to increase mpg what is the normal engine warm up time ?

[RedRobin]

.
I prefer to wait for my revs to drop after startup - With DSG, it will clunk if you select Reverse before the revs have dropped and i always have to reverse out of my batcave.

[stealthwolf]

Reset the meter once the engine temp is up to operating.

[Squeeguk]

I remember reading a technical article about whether to allow the car to idle or not and the pros and cons many years ago written by a very learned technical guru.

His view is not to let the engine idle to warm it up. That is one of the worst things you can do with an engine. The engine runs richer when cold and idling makes it take longer to warm up, all the time the richer mixture is washing the oil off the bores increasing wear. According to tests, over 90% of engine wear occurs on cold startup.

The best way is to get in, drive off and keep the throttle openings small and revs low, without labouring the engine, until there is some temperature in the engine. This is the most effective way of bringing the engine up to temperature, under load.

[GrayMK5GTI]

I remember reading a technical article about whether to allow the car to idle or not and the pros and cons many years ago written by a very learned technical guru.

His view is not to let the engine idle to warm it up. That is one of the worst things you can do with an engine. The engine runs richer when cold and idling makes it take longer to warm up, all the time the richer mixture is washing the oil off the bores increasing wear. According to tests, over 90% of engine wear occurs on cold startup.

The best way is to get in, drive off and keep the throttle openings small and revs low, without labouring the engine, until there is some temperature in the engine. This is the most effective way of bringing the engine up to temperature, under load.

Exactly the same as I've been told by numerous mechanics. The days of cars requiring a warm up are long gone I believe 

Theres hundreds of thousands of TFSI's all over the world that get started up and driven straight away on the school run without any failures being recorded.

IIRC the handbook doesn't mention the requirement to warm up the car. 

[mad_pete]

Mpg wise you are suppose to go straight away. Sitting with the engine idle you are doing zero miles to the gallon. Thinking is drive off straight away take it easy. Ideally drive off forwards as reverse uses more petrol ?

[bigmig95]

I remember reading a technical article about whether to allow the car to idle or not and the pros and cons many years ago written by a very learned technical guru.

His view is not to let the engine idle to warm it up. That is one of the worst things you can do with an engine. The engine runs richer when cold and idling makes it take longer to warm up, all the time the richer mixture is washing the oil off the bores increasing wear. According to tests, over 90% of engine wear occurs on cold startup.

The best way is to get in, drive off and keep the throttle openings small and revs low, without labouring the engine, until there is some temperature in the engine. This is the most effective way of bringing the engine up to temperature, under load.

An additional effect is that Idling a cold engine can lead to 'borderline lubrication' or in laymans terms areas of the engine do not see sufficient lubrication due to the oil being thicker and flowing less (increased viscosity).  This subsequently increases wear rates on components.

Typically engine warm ups for engine development on test beds are carried out at 2000 rpm and around 2 bar bmep (a light engine load) to ensure sufficient lubrication to all parts during warm up.

Whilst having some detrimental effects on the engine borderline lubrication can speed up the break in process should the engine require this for testing purposes. 

[Andy]

when i spoke to a few turbo companies with all the problems i was getting with my gttdi-I was told if you leave the car ticking over for to long the oil can get past the seals and start making the oil go through the exhaust

[andrewparker]

Oh yes, I knew I'd been doing it right all along!

[RedRobin]

^^^^
Oh dear! Does this mean I have been doing it all wrong for 104,000 miles?

That clunk of the DSG reverse is not an encouraging sound. And what about that very experienced Ferrari driver I used to know who always spent time warming up the engine?

Why is it different for a F1 racing engine? They are always warmed up before engaging gear?

Isn't this why the 2.0T FSI engine starts off at ~1000 rpm and doesn't drop revs for the first moments or two?

[scopes]

So leaving the car to tick over for 1 min, until the revs drop would be safe?

cause it normally only takes 1 min...

[RedRobin]

So leaving the car to tick over for 1 min, until the revs drop would be safe?

cause it normally only takes 1 min...

....Isn't this why the 2.0T FSI engine starts off at ~1000 rpm and doesn't drop revs for the first minute?

[rich83]

You cant compare a F1 car to a road car... totally different kettle of fish.

Usually... i start the car, put it in Reverse and get the hell on with my journey.   Life is to short to piss about waiting for ??? to happen on idle!

[RedRobin]

Usually... i start the car, put it in Reverse and get the hell on with my journey.  Life is to short to piss about waiting for ??? to happen on idle!

....But that's a choice you make because of your lifestyle and has absolutely nothing to do with whether it's good or bad for your engine, Rich.

[rich83]

Usually... i start the car, put it in Reverse and get the hell on with my journey.  Life is to short to piss about waiting for ??? to happen on idle!

....But that's a choice you make because of your lifestyle and has absolutely nothing to do with whether it's good or bad for your engine, Rich.

I think youll find that 98% of car owners do exactly the same Robin. My car uses zero oil and runs perfectly (.... ive done it now... my car is gonna explode, sh*t its pants and drink all its oil on my next journey)

 

[RedRobin]

^^^^
No-one is saying that a car will suddenly explode or have some serious crisis as a result but we are only discussing and questioning which is considered best practice.

98% of car owners drive off immediately without thinking because they don't think about the health of their means of transport and are mentally driven by the idea that they need to be somewhere as soon as possible. In planning any schedule I simply allow extra time for the car's startup.