I'm just not used to running 2500 rpms for 4 hrs.

2500 RPM's won't hurt it. A lot of PSD's spend their entire life at those or higher RPM. My 97 F-350 SRW ran about 72 MPH at 2500. That's where I drove it most of the time. The duallys had slightly smaller tires than the SRW. I have seen F-350 duallys run 2800 RPM all day.

 

What 444-4D said.

The '03 6.0L stock engine produces 325 horses at 3,300 RPM. It's a diesel, so it can run at the horsepower peak for hours on end and not hurt a thing but your pocketbook - because it doesn't get great fuel mileage at 3,300 RPM.

Many marine diesel engines are set up to run at near the horsepower peak for days at a time. So I wouldn't worry about it if you are only turning 2,750 RPM. But if you are geared down so you are only making 45 to 50 MPH at 2,750 RPM, then I'd speed up to 3,000 RPM or so and get some decent speed up the mountain.

What RPM should you shoot for? The torque peak is 2,000 RPM, so you never want to cruise at less than 2,000 RPM. About 2,500 RPM should be a good cruising RPM for compromising between torque and HP peaks. But you should be going a lot faster than 55 MPH at 2,500 RPM unless your 4.56 gears are way too short for your needs.

 

With this set up, I'd recommend you stop goofing around, and get an EGT gauge & learn to drive by it. No hotter than 1250* pre-turbo.

OMC

 

EGT gauge is already installed, it never goes over 800*. My concern was having the engine reved up 2700rpms, and from the kind advice I've recieved, it sounds like that can be normal operation.

 

Where do you have the Exhaust thermocouple installed that you are only getting 800*, before Turbo or after turbo ?

 

After turbo, on the down down pipe. Premix bio 50/50, keeps the temps down, its slower burning, less energy so when it comes out you get cooler, cleaner fumes(biofumes):thumbsup:

 

Don't pass 1250 from the manifold. Who knows what that would show post turbo? If you're ANYWHERE near 1200 post turbo you've already melted something.

 

well i was always told 900 on post turbo probes, and i have pushed that to 950 for some pretty extended hills, without harm.(on cats and detroits 60 series) has your speedo been corrected that might explain the rpm at 55 indicated. the thing to understand with a post turbo probe is that it will read lower because the turbo has extracted ENERGY from the hot gas. you could assume that regardless of what engine,(6.0, cat cummins detroit) that a "stock" turbo would have a similar efficiency and therefore a similar relationship between the post turbo temp and the actual cylinder temp. definately 800 is pretty safe. my experience with 18 wheelers is that to get from 800 to 900 you really have to work it awfully hard . i.e. peak torque rpms at full throttle and hold it there

 

well i was always told 900 on post turbo probes, and i have pushed that to 950 for some pretty extended hills, without harm. (on cats and detroits 60 series)

But 950° post turbo could be anywhere from 950° to 1,500° pre-turbo. So you don't have any idea whether you were in danger or not. The experts tell us that 1,250° pre-turbo is the red line, but you cannot use post-turbo EGT to detemine even close to actual pre-turbo EGT.

If your engine had a stock tune, then you were probably okay. But if you had a performance that burned even a smidgen more fuel than stock, then you were courting an expensive disaster.

my experience with 18 wheelers is that to get from 800 to 900 you really have to work it awfully hard . i.e. peak torque rpms at full throttle and hold it there

Same with a stock PSD. But when someone messes with the tune, the rules all change. With a 100-additional-horse tune on a 7.3L, you can get over 1,300° pre-turbo EGT in a very short climb up a steep grade with a loaded trailer at 2,500 RPM in direct drive. But depending on several exact conditions your post-turbo EGT may be way back down at less than 950°.

(The big-truck engines have a much lower RPM range than our PSDs, so you cannot compare RPM in a C-15 Cat to a 7.3L PSD.)

 

oh for sure with a tuner you're going to make way more heat much faster. I always felt that the temp drop through the turbo was directly connected to the amount of work being done by the turbo.i'm just curious though what factors would cause the the actual cylinder temp to vary so widely from the post readings. generally i couldn't care the least about shutdown temp, unless you just pulled a big trailer up a hill all thats needed is to use a light foot for the lastcouple blocks before you park. as a general rule most places in the real world that i park i can't go full speed up to the last second anyway. it a somewhat different sceneario but i was reading a flying article on turbocharged aircraft. the common wisdom there has been that you should run the engine for several minutes at elevated rpms after landing to cool down. however when they actually monitored turbo temps it was lowest when just down and actually went up.in this case they were actually at a higher power setting for high idle than what is used to coast in on the landing run. if i know where i'm stopping and generally i do i can ease upthe last minute or so