EGT Temp

[jnelson]

Upon acceleration from a stop light with my empty gooseneck (8,300lbs) with the egt probe pre turbo I could easily hit 1300*. With my egt probe post turbo I can hit 1100*. As the amount of weight increases the higher the egt's get. This is gradual acceleartion up to 70 mph. Stupid rumor? No. Just an accurate gauge.



If anybody is "simple minded" I beleive it would be you harwick.

 

[Hokey]

JHardwick, this is interesting since I am stock and put my EGT probe post turbo to monitor cooldown temps. Where is this temperature data you are talking about? Do you have a link or reference? I have heard that Cummins says not to exceed 1100 post turbo but I have not seen that in any official document either. Why is the 3rd gen different than the second where the 300 degree "rule of thumb" was pretty accurate? What's so different about the newer engine that causes this wide variation in pre-post EGT? Not flaming, just trying to find out more. I understand the 12 valves very well but I'm a newbie on the new common rail engine.

I have EGT pre & post turbo set up in my 05 and normally see about 50* difference at highway cruising unloaded and have seen up to 200*difference when putting my foot in it before I can't look at gauges anymore and have to look where i am going :-laf . i think it just depends on the turbo you have and other mods and how much foot you have in it. I think If your running at more than 200-300*difference your turbo is about to become toast along with some other components. This is just my opinion but if you were just relying on a post turbo reading I would use 500* difference to play it safe better yet measure pre-turbo. having had both for awhile I would never measure post again although it has been educational but pre-turbo is more useful in my opinion. flame suit on :-laf

 

[rbattelle]

The thing with pre vs. post temperature is a strong function of how much work the turbo is doing. Heavily loaded uphill at maximum boost and 100% throttle, the temperature difference could easily be 500 degrees or more.



Sitting in the driveway idling at 0 boost the turbo's not doing hardly any work (plus the engine's not putting out much heat), and the temperature difference should be pretty small (50 degrees or less, maybe).



The more energy that turbine extracts from the exhaust flow, the lower the temperature on the downstream side will be relative to the upstream side.



I think that's what JHardwick is getting at...



-Ryan

 

[JHardwick]

The thing with pre vs. post temperature is a strong function of how much work the turbo is doing. Heavily loaded uphill at maximum boost and 100% throttle, the temperature difference could easily be 500 degrees or more.



Sitting in the driveway idling at 0 boost the turbo's not doing hardly any work (plus the engine's not putting out much heat), and the temperature difference should be pretty small (50 degrees or less, maybe).



The more energy that turbine extracts from the exhaust flow, the lower the temperature on the downstream side will be relative to the upstream side.



I think that's what JHardwick is getting at...



-Ryan

Thank You Ryan :-laf I guess that did sound a little pricky

 

[Dieselnerd]

I understand what makes the temperature difference between pre and post turbo. I find it hard to believe that on a STOCK engine such as mine that as long as you stay within the published GCVW limits while towing that you would ever see a temperature difference of 500 degrees. Modified? Maybe, but it's not smart to tow with the engine turned way up either. If I modified my engine I would measure pre turbo too, just to protect myself since I would be providing the engine warranty. Has anyone that runs both probes ever seen a difference of 500 degrees? Just curious...

 

[robert4570]

My 2005 is stock except for MBRP muffler. I run my EGT probe pre turbo and get 600 to 650* at 70mph. Pushing a grade with 8000lbs behind her have hit 1300. But most of the time 1000 to 1200* in those situations.

Edgemann,

If its not too much trouble could you post a pic of your gauge setup and the probe location . Also the 600-650 range cruisingat 70mph , figures are empty with no grade ?

Any concerns with going pre-turbo other than metal shavings gettin' in there?



Thanks

Robert

 

[650mphDiesel]

My EGT peggs past 1500* when I turn the ignition on!!! But I probably have a bad amp box.

 

[robert4570]

Hey 650,



What kind of EGT's you gettin' on them GE CF6's and talk about torque -. 63,000 lbs thrust each

Any mods that are FAA approved.

 

[FJfonda]

Bone Stock:



Towing 12,000 lbs up a hill steep enough where it won't come out of 2nd at 2800 rpm... . 1350 deg pre turbo on a DiPricol guage.

 

[jnelson]

Towing 11,000 lbs pipe and a 8,300 lb gn up US 287 out of Denver I got my egt's up to 1550* pre turbo bone stock climbing the grades. With with my egt post turbot the hottest I have gotten it with my Edge EZ on low is around 1280*+-.



That would be a difference of 270* between pre and post turbo temps.

 

[650mphDiesel]

Surprisingly, EGT on the CF6 at mid level cruise altitude and M . 85 runs about 700*C or 1300*F, but I think that reading is taken pretty far aft of the burner can. The high stage bleed air is pretty hot and can melt some metals including aluminum. If we get a bleed leak near the airframe it can cause big time problems as you would imagine.

 

[CAT 385]

I need to update my last post because I have now pulled a trailer, except w/ exhaust change the truck is stock, up Hesperus hill in Durango CO and I can hit 1530*. Obviously elevation plays a big role in the temps if jnelson his hitting 1550* in Denver.

 

[AlexWV]

Not to distract from the pre or post turbo argument but what is a safe, pre-turbo

temperature for extended durations?



An example from CA is going up the Grapevine at the south end of I-5.

 

[ECappleman]

Not to distract from the pre or post turbo argument but what is a safe, pre-turbo

temperature for extended durations?



An example from CA is going up the Grapevine at the south end of I-5.

I never try to keep it above 1200 pre-turbo on duaration and 1400 on short uphill grades.

 

[hummincummins04]

meltdown!!!!!!!

i built a 5. 9 at school this year had 375 injectors, bored 20 over, new cummins block, new cummins head, High performance cam, extreme flow delivery valves, and we came out with 440 hp and 1044 ft lbs of torque on the engine dyno and my teacher didn't unload the dyno fast enough and she hit 1690 degrees and melted piston on #4 cylinder. all the rest looked fine. but there was aluminum wrapped all around the turbo and dripping out the air ventilation system. But the school gets to pay to fix it for me.

 

[TCordero]

Keith,

I don't know about these 1400+ temps?? I am running near stock, pre-turbo EGT probe, AFE Stage II intake and a Magnaflow muffler. Just pulled my 28' 5th wheel from 2,000' to a campground at 6,500' on the flats 600-700, on the grades at best 1100. Take into account I take my time on these grades, most pulled in 5th gear @ 50 mph. I guess if I got in a big hurry the boost and temps would go up, but I have never seen temps over 1200 on my truck...

Tim

2004. 5, 4x4, LB, QC, 3. 73's, 6 sp, 28' Wander Wagon Toy Hauler 5th Wheel

 

[Scrappy]

Mark @ TST told me the 600's are safe up to 1400 degrees sustaines and the 555's are good to 1350 sustained. He also told me that he ran his truck on the dyno @ 1500 degrees for 20+ minutes and all it did was blow a intercooler boot.

 

[crobertson1]

Keith,

I don't know about these 1400+ temps?? I am running near stock, pre-turbo EGT probe, AFE Stage II intake and a Magnaflow muffler. Just pulled my 28' 5th wheel from 2,000' to a campground at 6,500' on the flats 600-700, on the grades at best 1100. Take into account I take my time on these grades, most pulled in 5th gear @ 50 mph. I guess if I got in a big hurry the boost and temps would go up, but I have never seen temps over 1200 on my truck...

Tim

2004. 5, 4x4, LB, QC, 3. 73's, 6 sp, 28' Wander Wagon Toy Hauler 5th Wheel

Try towing where there is very little air, like at 10,000-12,000 feet above sea level . When we go over to Winter Park or up to the Eisenhower Tunnel, I have a hard time keeping EGTs under 1400 degrees. We still have plenty of throttle left, but need to keep backing out of it to keep it "cool".