This is not news by any means, but we've all seen many articles / posts / other sources regarding towing that suggest once you come off of a heavy towing stint that you should let the truck idle for a few minutes or until EGT's get down to about 200- 250* to let the oil cool down (these are some numbers that I have seen at one point or another).

It occurs to me that in neither of the two 7.3's that I have had will the EGT's get down that far. The lowest they go at idle, towing or not, is pretty consistently right at an even 300* when the engine is warm.

Do you guys get lower than 300*?

 

mope....., 300-350 is the range you want, I shut it down at just under 400 or I have to wait til the cows come home to get to 350...

 

Something is wrong with my guage, because when i pull off the road into my 100yd long driveway that is flat, i can idle in most of the driveway and then park, EGT is still 475-500* and i let it cool to 425 or 400 then shut her down.

 

The only time I ever see 200 is on a cold morning startup. After towing I usually wait until below 400 also. Revving the motor slightly in park will bring temps down quicker than just idling.

 

All depends on the outdoor temps. I can get under 300 degrees in the winter, but in summer with the A/C running that's impossible. If I shut the A/C off it still takes foooorrrreeeeeeevvvvveeeerrrrrrrrrr. Shut down under 400 degrees and you should be fine. I did that and when I pulled the stock turbo off after over 85K miles on it, it showed no signs of oil coking. But I do use synthetic which is typically a bit more resistant to coking at high temps.

 

All of the readings I see above seem too high, especially if you have a DP Tuner or any other chip for that matter. I got some info on this (EGT at idle) from Jody when I got my new DP Tuner and could easily switch back to stock. In stock 300F at idle is about as low as it gets no matter how long you wait. I'm always talking moderate or warmer weather because that's all I ever see. Start off with 300F at idle in stock and switch to DP 60 or 40 tow and it quickly falls to 200F and wait 2 or 3 min and it gets down to 150F-175F! Jody confirms that this is normal for his tunes versus stock.

When I asked Jody why stock runs so much hotter, his only answer was that's just the way they do it, it's all in the tuning! If you run a DP you definitely need his fast idle, and he says it's easier on the engine to use it for extended idle rather than his low EGT idle. When I switch to my old Superchip tune (I've got that as a setting on my switch) from stock, it only falls from 300F to 250F and never goes much lower no matter how long I wait.

What temp does everyone's EGT gauge read before they start their truck after sitting overnight? Mine reads a little less than the current ambient air temp (usually about 50F to 75F) because the up-pipe is still a little colder than ambient from sitting overnight.

To protect your turbo bearing when towing, you have to let it idle MUCH longer than just the time to bring the EGT down to a minimum. That turbo housing holds heat like a cast iron stove, which it basically is. When I pull over at a rest stop when towing and immediately click on it with my IR gauge, I see 600F or higher. After a 10 min break (with the hood up at fast idle) I check again and still see 400F! When I pull into an RV park (usually after a mile or more on a slow side road) and pop the hood I still see 500F. I register, mosey down to my site, mess with getting the trailer level, etc.. usually 10 to 15 min, and it still reads 300F, and truck's been idling the whole time! Dino motor oil shouldn't see much more than 250F, we need a water cooled turbo like the other brand has.

PS on edit... I used to have an EGT probe on my Banks downpipe, and if you compare pre vs post EGT at idle you'll see why just getting the pre temp down to 300F and then shutting off isn't good enough, as you'd still see a post temp of 400F or more! Cast iron stove effect!

 

I wait until 300* preturbo. Only time I ever have to wait is if I just hopped off a main road or highway and parked. Most of the time though the slow driving through our neighborhood is plenty, and it's at 300 or lower by the time I'm parked.

 

I can relate to the cast iron stove affect and I'm not arguing with you over it but, Banks Tech Support told me to add 300deg.F to calculate the true EGT's because the probe is in the down pipe where they claim its cooler. However, at idle even on days like today @ ambient temps in the high 80's my EGT gauge will read 275df at idle after a rush hour run to the campground (Not Towing). Now I am confused because if I add 300 and 275 that means I idle at 575.

 

I'm one of those people who lets the truck idle for at least 2 minutes before I shut down dang near every time. Good thing I'm never in a hurry. Spank me all you want, but at 97K miles my stock turbo is in PRISTINE condition inside. NEVER ran synthetic. Never went more than 3500 miles on oil changes though, either.

 

It's a lot more complicated than just adding 300 to your post reading to get your pre reading! For example, if pulling a long grade at 15-20 psi boost and pre reads 1200, then your post might read about 300 less or 900 (which is the max recommended by Banks), and your correction factor would be correct. It's the 300F temp drop across the turbine side that's causing the compressor wheel to spool up and create the high boost.

After you get to the top of the long grade pull into a rest stop and let the engine idle. The pre temp will fall very quickly, because very little fuel is being injected, the boost is 0, and the turbo is barely spinning, but as the exhaust gas passes through the cast iron turbo housing that's still 600F or hotter it picks up heat, and now the post temp reads higher than the pre temp by 200 or so degrees. The post temp will continue to read higher until the turbo cools down to the same temp as the pre temp exhaust gas entering it, and at that point, both temps will be the same. So your post temp might be 300 cooler or 200-300 hotter, or anywhere in-between depending on the time dynamics of the situation!

You definitely risk burning a piston by not having your EGT probe on the pre side, because the 300 delta example I gave is in the "steady state", in a transient condition you might get to 1400F on the pre side before seeing a 900 reading on the post side. The pre temp that the pistons and turbine blades see increases very rapidly at high throttle inputs, and it takes time before this is seen on a post temp probe.

 

I have my probe post turbo, at idle it can get down to 200* but that take about 10 minutes. When i move it to pre turbo, i wonder if it will ever see 200* anymore. I also do the same as ryan kinda, when i get close to my house, the roads get a bit sh!##y, and if i go remotly fast, i will probably hit a tree. So im going about 20mph for about a half mile before my house, then i have a 1/8mile driveway. By the time i pull into my house my pyro reads about 300*. I wait about 10 seconds and shut it off. Note i have blown a turbo(but i think we determined that it was dirt ingestion), but the second one feels the same as it did 20K ago. Ernest i know what you mean about the EGTs at idle with a chip, when stock my truck has a hard time seeing 250*before i shut it off. With the TS it will go down to 200*.

 

Let me ask this, I'm putting in a EGT senor from my Edge and it says to put it in the exhaust manifold. A buddy of mine was say that I should put it before the turbo. Says you get a more accurate reading. Is this right?

 

The exhaust manifold is pre turbo, if it is a clamp on style probe you can put it in the uppipe just past the manifold. The temps respond faster pre turbo and are closer to what the piston is seeing and that is what you are worried about when it comes to temps

 

The exhaust manifold is before the turbo, so you're friend is right. Mine is currently in one of the up-pipes (drivers side) and I'm now going to have to move it to the manifold since I'm going to replace the up-pipes at some point with the Intl's.

My EGT's are pretty much down to 300 by the time I am ready to turn it off. Sometimes I have to wait as much as 30 seconds or so if I've been greedy with the throttle.

 

You wouldn't have a pic, would you?