exhaust temp shut down

[tleclair]

Just a quick question. What is a good temp. to shut down at?

 

[DEZLPWR]

300 or less pre-turbo...

 

[fj40charles]

yep. what dieselpwr said.....

 

[K_Arts]

Out of curiosity... are you sure you don't mean Post? I have always been told pre turbo should be less then 400.



I have my probe pre and can not see below 350!!!



Kev

 

[abledog]

alot depends on what you are doing prior to shut down. If you were just crusing around town I don't think it makes much difference.

If you have been working the motor hard , pulling a heavy load or high speed driving I would let it idle 4 or 5 minutes to let everything cool reguardles of what the egt says



Terry

 

[JimP]

exhaust temp at shutdown

I shut my truck off now that the temperature has been in the 8o's, and it hardley ever gets below 400 Deg. regardles how long

I let it idle. I'm checking it pre-turbo.





2001 QC,354 gear,auto,4X2



JimP

 

[Jim Fulmer]

Like the others said, I try for 300 pre also but sometimes it just doesn't want to get there, depends allot on out side temp, if it doesn't want to cool down I just idle it for a while, yea I need a Turbo Saver along with the other toy's.



Jim P you sure live in a nice town, I was there today doing touch and go's at the Airport for 1 1/2 hours so I got to see allot of it.



Jim

 

[Royal]

My pre turbo always cools down to 300 ,even in Arizona in summer,but you have to turn off any load on the engine,mainly auto transmission in nuetral & A/C off.

 

[Chipstien]

I just go to 350. I rarely see below that.

 

[superdave]

I thought the egt is the temp caused by the firing of the fuel... . I was always taught in trucks and tractors to idle the engine for a few minutes after a long trip or heavy load, NOT TO COOL it, but to make the temp basically even so that certain parts of the assembly would have the temp more evenly distributed... . as long as the cylinders are firing, how does the egt go much below 350 or 400 degrees?? the explosion of the fuel causes that much at least doesnt it????I am not a mechanic but just remember from the last 40 years of dealing with them... . but what do i know.....

 

[jwdeeming]

I have the Turbo Temp Monitor from ISS Pro. It is preset from the factory for a <300 degree shutdown, and I run it off my pre-turbo egt probe. Depending on driving conditions and outside air temp, I see shutdown times range from 15 to 60 seconds.



JimD

 

[nevinst]

I've only had my EGT gauge mounted for a few weeks so I'm not sure what is normal, but... ... Pre-turbo, I hardly ever see it above 300 degrees after I drop to an idle. I don't pull or tow anything, I drive on fairly straight, level ground and I generally run 65-70MPH. Occasionally I get a little "wild" and run it hard through town under stop and go conditions but that's about it.



Running on the highway at 2000 - 2200 RPM I see a steady 750 - 800 degrees. When I romp on it, it can go as high as 1000 - 1100 but drops immediately when I let up. Even after running it up and down for a while, It returns to 300 almost instantly upon idling. I always let it sit and idle for 1 -2 minutes just in case but I'm not sure if it's necessary.



Is this typical with a basically stock setup (minus the muffler)?



Troy

 

[RBSOB]

very similar

Troy, your #s are almost identical to mine here in cooler Ct. . Mine also will cool to 300 pretty quickly. I'm monitoring pre-turbo with a westach probe and gauge. I also recently replaced my dented muffler with a much less obtrusive length of 4'' and don't see much EGT difference. There is no doubt that boost builds faster Have Fun, Jim G.

 

[JBlock]

Never see below 300 Preturbo

I recently installed a Isopro pre turbo, Idle hardly ever drop below 350 until the outside air is under 50F.



I see 1150-1250 if I go WOT for a few seconds, with an edge comp on 1x2, no pump fueling wire. Is my probe reading a little high. 700-900 aqt 60 mph with 3. 54



Thanks

 

[CAT 385]

The idea of the idle before shut down is to continue pumping oil to the turbo while it is spinning, once it has slowed down it is fine to shut off the engine.



If you shut it off with it still spinning 150,000 rpms and no oil to it, it would eat out the bushings in no time, causing failure.

 

[DocStressor]

No, the turbo slows down after only a few seconds at idle regardless of the temperature. The purpose of idling longer is to let the oiled turbo bearing cool down below the flash point of the lubricant (~350 degrees). If you shut down before the bearing cools down, the oil on the bearing cooks down into black crud. This is no good for the bearing during the next startup and also contaminates the oil. The problem with a pre-turbo probe installation is that there is time lag between the drop in temperature of the exhaust gas and the drop in temperature at the turbo bearing. That is because the metal turbo has a higher specific heat (you might think of this as heat capacity) than the exhaust gases. A post-turbo probe gives a better (but not perfect) indication of the turbo bearing temperature. Guys with both pre- and post-turbo probes might be able to say something about the lag time.



BTW, if you use synthetic oil, you have a bit of a safety margin becuase of the higher flash point of the lubricant vs conventional oil.

 

[JimP]

Touch and go's

J Fuller;



Thanks for the complement to our town,I'm curious why you fly so far to make touch and go landings





Good Luck;



JimPOo.