

[Foxspeed]

you need to confirm the statement "running rich"....

modern motors dont run like carb fuelled motors due to the cat in the exhaust and hence the lambda sensors in the exhaust to monitor fuelling

a re-map can help pick up more "mid range" torque and its this that can help with better fuel consumption as the car/engine will drive better at low revs and pull an higher gear and therefore "reduce" fuel consumption - all this is still dependant on the driver of course!

 

[skiptontweed]

you need to confirm the statement "running rich"....

not sure what you mean by this.

A rich air/fuel mix has more fuel
A lean air/fuel mix has less fuel

I forget the target mass ratio, but its the same regardless of carbs/injection.

I suspect the engine runs rich, particularly at motorway cruising speed, because it never seems to do more than 32mpg (ish) - there is no sensible reason for this as the car is not using big HP to run at a steady speed. My old 172 Cup would sometimes do 46mpg on a motorway, so I'm really trying to resolve the difference. The vehicle weight shouldn't significantly affect cruising mpg, and I don't think the drag coefficient/frontal area can be ~25% worse.

So yeah, I think the 200 engine is mapped to run quite rich. The lambda feedback loop jiggery pokery will correct A/F within set parameters.

Lets see what happens - I might just end up with a dead engine......

 

[Ollie RS]

Potentially it could improve mpg slightly however you will probably drive it that extra bit faster after the remap

 

[Mentalpen]

ALL RS's now run rich imo

 

[Applez]

When TDF mapped mine, he leaned out the mixture, so therefore less fuel, so more Mpg, and this was the case, used to get around 24-25 and now get about 27. However in colder conditions it does drop to about 20-22, for the same reason in that more fuel is needed.

Matt also explained that when you out 95 Ron fuel in, which can and usually does set the knock sensor off, the ECU loads it with fuel, to richen it up, and stop the knock sensor from going off. So that's why when you put the cheaper 95 Ron fuel in, you get worse MPG
Some useless info of you there!

 

[Iain 007]

On a 200 it will be negligible, motorway cruising at 70 will see around 32/33. I'd be very surprised if a remap on a non turbo car like this would change mpg.

Renault will have pretty much maxed out the mpg for emissions regulations. More fuel = more emissions.

 

[Foxspeed]

you need to confirm the statement "running rich"....

not sure what you mean by this.

A rich air/fuel mix has more fuel
A lean air/fuel mix has less fuel

I forget the target mass ratio, but its the same regardless of carbs/injection.

I suspect the engine runs rich, particularly at motorway cruising speed, because it never seems to do more than 32mpg (ish) - there is no sensible reason for this as the car is not using big HP to run at a steady speed. My old 172 Cup would sometimes do 46mpg on a motorway, so I'm really trying to resolve the difference. The vehicle weight shouldn't significantly affect cruising mpg, and I don't think the drag coefficient/frontal area can be ~25% worse.

So yeah, I think the 200 engine is mapped to run quite rich. The lambda feedback loop jiggery pokery will correct A/F within set parameters.

Lets see what happens - I might just end up with a dead engine......

by what do you know it runs rich i meant ie guess work?

the 32mpg is i would say given all the data on here pretty dam good for one of these!!!

if its cruising on the motorway and at small throttle it will be running in closed loop ie 14:1 for catalyst conversion/window via the lambda sensors - so wont really be running "lean" as such will it - unlike when cars ran carbs you could run them lean to save fuel when cruising..

anyway have the lambda/fuelling checked if you think its thirsty - it could still be putting in too much fuel - but these cars arent 40mpg motors :thumb1: