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EGT Too High

JohnShead

JohnShead

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Location
Kingsport, TN
Yesterday I was towing an empty cargo trailer, about 1400 lbs, on nearly level ground at 65MPH and my EGT went right to the top of the green arc, 850°. When going up a hill I had to slow down and downshift to third to keep it there. Occasionally I let it go into the yellow arc to about 950° to crest a short climb. We're moving cross country this year and I was planning to haul our stuff in this trailer but I'm worried about these temps, I know there are many grades much steeper than I drove yesterday along the route to our new place. Any ideas on how to lower the EGT would be appreciated.
 
Most of us go to 1050* without worry, WarWagon will push his to 1500*.

Have you pulled this trailer before? If so what were EGT's then? Is boost OK?
 
NVW said:
Most of us go to 1050* without worry, WarWagon will push his to 1500*.

Have you pulled this trailer before? If so what were EGT's then? Is boost OK?
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I haven't pulled it before and boost when I first noticed it on the flat was at 6PSI, climbing it would go higher, it goes as high as 15PSI under hard acceleration. When I slowed a bit to bring the temp down boost was around 3PSI. My pyro gauge red arcs at 1050° so I guess I'm still ok.
 
Is the thermocouple probe pre or post turbo? And I agree, running sustained EGTs of 1100-1150°F pre-turbo won't hurt as long as ECT stays below 210°F peak.
 
1050 post turbo is pretty warm IMHO. What all is done to this truck?

I would be questioning the accuracy of the egt 1st.
 
"Rule of thumb" is add 300-350°F to the post (after) turbo EGT to get pre-turbo EGT.
 
I monitor my EGT pre-turbo and with ECT in check all it tells me is when the turbo blanket starts to burn up. Non coated 6.2 pistons can take a sustained 1550 pre-turbo EGT pulling a trailer up a steep grade. So can the ATT turbo. The walking J turbo blanket will scorch black on the turbo side due to the red glow... I have looked for and not found a EGT that melts the engine down - and I have tried hard. Sane to me was cooling the tune down to below 1500 EGT, but, I do not get heartburn over EGT on this engine. (Another engine like a 5.9, 6.0, 7.3 can be a different story.)

Ran so may miles with extreme EGT towing it turned the blue paint on the passinger floor pan brown over the exhaust. On the topside under the carpet! Hint: use header wrap on the exhaust from the turbo to past the bend in the floorpan.

Sent one engine to the scrapyard over ECT as it scuffed a piston. Synthetic oil is not a bad idea if you are working her hard.

If you are going to worry about it get another EGT probe and install it pre turbo.

In general check airflow from dirty air filter sucking in hot underhood air to a restricted exhaust. Burning engine oil also can raise EGT and make the turbo glow.

Example of turbo glow on a CAT C15.
C15cat838.jpg

You say you are downshifting - depending on wind and conditions you may have to stay revved up in direct - 3rd. Hill... You mean "hill" or a out west vehicles burned up stains on the side of the road "grade"? :D
 
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The hills I climbed yesterday were probably nothing over 5%, but some were several miles long. Putting it 3rd at 60MPH kept the temp around 850. When I do the move I'll have to get over a few of those burned up stains climbs. It sounds like 850 isn't so bad and the highest I let it get was 950. I'm just used to it being 600 and below just driving without towing. Except for the Rotella that I used for the first 1000 miles on the long block Amsoil full synthetic diesel oil is the only oil that's been in it. I cleaned the air filter a couple thousand miles back but have driven through some blowing dust storms since, I'll clean it again and see if that helps.
 
I wouldn't panic on those numbers. Pay attention and watch the ect, yes, but don't panic.

If you want to bring the numbers down, and it's not an all the time issue, where would you like to kill the second bird with the same stone?

Propane will drop egt and based on quantity and usage can give you more power or more mpg. Wmi (water only) will drop egt and keep more soot out of the oil by not allowing cabin to build up and make its way past the rings as much. Wmi (methanol added) will clean less carbon drop egt about the same, but give a little more power- it will cost more to buy, however.

You can get the nice high pressure kits electronically controlled, or the low pressure DIY kits for a couple hundred bucks.
 
Am with the others that those numbers seem within range. Personally, I'd install a pre-turbo EGT probe and abandon the post-turbo probe.

For comparison, when towing the 6,500# RV, I usually set my throttle based on EGT's (pre-turbo).
> Flatland acceleration (stoplight, etc): 700 - 800 F.
> Grade climbing: 1,000 F.

When I see any hill that looks like it is more than 2% I manually drop the tranny into direct (3'rd) prior to entering the grade. This is to avoid lugging the motor and keep the ATT in its sweet spot.

Reason for the 1,000 F limit on long grades was that with the OE radiator and the A/C 'On' I found that EGT's above 800 F caused the ECTs to start climbing. By limiting the EGT to 1,000 F, the ECT's would stay in check and not go above where I wanted them by the time I crested. When doing this, I manually worked the tranny so that the RPM's stayed above 2K and just let the speed drop.
 
Thanks for all the feedback, I'll just do 3rd gear when needed and keep EGT below 1050° and watch ECT. I feel more comfortable now knowing it can run that hot. I towed the trailer again, loaded this time to 3600 lbs, and the same area that I first noticed the 850° the other day got no hotter than that this time.
 
If the truck is going to start towing on a regular basis check the RPM's in 3'rd at your normal cruising speed.

For the Burb, am seriously considering a change to 3.42's. With OE tires and 3.73, direct at 55 mph (my preferred speed with the RV in tow) is just a little too low when in 3'rd and a move to 3.42's would drop the RPM's some and still keep the ATT in its sweet spot. Secondary reason is to keep the passengers from bickering about the noise ;)
 
JayTheCPA said:
If the truck is going to start towing on a regular basis check the RPM's in 3'rd at your normal cruising speed.

For the Burb, am seriously considering a change to 3.42's. With OE tires and 3.73, direct at 55 mph (my preferred speed with the RV in tow) is just a little too low when in 3'rd and a move to 3.42's would drop the RPM's some and still keep the ATT in its sweet spot. Secondary reason is to keep the passengers from bickering about the noise ;)
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Disposable ear plugs are in the center storage. So are some face mask air filters. Never know when you will need them like at the dump. Not that I would give them to passengers, but, when bitching starts they pause while they wonder what I am rolling in my fingers and then shove in my ears. :)
 
Then there's always turning up the volume on the customized six speaker system in my Burb to drown out the passengers. I'm running a 4" straight exhaust with a 45° Elto angle it downward and outward before the rear axle underneath.
 
JayTheCPA said:
If the truck is going to start towing on a regular basis check the RPM's in 3'rd at your normal cruising speed.

For the Burb, am seriously considering a change to 3.42's. With OE tires and 3.73, direct at 55 mph (my preferred speed with the RV in tow) is just a little too low when in 3'rd and a move to 3.42's would drop the RPM's some and still keep the ATT in its sweet spot. Secondary reason is to keep the passengers from bickering about the noise ;)
Click to expand...

Glad to see I am not the only one with crazy thoughts of wanting to swap to 3.42s to tow with. :)

I feel they would work great if a guy pulled in direct (3rd on 4L80E, 4th on NV4500) and had enough power. Bone stock may not be a good idea, but with an a-team, I bet it would work good.
 
My only problem with 3.42's is the off the line power when loaded to the gills. Otherwise it matches the rpms to the att well.

I've ran 62 with 4.10 and the att in 4th on the nv4500. The truck just purred away.
 
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