05' Duramax boost/egt readings

I'm new around here so please bear with me and thanks for any input. I have a stock 05' Duramax 3500 Dually on which I recently installed a pyrometer and boost guage. The pyrometer is reading off of the exhaust manifold (pre-turbo) and the boost off of the intake manifold plenum. I'm wondering if these readings sound correct to everyone. Normally I pull a 33' Toy Hauler, but this weekend it was a 16' enclosed trailer full of furniture. Generally the egt was 800-1000 and the boost was 10-12 on flat land at 75 mph. I did see 1200-1250 degrees and 20 on the boost for a while on a couple of pretty good hills (6 or 7 degree). Is this considered normal? Also, what should I consider the "danger" numbers to watch for. Thanks!

Time is an important factor in determining maximum acceptable EGT. The LLY/LBZ is rated for 1365 degrees F continuous and/or up to 1435 for 5 minutes or less. We've seen 1400 or a little more for completely stock LLY's during a Pull-Off here in Montana.

We also know that a Duramax can tolerate 1800+ degrees during a 1/4-mile run with lots of fuel and nitrous oxide, and for those willing to accept more risk. It's only there for a few seconds, which helps make it tolerable... :D

We've tried to include EGT readings in the various Pull-Off truck tests. :)

Jim

Just returned from a 1600 mile trip pulling a 25' flat bed gooseneck trailer. First 800 miles empty and added a 4000lb press and came home. Total weight was around 8000 lbs with trailer and press. My egt were running around 850 to 1100 depending on the road and wind. Several time in the hills it would go past 1350. I have a 05 lly ccda dually with 19000 miles. Also the temp on the juice was running between 198 and 203 degrees and the next thing it would be over 225 and here comes the fan clutch and cools it down to 192 and fan clutch goes away. Does these trucks have one or two thermostats in the motor and why does it heat up all of a sudden like they do. My truck has the blocker plate with the finger stick and the juice. Will the 4" exhaust and cleaning out the cat help with the temp of these motors to help keep down the engine temp and the egr's.
Thanks
SatchMax
Lubbock, Texas

I agree with More Power as for the EGT. The max safe boost numbers that I have heard batted around are 30 psi. This is what I get with the boost stick.

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Originally Posted by More Power

Time is an important factor in determining maximum acceptable EGT. The LLY/LBZ is rated for 1365 degrees F continuous and/or up to 1435 for 5 minutes or less. We've seen 1400 or a little more for completely stock LLY's during a Pull-Off here in Montana.

We also know that a Duramax can tolerate 1800+ degrees during a 1/4-mile run with lots of fuel and nitrous oxide, and for those willing to accept more risk. It's only there for a few seconds, which helps make it tolerable... :D

We've tried to include EGT readings in the various Pull-Off truck tests. :)

Jim

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Not that I think your wrong but can you show me where you get these temp numbers at? 1365 continous? Sounds great. I have bounced off 1500 in mine. It had me worried.

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Originally Posted by WhiteMax

Not that I think your wrong but can you show me where you get these temp numbers at? 1365 continous? Sounds great. I have bounced off 1500 in mine. It had me worried.

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If your all stock I would not worry about it , EGT probes are not all that accurate . As long as you have over 20lbs of boost when you see high egt and your running stock fueling and nothing blocking air flow to the intercooler I would say your probe is the issue. The 1400* max number was on garrets web site in a specs article when the LLY was in preproduction back in 2004. Who knows if the info is still on there site.

According to the newest issue of Diesel Power(July) "The truth about EGT" article states that they(don't know who):

"We have a self-imposed limit of 1600 degrees while racing and 1200 degrees towing. Any higher than that and we'll look to water injection, intercooling, nitrous or using less throttle to cool things down."

My problem is this; my edge sets off alarms at 1350 degrees and i have seen this more than once. While towing down the highway I see 1200 + quite regularly. i have just put on 4" exhaust and need to run the truck with trailer again to see any and all changes but a lot of the time I put the edge back to stock to pull larger grades. If I am on level ground then I run on level 1. I am trying to be able to pull with traffic and not lose lots of speed. My trailer only weighs in at max 12000lbs.

What is next to keep EGT's in check. I wouldn't mind a truck pull tryout but am afraid of hurting the motor.