EGT question ?????

[HDR]

Whats the highest continuous EGT you would want to see while towing?

 

[HBarlow]

Whats the highest continuous EGT you would want to see while towing?

Cummins engineers found continuous 1425* exhaust gas temp operation during fully instrumented loaded testing of the '04. 5 HO engines in factory stock trim. An unmolested engine can safely operate at that temperature all day long without harm. If the engine is modified gauges should be installed and monitored not to exceed that temperature.

 

[HDR]

I've heard 1250 is max while towing. From what your saying sounds a little high.

 

[S.Morris]

The 04. 5 engines were able to run a little higher sustained temp because of a change in valve seat material compared to the earlier 03-04.

The later 6. 7 can runs well over this during some operating cycles... ... .



That being said, all different engines have a design temp recommended max and you should find out what it is for yours.



For my 04 , I use 1200 as max sustained and choose to err on the side of caution, as I am the one footing the bill regardless.



EGT spike temp can be higher for short duration, but you are inquiring about max Sustained Temp

 

[Bob4x4]

https://www.turbodieselregister.com/forums/5-9l-engine-transmissions-2003-2007/225007-egt-temp.html

 

[p-Bar]

Pre or post Turbo?

 

[HBarlow]

I've heard 1250 is max while towing. From what your saying sounds a little high.

There has always been a surplus of stupid opinions generously shared among Cummins owners and on TDR. The easy way to prove that opinion is based on nothing more than bullchips is to install a pyro gauge on a factory stock unmolested '04. 5 or newer truck, couple a trailer on, and put your foot in it. You will find that egt will reach 1450* on hard pulls and stay there.

Cummins designed, built, tuned, and tested those engines to be run at full throttle, full load, all day long, day after day, for several hundred thousand miles.

Limiting your engine to 1250* means you are limiting your engine to approximately 80% of factory torque and horsepower. Its your truck, use it as you wish.

 

[MegaJeff]

Even if you go pre-turbo, the exact location makes for some interesting differences. I my last truck, I had the EGT probe at the accumulator manifold right before the turbo... I thought it would give me a good sampling of the EGT right before the turbo. Now in my current 06, we put it in the runner favoring cylinder #6 because that one is said to run the hottest. I run a full 100 degrees hotter now on my guage and it's a difference of only a couple of inches. I don't know if I am safe making some mental allowances for the new location or not. The mods are the exact same for either of my 06's but maybe there could be some slight variation from truck to truck.

 

[Wingate]

I have always heard that the #1 and #6 cylinders run hotter also. . Must be some truth to that somewhere. . Usually, this can be attributed to the inlet air temp being hotter in those cylinders... a good example of this is the new 6. 7L Ford engine and its valve failures.

ANyway, I would not go over about 1300 sustained... not basing that on any tests, data, etc... Just from what I see day to day in my line of work... Everything I have ever seen go bad in a valvetrain always happened above 1300 degrees. . !!. . Like someone else said, I am my own warranty department. . I can back out of the "skinny pedal" and let her cool a little easier than I can rebuild the engine...

That being said, I pulled about 16K lbs. this past weekend pulling some decent sized and length hills and my post turbo EGT never got beyond 900 at 75 mph on the cruise going up some lloooonnngggg hills... boost was sitting on 33 psi!!. .

 

[HBarlow]

Post turbo pyro probes are not very accurate. I've read posts by TDR members, perhaps Bob4x4, who had pre-turbo and post turbo pyro probes installed. It is commonly thought that the difference between the two is approximately 300-400* but according to the member reporting it varies widely under driving conditons and the post turbo responds slowly to rapid changes.

 

[Wingate]

i trust mine... I have it deep into the exhaust stream, just off the back of the turbo, and it is slightly slower to respond... coming up and down, but im used to it. I ran the truck about 2 years before adding the Smarty Jr. and have noticed that I see it running cooler while pulling hard with the Economy tune than it did in stock form.

I feel like there is probably a 200 degree difference at sustained heavy loading between pre and post... I find it jsut as credible of a # for watching how hard the engine is working. .

With all the cylinder temp variations on the little 5. 9L... I'm not completely convinced that pre-turbo is any more accurate as to the overall exhaust gas temp of the engine... also, since I am my own warranty station, I would not appreciate a broken thermocouple being sent thru my turbo... eeekkkk!!!. .

to each his own, i guess... im accustom to my post turbo readings...

 

[AH64ID]

Stock motor, 04. 5-07, will run 1450° and do it all day, add some timing and that number drops fast.

Post turbo readings are really pretty useless, they very 200-500° from manifold temps, and based on the poor exhaust flow of the HE351 tell only a part of the story. Wagering your EGT's on a post-turbo pyro is far riskier than a pyro failing and eating a turbo, not to mention a turbo is far cheaper than a motor.

 

[NIsaacs]

Stock motor, 04. 5-07, will run 1450° and do it all day, add some timing and that number drops fast.



Post turbo readings are really pretty useless, they very 200-500° from manifold temps, and based on the poor exhaust flow of the HE351 tell only a part of the story. Wagering your EGT's on a post-turbo pyro is far riskier than a pyro failing and eating a turbo, not to mention a turbo is far cheaper than a motor.

Post turbo is not useless, they work fine. If someone wants pre, thats totally fine, any temp gauge is a good thing. I have and will wager my Cummins powered trucks on post readings.



Isspro has been making color coded gauges for ever. If the red line of 1050* post turbo was junk, they would not make them If post turbo was junk, truck and engine manufactures would not use them.



You can recommend pre all day long and I will not respond because any gauge is good. But if you say post is useless, I will respond.



Nick

 

[cerberusiam]

Post turbo is not useless, they work fine. If someone wants pre, thats totally fine, any temp gauge is a good thing. I have and will wager my Cummins powered trucks on post readings.

You are correct, they work fine in their intended applications. They work fine as long as the engine remains basically unmodified.



Modify the fueling and the differences began to tell. The readings and testing on a bone stock engine have been correlated tightly to the post EGT readings with the gauge marked accordingly. Nobody will argue that point and it has worked for a LOT of miles on the trucks so equipped.



However, modify the fueling and all the experience, testing, and usefulness gets tossed out the window. You cannot compare the two sceanrios and use the same criteria for each, any sharp diesel mechanic will confirm that. Testing backs it up, 1000 post turbo could easily be 1600 in the rear cylinders with a modified engine.



Also need to consider where these gauges are used. Larger slower turning engines with much larger turbos are a perfect fit. The variances and peak temps are not as radical. There is a significant difference between the 325\HE351 installed in these trucks to and ISX\ISL in a larger rig.



Both sides are correct. The Post EGT measurement is both useful and useless depending on context.

 

[HBarlow]

When I had my old '01 HO/six speed with Bosch RV275 injectors pulling a grade with a trailer on I could simply floor the accelerator pedal for a second and instantaneously peg my EGT gauge at 1600*. I would back out of it as quick as I floored the pedal and ease it back to 1300*.

A post turbo gauge would never see that instant rise to 1600*.

 

[AH64ID]

The problem with post-turbo is the rpm/boost dictates the temp drop across the turbine, and it's never constant.

On a stock motor it would be fine considering you would get a feel for what means what and you know it won't melt, but anything modified doesn't tell you enough.

 

[Wingate]

The problem with post-turbo is the rpm/boost dictates the temp drop across the turbine, and it's never constant.



On a stock motor it would be fine considering you would get a feel for what means what and you know it won't melt, but anything modified doesn't tell you enough.

Exactly... Like I previously stated, I ran my pyro for a year or two thru a WIDE variety of conditions with the engine is stock trim before adding the Jr... I can say that my overall EGT is significantly lower with the Jr. than in stock form in any condition... . stop and go, unloaded, overloaded, 95 MPH on Interstate. . etc... I completely agree, stock and/or lightly modified (jr) the POST is a very useful tool...

Cerb/AH/Harvey... Yes, on larger engines, and heavily modded engines, pre-turbo is the only way to accurately monitor and trend what is going on inside the cylinders...

Actually, your single pre-turbo thermocouple is what is useless in that situation, you should have each exhaust port individually tapped and a thermocouple installed in each port. Connect it to a digital exhaust temperature scanner that way each cylinder is monitored.

In the industry I work in, cylinder port temps. are critical... Natural Gas and Diesel applications... I'm talking real diesels with real horsepower though... not little OTR engines...

:-laf:-laf:-laf

 

[NIsaacs]

When I had my old '01 HO/six speed with Bosch RV275 injectors pulling a grade with a trailer on I could simply floor the accelerator pedal for a second and instantaneously peg my EGT gauge at 1600*. I would back out of it as quick as I floored the pedal and ease it back to 1300*.



A post turbo gauge would never see that instant rise to 1600*.

If you would have had a boost fooler and boost elbow you could have floored it and kept it there. The RV's are not a good stand alone mod. If you tow, there is no reason to build anymore power then you can use. All my trucks are modified and I can stand on the go peddle as long as I keep the RPM under 2100/2200 and no lower than 1700.



Back in the day with big trucks and before oil cooled pistons there were guys that could just tear me up on a short steep hill but give me a few miles and they were history. The norm then was 1200* pre and 900* post and ya better not push it either.



Nick

 

[HBarlow]

If you would have had a boost fooler and boost elbow you could have floored it and kept it there. The RV's are not a good stand alone mod. If you tow, there is no reason to build anymore power then you can use. All my trucks are modified and I can stand on the go peddle as long as I keep the RPM under 2100/2200 and no lower than 1700.

Back in the day with big trucks and before oil cooled pistons there were guys that could just tear me up on a short steep hill but give me a few miles and they were history. The norm then was 1200* pre and 900* post and ya better not push it either.

Nick

I had only owned my '01, my first ever diesel, a couple months and been a member of TDR about the same length of time when I attended a TDR rally in Kerrville, TX. Several of the big name vendors were there - Bill Kondolay, Piers, etc. Joe Donnelly gave a talk on the Bosch RV275 injectors and had a set or two he could sell and install. I bought a set from Joe and he installed them in the RV park where we were staying. The injectors alone made a huge difference in the way my truck ran and are still in it today after many hard miles.

I was not knowledgeable about all the additional mods and really wasn't interested in going any further. Over time I realized that the injectors were not a complete modification because without added air the power could not be fully utilized but as long as I watched the egt I could use much of the added power and never melted a piston. The old truck has around 365k on it now and still runs good.

 

[AH64ID]

Exactly... Like I previously stated, I ran my pyro for a year or two thru a WIDE variety of conditions with the engine is stock trim before adding the Jr... I can say that my overall EGT is significantly lower with the Jr. than in stock form in any condition... . stop and go, unloaded, overloaded, 95 MPH on Interstate. . etc... I completely agree, stock and/or lightly modified (jr) the POST is a very useful tool...
Cerb/AH/Harvey... Yes, on larger engines, and heavily modded engines, pre-turbo is the only way to accurately monitor and trend what is going on inside the cylinders...
Actually, your single pre-turbo thermocouple is what is useless in that situation, you should have each exhaust port individually tapped and a thermocouple installed in each port. Connect it to a digital exhaust temperature scanner that way each cylinder is monitored.
In the industry I work in, cylinder port temps. are critical... Natural Gas and Diesel applications... I'm talking real diesels with real horsepower though... not little OTR engines...
:-laf:-laf:-laf

With the tight turbine housing and little exhaust wheel I think the HE351 makes a poor turbo for watching post temps, it would vary too much. But maybe that's just me.

The Jr does do a great job of lowering EGT's, but if you were to run stock EGT's with a Jr you could easily melt something. So it's not really apples-apples. Stock can hold 1450° in the manifold and be fine, but I wouldn't hold more than 1300° with a Jr.