Exhaust Temp? What is to hot?

[D-n-Tyke]

Making our first trip with our new (to us) '98 Discovery. We have been pulling some pretty good grades and they have been causing the exhaust temps to get up there. The previous owner put a power chip on the motor so that is adding a little bit more temp. The motor is the ISB 5.9 (non-53) and is pulling like a monster. I just don't want to hurt anythinig getting things to hot. When I was pulling my fiver with my durmax I never let the EGTs get higher then 12,500 deg. Is that still a safe temp with the 5.9?

[RustyJC]

I'm assuming that, since you're referring to a 1250 degF maximum EGT, you have a pyrometer installed in a pre-turbo location (i.e., between the engine and the turbocharger's turbine inlet). With that as a basis, you'll have lots of opinions regarding maximum sustained EGT for the VP-44 injected 24 valve Cummins.

1250 degF probably is a safe guideline. Personally, on my previous 2002 Cummins HO that was running an Edge EZ, Diesel Dynamics stage 2 injectors, 4" exhaust and modified air filtration (BHAF), I tried to keep it at or below 1200 degF on the long grades when towing our 5th wheel. At 1200 degF, we never had a problem. Others may think my arbitrary limit for sustained EGT was overly conservative, and perhaps it was - but I never had to walk home!!

I'm personally not a big proponent of Banks Engineering, but they do have a pretty good article on EGT - see HERE.

Rusty

[D-n-Tyke]

Thanks Rusty,

Yes the probe is installed pre-turbo (in the exhaust manifoild about 1-1/2 from the manifold flange right above the turbo inlet). I was seeing sestained temps of 1200 pulling the long grades, but would never exceed that. Just wanted to be sure the 1200 for a period of time would not do damage. Motor still runs strong just double checking.

[Dave1956]

On my 2003 5.9 with a complete Banks kit the max setting is 1200. Banks represenative tells me that the brain will not allow it to exceed 1200, but I watch it like a hawk anyway. I bought the MH used and the Banks was already on it. Mine will go right up to 1200 if I am climbing and really pushing it. I am learning to downshift and take things much slower.

[Triker56]

From Banks PowerPack Instructions.
Use your pyrometer gauge to monitor exhaust gas temperature (EGT) in the engine. At idle, exhaust gas temperature will be very low, perhaps only 300° F.

As the engine is accelerated for higher speeds with greater loads, the EGT will rise. The highest EGT will be seen under maximum load at full throttle, such as climbing a steep grade with a heavily laden vehicle.
Use caution if your pyrometer reading approaches 1275° F, with 1300° F being the ABSOLUTE MAXIMUM!

Exceeding these figures for more than a brief moment may cause engine damage. If the vehicle reaches maximum EGT under these conditions, downshift the vehicle to reduce load, or back off the throttle.

[spike45]

Quote:

Originally Posted by RustyJC Others may think my arbitrary limit for sustained EGT was overly conservative Rusty

Current ISB6.7 for RV rated at 360 HP per Cummins Global Customer Engineering Database engine data sheet that the Peak Torque EGT should be 971F at peak HP and 978F at peak torque. How is it that you would consider 1250 conservative? You are either over-fueling or operating in a high state of lugging. Increased EGT in the long run is detrimental to the turbocharger turbine and has been known to make the blade metal disappear!

You can have standard rating performance and long less trouble engine life or you can have over the top performance with less component life. Sorta like...."there are old pilots and there are bold pilots....there are no old, bold pilots."

I am just an old conservative engineer who does not get it why you want a race car this size.

[RustyJC]

Quote:

Originally Posted by spike45 Current ISB6.7 for RV rated at 360 HP per Cummins Global Customer Engineering Database engine data sheet that the Peak Torque EGT should be 971F at peak HP and 978F at peak torque. How is it that you would consider 1250 conservative?

Unless things have changed, Cummins publishes POST-TURBO EGTs. The figures I quoted were PRE-TURBO (see the 1st paragraph of post #2). There's typically 200 degF to 300 degF difference between the readings. Therefore, 978 degF post-turbo generally would correspond to 1278 degF pre-turbo - close to 1250 degF, huh?? As an aside, my 2002 Cummins HO ISB would hit 1350 degF pre-turbo when absolutely box-stock - without lugging.

By the way, I've worked for a manufacturer of large industrial engines, compressors and gas turbines for 37.5 years with most of those in technical and engineering management. We measure EGTs at each cylinder, combined pre-turbo and post-turbo, and 1250 degF combined pre-turbo is pretty conservative.

Rusty

[spike45]

Quote:

Originally Posted by RustyJC Unless things have changed, Cummins publishes POST-TURBO EGTs. The figures I quoted were PRE-TURBO (see the 1st paragraph of post #2). There's typically 200 degF to 300 degF difference between the readings. Therefore, 978 degF post-turbo generally would correspond to 1278 degF pre-turbo - close to 1250 degF, huh?? As an aside, my 2002 Cummins HO ISB would hit 1350 degF pre-turbo when absolutely box-stock - without lugging. By the way, I've worked for a manufacturer of large industrial engines, compressors and gas turbines for 37.5 years with most of those in technical and engineering management. We measure EGTs at each cylinder, combined pre-turbo and post-turbo, and 1250 degF combined pre-turbo is pretty conservative. Rusty

Enjoy the diesel hot rod, Rusty! I inquired of the Assistant Chief Engineer and consulted the QSOL Cummins website. Midrange engines do not have an EGT sensor but curiously enough they do have an EGT value that is calculated based on ECM data parameters from the intake air temp, boost, engine RPM, fuel delivery rate and EGR valve pressure (if equipped)....virtual reality! Data sheet temps are listed by Cummins as after the turbine or stack temperature.

[RustyJC]

Quote:

Originally Posted by spike45 Enjoy the diesel hot rod, Rusty!

Check my signature. My current ride is absolutely stock! I do miss the 347 BHP/762 ft-lb torque of the 2002 5.9L - as measured on a chassis dyno at the rear wheels (about 400/900 flywheel). The friends we sold it to are still enjoying it as they tow their TT or 5th wheel.

Gary, mine was a mild towing rig. I'm sure you don't want to know about the 10 second drag racers, the truck pullers and the dyno queens that are kicking out 800/1200 from a 5.9L Cummins. I'm sure, though, that some of the Cummins engineers sneak a look on the Turbodiesel Register and similar forums just to keep up with what's going on - in fact, Cummins just hosted a get-together for the TDR bunch at Columbus, IN.

Quote:

Originally Posted by spike45 I inquired of the Assistant Chief Engineer and consulted the QSOL Cummins website. Midrange engines do not have an EGT sensor but curiously enough they do have an EGT value that is calculated based on ECM data parameters from the intake air temp, boost, engine RPM, fuel delivery rate and EGR valve pressure (if equipped)....virtual reality!

They extrapolate post-turbo EGTs based on extensive test bed data. The 6.7L Cummins as used in the Dodge 2500 and 3500 pickups, however, has thermocouples in the exhaust that the ECM uses to manage the NOx adsorber, SOx and DPF regeneration functions. This post-turbo exhaust gas temperature data is available on the CANbus.

Quote:

Originally Posted by spike45 Data sheet temps are listed by Cummins as after the turbine or stack temperature.

Yep, post-turbo, as I said. Therefore, the 1200-1250 degF pre-turbo EGT is, I maintain, a conservative maximum for the long grades and is comparable to (or even less than) the post-turbo values you quoted.

Rusty

[Mr_D]

On our ISC 350 W/Banks Power Pak (I know, different engine) the electronics are set to de-rate the engine (cut back on fuel delivery) at 1300° or slightly lower. This is pre turbo temp.

[Triker56]

Quote:

Originally Posted by Mr_D On our ISC 350 W/Banks Power Pak (I know, different engine) the electronics are set to de-rate the engine (cut back on fuel delivery) at 1300° or slightly lower. This is pre turbo temp.

I have the Banks Power Pack on my ISB and nowhere in the install manual or owners manual does it say it will de-rate at 1300º
Could you post where Banks has that information in your manual or on their web site.

From Banks Manual

Use your pyrometer gauge to monitor exhaust gas temperature (EGT) in the engine. At idle, exhaust gas temperature will be very low, perhaps only 300° F.

As the engine is accelerated for higher speeds with greater loads, the EGT will rise. The highest EGT will be seen under maximum load at
full throttle, such as climbing a steep grade with a heavily laden vehicle.

Use caution if your pyrometer reading approaches 1275° F, with 1300° F being the ABSOLUTE MAXIMUM! Exceeding these figures for more than a brief moment may cause engine damage.
If the vehicle reaches maximum EGT under these conditions,
downshift the vehicle to reduce load, or back off the throttle.

[Mr_D]

Quote:

Originally Posted by Triker56 I have the Banks Power Pack on my ISB and nowhere in the install manual or owners manual does it say it will de-rate at 1300º Could you post where Banks has that information in your manual or on their web site. From Banks Manual Use your pyrometer gauge to monitor exhaust gas temperature (EGT) in the engine. At idle, exhaust gas temperature will be very low, perhaps only 300° F. As the engine is accelerated for higher speeds with greater loads, the EGT will rise. The highest EGT will be seen under maximum load at full throttle, such as climbing a steep grade with a heavily laden vehicle. Use caution if your pyrometer reading approaches 1275° F, with 1300° F being the ABSOLUTE MAXIMUM! Exceeding these figures for more than a brief moment may cause engine damage. If the vehicle reaches maximum EGT under these conditions, downshift the vehicle to reduce load, or back off the throttle.

As I said, "On our ISC 350 W/Banks Power Pak (I know, different engine) the electronics are set to de-rate the engine (cut back on fuel delivery) at 1300° or slightly lower. This is pre turbo temp."

but just to please you here is the statement from the owners manual:

Quote:

Your OttoMind is calibrated to maintain a maximum EGT of 1300°F. The EGT may exceed 1300° for short periods of time during highload conditions. This is normal and EGT should return to at or below 1300° within a few seconds. If you find that EGT remains high for any length of time, check for boost leaks of a dirty air filter. If the condition persists, contact our technical service department at (888) 839-2700.

Here is the link to the owners manual for the Banks kit (that you could have looked up yourself) Check page 9