understanding Max or safe EGT during hill climbing (1 Viewer)

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Hi, new to diesel new to turbo :) done some searching but this must be so basic no one bothers to discuss? the previous owner put a little garret turbo on the 2h in my 1982 hj47 troopy. it has a straight 3" exhaust. the alarm for the pyro meter was set at 460c. I know barely anything about the dynamics of a turbo and its negative effects on an engine. I want to know what constitutes a safe egt max and prolonged use under that max? I'll climb hills and the egts will start climbing and so i let off the gas. but it feels weird to have so much potential power but not use it cause the EGT temp is too high. Right now I try not to go over 460 as that was how he had the alarm set, sometimes ill let it get to 500c but for like 1min lol. Id love to fully understand my limits and all.

What would someone say is too high a temp to run for too long climbing a hill on the highway with a 2h?
 
Wrong forum to ask a diesel question , there is a diesel forum here to answer your question. I have a turbo diesel and 500 is way low for egt. Max is generally around 1200! I usually max at 1000 going up hills as a 2h wasn’t designed for a turbo, unless you build it to take a turbo. The plus of staying around 500 is it will last a long time and stay reliable!
 
Wrong forum to ask a diesel question , there is a diesel forum here to answer your question. I have a turbo diesel and 500 is way low for egt. Max is generally around 1200! I usually max at 1000 going up hills as a 2h wasn’t designed for a turbo, unless you build it to take a turbo. The plus of staying around 500 is it will last a long time and stay reliable!


He is talking celsius.

What I tell customers is short pulls 1200* is fine but for sustained 1000* max.

Cheers
 
Wrong forum to ask a diesel question , there is a diesel forum here to answer your question. I have a turbo diesel and 500 is way low for egt. Max is generally around 1200! I usually max at 1000 going up hills as a 2h wasn’t designed for a turbo, unless you build it to take a turbo. The plus of staying around 500 is it will last a long time and stay reliable!

Celsius or Fahrenheit? 500c is a 1060*Fahrenheit.
 
You need a boost gauge as well as a pyrometer. Watch them both and if the temps are high and the boost pressure is low climbing a hill then you need to down shift to bring up the boost pressure.

It is about air flow across the head the higher boost provides more oxygen for combustion and as the air moves across the head it will carry heat away to keep the exhaust temps lower.

You also watch the tail pipe in the mirror because if you are putting out smoke you are over fueling and burning efficiently.
 
Shows how much I know. Figured having a gas pedal in a diesel would be a huge problem. LOL
I can be part of the problem if you have the pedal mashed to the floor with high temps and low boost. It can help to back out but down shifting will make a quick change to the situation.
 
Ok! thank you this is what I was looking for! Didn't realize there was a specific diesel vs cruiser tech. Ill post there next time :)
 
There are a lot of articles on line that discuss operating a truck with diesel engines. I read a lot and have had a diesel pick up since 1995 and have driven back and forth across the continental US with them. I live in the mountain west so get a lot of practice watching my gauges wither loaded or empty. I also looked up the safe EGTs for the Cummins 5.9 and 6.7 since they are what I have driven the most miles with. My first diesel did not have a turbo and it smoked at higher altitudes and there was not much I could do about that one other then get out of it if the smoke was dark and thick. That one looked like an F4 jet with haze it put out at elevation.
 
Where is your EGT probe?
If it's pre-turbo, don't take an IDI engine like a 2H above 650C although you'll most likely find that you run into coolant temp issues with a sustained pull before you run into EGT issues. I'd want to keep it at 600C or below for a very long sustained pull.

A direct-injection engine like a 12HT, 1HDT etc will have no issues with 700-750C sustained. I've run a 1HDT (mine, not a customers 😅 ) to 900C with no issues playing around on the dyno but wouldn't recommend going this high on a DI engine.

If the probe is post-turbo, put it pre-turbo.
 
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Where is your EGT probe?
If it's pre-turbo, don't take an IDI engine like a 2H above 650C although you'll most likely find that you run into coolant temp issues with a sustained pull before you run into EGT issues. I'd want to keep it at 600C or below for a very long sustained pull.

A direct-injection engine like a 12HT, 1HDT etc will have no issues with 700-750C sustained. I've run a 1HDT (mine, not a customers 😅 ) to 900C with no issues playing around on the dyno but wouldn't recommend going this high on a DI engine.

If the probe is post-turbo, put it pre-turbo.
Thanks @AussieHJCruza Im not sure where it is at the moment (at the office right now haha) but will check after work. thanks for this, even tho I didnt put it in the diesel section, I got a lot of good info here ;) well ive been keeping it at 460c lol maybe touching 500 for like a second hahah. so this is game changing for me.
 
Aluminum melts at 1250ºF.

Bursts to 1600+ are fine, just don't sustain it for long.

I never worried about anything below 1200
 
EGT is only one piece of the puzzle, timing also has an effect as well on where the heat goes, i.e. into the cylinder head or coolant or out the exhaust, plus the engine design - IDI engine puts a lot more heat into the cylinder head and subsequently the coolant than a DI engine. From observation, if you advance the timing , you might notice lower EGTs, but coolant and/or oil temp may increase slightly.

The other thing is the piston crown gets cooled by the air charge on the intake stroke and on most engines, by the oil from the piston jets as well, you'd have to run a very long hard pull to heat-soak the piston to 1200F.
 
Pre-Turbo is the only safe way to monitor the heat. RPM, load and EGT / Smoke are the only way to know for certain. Like others have said, IDI vs DI engine tells a lot. It's not just the pistons that melt, you can crack pre-chambers, overheat, crack heads etc. You can get away with a lot more temp in a quick burst, than at the end of a 10 km long hill with a steep grade. Piston squirters are also important. Without them, the pistons will overheat a lot quicker and scuff in the bore, if they don't crack or melt on some portion. Stick with the low side of the recommendations for max EGT, just in case your EGT probe is slow or lazy. The difference in speed between 1200 degrees F. and 1300 degrees F in my truck isn't worth the risk. Unlike overheated coolant, a melted piston isn't something you can exactly pull over and cool off from when it happens.
 

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