35D turbo cool down

[bim_power]

I am from the old school where after a drive on my 35D, I tend to let the turbo cool down before cutting the engine off. Is this necessary anymore in this day and age with a modern dual stage turbo?

I did notice when the eco pro or comfort mode with start/stop feature on, the engine will not cut off when I pulled to a stop right after a hard drive. So is the engine compensating for the turbo temp?

[kip1]

I always cool my engines down before shutting the engine, after a highway run stopping at lights I also leave the engine on/ turn stop-go off.

[Armen383]

IMHO if you go into aggressive driving (constant flooring, high RPMs, etc.) - it's best to leave the engine running for 1-2 minutes before shutting down after a full stop. In normal mode though I keep it running for 20-30 seconds max.

[barcelona]

Good question, surprised no one raised it sooner. I do w/up c/down, winter w/up is long. I understand the turbos work at 2100rpm.

Source: Mike Miller pg.7 (he asks not to post his schedule... one can google it)
Second, practice traditional turbocharger warm up and cool down procedures. This means allowing the engine oil to reach operating temperature before spooling up the turbos (keep the rpms low), and allowing the turbos to cool down before shutting off the engine by driving gently at low rpm for several miles before reaching the destination.

[MrTookies]

Originally Posted by barcelona

Good question, surprised no one raised it sooner. I do w/up c/down, winter w/up is long. I understand the turbos work at 2100rpm.

Source: Mike Miller pg.7 (he asks not to post his schedule... one can google it)
Second, practice traditional turbocharger warm up and cool down procedures. This means allowing the engine oil to reach operating temperature before spooling up the turbos (keep the rpms low), and allowing the turbos to cool down before shutting off the engine by driving gently at low rpm for several miles before reaching the destination.

So just driving gently at low rpm for several miles before reaching the destination will be enough or do you still have to let the motor/turbos cool down when parked for 30sec ?

[barcelona]

Originally Posted by PlayTookies

So just driving ently at low rpm for several miles before reaching the destination will be enough or do you still have to let the motor/turbos cool down when parked for 30sec ?

I would assume the latter is not necessary, but it cannot hurt. On start up I wait until the car idles down before engaging drive. A guy like 42Pilot would have a more educated answer.

[MattBianco]

Originally Posted by barcelona

....... A guy like 42pilot would have a more educated answer.

+1

[stewy604]

Just turbo etiquette 101 to practice proper warm up and cool down procedures. On my Audi especially (400 hp BT), I try to stay out of boost until the oil reaches at least 75-80 degrees. Same goes for cool down, typically 1-2 minutes of idle time following a "spirited" drive.

[mrquick68]

I agree with all that's stated above, however...

These engines have electric water pumps and circulate coolant through the turbo(s) even after the engine is turned off. So, it's not like the old school days 100%. you no longer have coking issues in turbos anymore. It's still good practice to let your oil temps get up before any hard acceleration and the same goes for the last few blocks on the trip home (drive it easier before turning it off). But, i don't think its necessary any longer for prolonged idling for "cool down". They make the cars pretty dummy proof these days.

[Alan l.]

Originally Posted by mrquick68

I agree with all that's stated above, however...

These engines have electric water pumps and circulate coolant through the turbo(s) even after the engine is turned off. So, it's not like the old school days 100%. you no longer have coking issues in turbos anymore. It's still good practice to let your oil temps get up before any hard acceleration and the same goes for the last few blocks on the trip home (drive it easier before turning it off). But, i don't think its necessary any longer for prolonged idling for "cool down". They make the cars pretty dummy proof these days.

I agree with this 100%

Out of habit i never let the tach get up pass 3K until the engine is warmed up and I usually stop all aggressive driving a few miles before i reach my destination. If not i will usually just let the car idle for a 1-2mins before shutting it down.

Alan

[Jimmie48]

Are most of you using the start/stop on? I find it kind of annoying and since I do a lot of city driving I have left it off completely. I would think it would be hard on the starter if you kept that on all the time and did mostly stop and go driving....tell me I am wrong

[MrTookies]

Originally Posted by Jimmie48

Are most of you using the start/stop on? I find it kind of annoying and since I do a lot of city driving I have left it off completely. I would think it would be hard on the starter if you kept that on all the time and did mostly stop and go driving....tell me I am wrong

I have it 100% of the time turned off, start/stop of the motor has the most wear. Further more it is annoying like you where saying :-).

[Kzang]

Originally Posted by PlayTookies

I have it 100% of the time turned off, start/stop of the motor has the most wear. Further more it is annoying like you where saying :-).

+1, it increases wear and tear but it does save fuel. I find it ridiculously annoying and turn it off.. good thing it never gets engaged when in sports or sports+ mode.

[42pilot]

Originally Posted by mrquick68

I agree with all that's stated above, however...

These engines have electric water pumps and circulate coolant through the turbo(s) even after the engine is turned off. So, it's not like the old school days 100%. you no longer have coking issues in turbos anymore. It's still good practice to let your oil temps get up before any hard acceleration and the same goes for the last few blocks on the trip home (drive it easier before turning it off). But, i don't think its necessary any longer for prolonged idling for "cool down". They make the cars pretty dummy proof these days.

This is mostly true - meaning the 35d and 3.0L do not have a cooled center sections on the turbo. The 5.0 definitely has a separate cooling system since the turbos sit in the center of the engine and there are two of them located next to each other. For the 5.0, you can run the hell out of the engine, shut it down immediately and the computer will keep the coolant flowing until it gets to a predetermined temperature.

Because we use 0w20 or 0w30 engine oil (low viscosity), there is no need to wait to drive the car normally. The turbo bearings are more "bushings" as ball bearing center sections are more costly and aren't normally installed in OEM vehicles. Bushing type bearings take a bit longer to function efficiently, but not too much longer. Ball bearing turbos spin faster and cut turbo lag but this is now mitigated by VGT technology. In any event, our turbos will spool close to 110,000 rpm (max) but I would bet most of our driving is probably bumping the lower efficiency curve of the turbo - probably around 65,000 rpm (I'm guessing as I've never seen a compressor map for these turbos) around town on average. Since the turbo works off of exhaust gases, and our exhaust gas temps are between 650 and 1500 degrees, the turbo warms up real fast, even on cold mornings.

Since I own my car (not lease) and because I've owned turbo cars for 35 years, by habit I let my car/pickup idle for a couple of minutes after a long drive = more than an hour or so at highway speeds. Is it needed these days? Maybe not, but it can't hurt under the above circumstances. For trips around town or city driving? I think it's a waste of time as the turbo never gets real hot (bearings don't get above flash point of oil and won't coke the oil) - but it won't hurt. At idle, the exhaust gas temps get down to about 450 degrees at the manifold, and by the time the gases get to the turbo, temps are lower. At highway speed, EGTs get to about 950 - 1050 degrees F on our diesels. This is why it helps to cool the turbo by idling a bit after a long trip.

[42pilot]

Originally Posted by Jimmie48

Are most of you using the start/stop on? I find it kind of annoying and since I do a lot of city driving I have left it off completely. I would think it would be hard on the starter if you kept that on all the time and did mostly stop and go driving....tell me I am wrong

Mechanically, this is possibly the worst thing ever invented by an engineer for a motor, for the sake of emissions (idling emissions) and economy. It is still a fact that the majority of wear (metal on metal) is done on start up, waiting for the oil pressure to come up and lubricate all rotating parts. And you are right about the starter too.

If you lease it, and enjoy the golf cart effect, let'r rip.

Anyway, I coded mine to stay off, even in Eco mode - which I never use.

[MrTookies]

Originally Posted by 42pilot

Mechanically, this is possibly the worst thing ever invented by an engineer for a motor, for the sake of emissions (idling emissions) and economy. It is still a fact that the majority of wear (metal on metal) is done on start up, waiting for the oil pressure to come up and lubricate all rotating parts. And you are right about the starter too.

If you lease it, and enjoy the golf cart effect, let'r ride

Anyway, I coded mine to stay off, even in Eco mode - which I never use.

Thank you so much for your contribution to this topic, really puts a nice light on everything!