Warming Turbo Before Driving Hard

[Macktheknife]

  Cro said:

I do it anyway, have a smoke whilst I warm up the engine...sometimes to cool it down as well. Don't know what I'll do if I ever quit smoking 

You'll live longer and T will die sooner.

Sorry Cro not helful I know. Just having one of those days....

[Cro]

[IH8TOADS]

When driving one cold morning with the old man in a GTP, I said it aint good to drive like he was when the engine was so cold. His reply "but its warm now".

[Lawsy]

As long as the oil is circulating, then everything is fine...

When a motor is at a standstill, gravity will naturally drip the oil to the lowest point possible. So, some components are going to have less oil at start up as a consequence.

There is enough clearance and just enough tolerence throughout the engine to ensure that, as long as there is oil between any two surfaces, the components will perform to within design parameters and within design component wear.

Heres why.

It takes roughly 3 seconds for oil pressure hit 95%, a further 3-5s to hit 100% at any point in the system. It then takes another 20 - 40 seconds for any part of oil to do a full circulation of the system (roughly at idle), and another minute or two for each component to well and truely have enough oil and heat to perform its duties under any circumstance...

I reckon that's about 3 to 5 minutes, but not 10.

If you thrash an engine after its been running for 5 minutes, you'll do no more damage than if you had let it idle for half an hour.

So let the car sit for at least 20 seconds before moving off. Apply nothing more than 10% throttle for the next minute or so, no more than say 2500rpm for another minute or so and then drive it like you stole it. After that 3 - 5 minute mark, there is so little difference in the lubrication of the engine that it makes me want to punch TV ever time I see the add 'the first 10 minutes is where most engine wear occures'... Of course it is...

But its the same as saying this. If you are taking a 10 hour trip, the first 5 hours is where most engine wear is going to occure...

Why? Because most of the engine wear was in the first 3 minutes, and the first 3 minutes just happen to be in the first 5 hours of travel. AMAZING, that truely is. Who would have thought that the first 3 minutes happened first....?!? Idiots..

The 10 minute rule is a load of crap when talking about modern road cars. It only applies on a hand full of older engines, or race engines (some of which require a 20 minute warm up, but for good reason), that's about it.

So unless you are running a full bred race car, or a model T, then you don't have anything to worry about after the first 3 - 5 minutes of your drive.

[SavageF6]

Good advice says I.

My personal tactic is to idle for no more than 2-3 mins, then drive like an old man (no offence to old men), until I notice the needle in the operating range. Then I grin, and up the volume!

Not as scientific as Lawsy's explanation, but follows the philosophy methinks

[mickq]

I partly disagree.

There is NO WAY all parts of an engine reach operating temperature in 3-5 minutes, unless the ambient temperature is very hot (say 40 degrees) or the car is being thrashed over that 3-5 minutes.

Even modern engines contain a variety of different metals, and they take differeing times to reach operating temperature. Its not all about oil - its also about allowing time for expansion to occur.

If you dont let it occur and hammer, you have a much higher chance of both wear and failure, because the tolerances engineered in the engine can be out of whack when they involve two very different materials in very close proximity - especially if you start it cold and simply floor it. Even if the car happened to be all lubed up somehow, you are still at a much higher risk of engine damage because metal things dont generally like belting against other metal things they arent meant to touch. This can occur when one part is already warm and the other is not at all...and thus one part has expanded and the other has not...and you then throw a ton of load into the picture. People often say many cars have modern all-alloy engines mean this isnt an issue. It is...because an engine will contain a dozen+ different types of metal...for example your rings.

Also, oil circulation is, in general, highly dependent on oil temperature. And guess what....oil temp is highly dependent on engine temp. And guess what happens if you drive a car really hard when the oil is cool...even if it is already circulating everywhere? You can easily get inadequate oil movement because it is more viscous, which can lead to oil starvation which can lead to both wear and if you are unlucky, component failure. Your advice does not take that into account, especially with heavier mineral oils that can markedly change thickness as they warm up. (Some synthetics like Mobil1 dont normally have that problem as their viscosity doesnt change much over the normal operating range).

Now factor in a turbo, which has a much closer tolerance than any other part of a car, and think about how the bearings will react if they get a 2 second oil starvation event when the impeller is spinning at 100,000rpm....

As you said, idle it for a minute or so. Keep revs lowish, but most importantly dont load the engine up (regardless of revs) for the first 500m or so. Then you can start adding more revs and load for a few minutes....but Id allow a good 10 mins+ of normal driving before thrashing it, to allow everything from engine, oil, coolant, gearbox and diff to warm up near operating termperature. Max driving before then WILL increase wear AND while you do it you will be at an increased chance of a component failing.

The engine will continue to warm up even after that, depending on how you are driving and the ambient temperature, and things like whether you are spending a lot of time idling in stop start traffic.

As probably everyone knows, when you engine is guaranteed to be 100% operating temperature, for example after a long drive, they tend to run much better and rev more freely, and not all of it is related to blowing the crud out of your cylinders. It also has to do with tolerances being exactly as they should be because eveything has reached the right temp, and from excellent oil circulation because the oil is at the right viscosity.

  Lawsy said:

As long as the oil is circulating, then everything is fine...

When a motor is at a standstill,  gravity will naturally drip the oil to the lowest point possible. So, some components are going to have less oil at start up as a consequence.

There is enough clearance and just enough tolerence throughout the engine to ensure that, as long as there is oil between any two surfaces, the components will perform to within design parameters and within design component wear.

Heres why.

It takes roughly 3 seconds for oil pressure hit 95%, a further 3-5s to hit 100% at any point in the system. It then takes another 20 - 40 seconds for any part of oil to do a full circulation of the system (roughly at idle), and another minute or two for each component to well and truely have enough oil and heat to perform its duties under any circumstance...

I reckon that's about 3 to 5 minutes, but not 10.

If you thrash an engine after its been running for 5 minutes, you'll do no more damage than if you had let it idle for half an hour.

So let the car sit for at least 20 seconds before moving off. Apply nothing more than 10% throttle for the next minute or so, no more than say 2500rpm for another minute or so and then drive it like you stole it. After that 3 - 5 minute mark, there is so little difference in the lubrication of the engine that it makes me want to punch TV ever time I see the add 'the first 10 minutes is where most engine wear occures'... Of course it is...

But its the same as saying this. If you are taking a 10 hour trip, the first 5 hours is where most engine wear is going to occure...

Why? Because most of the engine wear was in the first 3 minutes, and the first 3 minutes just happen to be in the first 5 hours of travel. AMAZING, that truely is. Who would have thought that the first 3 minutes happened first....?!? Idiots..

The 10 minute rule is a load of crap when talking about modern road cars. It only applies on a hand full of older engines, or race engines (some of which require a 20 minute warm up, but for good reason), that's about it.

So unless you are running a full bred race car, or a model T, then you don't have anything to worry about after the first 3 - 5 minutes of your drive.

<{POST_SNAPBACK}>

[Guest beags]

I have owned turbo cars for years and would always recommend a warm up b4 going hard.

[X-WING]

I always thought a warm up drive much better for car than just idle that way gearbox and diff come up to temp too not just the engine.

[harvyk]

I'm not so convinced that warming up 100% is nessacery... It's important that everything is properly lubricated (so there isn't excess friction) but with metal expansion things are more likely to touch when they are hot (as the metal surfaces will be closer due to expansion) I can understand that you would want to give the oil a chance to lubricate everything so that when the metal does expand it doesn't cause excess friction, but outside that a cold but properly lubricated engine shouldn't have any issues with being put under load as ultimately (IMHO) it would be excessive heat (due to friction by not properly lubricated parts) as the engine killer, not excessive cool (otherwise you would need to use a heater on your engine before you started it)...

[cobrav8]

Problem is that as metal is cold - it expands. So - eg a crank running in a bearing - the bearing cases make the hole smaller, and the crank gets bigger - so the gap between the two gets smaller, lets less oil in, and more chance of friction.

So - it is just about letting the metal get up to temp, and the gaps running at what they are designed to run at.