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Discussion Starter #1
here's probably a stupid question: i know that with these turbo charged trucks you have to let the turbo cool down after having driven for awhile. how long is long enough?? i would imagine that its common sense. longer cooldown after coming from a highway drive towing a trailer. just thought i'd get other's inputs...... cheers!:smoke
 

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do you have an egt guage? if you do then most people say you gotta let it get down to like 300 degrees, not sure how strict that is but that's what i'd do.
 

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Usually when my pyro hits 300ish... doesn't take very long if I'm not on it beforehand....
 

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BUG JUICER and
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EGT represents the temperature of exhaust before it has even arrived at the turbo. How does that help gauge anything? Not trying to be argumentative here, just factual, so consider what I am saying for a moment. I can raise or lower my egt 50-75 degrees just by switching the AC on and off. Is AC affecting the temperature of my turbo?

I know this has been used as conventional wisdom for a long time, but somebody please find the guy who started this EGT thing, and shoot him.
 

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SRW Cartell #27
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What is your method Killerbee or do you have one?

Personally on a normally daily drive when you get home if you wait for the EGT to drop to 300deg that will take anywhere from 30 seconds or more depending on your truck setup. Factory trucks may take longer. But it is not a reference of the degrees but the time it takes to drop too 300 Deg. After I have been pulling a load for a while it can take up to 5 min to get it to 300deg . Usually it will set on 400-500 for about 3+ min. So it is not in reference to the actual EGT TEMP but to give a delay before shutting it off. It is an easy reference.


Now personally I will let my truck set and idle for long periods of time after a good haul it is not uncommon for me to leave it running for 30 min before I shut down. Do you have to ….. NO I know guys that never run thought cool down and their trucks are running just fine. Personally i think it is a good idea ...
 

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Discussion Starter #7
i've never let my truck idle for half an hour but i know where you're coming from. i don't currently have an egt gauge but i think i'll get one. i tow a fifth wheel in the summer months here. i don't abuse or push the truck hard but i can still imagine how hot that turbo must be getting. usually when we get to a campground i let the truck idle the time it takes for me to position the trailer in the site and unhook truck from trailer(10-15 minutes) now while driving without towing anything i usually only let the truck idle a minute or so, especially intown driving. and i'm really very easy on my vehicles. no abuse...........:smoke
 

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BUG JUICER and
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Stacked6600 said:
What is your method Killerbee or do you have one?

Personally on a normally daily drive when you get home if you wait for the EGT to drop to 300deg that will take anywhere from 30 seconds or more depending on your truck setup. Factory trucks may take longer. But it is not a reference of the degrees but the time it takes to drop too 300 Deg. After I have been pulling a load for a while it can take up to 5 min to get it to 300deg . Usually it will set on 400-500 for about 3+ min. So it is not in reference to the actual EGT TEMP but to give a delay before shutting it off. It is an easy reference.


Now personally I will let my truck set and idle for long periods of time after a good haul it is not uncommon for me to leave it running for 30 min before I shut down. Do you have to ….. NO I know guys that never run thought cool down and their trucks are running just fine. Personally i think it is a good idea ...
FWIW, I don't use a method, but common sense, like you have shared in your post. Though I have an idea that 30 minutes is a 29 minute waste of the ozone layer. But your point is well stated, and the most important thing is having some situational awareness that the charger is hot, like you say, after sustained high load boost.

What is really an improvement these days, over the oil cooled designs of yesteryear, is that the water jacket will liberate an enormous amount of heat vaporizing the coolant locally. This act keeps the turbo oil well below the 450 degree coking temps, as the evaporation occurs under 300 F.

But if I were going to suggest a better method, for the older turbos that are not jacketed, it would be oil pan temps. Even that has some debate, but at least you are measuring the properties of the medium that is the applicable concern, oil, and oil coking.

I don't remember ever hearing about a coking issue with these turbos, so this whole thread, and the countless others like it, might be mute discussions.

In my own venture, I did find that it is very difficult to get EGT to reduce, and in a big part of that was the rise in airbox IAT as it sits idling, compounded with no flow over the CAC. It is physically impossible to get EGT below 350 degrees here, as others will report from time to time. IAT will rise as high as 190 sitting in the drive, and post CAC temps have gone to 240. That is because of the AC condenser heat load, and the ever rising IAT. So I guess the "300 or whatever" rule is arbitrary.
 

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SRW Cartell #27
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Jduramax said:
i've never let my truck idle for half an hour but i know where you're coming from. i don't currently have an egt gauge but i think i'll get one. i tow a fifth wheel in the summer months here. i don't abuse or push the truck hard but i can still imagine how hot that turbo must be getting. usually when we get to a campground i let the truck idle the time it takes for me to position the trailer in the site and unhook truck from trailer(10-15 minutes) now while driving without towing anything i usually only let the truck idle a minute or so, especially intown driving. and i'm really very easy on my vehicles. no abuse...........:smoke

Jduramax You are doing fine just like most people here and like KillerBee said just use common sence.. If it is hot it doesnt take a long time to lower the temps on the turbo but yes it is a good idea. In the 10-15 min it takes to park your trailer that is more than enough time to cool down after a long load.:Thumbup: and as far as in town driving your temps are not sustained long enough to really heat the turbo up .. The time it takes to pull in the drive way and park is probibly good. :Thumbup:
 

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diesel idiot
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You just have to know your truck...like these guys said its common sense if you run it harder, you let it cool down longer. At the most if im on it hard in the summer ill let it idle down for about 5 min which usually translates to about 300*. So i do think 300* is a good reference point for cool down but offers nothing for your ACTUAL turbo/coolant temps.
 

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SRW Cartell #27
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:Thumbup:
 

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Nasty Girl
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There are so many factors here to take into consideration! The biggest of course is what a person is running for a turbo or turbo's. In some cases it is a matter of preference others a matter common sense. IMO EGT's are an old wives tale for determining when the turbo is cool enough and when to shut it off. Here is an example of why:

My truck runs EGT's of no more than 1300 Deg. and after say a mile at WOT I come to a stop. Before I put her in park my EGT gauge is at 350-400 Deg. The reason is I have headers and the probe is in the collector. The temp. of the turbo's in comparison to the EGT's is completely different due too rapid cooling of the headers. The EGT temp and the actual turbo temp will be different in any senario including this one. IMO your best option is a turbo timer for your truck to insure proper cooldown. This will also save you the waiting time and having to go turn the truck off.


Keith
 

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Like some already said, the main thought behind idling is to let the turbo cool down so it doesn't cook the oil and damage the bearings. By idling, it will also allow other engine/trans. components to cool also. I don't idle mine for more than 5-10 min. depending on outside temp and how hard I work it. i also include (when camping) registration, finding my site into the time.
 

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I too was worried about cool down, i installed a cooldown timer from BD Power. Its a very cheap investment that works wonderfully. I have two probes on my truck and i run the timer off of the post turbo probe so i know that when that temp is at 300deg the rest of the system is nice and cool. I work for a turbo remanufaturer and have seen first hand what hot shut down can do to a turbo.
 
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