E.G.T. proof wanted
02-09-2008, 02:57 PM
#1
Registered User
Thread Starter
Join Date: Mar 2006
Location: somis,CA.
Posts: 342
Likes: 0
Received 0 Likes
on
0 Posts
E.G.T. proof wanted
I would like to see where cummins says something about the safe E.G.T. range. And how long it can be sustained.A link would be great. I know a lot of people have hit some high numbers, however I want to know if I can run at 1200* for an hour or not.
02-09-2008, 03:43 PM
#3
DTR's Toad Wrangler
Join Date: May 2005
Location: N 48 25.707 W123 21.887
Posts: 892
Likes: 0
Received 0 Likes
on
0 Posts
Here is a page you can look at
http://dodgeram.org/tech/dsl/Facts/96specs.html
http://dodgeram.org/tech/dsl/Facts/96specs.html
02-09-2008, 05:14 PM
#4
Registered User
The link above shows the spec at 1250 degres F. The pistons are aluminum and I believe aluminum melts around 1650 *F (You need to verify that...its from my bad memory). I have heard of running at 1200*F but I would not want to keep it there myself for more than 10 minutes or so. Too much heat and you get piston meltdown amd probably blow head gasket. I haven't tried it so its just my opinion. I'd be interested to hear others experience at sustained 1200*F towing.
Edit: Also keep in mind the 1250 F is a RATED HP. How would max EGT's be effected if you have higher HP than stock? Also, that rating is Pre-Turbo in the exhaust manifold.
Edit: Also keep in mind the 1250 F is a RATED HP. How would max EGT's be effected if you have higher HP than stock? Also, that rating is Pre-Turbo in the exhaust manifold.
02-09-2008, 05:24 PM
#5
Registered User
Join Date: Apr 2003
Location: Cummins Technical Center, IN
Posts: 6,564
Likes: 0
Received 6 Likes
on
5 Posts
The melting point for the 2618 Aluminum alloy used in many "high performance" forged pistons is only 950ºF.
The hypereuctic alloy used in most OEM pistons is a little lower, as far as I know.
EGTs and piston temps have very little correlation at all. I'm told that the EGT limit cited by Cummins is primary for the turbocharger, not the engine's internals.
Even with EGTs at 1200, your piston crown temps will be nowhere near that.
JH
The hypereuctic alloy used in most OEM pistons is a little lower, as far as I know.
EGTs and piston temps have very little correlation at all. I'm told that the EGT limit cited by Cummins is primary for the turbocharger, not the engine's internals.
Even with EGTs at 1200, your piston crown temps will be nowhere near that.
JH
02-09-2008, 05:28 PM
#6
Registered User
I picked this discussion of max EGT's from the dodgeram.org link above and here:
http://dodgeram.org/tech/dsl/FAQ/turbo_faq.htm
Here is an exerpt that might be worth reading and see what you think:
http://dodgeram.org/tech/dsl/FAQ/turbo_faq.htm
Here is an exerpt that might be worth reading and see what you think:
What is the max Allowable Exhaust Gas Temp?
Engine Load Exh Manifold Turbo elbow - Sustained* Turbo elbow - Peak
Torque Peak 1250° F 810° F 900° F
Rated Power 1250° F 950° F 1000° F
* Aproximately = 1250° - (10° x boost psi)
Exhaust Temp discussion form From the Cummins Mail list
Subject: Re: boost and exhaust temperature
Date: Tue, 4 Feb 1997 10:04:01 -0800
From: Blaine Hufnagle <powrlftr@ix.netcom.com>
To: cummins
At 07:24 2/4/97 -0800, you wrote:
> 1. Max boost is about 25 psi, and exhaust gas temperature (egt) is about
> 1200-1250 degrees (probe in the exhaust manifold, about 0.7" before the turbo
> flange). Are these correct? I have heard about the 25 psi before, but the
> egt is a lot higher than Josh Berman showed for cpl 1550 at 900 in the
> manifold.
This sounds AWFULLY high. Your turbo housing *should* be glowing red hot at these temperatures, as should your exhaust manifold. (Look at them after dark with no lights.)
Mack recommends that exhaust temperatures never exceed about 1000 degrees or so (below the turbo). The ones I've seen, when loaded 12,000 lbs over gross weight, will run "only" about 800 or so, under full boost of 28-30 psi. Mack also recommends that you never exceed about 1050-1100. They say to "reduce engine power or downshift" to bring down engine temperature.
> 2. What egt is safe max for instantaneous, brief, and prolonged periods for
> my cpl?
I'd say Mack's recommendations are pretty close to right on.
> What "safety factor" is built in here?
Absolutely none. Remember that most oil will burn at about 450 degrees (that's with a FLAME.) The turbo is oil-cooled. Even though it has a high flow rate, you can't take that much heat out that fast.
Indeed, the cast-iron turbo housing and exhaust manifold start glowing around 1150 or so. It is worth noting that the crystal structure of iron-base metals changes at 1200 degrees, and as such 1250 degrees (give or take a few) is the post-heat temperature of choice for tempering in the "quench and temper" process. (I can go into the metallurgy if necessary by request.)
This is perhaps the most important reason to have a cool-down period of three to five minutes at idle when you've come in and parked, especially after a loaded run. No-load exhaust temperatures are well under 300 degrees (the lower limit on Mack pyrometers). The cool-down time allows the moving exhaust gas to cool the turbine and housing, and the high oil flow will cool the rest of the turbo down to something a little less resembling Hell itself.
NOT doing so is THE fastest way to coke a set of turbo bearings.
Engine Load Exh Manifold Turbo elbow - Sustained* Turbo elbow - Peak
Torque Peak 1250° F 810° F 900° F
Rated Power 1250° F 950° F 1000° F
* Aproximately = 1250° - (10° x boost psi)
Exhaust Temp discussion form From the Cummins Mail list
Subject: Re: boost and exhaust temperature
Date: Tue, 4 Feb 1997 10:04:01 -0800
From: Blaine Hufnagle <powrlftr@ix.netcom.com>
To: cummins
At 07:24 2/4/97 -0800, you wrote:
> 1. Max boost is about 25 psi, and exhaust gas temperature (egt) is about
> 1200-1250 degrees (probe in the exhaust manifold, about 0.7" before the turbo
> flange). Are these correct? I have heard about the 25 psi before, but the
> egt is a lot higher than Josh Berman showed for cpl 1550 at 900 in the
> manifold.
This sounds AWFULLY high. Your turbo housing *should* be glowing red hot at these temperatures, as should your exhaust manifold. (Look at them after dark with no lights.)
Mack recommends that exhaust temperatures never exceed about 1000 degrees or so (below the turbo). The ones I've seen, when loaded 12,000 lbs over gross weight, will run "only" about 800 or so, under full boost of 28-30 psi. Mack also recommends that you never exceed about 1050-1100. They say to "reduce engine power or downshift" to bring down engine temperature.
> 2. What egt is safe max for instantaneous, brief, and prolonged periods for
> my cpl?
I'd say Mack's recommendations are pretty close to right on.
> What "safety factor" is built in here?
Absolutely none. Remember that most oil will burn at about 450 degrees (that's with a FLAME.) The turbo is oil-cooled. Even though it has a high flow rate, you can't take that much heat out that fast.
Indeed, the cast-iron turbo housing and exhaust manifold start glowing around 1150 or so. It is worth noting that the crystal structure of iron-base metals changes at 1200 degrees, and as such 1250 degrees (give or take a few) is the post-heat temperature of choice for tempering in the "quench and temper" process. (I can go into the metallurgy if necessary by request.)
This is perhaps the most important reason to have a cool-down period of three to five minutes at idle when you've come in and parked, especially after a loaded run. No-load exhaust temperatures are well under 300 degrees (the lower limit on Mack pyrometers). The cool-down time allows the moving exhaust gas to cool the turbine and housing, and the high oil flow will cool the rest of the turbo down to something a little less resembling Hell itself.
NOT doing so is THE fastest way to coke a set of turbo bearings.
02-09-2008, 05:31 PM
#7
Registered User
Join Date: Oct 2005
Location: pocatello, ID
Posts: 113
Likes: 0
Received 0 Likes
on
0 Posts
this is just my 2 cents. when i am sled pulling, I see egt's as high as 1775*. Driving down the highway with my work trailer, I run a constant 1100-1200* for 20-100 miles. Pulling up the hills around here, I see 1400-1500* up hills that are 2-3 miles long. I did this more times than I can count last summer and this last December I had the head off, and everything looked as if it were new. Cometics head gasket on now and still diong it. Cross hatching still on the cylinder walls, and no signs of excessive heat. All depends on how you want to drive and it you want to take the chance of melting something I guess. again, jmo.
Trending Topics
02-09-2008, 06:32 PM
#9
Registered User
Thread Starter
Join Date: Mar 2006
Location: somis,CA.
Posts: 342
Likes: 0
Received 0 Likes
on
0 Posts
this is just my 2 cents. when i am sled pulling, I see egt's as high as 1775*. Driving down the highway with my work trailer, I run a constant 1100-1200* for 20-100 miles. Pulling up the hills around here, I see 1400-1500* up hills that are 2-3 miles long. I did this more times than I can count last summer and this last December I had the head off, and everything looked as if it were new. Cometics head gasket on now and still diong it. Cross hatching still on the cylinder walls, and no signs of excessive heat. All depends on how you want to drive and it you want to take the chance of melting something I guess. again, jmo.
02-09-2008, 10:40 PM
#10
Registered User
Join Date: Jan 2008
Location: CHAMPAIGN ILLINOIS
Posts: 126
Likes: 0
Received 0 Likes
on
0 Posts
I Too Have Thought That Question. Alot Of Talk Goes Around But You Know How Facts Can Get Changed. From My Experiance, At Least With A 12 Valve Is That You Can Tow With Them Running Pretty Hot. I Will Use My Brothers Truck As Example Because That Is The One We Use To Tow Most Of The Time. It Is A 97 Ext. Cab 4x4 With 287,000 Miles. We Did The Auto To Manual Swap, 5000k Gov. Springs, No Plate, Gutted Afc, Full Cut Delivery Valves, 18* Timing And 300 Marine Injectors. Had A J.r. Adkins 55 Turbo On It Until He Blew It Apart. Any Way Thats The Mods And When We Tow My Truck To Pulls Or Haul Seed Or Chemicals, It Will Run 12 To 1250 Egt All Day Long. When You Pass Cars Or Hit Hills, It Will Bury The 1600* Pyro, But As Soon As You Back Off The Throttle, It Will Come Right Back Down. If You Can Get Out On The Highway And Run 75mph, It Will Cool Down To About 1050* With The Cruise On. Not Saying This Is Good Or Everyone Else Can Do The Same, But We Have Been Doing It For About 2 To 3 Years Since We Had The Truck. Tim
02-09-2008, 11:46 PM
#11
Registered User
I will raise another point here, if I may. On the 04.5 and newer, 600 series engines, it has been noted here several times, that a completely stock engine is easily able to reach EGTs of 1400 degrees while climbing a hill. I have confirmed this on an 04.5 truck I installed a pyrometer on. According to Dodge techs I know, more of these newer engines are failing than ever before. The question I have is are these engines any more capable of handling these higher temperatures than the older ones? The failures are telling me no, but I can't believe Dodge and Cummins are letting these stock engines reach these temperatures without having them built to handle it, such as a different alloy used in the pistons. I'd like to find out Cummins' opinion of the maximum safe sustained EGT of these newer engines.
02-10-2008, 09:50 AM
#12
Registered User
Join Date: Apr 2003
Location: Cummins Technical Center, IN
Posts: 6,564
Likes: 0
Received 6 Likes
on
5 Posts
IL Ram-- one capital letter when needed will suffice, thanks.
Torquefan--
The completely stock 600 engines that hit 1400 degrees are designed to handle it. They have different exhaust valves, different valve inserts, better piston cooling (via direct oil ports, not just random spray), and such.
Many of the newer engines may in fact be failing than ever before, but that doesn't necessarily have anything to do with the higher stock EGTs. Power mods for these engines can be MUCH more aggressive than for past engines. The HPCR leaves no room for error, and a malfunction that would previously cause a rough running engine will destroy an HPCR engine.
See the point?
JH
Torquefan--
The completely stock 600 engines that hit 1400 degrees are designed to handle it. They have different exhaust valves, different valve inserts, better piston cooling (via direct oil ports, not just random spray), and such.
Many of the newer engines may in fact be failing than ever before, but that doesn't necessarily have anything to do with the higher stock EGTs. Power mods for these engines can be MUCH more aggressive than for past engines. The HPCR leaves no room for error, and a malfunction that would previously cause a rough running engine will destroy an HPCR engine.
See the point?
JH
