I am running an Edge Juice/EZ stack on my 04.5 600. I have an AFE Proguard intake and the stock exhaust. I have had this stack for 2 months and the Cummins is running great.

Here in Arizona, it is starting to warm up, got up to 95 Degrees yesterday in Phoenix.

I have been watching my EGT's and they seem to have jumped by about 100 degrees lately. I do 80-90% city driving, usually on trips of 10 miles or less. On a moderate acceleration from a red light (40-50% throttle) I will see EGT's go to 750*. A month ago, wih temperatures in the 70's, this same take off would have only heated the exhaust of 600-650*.

Is it possible that my Cat is getting clogged from the excess fuel I am dumping into it, or am I just noticing the effect of the higher air temperatures?

 

I'm willing to bet money that it's just the air. A 20* jump in the temp is pretty significant.

 

you might throw a 4inch exhaust on your truck and the egt's will prolly go down

 

If I remember correctly he already has a 4" exhaust on the truck. That is standard with the 04.5 600's

 

That is correct, I do have the stock 4" exhaust.

I am curious why a 20* increase in air temp would result in a 100* increase in exhaust temp? I would think the relationship would be linear. In other words, if all other variables are the same, wouldn't a 20* increase in air temp result in a 20* increase in exhaust temp?

 

Nope...

Starting with warmer air, compressing warmer air...makes it even warmer, and then trying to cool that compressed warm air with warmer air. It adds up.

 

i say yes, it could be...

when i had my tahoe with the 6.5 TD and egr system [evil POS egr is] i had a massive low power situation, that was diagnosed as a plugged cat.. they changed that out under warrenty... now, i later [a few months] had an egr malfunction that made it stick open, making the engine blow massive amounts of black smoke... it was intermittent problem that lasted about a week until the low power problem came back... dealer fixed the egr, and, new cat installed...

diesel cats work if you can keep the heat in them to burn off the HC build up in them.. if they don't get hot enough to start to burn/oxidize the HC build up in them, the will begin to plug up... get them hot enough to burn them clean and they are good for service again

 

The hotter it is outside the higher the egt.