Engine/Transmission (1998.5 - 2002) Towing & E.G.T.'s

[Walleye mike]

Bought a 31 footer and hooked it up yesterday can get to 1200 pushing a headwind very easy. What is the max I want to go? I have done a few searchs and some are running 1500 in the mountains some say never over 1150? the trailer with all the junk it weights around 9000lbs.

 

[terrywerm]

It all depends on where the pyrometer probe is on your system, plus everybody has his own comfort level in regards to EGTs. For the most part, if the probe is in the exhaust manifold prior to the turbo, 1200 or 1250 is a good practical limit. If your probe is after the turbo, I would say nothing over 1050.



Those that are running 1500 may be hitting that temp, but they dare not hold it for long without meltdown. Some guys will push the edge and take them up to 1300 or so, but personally, I would sooner err on the side of keeping my engine in one piece, especially on vacation!



Just my opinions...

 

[PC12Driver]

How much boost are you seeing?

 

[Walleye mike]

Pyro is in the exhaust manifold, pre turbo. up to 31lbs.

 

[RustyJC]

Box stock (except for the Jacobs exhaust brake), my HO/6-speed would hit 1300 degF pre-turbo EGT towing our previous (lighter) 36' 5th wheel. With my mods, EGTs can get pretty toasty when towing our current 5th wheel, so I'll tend to drive by the pyrometer.



Typical EGTs when towing are 700-800 degF on the Interstate at 70 MPH, 1350 degF peak accelerating through the gears and over 1300 degF on 6% or steeper grades IF I don't watch the temps. Being a conservative guy who doesn't care to walk home, I generally try to hold sustained EGTs on grades, etc. in the 1100-1200 degF range.



Rusty

 

[amnewsom]

I just got back from a 1200 mile round trip pulling a car hualer with a 4000 pound load - roughly 7000K total weight, headwind at 70 mph, before the edge box and AFE, 21 pounds of sustained boost at 1000*, hit 1200 once over a pass holding 70 mph.



My brothers 04 was holding at 1100, with a AFE, edge box and pulling a 2 car low deck gooseneck. he hit 1350 once.

 

[plongson]

I am not sure where the "Melt down Point" of my engine is, but I set a personal limit at 1100°. Pushing it beyond that yields little, so I give the engine a bit of a breather.



Another consideration not given much thought is how to properly back off the throttle. Think about this 1100° to 1200° in the manifold/turbo and when you crest a hill, for example, the EGT goes to 200° or 300°... . over and over this is tough on manifolds etc. I tend to back off just before cresting a hill or after a hard pull to let the EGT go to 7-900° before letting off all the way.



Just my driving style...

 

[terrywerm]

Rusty brings up a good point: Sustained EGT - Hitting 1300 or so isn't so bad for very short periods, but a continuous temperature that high might bring about some problems over time. Mike, since your pyrometer is pre turbo, your maximum temperature should be somewhere in the 1200 to 1300 range, depending on your personal preference.



As Amnewsom and Plongson have pointed out, the temperature that you allow your system to go to is largely dictated by driving style and personal preference. One thing that I always try to keep in mind is that pyrometers, like any gauge, can vary a bit. If one truck had two pyros on it, with the probes right next to each other, they would probably read a bit differently from one another. I try to keep in mind that mine may read a bit low, with the actual temperature being a bit higher than indicated. As a result, I try to keep my temps down a bit, just for that extra bit of 'comfort level' since I am as allergic to unplanned hiking just as much as the next guy.



I also notice that you do have an EZ and have the boost elbow installed. What kind of maximum boost pressures are you seeing? You might want to open up your boost elbow a bit (if it is adjustable) to increase your boost pressure to 30 to 35 PSI or so if it is currently lower than that. If your boost pressures are currently down near stock, an increase in pressure would help to bring your EGTs down a bit. More pressure = more air flow = lower EGT.



Enjoy that new trailer!

 

[Froadin]

Cummins says no more then 10 seconds above 1250°.

This lets you hit higher temperatures when shifting, or while passing, but not sustained.

I agree that I don't really trust my probe that much, so I typically don't go over 1200° for any length of time.

Another thing to watch when you sustain the high temps is that your coolant temp is going to start rising, this usually ends up being the key to how fast I pull the long hills with a decent load.

 

[RustyJC]

Cummins says no more then 10 seconds above 1250°.

I find that extremely interesting since, as I stated, my box stock 2002 HO would hit 1300 degF, and I've seen many other HO owners confirm this.



Now, there are far more of these trucks like mine running around without gauges than with, and at least some of these trucks are dragging trailers up hills and mountains, and some of the drivers of these trucks are going up those hills and mountains with their right foot planted to the floor, thus ensuring at least 1300 degF sustained exhaust temps.



Froadin, I'm not flaming you. I'm just saying that, if Cummins really published a 1250 degF/10 second limit, they produced an engine configuration that violates it off the showroom floor.



Rusty

 

[Froadin]

Rusty, I totally agree with you on this one.

In stock form I KNOW I I went over the 1250° on a number of occasions.

I can't find the text from Cummins right now, but I have found a few places that state the same thing.



A quote from the dodgeram site ( http://dodgeram.org/tech/dsl/FAQ/turbo_faq.htm )



"Indeed, the cast-iron turbo housing and exhaust manifold start glowing around 1150 or so. It is worth noting that the crystal structure of iron-base metals changes at 1200 degrees, and as such 1250 degrees (give or take a few) is the post-heat temperature of choice for tempering in the "quench and temper" process. "



That site lists the 1250° mark as well.



Of course Cummins does revise it's facts, so maybe that has changed now. Just like they have revised their max safe boost levels.



And to add even more to the stock truck issue, how many of those people out there run their truck HARD, and then just turn it off without a cool down! Cummins probably said that number to be safe, but there were most likely reasons behind it.



No flame taken. Just because someone says something doesn't make it a fact. And helps people RESEARCH the information for themselves. Which of course I am trying to do to back up my statement about something I read a while back.

 

[Big A]

I was told 1350* from an extremely reliable source, but I will not name him, to save him the hassle. I keep my limiter at 1250*

Big A

 

[PHellen]

i was told 1350 no more than 15 seconds. If i hit 1350 i try to let off between 5-10 sec. with a load. My buddy hits 2000 egt in his 12 valve alot, truck still runs with 250,000 miles on it. He's crazy

 

[Walleye mike]

towed the camper out to the mississippi river this weekend. Went up some nice hills. The max boost I could get was about 30psi and the hottest temp was 1200, I tried to hold 70-75mph but on some hills when the egts would hit 1200 i would let off and kick it out of O. D. and they would fall to 1100 and speed would drop down to 60-63.



Its really neat the power this thing makes with a load. I have drove it for five years without knowing what it really has to unleash!

 

[Supermod56]

I never climb hills in O/D, one so I don't blow the 4500 all over the ground, and two to keep the temps down, I have never been over 1100 with 10K behind it, I drive by the pyro always!!! I can't wait till I get my 14cm turbo housing bolted in, that should help even more!!



Tom

 

[OTRPU]

Those that look at 1,250 long enough won't look at it long. You can all come view mine laying in a heap o'er at DOC's place, Dave's Diesel in Angola, IN if you wanna. I tow all day bout every day. Anymore if I see 1,200 I start backing outta her. Point is to get there. . . not get there first.



Cheers,

Steve J

 

[Horsepuller]

I have 9-10K lb GN horse trailer. Up long grades, if the RPMs drop below 1750 and I keep it in 6th and I try to maintain my speed (60-70mph), I will enter the 1200 + range. Usually just a slight pedal adjustment brings the EGTs down into an acceptable level. 95% of the time, I can haul anywhere above the towing speed limit and stay within the 800-1200 degrees.



BTW, my pyro is mounted pre-turbo.

 

[ThrottleJockey]

A set of twins and ALL those problems will literally vanish.

 

[Froadin]

A set of twins and ALL those problems will literally vanish.

Yeah, along with all your money!

 

[ThrottleJockey]

Yeah, along with all your money!



:-laf :-laf



But at least no one will be crying about EGTs!