General observations on temp/boost

[JohndeereG]

While I am not new to the gauged diesel truck world, I am new to having gauges in my 03. Having read the post on proper shut down temperatures late last week. I decided to watch the gauges a little closer over the weekend.



First I would like to stir the $*it pot. For all of you folks who do not have gauges and think your truck doesn't get really hot when driving around town... your wrong.



I can hit 900 degrees just driving up the street from house. No I'm not standing on the pedal... No I'm not tached out... Yes I am shifting at around 2K rpm and I never went any higher than 4th gear.



(Different scenario) While preventing grandpa in his cadillac from passing me going up one of the typical 7% 4 mile hills here in W. Pa, I noticed the boost at 23psi and the egt at 1250 and climbing. OUCH I gotta get rid of this stock exhaust system.



Highway driving at 65-70 mph on fairly flat roads will yield around 600-750 degrees and around 4-7 psi of boost.



Final conclusion, our trucks do cool quickly regardless of driving conditions. I have found that downshifting cools the quickest (lots of air/little fuel) When idling through the parking lot here at work this morning, I was around 425 degrees. I let the truck idle down to 300 before shutting down (total time was less than 30 seconds)



For what it is worth

 

[ImagesThatSing]

Which of these numbers represents a problem?

"I can hit 900 degrees just driving up the street from house.



I noticed the boost at 23psi and the egt at 1250 and climbing. OUCH I gotta get rid of this stock exhaust system.



Highway driving at 65-70 mph on fairly flat roads will yield around 600-750 degrees and around 4-7 psi of boost. "







For us unitiated, maybe if someone could clarify the problem with a bit of defining detail. We have the facts here, but since they are not tied to the critical threasholds (the uninitiated don't yet have in their knowledge base) their significance is unclear.



What is the problem with 900*? It is unclear to me. And is there a problem with 650-700*?



I have read that aluminum melts @ 1300*, and the pistons are aluminum. That is straight forward, since melted pistons cause fully obvious problems, but do lower temps cause less obvious problems? And does that mean if the exhaust temp reaches 1300* that the entire engine block and contents are at that temperature, or does it take a while to reach that temp if ever?



We don't have gauges yet, and have read some stories that just driving down the road on a flat surface, unloaded, but with a few mile an hour headwind can be a serious problem. Can anyone clearly separate "Chicken Little" from Mr. Peabody. (Rocky & Bullwinkle).



Really, on one hand it looks like you can melt your engine with very little more than normal drivning, which is seemingly contradicted by the large number of diesels you see driving down the road with no such apparent maladies - further muddied by the observation that if this was such a huge problem, why aren't some form of gauges installed factory like say an oil pressure gauge is for the same reason - even with cummins demanding such a measure to protect their reputation. And if the installation of a boost is so important, and the installation can easily damage important components (the stories of the questionable techniques abound -- certainly risky at the least), then why isn't any attempt at even a nominal boost indicator included at purchase?



After all, most of the things we need are atleast offered as options e. g. tow packages.



One one hand we are told that you can ruin the engine with seemingly normal reasonable use, on the other hand the observable normal data does not support this position. (Many diesels apparently running fine without such expensive and closely monitored gauges).



Is this because it is assumed that the average user here @ TDR is pulling a lot of weight, has heavily modified his CTD, and is using his Dodge for a living commercially, pressing it to the max, or is it that it is just a sort of interesting topic, and fun to discuss after having invested hundreds of dollars in this accessory?



While this may, and probably does sound like foolishness to those veterans of diesel use and study, I would bet there are just a whole bunch of folks both as formal and informal subscribers who would appreciate a thoughtful, calm, informative, non "crying wolf" or isolated incident as evidence type explanation.



We have read in TDR magazine that if you want their help, the first thing they will ask is the data from your gauges. And for people who haul for a living I can understand the need for the data and this resource.



Do normal trucks, not bombed need gauges, or is this an abaundance of caution thing?



Retiring to the back of the room donning flame suit, and lowering visor now.

 

[JohndeereG]

In my opinion (which is just that), does the average person who drives their CTD in a manner that is not excessive, cautious of the load and the manner in which it is hauled/towed NEED gauges.





NO



I personally have invested around $250 for gauges because #1 I like the looks #2 I like to monitor what is happening under the hood (other than speed/gas my wife is like most drivers... then don't look at anything else) #3 Cheap piece of mind as I pull 12K of trailer/pulling tractor over the hills and through the woods of W. Pa.



In reference to your question of melt down. The "red" line of my EGT gauge is 1250. This is a short period of time and not sustained driving. Gauges and other "goodies" are sold as options. If you feel they are warranted then you have them available for purchase, you don't feel that way you can certainly ease off of the pedal and arrive at point B just like the driver with gauges.

 

[MattSt]

Where is your EGT probe located? I'm seeing about the same temps but with a chip on HIGH. So something is not adding up. I have mine tapped into the manifold right before the drop to the turbo.

 

[MCummings]

GSevison,



You are a smart man.



JohnDeereG,

When you saw 1250, Did you stay in it, and see if the temps continued to climb?



Where are you picking up your EGT? Your numbers do seem a little high.



BTW, When you are coasting,, (foot off fuel pedal) and your RPM is Above idle, there is NO fuel being injected, the EGT you are seeing is only residual heat that has been absorbed during cruise/acceleration, and your oil/water giving heat into the cylinders.





If you were to coast down a long hill, eventually you would see EGT of ~100*. If you want to test the theory out, Start up your truck, and before you really start to move your Water Temp off of the cold side,, coast down a long hill with your RPM around 2K, do not give your truck any "fuel" to maintain the speed, but let the truck slow down, and you will see EGT quickly fall to 100*, if you then "get on it" you could EGT of 800*+ within 1-2 seconds.



Many, Many Dodge Cummins trucks wil be used to tow heavy loads beyond reality, and will not have gauges, or any type of device to measure heat except for the water temp gauge. I sure hope all trucks do not see 1250 and CLimbing empty, otherwise, we may start seeing failures of pistons, and heads. The 2nd Gen S. O. trucks couldn't really get above 1,000* in a stock configuration, but the H. O. 's could see 1200*. running hard.



I'm curious that your EGT gauge may be lieing to you.



Just my $. 02



Merrick Cummings Jr

 

[JohndeereG]

Originally posted by MCummings





JohnDeereG,

When you saw 1250, Did you stay in it, and see if the temps continued to climb?



Where are you picking up your EGT? Your numbers do seem a little high.



I'm curious that your EGT gauge may be lieing to you.



Merrick Cummings Jr

I can't argue with the notion that the EGT gauge may be off. I don't feel that it is off that much. I have the EGT sensor just aft of the #3 cylinder prior to dropping down.



I should of added that when I saw the 1250 that was climbing a really steep 3 mile hill on route 28 between New Bethlehem and Kittaning. The pedal had been on the floor from the beginning. I took notice the gauge prior to slowing down for the turn in the road, so I can only speculate on the temps rising.



BTW, I was in fourth gear when I saw 900 degrees. Sorry for the confusion.

 

[MCummings]

Originally posted by JohndeereG

I saw the 1250 that was climbing a really steep 3 mile hill... . ... . The pedal had been on the floor from the beginning.

SO, under the circumstances, the truck was "fully loaded" atleast as far as the load on the engine is concerned.



Thanks for the details.

Merrick Cummings Jr

 

[Agades]

u guys use a lot of big words

 

[ttreibel]

Those numbers sound a little warm for a stock truck.



I recently had a chat with the guys down at Cummins North West about the need for EGT gauges on a stock truck. "Unless you plan on adding a fueling chip the B-series does not need one, just drive it".



I then asked about climbing grades with a heavy load again not needed and he did suggest not shutting off the truck right after the climb.



About oil changes he thought 7500 was to long to wait and suggested 6K for the frequency... . oOOppPs I am not trying to Hijack this thread.

 

[Fireman]

JD,



A 4" exhaust will help, so will a cold air intake. You should see a significant drop in EGT with the cold air intake alone, and the exhaust will reduce it further.



As a note, I see my EGTs fall rapidly when I back out off the accelerator. The needle on the pyrometer rises and falls almost as fast as the needle on the boost gauge.



I agree with the guy from Cummins, I don't think you would melt down a stock engine. If you are a worrier get a good air filter and 4" exhaust and then I am sure there would be absolutly nothing to worry about.



Fireman

 

[Johnstra]

If you do manage to get EGTs up to ~1250* range, shouldn't the water temp guage read high?



I don't have guages on my stock 03 and I climb up a 20 mile mountain road every day (from 6 to 9k ft)... I never see my water temp go over the halfway mark. I do give it a few minutes to cool when I get home though.

 

[JohndeereG]

Originally posted by Fireman

If you are a worrier get a good air filter and 4" exhaust and then I am sure there would be absolutely nothing to worry about.



Fireman

Originally posted by Johnstra

Johnstra

If you do manage to get EGTs up to ~1250* range, shouldn't the water temp Gage read high?

Fireman, I believe it was GSevison that express concern regarding the melting point. I did away with the factory air box and have my rig equipped with the aFe filtering system. I am interested in the aeroturbine system for the benefits and sound. I just would like to find someone near W. Pa that has one installed.



Johnstra, as I am sure you know the probe for the EGT gauge is mounted directly in the exhaust manifold. The reading on the EGT gauge would be "real time" sensitive when compared to how long it would take to raise the total cooling system temperature and be seen on the dash gauge.

 

[RJOL]

Originally posted by ttreibel

... I then asked about climbing grades with a heavy load again not needed and he did suggest not shutting off the truck right after the climb...

This is exactly why I like having an EGT gauge. I tow a 11K 5th wheel and I rarely see temps over 1200. But when I'm driving around in town with no load (speed limit is 25MPH) and drive up the hill to the local bank, my temp gauge is around 450-500. Many threads, on TDR, have said that if you routinely shut your engine down with temps over 300, you can cook the oil that lubes the turbo. In my experience 300 is easy to exceed, even in town at low speed, and no load.

 

[KLockliear]

Personally I think the new trucks (and this applies to the '03 6. 0l Frod as well as the new ISBe's) may run hotter than we want to see, as they are stock. This may be because of other things, like bigger oil jets under the pistons, different piston materials, etc.



Our '03 HO would get to almost 1400*F pre-turbo pulling a 14k 5er all stock. If Cummins/DC think that's safe, and put out a truck that will do that, I imagine they have done enough homework to determine that that much EGT won't kill it. That being the case, I recommend that all new truck customers put gauges on first and go see how hot their truck will get in stock form. Their upper EGT limit is then set as 1250*F or as hot as it will get stock.



If it will get to 1400*F stock, then modified as long as it stays below there, you are as safe as you were when stock.

 

[CROW]

Can I throw in a question? I do not have gauges, but pull a large 5th wheel with my 6 speed truck. Assume you are pulling up a long hill, engine is still pulling OK at maybe 1,500 rpm (if memory serves these engines make good torque all the way down to 1,4000 rpm) but you are fueling it pretty good. Are you better off, as far as keeping EGT down, to downshift to 5th gear or to let it run at the lower RPM? Or, does it really make any difference?

 

[Agades]

higher RPM = more air flow = lower EGT



lower RPM = less air flow = higher EGT



does that answer your question?

 

[MCharlebois]

temps

glad i ordered gauges for my STOCK truck-gauges exhaust-box-in that order

 

[JD SLVR 03]

Yes Tom it does make a difference. Lugging the engine in 6th at say 1500 you will see egt's climb very quickly. Down shifting to 5th you will see the egt's fall back down very quickly. Even though egt's rise quickly when lugging the engine, with my ez on level 6 and towing 7k I have yet to see it get into the red. As soon as you let off egt's will fall back down to say 600 or less. Like someone said before it rises and falls alot like boost does.

 

[rbattelle]

Well, I'm bone-stock and don't ever plan on any power enhancements, but I have a boost pressure, oil pressure, and soon-to-be post-turbo EGT. Eventually I will add pre-turbo EGT, and a slew of temperature gauges (oil, transmission, axle, etc). Why? Well, not because I need them! I drive around unloaded all the time. I'm just obsessed with monitoring every parameter I can.

 

[Diesel Nut]

I think these motors are alot tougher than everyone thinks. I have a buddy that has Doc Performance's biggest injectors and an Edge EZ in a 3500 HO 6 Speed with a 4. 5" lift and 35's and tows a backhoe, GCW 30,100#!!!!!!:--) And he is NOT nice to it!! No gauges at all and been that way for the last 12K miles. Not smart, grant you, and I wouldn't dream of doing it, but thats a hell of alot of abuse!!