Warming Up an FD

[J.j.]

haha, is it me or is that maths a little off? If you sit for 60 secs, drive under 3k for 10 minutes and then do another 2 miles that\'d be more like 15 minutes surely? I still don\'t agree with the letting the car sit for 30-60 seconds once it\'s started.

Sorry, was trying to link it up from the quote so wasnt clear.  10 minutes would be the total warming time, not 15.


1. Start the car, wait to warm up - 30~60 secs
2. Drive under 3k for a while no boost - try avoiding positive boost, let the turbos warm up(no wot for 2 miles), this would take 4 to 5 minutes
3. stay below 4k for another 2 miles(no wot), this would take another 3 to 4 minutes
4. Floor it  

The total warming up time, about 10 minutes.

I didnt make these up myself.  Was quoting from rotechniks.  Found them quite reasonable, so followed ever since.

[Jake]

Cool, was there any explaination as to the benefit and reason to idle for 30-60 seconds before you pull away?  I\'d be interested to know as it\'s something I\'ve never done or heard a good explaination as to why I should.

[MillSpeed]

I also do not sit in my drive waiting for it to cool down for 10 minutes - i used to, but don\'t anymore. The reason you\'re meant to is that oil used to get burnt (carbonised) to the oil supply lines of the turbos when hot, but with modern turbos that are water cooled, they will cool down slowly anyway, and therefore not have this problem, so i see little point in sitting in my car for no apparent reason.

Might be worth getting a turbo timer. Think about it though, the only way the water cooling is going to have any effect on the temperature of th bearing cartridge is if the water is circulating. If you come in from a hard drive, your turbos are gonna be hotter than hell (especially since they\'re bolted to that big-ass cast iron manifold). If you just switch the engine off, then the essentially stationary coolant in the cartridge isn\'t gonna do squat (asside from getting very hot!), and if you\'re running mineral oil it\'s just gonna gradually coke up your bearings. Now if you let the coolant circulate, at least it\'s gonna carry some of the heat away from the bearing cartridge before you shut it down. Remember that the circulating oil will also have a similar effect. What\'s needed ideally is a switch to turn the fans on continuously while she\'s idling, to strip out as much heat as possible before you turn it off.

[Jake]

Yeah I wouldn\'t go turning the engine off straight away after a drive as wihtout fluids circulating everything will cook.  I always idle for a few minutes after a drive to give the temps in the turbos time to come down by letting the oil circulate for a while.  Even better I cruise around at 30mph for a few minutes before coming to a stop to help everything cool.  I\'ve also got a billion variable fan controller which is fantastic.  The fans come on even if the engine temps go up a bit over normal operating temperature, great at keeping the water temps constant.

Aren\'t the turbos on the FD oil, not water cooled?

[nikp]

Well, i still disagree.

Ok, turn the engine off straightaway. Result: no water being moved round the engine and ancillaries. Bad? Maybe - but, that also means that the hot engine that will increase the temperaturee of the coolant that is still around the engine - and therefore this hotter coolant will not be passed around the turbo\'s. Ok, but there\'s still hot coolant around the turbo\'s - well, firstly, you have that all the time anyway. Secondly, the coolant around the turbo\'s will cool down gradually, thereby allowing the oil to cool gently too - not cooling rapidly, therefore allowing the oil to bake. So, i yet to remain convinced.

However, i\'m open to opinion and well balanced argument or proven results!

[MillSpeed]

I\'m not really sure what you\'re getting at. Think of it another way, during normal operation, why doesn\'t the oil coke up in the cartridge? Because the oil is flowing so it\'s not exposed to extremely high temperature for an extended period of time. But the oil is still degraded, just by flowing through the turbo bearings, that\'s why it\'s recommended to change the oil so frequently in a turbocharged car. So what happens when you shut your car down without giving the coolant flowing through the cartridge chance to reduce its temperature? Well, the stationary oil sat in the cartridge is just gonna turn to sh*t, I mean what\'s the temperature of the metal on the hot side of a turbo after a good run? A damn sight higher than the oil can stand that\'s for sure. And it\'s not just the turbo\'s that benefit from being allowed to cool down a bit, when the coolant stops flowing, the heat stored in the metal of the engine and the coolant in the body of the motor has no where to go...it\'s not going to be removed from the radiator via the fans, so the temp of the engine is gonna go through the roof. Remember, the rotary engine is just a big sandwich of iron and aluminium, thing\'s are gonna start to warp. No wonder coolant seals are failing all the time.

[gsb876]

"Gsb, no beef m8, but there is a difference in sarcasm and questioning/objecting. You won\'t know the latter because you don\'t know any better." - quote

Hmmmmmmm, somebody take me back to early learning centre please as i dont understand ?  :rolleyes:  :rolleyes:  :rolleyes:

Thats sarcasm as i dont know any better  :p

[TRex]

Going with Nik abit on this one.
 When after driving I would not really let the engine just sit there idling for a period of time really.
All that does is create more heat, \'heatsoak\', which is actually worse as it\'s building a heatsoak and not moving to get fresh air to cool/dilute.

 My way is about a normal drive I just park and shut off...  After a good hiding, drive off boost etc for about a mile or so then park and shut down.

[nikp]

Well, i don\'t kow for sure which way is better. I guess the discussion could go on for a long time. I\'ll stop arguing my side now, as this could go on for a long time. I\'m not saying I\'m wrong however, but neither am I saying you\'re wrong either!

And, yes, the previous reply wasn\'t very eloquant - but i think you got the gist of what i was trying to say!

[MillSpeed]

Well that\'s what the radiator fans are for. I still maintain you\'ve gotta get the heat out of those turbo\'s before you shut her down. Like you say, driving off boost is a good way to do that, but I still think the benefits of idling for a bit with the fans running outweigh the possibilty of heatsoak, the engine\'s not gonna generate more heat idling than it would under load. What is certain is that the turbo\'s are gonna be alot hotter than the engine. Alternatively you could rig up an electric pump to circulate the coolant after the engines been shut off, perhaps in conjunction with the fans....would hammer the sh*t out of your battery tho.

[nikp]

To demonstrate a good example of heatsoak is as follows, but oinly works well with an aftermarket coolant temperature gauge: switch your car off after driving when the coolant temps are quite high (Not really really high though) and come back to it after 10 minutes. Switch the ignition on and you will see the temps have actually gone up. The radiator fans may even come on - thereby cooling the water in the rads, but nowhere else. If the car is started then those coolant temps come down very quickly.

I\'m not sure what I\'m proving here! :p Other than heaksoak is easily noticeable after 10 minutes of a car sitting around.

[TRex]

No Nik you proved it spot on really...  :cool

[MillSpeed]

when the coolant stops flowing, the heat stored in the metal of the engine and the coolant in the body of the motor has no where to go...it\'s not going to be removed from the radiator via the fans, so the temp of the engine is gonna go through the roof.

You just proved my point for me, the coolant\'s gotta be flowing to remove the heat from the system (and ideally the fans have gotta be goin too!)

[g11ary]

depends on several things, TREX said drive off boost for a mile or so, so he has in effect cooled th eengine down, like you would on a warm down lap.
But if driving hard and then stopping, you have several issues. Yes water temps will rise as will heat soak, but the rad controls that heat easily and heat soak is not a problem as you as stopping not about to blast off. Its the oil and engine materials that are the most important things, several different material used in the engine will cool at different rates, so if engine goes from 4-5k rpm to 750 for a while it gives the materials a better chance to move (shrink) at a slower rate, also oil will still be moving around and may get hotter before it cools but wont sit in a caverty boiling away because of lack of movement, and then next start up have boiled thick usless oil that wont pretect on start up.
I would air on the side of caution, its like so many things, you can abuse and see no physical difference until one day come rebuild time, when you ask yourself could I have got a few extra miles out of her.

[nikp]

but switching the engine off will remove the heat - the engine itself will no longer produce heat, and all components will begin to gradually start to disipapet their heat to the air around. The hot oil will slowly lower in temperature, radiating to the water, which itself will radiate out of the coolant lines into the air around.

It does not need to be pumped around the coolant system, because it does not need to remove heat from the engine any longer, as it is no longer producing any heat. The same for the turbo\'s.