Re-mapping

[Danielpsmith]

Hi this post isn't directly linked with a Volvo so sorry if it upsets anyone I had a meeting at work last night on how to achieve better mpg from the fleet of trucks obviously it comes from the driver ultimately but they were asking for suggestions on how to improve it so I suggested re-mapping them for better mpg I was arguing this saying you don't have to map them for all out power so I am doubting myself now can you map a Diesel engine to get better mpg or won't it really work thanks a lot

Daniel

[kenny]

You are quite right, many national companies are having economy maps done to save fuel and cut emissions.
Strangely a performance map can also save some mpg, the explanation being you don't have to push a more powerful engine as much as a standard one.

[Danielpsmith]

Thanks for the reply that is what I was saying but he was having none of it I was starting to think I was wrong thanks again

[RoyMacDonald]

Originally Posted by kenny

You are quite right, many national companies are having economy maps done to save fuel and cut emissions.
Strangely a performance map can also save some mpg, the explanation being you don't have to push a more powerful engine as much as a standard one.

Performance maps also increase the torque and that allows the use of a higher gear for the same rpm which cuts fuel consumption. 5% to 10% improvement is the quoted figure.

[Tannaton]

I gather most Fire Engines are remapped as are many large fleets.

[Shadeyman]

A remap alone cannot increase MPG as there's only one way to increase engine power, burn more fuel.
If you burn more fuel you lower MPG.

So the only way to truely increase MPG is to drive appropriately using the extra torque a remap provides by selecting a higher gear when possible.

[Danielpsmith]

Thanks for the replies had a look at some websites and they say 8-15% better mpg with more power and torque I thought they could be mapped to pull smoother with more power but better mpg I know they all come with generic maps half our trucks pour out black smoke under load which Is un burnt fuel so I thought you could map them properly to eliminate this a burn more efficiently thanks again for the replies

[Tannaton]

Originally Posted by Shadeyman

A remap alone cannot increase MPG as there's only one way to increase engine power, burn more fuel.
If you burn more fuel you lower MPG.

So the only way to truely increase MPG is to drive appropriately using the extra torque a remap provides by selecting a higher gear when possible.

It's the way in which the fuel is burned that makes the difference - cars leave the factory in a state of tune to meet the emissions regulations, and that's not just about CO2 it's nitrates and all sorts of other stuff too. To do that the car is programmed to burn a certain amount of fuel in a specific ratio with a certain amount air that will give the desired balance of low emissions of certain key pollutants. This is usually not the ratio that gives the best power/economy - in Petrol engines it usually means effectively running them slightly lean. Hence we have a strange situation where the lowest polluting engines aren't necessarily the most economical....

By adjusting the fuel/air ratio, on some cars it is possible to gain some improvement in combustion efficiency and hence power and MPG. There is also the factor of increasing the engine power at lower RPM by supplying more fuel and boost means that for the same power output the frictional losses in the engine/gearbox are lower and it is turning slower. A driver of a more powerful will shift lower and autoboxes will shift lower too as the shift points are calculated from engine speed, throttle position etc.

The difference to MPG though? Probably not even 10%.

[Chesney46]

A lot also depends on the age of the truck (I take it we're talking HGVs here?)
Anything after Euro 5 is not easy ,if not possible, to remap, due to emission regulations. I worked for a large distribution company and our trucks were dropped to 50 mph. The argument there was that a lower motorway cruising speed would help lower consumtion. The downside was that in the south east, you don't really spend enough time on a motorway to really gain any beneifts.

[Curly59]

Originally Posted by Shadeyman

A remap alone cannot increase MPG as there's only one way to increase engine power, burn more fuel.
If you burn more fuel you lower MPG.

So the only way to truely increase MPG is to drive appropriately using the extra torque a remap provides by selecting a higher gear when possible.

Spot on Shadey. Now driven 50k on shark remap. No obvious difference. Do shift up the gears early to use torque but this is countered by using the performance at other times and you really do want to use the performance!