12.7 maximum pyrometer temp?

I have an 18 speed. I can pull some steep grades very very easily in 6 high. But I downshift into 5 hi. Why? Even though my truck will keep pulling into 7th gear my pyro will reach temps of up to 1300. But I feel anything past 900-1000 is no good for motor. So even though the pulling power is there, I will down shift and keep my rpms in the range where my pyro is reading 900 degrees all the way up the hill. I don’t give a #### how pissed off the people behind me are or how long the line is behind me

 

Keep it under 1000 and you'll be fine.

 

Are you saying 3 inches passed the turbo flange in the exhaust pipe? (Meaning post turbo)
I have a 14.0 liter and my pyro is in the head flange before the turbo ( pre turbo) and I can sometimes see 1100 -1200 in a long hard pull.

 

Aluminum melts at 1121 degrees. Unless I'm mistaken aluminum has the lowest meeting temperature of any material in an engine. So technically 1121 is the hottest you want, however just because you see 1150 on the pyro doesn't mean your bearings are anywhere near 1150. The combustion chanber and valves will be the hottest point, with the exhaust cooling considerably by the time it gets through the turbo to the pyro. This is down by a difference of about 200 degrees if your pyro is post turbo or pre turbo.

With my 12.7s i never got concerned unless it spiked over 1200, and then i would drop a gear or two to get the boost down. And never ever had a problem from those temps.

The more boost, the more fuel, the more fuel, the more heat.

 

There is about a 300 degree temp difference between pre and post turbo.


This is why I say 1000 post and 1250-1300 pre. Max.

Also you have to take into consideration what type pistons you have. All aluminium, steel tops or all steel monotherms. Also some older 12.7s didnt even have oil cooling piston squirts. Lots things to consider. There is no blanket statement as far as egts go.

 

When did they put oil coolers on? Ddec 3 wasnt it?

@BoxCarKidd If you give me your engine model number i can look up what pistons you got. That will help us figure out not only a safe max for your engine, but also what you can do to her to get more juice.

Edit too add: soother thing to keep in mind, if you are running stock equipment and factory tunes you really have no worry, the ecm programming simply won't let it self destruct. It isn't till you start doing things liked putting bigger injectors, cams, a better turbo and after market "performance" tunes where you got to really pay attention. I've seen well built 12.7s putting over a thousand hp to the ground. I've also seen those same engines implode because the operator drove it like it was stock, pedal to the floor mentality.

 

In my time Mr Pyro is limited to around 900-1100 at most. This is for normal working going uphill and down etc.

When confronted with a real mountain upgrade such as say Cabbage in the west on 84 I think, I allow Mr Pyro to go to 1400 max. I know I can ask Mr Pyro to get me close to 1600 for a limited time by stopwatch, I think 4 minutes max if I had to.

I ignored Mr Pyro twice in my life on a grade that is so steep and still another 45 minutes to the top halfway up. I think I exceeded 1550, 1650 or so and maybe have done some damage to the actual metal around the Cat engine block (Manifold, turbo etc) but the company shop never found anything really wrong so I consider myself lucky.

I don't know anything about today's engines metal work, and will be the first to admit it. I think I would for conservative sake apply the old 800-1100 limit with a 1300 degree over 5 minute absolute limit.

They have overbuilt the turbochargers with fancy vanes, values, and so on which I consider BS and unnecessary. With that in mind, I require a big fat Turbo of the old school off the intercooler and adequate oil pressure and good temperature to feed it from the engine oil block supply. I keep an eye on that along with the transmissions, drive axle oil temps and especially the engine coolant among others.

Today's computer trucks have made me feel, less valued and somewhat dumb because all I have is RPM, speed, fuel and air gauges that's it. Nothing else to work on. It's as if my own mental experience gathered over the years with the old iron and say 60 dashboard gauges has no value today. Makes me feel badly.

 

60 gauges huh? That's only twice the amount that the most specced out trucks have ever had.