Duramax EGTs

[Bill Hill]

We have a '04 Duramax CC 4X4 and are towing an S.O.B.(some other brand) travel trailer (we get our Montana next year!). I just weighed the entire rig before a recent trip and the truck came in at 8040 and the trailer at 5650 for a total of 13,690 lbs. We drove from Los Angeles to Big Bear Lake, about 150 miles and 6,000 ft. rise. I have a pyrometer that was installed early this year by STC Performance in Santa Fe Springs, CA.

I feel the engine is running pretty hot, with temps reaching 1000 deg. F on long freeway inclines and up to 1,300-1,350 for up 1 minute on mountain grades. When I'm not towing I can easily hit 1000 degrees by flooring it up a hill. However, my water temp and trans temp gauges are well within the normal zones: water temp never budges from 205 deg. F and tranny temp around 160-180 deg. F. I'm told by STC that these EGTs are typical for the conditions I've described. Also, I've already had the gauge replaced once as the first gauge was sticking, but it registered lower temps.

Does anyone have experience with EGTs? Do these temps and conditions sound right? Inquiring Minds Want To Know!

BH

[Montana_1152]

Bill,

I think there is something wrong with your gauge. I'm not very familiar with the Duramax EGT's, but I do drive the same freeways and have been to Big Bear many times in my Ford and do not come close to those EGT's. Last month, I pulled my 13,000+ Montana up the Cajon Pass and several others that were worse on my way to Yellowstone and I only hit 850 degrees at 60 MPH up the Cajon. I hit 950 on a couple of grades during my trip, but that was when pushing the truck pretty hard and for short periods of time.

My Pyrometer is mounted post turbo and 1100 degrees is my critical heat threshold. If it were pre turbo, that threshold would be 1300 degrees. Your gauge is indicating you are reaching and surpassing those limits. Is your pyrometer pre or post turbo?

I can not imagine there is that much difference between the Chevy and Ford as far as critical thresholds. Someone with a Duramax will be along to give the specs for the Chevy.

I would look into the gauge being faulty, and if it is reading properly, I would look into a bigger exhaust to lower those temperatures. The trailer you are towing is relatively light and you should not be anywhere near what you are registering.

[lightningjack11]

Bill,

My EGT pyrometer is installed in the engine exhaust pipe about 3 inches back of the Y pipe on my Ford. I think you will find that placement is important. In other words placement will affect temperature. Also you might get a zero shift on the gauge so you might have to subtract your initial reading from you hot reading.

Try to keep your pyrometer reading as low as possible. For example when your climbing a hill you will find that if you downshift it will lower temp. Try not to accelerate rapidly unless you need to.

My readings get as high as 1200-1300 when climbing. The recommended place for mine in the exhaust was 2 1/2 inches but due to the mounting I put it at 3 so my temps will be higher than one at 2 1/2 inches.

But I am still learning about it.

[Bill Hill]

Thanks for the input guys. I forgot to mention that the probe is installed in the exhaust manifold on the passenger side of the engine. I have been told that a larger exhaust will help lower the temp, but was hoping not to have to spend that money until we get closer to getting the new trailer. I think I'll take the rig back to STC and have them check the gauge out.

Thanks,

BH

[NJ Hillbilly]

I put on the Banks Monster exhaust and the temps went down a little but they do recover faster when they do increase.

Your readings are well within what I see with mine. The gauge gets a very accurate reading since it is getting hit by the rear clyinder. Those who see 950 max or so are measuring post turbo where the readings are 300 deg or so lower.

John

[jerryb]

Post turbo 1250 is max, pre-turbo no problem.

[Northstar]

Thanks for the postings. Great info to have. Happyrving......

[Montana_1152]

This is from the Banks Website:

"So the big question is, what constitutes excessive EGT? If everything is working properly, 1250º to 1300º F. is a safe turbine inlet temperature, even for sustained running, mile after mile. Above 1300º F. things start to get edgy. EGTs of 1350º to 1400º F. usually can be run for short spurts of less than minute or two, but it’s not recommended. Remember, excessive EGT damage is cumulative. Over 1400º F., you’re gambling against a stacked deck and it’s only a matter of time until you lose. The higher the EGT, the shorter that time will be."

There is a whole article related to this: http://www.bankspower.com/Tech_whyegt.cfm

[jerryb]

The only way to get EGT's too high even with mods is by lugging the engine, if you always keep rpms up and don't use max power for extended time you will not have a problem.

[sreigle]

Mine is in the exhaust manifold and the readings are similar to LightningJack's, maybe just a hair lower (no more than 100 degrees lower). I agree that if your sender is post-turbo the readings will be much lower, similar to the numbers you are seeing. I've been told never to exceed 1270 degrees so at 1200 I back off the throttle slightly. I've found just a couple of mph can bring the EGT back to a more comfortable level. Mine only exceeds 1200 on grades of 8% and higher. The Montana scales at 13,980 lbs.