What your Exhaust Temp is saying about your Diesel Engine. EGT.
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- Опубліковано 7 лют 2025
- In this video we are discussing the contentious subject of EGT and Exhaust Temperature.
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I had an hot rod vw 1.6td and ran an egt as that combo had dropped a prechamber at 1600f
I swapped to a 1.9tdi with same turbo setup. Same sensor in same location.
And the egt was about 3-400f cooler across the board. Even more at high temp. The 1.6 idi has no problem breaching 1600f.
Runs so much cooler, like 450-700f on highway.
Making much more power it was
Unable to breech 1100f I removed the sensor and sold it.
The biggest determining factor in EGT is how good your engine really is.
New engines run super hot. And cleaner. And more powerful….
But mine runs forever.
And on a new 2.0 Tdi with dpf and throttle body in the exhaust…. Lord knows how hot their egt is.
I have as much as 32 psi boost on the retarder.retarded..
So must be some temp
Hey Josh! Good morning! My name is Keith and I am a Diesel Technology State Instructor and was wondering if at all possible you could make an addition to this video by making one over.. How exactly a "Pyrometer" works to provide the EGT. I know it's more component specific instead of the over view angle of EGT's and diagnosing why one might be higher than normal ranges but I do share several of your videos with my students both in Class and Labs and think they would like to know more about what is a Pyrometer as a sensor and or tool to find EGT. I can take it step further with having an assignment on the history of this component but this generation of students are very much visual learners and I think would learn again more on this subject if there was a follow up on the actual instrument. I know you are busy as we all are but if you have the time... Thank you for making such awesome videos and as always looking forward to more and sharing them with our students. Sincerely, Keith A.
I need to about more information CAT engine and Cummins engine please you can help me and contact with me by the whatsApp
I'm Abdullah from the Iraq
@Nathan Brame , Aren’t the 1.9tdi engines the ones that had the problems with cokeing up?
I was told by an old deisel mechanic many moons ago "never lug on a heavy load or hill " let it rev.
That’s not just for EGTs. Oil thins out a lot on hot days and steep hills. You don’t want to lug when oil pressure is low.
Depending on what motor you got. V8 like to Rev. 6 like to lug and pull.
I was taught to pull a hill in a gear that will allow you to accelerate.
@@chrisleggett685 than you aren't using the torque the engine has.
@@charlesfuglie2491 yeah, you’re using the horsepower.
I have worked on marine engines my whole professional life - about twenty plus years ago I worked for a place that was a distributor for MAN diesels- we had some 1000 hp V12s in twin application, in 60 foot fiberglass sport fishing boats- they had lots of piston seizures and it came down to two things- the load on the engines accelerating the hull up on plane (similar to getting a loaded truck to highway speed) caused combustion gas temps to spike, and the engines used a sea water to air aftercooler (as do most high performance Cat marine engines, Cummins etc) and the sea water pump and system supplying the water did not have the flow at mid RPM to supply enough cooling to keep the inlet air temps down when the load spiked, and lo and behold we had piston seizures. This was also in the days of totally mechanical injection that could not alter fuel timing etc to assist with these issues. The cure was larger volume sea water pumps and larger aftercoolers. Also, unlike a truck with gears, the engines were coupled to fixed ratio transmissions and fixed pitch propellers.
that sounded expensive
@@calthorp It cost them lots of money in warranty for sure, and a fair bit of sales! I sure learned how to change pistons and liners at the time!
That's why i liked my 96 pete. It had gauges to monitor engine. We had general rule with 3406b , don't let pyro pass 1200f. Thx for your video!
on my 3406a it was either 1325, or 1375. i cant remember. it's been 27yrs. i just dont remember.
I worry at 900
Interesting, this would be the opposite effect of a gasoline motor.
When towing RPM is your friend. I always tell my wife and others, I don't drive by MPH. I drive by RPM. I have a 5.9 2005 and have done lots of work and upgrades to and it tows very well. I don't tow under 1900 rpm ever and cruise around 2100. Going up to 2300 to start big inclines. Proper lubrication, filtration and RPM works for me.
I try to keep this in mind when the temptation to lug an engine comes up
Lugging a hot engine, bad for the bearings.
I am a Cat guy. Had yellow under my hoods for several decades. Even white. (Most A models) A,B,C,Peec,E,and 6nz I would run to 1300. I had 3 b models with a pyro installed pre turbo and behind. 1300 hundred hard pull would usually be 1370ish before turbo. I run ACERT to 1100. But the ACERT will cool down faster. From my experience all cats feel like at a certain point they are losing power but if you back off the throttle and lay into it again would start yanking hard again. Older cats would need a downshift at this time. Not because they needed it but because you needed to bring the egts down. I have found that the C15 will fairly quickly lose exhaust temps then lay back into her in overdrive.
The old mechanical pumps did really well with throttle pumping (or whatever you can call it), where you’d just go on then back off the throttle. They climbed a lot better doing that instead of just keeping the foot down.
Thanks Josh! It's great to finally get a straight answer! I've always just followed the rule of not letting it go over 1100°F.
Very good point about raising RPMs to lower egts. I've always done that to lower coolant temp but never thought about it for egts kind of obvious when you think about it though LOL
I climb hills in the summer like a icy road, with the engine fan on and I watch the temp gauge and boost very closely. Rpm around 17-1800 rpm I have crossed some big mountain hills at 80,000 pounds just being patient and “easy” on my engine. Thanks for your videos.
Yep seems to be the sweet spot in rpm for my 3406e for hot days climbing steep grades 80-100k
I appreciate the dedication to know everything about these engines by asking about the rep (then asking the engineer) to know the EGT upper limit
If I remember correctly from my days of running around in big hp Cat engines, for every 1 degree of intake air temperature increase (or decrease) the exhaust temp will change 3 degrees in the same direction. I had a C16 with lots of big parts in it and put every gauge imaginable in that dash to monitor things. I had 2 temp sensors on the clean air side of the engine, 1 before the CAC and one after. And had 3 temp sensors on the exhaust side. 1 in the manifold for the first 3 cylinders, and 1 for the back 3 cylinders, and then 1 behind the compound turbo setup we made for it. The front 3 cylinders almost always run cooler due to the way the cooling system is set up. And whenever I kicked on the engine fan and dropped the intake air temp by 20-30 degrees, the exhaust temp would drop from 50-90 degrees inside the manifold. The difference in temperature from before the turbo and after is all relative to the amount of work you’re asking the engine to do. A turbo takes a lot energy out of the exhaust stream by way of heat. So an engine that’s fully loaded and running up a mountain might have a temp difference of closer to 400 degrees from one side of the turbo to the other
I put a bar and plate CAC in mine (C16 dynoed 944) and it dropped the egt’s 50 degrees. I always flip fan to manual before a hard pull since water temp never gets hot enough to trip it on usually
Well shit now, guess I’m buying a 2nd pyro. This knowledge and willingness to teach free and charge to boot is mind blowing. The things I’ve learned and the engine work I’ve done, not possible without your help. Thanks!
Very interesting. EGT temp of 1200 before turbo was understood in the mechanical engines as max. In Northern Calif. logging country there were some real guru's at building 600 + horse power while keeping EGT somewhat controlled. As you are saying it was all about fuel; air; timing. It took a good driver to keep pistons from cracking.
Something to keep an eye out for is a burnt ground wire between starter ground and engine block. Which would indicate a short in Alternator Positive cable to engine block.
1250 continuous, 1250-1350 intermittent less than a minute or two 1350-1400 less than 15 seconds. That’s been my rule of thumb.
Excellent information. Makes me happy that I installed 2 automotive cooling fans on my 3126 in my DP to help pull air through the CAC and radiator., I can see my engine temp drop a few degrees anytime that the fans kick in, even when we were going up the grade out of Vegas to California. It just made sense to me to boost the airflow to help the engine cool down, and it's done wonders.
Excellent video I’m new to HGV mechanics I’ve swapped careers from auto electrical to HGV mechanical and your videos have be excellent mate! Thank you very much for your time and effort.. 👍
I love your Channel! I will be soon looking for an RV to retire into. Started driver professionally in 1988. My check driver hammered into me the 3 major rules. 1)NEVER exceed 1250 pyro. Ask why and was told go ahead and melt the valves. Good enough answer for me. 2) if you hear on the CB a monfort coming stay right.and 3) watch out for swift and company. I knew a lot of the Willis Shaw Frozen Express driver from when I worked at Lew & Teds. WSFE was my first company. He explained that the pyro was how hot and metal like are skin can only handle so much. I never crossed 1200. KEEP UP THE GREAT INFORMATION!!!
I was a heat treatment operator if fact I heat treated lots of automotive screws head bolts for Polaris, grade 8 10 point flange bolts that went to Cummins, and tiny 4mm flange screws that went to detroit. Grade 10 grade 8 and grade 5 five where all typically made of the same steel alloy SAE4037 steel. They were all hardened the same way (heated to 1550° Fahrenheit in a .37% carbon atmosphere for 45 minutes then quenched in 150° oil. The tempering furnace is what changed the grade of the steel. A hotter tempering furnace equals a weaker grade of steel if we tempered and the bolts at 750° for 2 hours we got grade 10 bolts 875° we got grade 8 bolts, 1050° we got grade 5 bolts. My point is that if you got steel hot enough if will permanently soften. Heat treatment creates martisite in steel which is basically a ceramic and adds strength while reducing ductility tempering will remove a certain amount of the martisite and soften the steel. Above 1400 degrees steel starts to leach carbon if there is none in the atmosphere (or absorb carbon in the cast of anything in the motor oil which can make parts harder and brittle) around this temperature the grain structure of the steel starts to change and dramatically soften. Some steels are going to soften at a much lower temperature.
I know little to nothing about diesel mechanics but I am going to be starting at my dads shop soon after my vacation and they will show me everything as long as I'm willing to learn and work hard they will train me going to start with fairly simple things like oil changes and brakes and tires.
Man, this answered a lot of questions for me as I run a MBN everyday and I've always heard of the high EGT's that come with the it. I don't have a pyrometer so I've always been a little nervous about it and the only thing I can think of doing to help keep it low is to run my fan more often than not especially when pulling hills. I'm glad that you touched on that and confirmed that what I was doing could help. I haven't had any problems with it but I've heard that it could melt pistons and such. Thanks for the video!
Don’t lug the engine under a heavy load is going to help EGT more than just running the fan. I try to maintain 1400 or higher when heavy.
MBN's left the factory hot, Cat has new FLS/FTS and flash file to help with this. Seen several turbo's and exhaust manifolds crack.
Ok 😮
I’m hauling mbn same all the time pero gage 1200. +
I tow recreationally with an old 1st gen Dodge. Have crossed the country a few times and my rule of thumb is to back down at 1,200F. My pyro is a legit Isspro and is Pre turbo.
Great video! Keep them coming. I am a guy people would call when they had mechanical and other problems. As I age I find I have forgotten some things. So I started writing down things like this, I am now around 400 pages and a few videos of information. Yesterday I had a problem that I faced many years ago and was trying to solve, when I blindly started working on it, it all came back to me, and I added it to my book. About 50 years ago I worked on a job with an old guy who soon retired. He told me of the hazards on the job. About 20 years ago they sent a crew to work on it, but no one advised the crew of the dangers. Two people needlessly died on it! Please write a book or have these videos accessible for future generations.
I'm a mechanic myself and I have to say this was a very correct and informative video and I want to thank you. Now a little bit of creating confusion: engines running rich can actually have a cooler EGT sometimes depending on "variables"...
Indeed they can. Variables tend to be more on the extreme side and thus not very common.
I know with gas engines they run hotter when the mixture is lean
@@GenesisRC That contributes to the conversation how?
Cool with fuel or cool with air (lean of peak EGT)....hard to do with an over the road diesel. I'd love to do some testing with adjustable mixture control (injector duty cycle) and see if you could actually get a big diesel engine to run lean of peak (with an accepted 4 to 6% loss of power).
Great video Josh! Shows why a pyrometer is so important!
I’d like to agree with you. You’re saying more air less fuel will reduce egt. I use to drive a Mack r686 with a 300 thermodyn. On an uphill climb, if I was close to the crest and it wasn’t worth changing down, I feathered the throttle at around 1200rpm and the torque would really kick in and carry me over the crest. At the same time I had to watch the pyrometer and it climbed very quickly from a normal running temp of around 780-800. I always allowed the temp to get to 1200 degrees but very little more. If I timed it right, that extra surge of torque would carry me over the crest and the temp then would drop.
So what I was doing to get this result by feathering the throttle was actually leaning out the fuel/air ratio. It worked well and that engine gave me 1247000 miles before rebuild.
As a marine engineer on tugs we was always taught to not worry about EGT on the pyros I’d they generally all somewhere near each other. We was taught peak pressures of each cyl was the important bit.
I actually did a test one time where I installed both a pre turbo and post turbo pyro to see what the difference would be and I found peek to peek is pretty close within 100* on a long hard steady pull. However the pre turbo is much more reactive. It will react very quickly where post turbo is much slower to come up so you may not see true peeks till you have been pulling steady for 30-45 seconds.
Great info, some other advice I've heard about "peak" EGT is that a high brief peak is fine because it takes some time to heat soak into most components (turbo, manifold, pistons). Exhaust valves probably the main exception as they're small and light. So you can have a high brief peak but a lower sustained peak - and having a post-turbo figure to stay below is sounds like it's enough for most people.
very interesting!
unrelated question... was literally just watching your old video on Jake trouble shooting.
in the oem side you diddnt mention switches on clutch or brake. my 3406e Jake just quit working .
I have an old Pete and use your channel a lot. lol
I appreciate what you're doing 👊🇺🇸
Jake Brake in order to activate, engine has to be under 1,000 RPM's. Clutch switch was to be in the off position. Programming of the cruise could be manual, latch or coast, which affects Jake Brake.
So first thing can you raise engine at idle with the cruise switch?
That was a very good explanation on how it works. On the 3406a and b's 1200 was the hottest we took them with the fuel turned up, back off the pedal
The best as usual. Wish you lived near me. Would be great for my truck. 👍🏻
I have driven trucks with a pyrometer, and I was taught that when pulling a steep grade. a person can melt down the exhaust side of the turbo charger starting around 1000°. and can burn down the whole engine. meaning melt down the pistons causing catastrophic engine damage at around 1300°. ideally a person should try to operate the engine at 900° or lower. to decrease the the chances of catastrophic engine damage. by not forcing the engine to lug and or pull so hard on a a steep grade. even to the point a person has to shift to a lower gear. to keep exhaust temperatures in a safe operating range. and if you don't have a pyrometer coolant temperature applies the same way. and a person shouldn't shutdown a turbocharged diesel with exhaust temperatures around 800° or higher. because it can cause damage to the turbocharger. these perimeters can vari some between different diesel engines. and I have had really good success providing I stay within these perimeters. in my many years as an OTR truck driver.
TIT
MP
Turbine inlet temperature and manifold "pressure" are what pilots are taught to observe and adjust as needed, about the same as you explained.
As the exhaust gasses pass through the turbo, they do work, expand and cool.
The exhaust gas (any gas for that matter) will naturally cool with expansion. (Eg Charles' and Boyle's law)
The temperature difference between inlet and outlet of any engine, turbo etc, is a direct correlation with efficiency-cooler exhaust -more efficient.
Check out the exhaust scavengers on super constellations.
Nice presentation you gave.
All good info. High get can also be from bad wheel bearings or bad calipers causing resistance increasing the load.
this guy is something else!!! wish we had one like that for detroits
Took me a while to finally figure out mine in my 2001dodge 5.9 2500 ,, larger intercooler, better air cleaner, better injectors, larger radiator, updated exhaust manifold plus my truck tow button .
The solution was engineered to be $$$$$$$$&&&&
In the summer, back in the day in a '79 Pete with a not stock Big Cam "400" Cummins, 15 over and 4.11s with tall rubber, from Missoula to Butte on I-90 (essentially all slightly uphill) I made myself stay in 14th gear at 2000 RPM specifically for reasons you mention here. Keep in mind the speed limit was 55 and, in that gear at 2000 RPM I was doing 62 mph. I preferred to run in 15th at 1600 RPM but, to me, there is nothing worse on an engine than essentially lugging it in summer heat for two hours. Could I have upped my speed (and therefor engine RPM) in 15th and done 70? Or 75 mph? Sure, that "400" would've easily done that. But I was conscious of fuel mileage and Montana cops loved looking for speeding trucks preferentially. Hell, they still do. Great video. Oh, and I always turned my fan on in the summer prior to climbing Bozeman, Cardwell, Homestake, Lookout, 4th of July, Vantage, and Snoqualmie. Everything stayed cooler including pyro. Did all the above with 3406A 400s as well although they didn't run as hot of EGT at lower RPM as the "400" Big Cam.
Very relevant and interesting comment. I was driving up 4th of July pass a couple weeks ago.
Yep right down around that curve
I've been always told by those in the automotive diesel world, not exceed 1200⁰F on the pyrometer for EGTs. If you are going to install one, do it at the manifold, pre-turbo.
I got a 97 7.3 all people give a stink eye ... my truck starts every day and I can diagnose under a tree they get 12 thousand dollar shop bills. They don't make em like they used to
This is the way
Always heard that you can bet around 300 cooler post turbo, reason people do post is less likely the sensor will melt off in a high temp situation and destroy the turbo
I guess 1600 wasn't so cool on my old turned up 1.6 VW turbodiesel, but it lasted for 3-4 yrs and got swapped into something else.
My pyrometer probe is installed in the manifold of my 6.7 cummins. So far everything seems okay
Been watching you for awhile now and I really enjoy your content. I been working on gassers for 50 years and now I’ve got a diesel I can work on. Pretty simple, pretty much the same as gas but much bigger and much much heavier. Keep up the great work.
Thank you for the video. It would be interesting to mention why Diesel engines can run very lean with high temperatures; whereas, gasoline engines if run lean at full throttle are thought to start to burn metals such as aluminum!
Thanks!
Thank you.
Shout out to Mack for still offering a Pyrometer from the factory.
Every modern emission engine has EGT probe. But if your engine is stock you dont have to care.
As an engineer that has done dyno testing with an IndiCom2 and the older IndiMaster dating back to the 1980's, I can say that the max intermittent exhaust temp is 1350F at the exhaust port. That is when the exhaust valves are chemically damaged and the manifold studs, bolts, and manifold castings are chemically damaged. We do have different temperature limits for high output military engines, but nobody here is using those engines. Also, the military engines have a small-small life before rebuilds, MUCH smaller than a commercial truck.
Excessive turbo boost messes up exhaust temps. Degraded injectors with shifted timing messes things up. DPF restrictions and poorly mixed EGR messes up things.
Turning the cooling fan on won't really help that much. I've been required to add the FMEM of a severe derate to get those exhaust temps down. Usually management gets angry with me when I force a derate.
What do you mean by intermittent. 10-15seconds? a minute?
Always enjoy your video. Thanks 🙏 all of time for your information SIR 👍
Really good and very professional explanation, is actually talant to explain difficult thinks sumply. And that can be done when You really understand the topic. Awesome 👍🏆
I have experience with both semi trucks and diesel powered pick up trucks, and I have noticed this. In the semi truck world, you are correct 98% of the EGT probes are installed post turbo. However in the pick up truck market 98% are installed in the exhaust manifold. Personally I like the exhaust manifold installation better because I feel it is more accurate. It is a general rule of thumb we tell people that you can run them at 1250° all day long without a problem but temperatures over 1300° should be limited for extremely short periods of time.
New trucks have a lot. My Colorado has I think 5 at various points in the exhaust. You can read them all with an OBD scanner tool and they get significantly hotter during Regen, as expected.
@5:24 - Killer graphics dude. 😁
My father bought a Kenworth in 1999, with a C-12 Cat engine, and right from the beginning it had really high exhaust egt. It destroyed 2 exhaust manifolds and 2 turbos in 12 months. Cat eventually admitted the engine needed a bigger,different part number turbo. Once they did that, the egt dropped a lot, turbo boost improved and the engine pulled a lot better, and it stopped destroying manifolds. What they couldnt fix were the crank angle sensors that randomly failed every month or so..........
Gas turbines has an EGT.
Starting those thing will get the egt to ridiculous levels as the injectors start pumping fuel to the combustors and the igniters tries to light up a fuel rich system. Until such time that the compressor can deliver correct air to fuel ratio that the egt slowly climbs down at idle. At full thrust the egt can move a little bit as very large amounts of gas pass through the exhaust that it has little dwell time to raise the surrounding temperature.
Pretty awesome destruction of the week. Not the usual subject. It's a smokin hot fan😆🔥👍💪
Love your channel! Good info & no BS! We pulled a D21 Allis Chalmers in heavy diesel class. Twin compound chargers. Pull pyrometer in before bottom charger and it was about 1850. Put another water nozzle in and got it down to around 1725. Ran motor at about 4500 off the line so it pumped a lot of air. Burner 4Qt fuel and 5Qt of water in 15 Second pass. Never melted a piston surprisingly! 😅
I love the videos I learned a lot watching them keep up the good work 👏👍
Thanks for watching. If nobody watched them I would stop making them.
I like your videos. I'm cat mechanic and it is good information. Keep the videos going. It is good information
My grandpa always said, keep the motor spinning when climbing hills. I keep the Pyro below 1000f and coolant below 210f with fan On way before starting the climb. When oil temp shows 220f, I split gear down to keep Temps down. I also don't gear up as fast to keep Temps down especially when it's hot out there. One thing that did throw me was fuel temp. Motor threw a code and derated motor on me wich caught me off guard. It was 95f overnight in Phoenix the night before and I left engine running with the a/c. So half way up the hill on I-17 I sat with hood open for over an hour. My local cat shop gave me a cheat sheet of all the codes years back, and found fuel temp went above 160f. Guess I never thought of fuel temp in summer, but I watch it in cold weather, so I don't get stranded in the middle of nowhere when filters might plug up.
My old '93 that had a 3406c in it didn't care how hot or cold it was. It ran. This '06 c-15 on the other hand is quite finicky. Seams sluggish under 40f and again above 80f outside temp. I wish I had my 3406c back.
We used to figure 1200* before the turbo and 900* after. Better materials in newer engines may allow more heat. If you burn holes in the pistons, your exhaust temp is too high, and that happens on both old and new engines. The reason for putting the pyrometer after the turbo is that if your sensor breaks you don't ruin your turbo. Over speeding or lugging your engine will raise EGT, some engines like Cats allow you to exceed full rated speed which causes more heat. A lug condition exists when you cannot accelerate to full rated rpm.
Exhaust temps can be found in TMI under the DM/TM number.
ENGINE SPEED RPM 2000, ENGINE POWER BHP 425, ENGINE TORQUE LB.FT 1,115.93, ENGINE BMEP PSI 188.26, FUEL BSFC LB/BHP-HR 0.34, FUEL RATE GPH 20.31, INTAKE MFLD TEMP DEG F 116.78, INTAKE MFLD P IN-HG 42.35, INTAKE AIR FLOW CFM 1,159.03, EXH MFLD TEMP DEG F 959.72, EXH STACK TEMP DEG F 753.62, EXH GAS FLOW CFM 2,600.57.
MBN's was the hottest I have seen on the dyno. Seen stock engines hit 1200 F in the stack.
Rule of thumb on coolant temp., is engine temp will be 110 F above ambient temp.
TMI has saved my ass so many times. All sorts of great info on there.
You are so knowledgeable and versed
Another thing to check if you have a high egt, make sure your injecter numbers are correct. Had mine read and the proper numbers put in the ecu, since then my pyro number has not gone above 900 degrees, even when pulling hard.
Trucks working in the field can suck straw and grass debris in to the aftercooler and radiator fins causing lack of air flow.
The front of the aftercooler may look clean but there can be debris stuck up in between the two as I have experienced, all of this increases the EGT. If you suspect the above it definitely pays too remove the aftercooler and thoroughly clean the radiator fins.
When removing the cylinder heads you find cracks in the top of the pistons you can be sure the EGT has been too high.
My f250 got to 2000 when pulling the camper to Tennessee. Ended up replacing up pipes and manifolds. Never see that again. Guess it was a slight restriction in the exhaust. I understand this video is directed towards the big trucks but it was still a diesel. Have a ram with the Cummins and I have only seen just over 1,000 degrees in the exhaust.
I second your comment. I have a 6.0 F-250 and I peak around 2,000 degree for very short periods of time. I have my warning light on the Edge display to light up at 1250 degrees as a safe temp. But, a lot of fuel, a lot of boost, and load... It will peak above 2000.
My 97 7.3 I'm getting ready to install a probe. I might later look to intercooler it running 180cc injectors and slightly larger turbo 3inch down 5inch straight pipe and s and b air box and chip
Interestingly the temp limit for my Lycoming aircraft engine (gas) if turbocharged is 1400F. Non turbo engines try to operate about 50D below max (achieved at optimal mixture) most run rich of peak others run lean of peak. I generally lean to 1400 and leave it there, the engine runs happy, and I don't have to continually monitor it, sparkplugs last a long time and don't need cleaning.
I find your videos very interesting you should do a video on turbo blankets exhaust wrap and blocking egr valve do this help a diesel engine?
I ran a tuned 1.7L Fiat Punto TD for over 170,000km on waste veg oil with a 2.1 bar boost, enough fuel flow to beat the 140cv Golf TDI during accelerations, and it reach almost 980°C/1800°F as pre-turbo EGT.
Maybe I was pushing too hard...? 😂😂
I have a pyrometer pre and post turbo on my kenworth. It has a 3406b with a s410 75/96 inducers. My post turbo gauge has never been over 650*. My pre turbo gauge will read anywhere from 400 to 600* over my post turbo readings on heavy pulls. I try to always keep my pre turbo temps below 1200 degrees.
my dad always told me to back it out when you get close to 1200, i’m gonna guess because no one wants to find out what happened higher than that.
It takes a while ,I ran a VW 1.6 turbodiesel with about 35psi of boost for 3-4yrs and saw 1500-1600 often.
I own a freightliner Argosy which has a series 60 detroit non egr. We put a new head and cam in 6 months ago. Top wasn't completed correctly. Thus caused the backing plate on 3 turbos to let go. I keep taking it back down on power. Pyro climbing up over 550degs center grade. On the third turbo replacement they finally started to look at what was going on. All the intake valves where super tight. My egt is post turbo so can only imagine as to what temp was coming out of the cylinder head.
As a young man I was always told 1200 was max. That was if the probe was after the turbo. I have a 07 ram Cummins with 500k and the pyro can hit 1350 with the probe before the turbo. This is controlled by the stock computer. I put a boost fooler on and it Makes 8 lbs more boost and dropped the temperature by 100
My running temp at Hwy speed 800-1000° I stay under 1200° on big climbs I will turn off the over/d and drop to 55mph if I can’t . Mounted In the middle of a Stainless exhaust manifold with compound turbo 1997 6bt
Good video. I am just a little disappointed that you missed the most common cause that I have run across in 20 years of driving trucks. I have seen as much as 250* drop from tightening loose clamps in the air-to-air system. Do not assume that all drivers know what is loose and what is too tight. I have also seen similar issues in cooling systems. A lot of people don't understand what a cold leak is.
I used to tune engines for OEMs and now operate a 3126B that I have an EGT on and have observed its behavior. A few points:
- Turning on your cooling fan will also increase the horsepower required by the engine a great deal (especially at higher RPM). You still have to produce the same horsepower to go up that hill, but the fan will then create an additional demand. It might lower your EGT (due mostly to more air through the CAC), but it may not.
- Freer flowing exhaust will help reduce EGT
- A scoop of some sort that helps increase the pressure to the turbo (albeit slightly) will reduce EGT because the pressure ratio the turbo then has to create (manifold pressure/ambient pressure) will decrease slightly. Believe it or not this can make a significant difference depending on how bad your air intake setup. I put a scoop on my RV and it reduced EGTs by around 100F.
- When you climb that mountain and have a wastegated turbo, your EGTs will increase as you go higher because the wastegate will have to close more to create the same airflow, and that increases exhaust manifold pressure, which increases temperature (if you have an exhaust brake as opposed to jakes, when you turn on the exhaust brake, which closes its butterfly valve, you'll see an increase in EGT from that as well)
- If you're installing a pyrometer, it really is best to do in the exhaust manifold. A lot of people are afraid of drilling the manifold and getting bits going through the turbo. This is a risk, but in reality it's not too likely of a problem if you put grease on the drill bit and take your time. It may take multiple attempts (I also started with a pilot hole followed by the full sized hole). Also grease on the thread tap. No issues. This gives you the "real" EGT. I agree that 1400 is a good limit, I use that as my absolute limit, but generally try to keep it below 1200 in the flatlands and 1300 in the mountains.
I always hit my fan switch and keep my RPM at a minimum of 1500 RPM when pulling a hill loaded....exhaust temp stays at 800° or 850°... No fan and under 1500 rpm my truck will be at 1000° in seconds. Stock 6NZ.....seems more sensitive than it use to be.... Thinking I should get my CAC checked and do an overhead.
A tuned engine that's pissing fuel smoking all over the place will cause high egt. Clean up the tune and adding a turbo properly sized will reduce egt. Also better more efficient after cooler. If you don't want a bigger turbo getting a larger ar. exhaust housing will also help.
I have a 1992 7.3 IDI in the vehicle and 2 as backups in the garage. I don't play silly emission games.
I have a 3176B with pyrometer in the manifold 30 lbs of boost foot on the floor up hill in overdrive 1200-1250 is the most I ever see. On my duramax had pyro before and after turbo would see 100-150 degree difference. The longer the grade the closer the temps get to each other till they would be the same.
Just an fyi that temp is what they recommend. If you measure any stock brand new diesel engine they see egt temos of up to 1700 and some as high as 1800 in stock form when hauling loads in normal driving. The engines run fine as we all know that they do. It isnt until we install gauges that we try to start changing our driving habits and asking what we are doing wrong and why its so hot in reality nothing has changed. We are since, informed of what the engine has been seeing the entire time. 1800 Is more realistic as far as limits in egt go.
I seriously wish you lived in Georgia man! Took my truck to a cat dealer who replaced my entire fuel system and I mean literally the ENTIRE system on my rebuilt 3ZJ ! Yet under a hard acceleration my fuel pressure drops to 5 psi !???? I've replaced suction lines myself, replaced hand primer pump, transfer pump, pickup tube, return line orifice... finally have idle fuel pressure higher but fluctuates between 37 - 45 psi yet still under full throttle it drops to 5 or 10 psi, sometimes zero psi fuel pressure... nobody seems to have a clue what's causing this and at this point I'm about to put an electric in line fuel pump on this thing in hopes that I can maintain pressure when driving ???
The hard max temperature for EGT is due to the metallurgy mostly the turbine sometimes the valves, it can and is exceeded by the off-road boys spewing smoke, but that's momentary and does not allow for heat soak and they don't care so much about rebuilds.
Running comfortably close to max with an old diesel makes it go like stink.
I'm thinking the temperature given as the max is due to the metal becoming weaker at that point, which is why it doesn't matter what brand it is anymore. Unless they change the metals used to make the engine, you will have issues at those temperatures. I have heard that diesel engines love the heat, and its only limited by the actual metal of the engines. I'm sure there can be some alloy that can take a lot more heat, but you also have to consider cost, and strength. Also, no reason to use something more expensive when what is being used is working.
Those pistons are aluminum....anything above 400F the strength starts to decrease dramatically. Oil cooled undersides and proper ring/land clearances as well as piston to cylinder clearances all help reject heat into cooler regions.
I had a cracked intercooler (boost leak) pic hat skyrocketed my EGT’s
I've seized a turbo that heated mine up too. Same thing when a boost hose busted.....had to really baby the engine to get home.
my question is simple...what is the temperature of the air being compressed in the cylinder before the diesel is introduced?..
I got a 78 r modle mack with a 315hp mack e6 and on the dash it has a sticker from the factory that says do not exceed 900° F if so downshift to the next gear.
Are most Mack pyrometers are mounted after the turbo?
I got to get the plug out so I can install my probe. When I had my 7.3ps turbo replaced I drilled the new y collector drilled for a probe right before the turbo since manifolds are still good. I just got new tunes trying to clean my exhaust up
What actually EGT is point it, is how close your engine is running to the DETONATION.
1300-1400F is actually mean your engine is close to the detonation of fuel into cylinder, what can occurs to damage of piston and rings.
Lol wow!
Very Adept, Big Thank You for taking the time to make these videos, and for such useful content, You are or have already built a great Library. I've been following for several years now and I, Introduced your channel to friend who has a Cat 3406E and he has used Your content to save himself quite a bit of $$ by tackling things himself when he is able to. Thanks again, and myself I, have a 2005 6.0l Powerstroke and yes I, did a no no and had a Boost fooler installed so at times I,will shoot The Boost past the 26.psi factory cut-off, and I, ran it for a couple of years prior to having a EGT setup Installed and Living in Arizona and towing a 5th wheel up to the 7000 ft. Level I,was lucky that I,didn't melt that motor in to a pile of Molten metal. And I've starting to believe that I was dealt a good hand and have the elusive Unicorn 6 liter Powerstroke still has the factory head gaskets and the Dastardly head bolts. Knock on 🪵.
And again Thanks for all that you do for The Diesel community!
14:14 - the waste gate on my 550hp. 2WS Cat is disconnected. When I reconnected it, the EGT’s actually climbed higher, quicker, than disconnected.
Needless to say, I run it disconnected for lower EGT’s.
More boost, but not adding extra fuel will push more air through the engine. Will increase cylinder pressures, but lower EGT temperatures.
I blew the head gasket on a 871 cummins that made a lot of boost and ran about 600 degrees post turbo in a hard pull it had a hack tune in it found a good tune that lowered my boost but upped my egts to about 750 post turbo truck runs way smoother and efficient. And so far has ran a lot longer lower egts and high boost is not the answer unless you engine is built for it
Wait, are the higher RPMs cooling the temp due to a leaner mixture or because of decreased loading?? I thought a leaner mixture burns hotter under load not cooler. Increasing the RPM in effect is supposed to reduce load thus reduce the required air/fuel ratio..so even if you're traveling same speed the heat produced from the fuel mixture is also less. So I imagine running more fuel under load reduces the volumetric efficiency even further, reducing the amount of burned mixture thus reducing temperature.
Diesels typically run very lean to begin with. So adding air (let’s say by downshifting and bringing rpm’s up) to this already lean condition won’t add heat it will only cool. Adding fuel to this equation will however add heat because there is an abundance of air to burn it.
Correct, even when a diesel is overfuelled to the point of smoking, the mixture is still lean by gasoline standards. Also remember a diesel compresses the air by itself and then adds the fuel, so you don't get the charge cooling effect of a rich gasoline mixture.
To me 1400 degrees is way way to hot and I try to stay 1200 degrees and lower and can be done easy just drop a gear. I bought my first Dodge 1992 12 valve and when out west in the hills I just watched my water temp gauge and normal temps is 1/4 on the gauge and when it would get to the 12:00 a clock on temp gauge and temp would drop to normal which is 1/4 on gauge and I was pulling a 25’ camper and if I would set my cruse at 72 mph and that little cummins would just walk the dog up and down hills , but that’s what worked for me .
Would adding a cooler on the fuel line help anything? Maybe increase the life of fuel injectors or pump? My fuel tanks in this Texas heat feel like bbq pits!
Good idea.
Single fuel tank trucks needs a fuel cooler. Running low fuel in the tanks causes problems as well. So a fuel cooler no matter what helps and will add some life to your EUI's. Have seen EUI's fail on the dyno when fuel temp hits the 190 F range.
Why? Fuel is at its coolest coming from tank. What would be benefit of cooler?
Fuel is also cooling the ECU
@@kenmeuse2226 My tanks get hot and fuel is warmed by return after hours in hot weather.
What’s your favorite Cat engine for road tractors ?
As per all the Cat training material I've seen. As a rule of thumb, the exhaust temperatures are going to be 3 times higher than the intake temperature when it is measured in Celsius. I've noticed this to be pretty close when doing the OEM industrial audits I've performed.
Are you sure that isn't Kelvin instead of C? It seems reasonable for K, but I don't see how you'd ever get an EGT of under 100F when it's 50F outside.
@@wcvp Cat does all their measurements and test specs under 100% loaded conditions with the exception for EPG applications where they publish numbers from 0 percent load to 100 percent load. Cat really doesn't use Kelvin, even though it makes more sense at times. All testing for the engineering, application, and installation testing, Cat prefers Celsius for some odd reason.
with higher temps the tensile strength of materials go down sometimes the half at 400°C compared to room temp.
I haven’t seen any official documents on it, but I’ve always heard 6bt Cummins are rated for 100% duty cycle at 1250° pre turbo temperature
Cummins is junk. The 6BT is in dodge trucks.
@@jaredmayer3960 “the 6bt is in dodge trucks” thanks captain obvious 🤣
When you have an engine a man owns let me know.
@@jaredmayer3960 And I’m supposed to care about your option why?
I have an old toyota IDI with a mechanical bosch VE pump. I'm getting a lot of smoke whenever I try to accelerate fast but my EGTs are relatively low, hasn't gone above 800F. I get injector rattle if I feather the throttle while cruising. If I pull the timing back the smoke goes down but so does the power.
I have a 06 freightliner century I just a week ago had a water pump replace and turbo VPOD at same time
the check engine light been coming on and had a fault code high exhaust temp.
and also had the other day the boost sensor replace and the EGR valve was replace and soon as I pull a very heavy load and the first big hill climb the check engine light came on there's no smoke coming from the exhaust I can hear the turbo more now after the EGR valve was replace and the fault code for the turbo comes up and also a High exhaust temp comes up the Freightliner in Montgomery, AL done all the work I'm just puzzle on what the problem could be the freightliner tech guy check the turbo and said the turbo is ok the turbo is just over 2 years old
Always a good video Apeman
Harvester had egt specs for their Ag engines in the fuel pump spec manual.sensing was before the turbo.old red wrench
Thanks bro. Very educative
Excelent video.. I am looking for information on the ipd overhaul kit (16.1) if it has the same quality as the original cat kit..
Ipd is one of the very best.
I have Exhaust T3 temperature 60 degrees over normal when doing Parked Regen on Volvo VNL.
My diagnostic computer said Regeneration completed 100%,but my truck is like I didn't di regen and ask again to do a Regen.
Volvo dealer said when is truck on Parked Regen,7th injector stop operation until that temperature drop on normal and than 7th injector again start work.
If was multiple times T3 temperature goes 60 degrees over and 7th injector stopped until temperature drops down.
Not sure what to do.
I thought to change that T3 tepmerature sensor but I don't know where is located.
Other option I thought to do is to update software.
Mine is a gas motor but one side of exsaust is 150 degrees hotter one side than other like right side colder could be o2 or fuel cross over or fuel rails but don’t have any idea why