Cummins specs out 1250* continuous use.

I see well over 1500* in my truck for 10 seconds or so on a regular basis.

 

bobby; you might as well be a test pilot by trade bud... just about everything you really arent supposed to do... you do it; even if it breaks... you keep doing it hahaha

 

1500 for 10 seconds isn't bad; on the drag strip you're doing okay as long as you can keep the needle on the face of the pyro. If you watch video of sled pullers and drag racers, you'll see a lot of those guys max their pyros almost immediately, and considering how common 1600+ degree EGT's are molten pistons are relatively rare. Obviously overtemped pistons upon rebuild are more common than molten pistons, however. I need a lot of water to avoid doing 1600+ EGT thing on my truck when I drag race.

Keep in mind that injection timing plays a role in this. A truck with advanced timing is going to have a lower EGT threshold than a truck with retarded timing; advancing timing lowers EGT's but puts more heat into the piston, because it gives the injected fuel more time to burn in the combustion chamber. On a truck with retarded timing, more fuel tends to burn in the exhaust manifold, which causes "afterburning" EGT's that don't affect the pistons very much.

Things get more complex when you consider injection system efficiency. On inefficient injection systems, VE's especially, more fuel tends to increase afterburning EGT's but actually cool down piston temperatures because it absorbs combustion-chamber heat similar to water injection. On more efficient, higher-pressure injection systems (common rails especially), afterburning isn't as much of a factor so what you see on the EGT gauge is closer to what the piston temperatures are.

For drag racing and sled pulling, your pyrometer is less important than keeping track of whether people are melting pistons with similar modifications. For multi-minute towing and cruising the pyrometer is crucial and 1250 is a good limit to hold yourself to, maybe a hundred-or-so degrees lower if your timing is advanced with stock-sized injectors.

 

just my two cents... before i intercooled my 90 the pyro would see 1400 alot on a hill, a couple of times even hotter(my brothers girlfriend pointed out to me one time when the needle went past 1600 with a "hey should that thing be pointing there?"

 

and exactly why is she your brothers girlfriend and not yours? hahaha

 

Can't stand her she's got a really big mouth,and not in a good way