MPG vs engine temp.

[allias]

Recently I noticed that my car dont get to right temp. So I will be looking to change my termostat. That mae me think: how badly temperature of engine is effecting mpg? Is it that ECU is correcting fuel dose to reach certain engine temp? If so what sort of diffrence can be expected on engine that runs around 65-70 and 80-90 deg.

Anyone has previous expirience with that?

 

[renault12ts]

Your MPG will improve when you replace the stat.

 

[Bellow]

Less the ECU making the correction but your right foot! Heat lost to the coolant is horse-power lost to the flywheel. To obtain the performance you want you will end up pushing the right pedal further - giving the engine more fuel.

Doesn't Diesel change to winter formulation around now leading to lower MPG?

 

[Chrishazle]

Changed the thermostat on my C270 earlier this year, engine temp went from 60 max to 90, average MPG on long term trip meter increased from 41mpg to 45mpg over about 2000 miles, no change in driving style. £80 well spent (cost of stat plus fitting by local village garage).

 

[allias]

Just installed new termostat. It goes up to 90deg in no time. It gets warm inside in just over 5-8 miles of city driving. But the best part is.... MPG.

I understand it was short distance of 10 miles but I combined city and motorway and at one stage I was able to see 50mpg. :bannana: I understand short distance is no good for that type measurment but at least it showed its possible to go over 40mpg where before I was struggling to get to 40mpg even on motorway driving. I really cant wait to make a longer trip now. I really want to see what it can do on stricly motorway driving on long distance.

BTW. When I got home at the end of this road test I had 41.2mpg.

 

[st4]

Doesn't Diesel change to winter formulation around now leading to lower MPG?

Yep, knocked about 25% off my old 220cdi's economy that winter fuel. Was really bad.

 

[gkerr4]

i didn't think diesel changed formulation any more - are we sure about this? - isn't it just the colder air and longer warm-up times that make things worse? diesel is so full of additives now - even the regular stuff - that I would doubt thereis a different winter formula?