"crispy zone"

[new-dieselman]

Well.....towing season is quickly approaching and i've installed my pyro-pre-turbo already and my boost gauge will be in by next weekend. My question is about the so called crispy zone where one shouldn't let the egt's go past a certain point. I've seen different opinions on this ranging from 1050 -1200 degrees. Remember i'm pre-turbo. My thermo-couple is installed about 8 inches down from the flange on the crossover pipe driver side. After test driving up some local hills in the neighborhood without a trailer with very cool ambient (40-50 f)temps i was able to reach 1000 -1050 degrees. It scares me to think what i might reach while pulling my 24 ft TT up the Coquihalla in the summer. My rad was cleaned in the spring of 06 and also flushed and replaced dex-cool with regular antifreeze 50/50. The truck doesn't get that many miles on her so the rad should be ok. Looks to me like she's gonna cook bad this summer . I was hoping to install a chip also but now i'm worried about it. What do you guys think of my temps? Any thoughts much appreciated.

[Jochen Woern]

Hello and good evening, how are you?

In a different thread you are asking my WHY I am running the Turbo Master AND the Max-E-Tork from Heath. Simple answer: I do not like the vaccum system on my Sub and the Turbo Master easily let's you adjust the boost pressure with a simple turn of a screw (well actually a nut), adjusting the spring. My question to you now is: what boost are you running on your truck? Stock, mine was around 5-6 psi at full throttle and somewhere in the 1-2, sometimes 0 psi at cruising speed. Since installing the Turbo Master as well as Heath ECM/PCM upgrade, I was able to adjust my boost to 10 - 12 psi at full throttle, running around 7-10 psi at cruising.

Remember, higher boost will lower the EGT's and will keep you out of the "crispy zone". I personnally do not let my truck get hotter than 1000 degrees, pre-turbo as well. I have not towed with my truck as of yet (since installing the HEATH upgrades) but I believe that I will see a major improvement in the towing performance without entering the "crispy zone".

Adjust your Boost pressure (but in my opinion not higher then 12 psi max.) and you should see your EGT's go down.

Hope this helps and Good Luck.

[Robyn]

One thing to remember is that the factory chip does not have the best fuel and timing curves and can lead to pretty toasty temps.

The TM as has been mentioned will allow a lot more air to flow into the engine and lots of air will create a much cooler burn (EGT)

The issue is not to exceed about 10-12 PSI max on the boost without an aftercooler.

Now, you said you have the pyro, get the booast gauge installed and then do the same test runs and let us know what the boost is. IF your boost is fairly low due to the factory controls possibly not working up to snuff this can explain the high temps.
My DaHooooley will rarely get up to 500F running light even on the nastiest grades running at speed in the hotter weather.
If your system is only making 2-4 pounds of boost ??????? and you have your boot on it the extra fuel is going to create some very toasty temps.
Getting some wind into the engine will cool that right down.

You can install a small aluminum tank and run a water alcohol injector system. These little goodies will drastically drop the intake air temp as well as the EGT and with the alcohol added will produce more power too.

The addition of an aftercooler can really help intake temps but the expense can be an issue as well as the work to install.

If you are doing some serious towing in mountainous country an aftercooler is the only way to fly though.

If you get the chip and the TM installed you will see the temps drop quite a bit.

The factory setup is marginal at best when it comes to managing temps.

My DaHooooley has the Banks system and they place the Pyro in the down pipe and I will see 900F under a hard pull on 10% grades with the 40Ft horse trailer. (7000#)

Best

Robyn

[GMC Hauler]

It is easy to hit those hot hot temps isn't it???.

I learned on my cross country trip that the difference between 1000 and 1200 is very little in speed.

I know you can run 1250, but consider this. One cylinder can run hotter than another. If your pyro is in the crossover, it reads an average of the driver bank. 3 cylinders may be 1225, but one may be 1300, and come out to some average around 1250 (that may not work out perfectly, but you get the idea).

Therefore, you can be hurting your engine without even knowing it.

Remember, there is no magic number where damage all of a sudden starts to occur. You can't really be fine at 1250 F. and destroy the engine at 1251 F. You need a "margin of error" for meter error, cylinder diferences, etc. We are talking at least 100 degrees. The more the better.

I now don't take it into the yellow (1000+). Can't gaul a cylinder if you don't get it too hot.

Take it easy and slower until you get your engine modded. Your pocket book will appreciate it.

My .02

[MarkMorissette]

Sorry to hijack the thread, but I continually read all these horror stories of EGT's.

Assuming a bone stock 6.5 (except for a K&N and remote PMD with cooler) wih fresh injectors, should I be worrying? Is it only those with tons of mods and chips that need to worry about this?

We're going out west this summer towing a 34' Travel trailer and of course will be pulling the rockies both ways, as well as some other major ranges in and out of Yellowstone national park.

No guages at this point other then boost, but then again, no mods - I want fuel economy, not raw wheel spinning power.

Should I be worried? I hate to spend the money on a pyro if it's really wasted in my situation.

[Robyn]

A pyro is definately not a waste on these engines, even in stock form if your going to ask it to work. A 34' trailer is going to work the snot out of that rig and the Rockies will really give it a workout.
Get the pyro and the boost gauge and drive the rig with the gauges.

The crispy Zone is a very elusive place and it only takes a few seconds at times under the right conditions to melt the poor little creature.

One of the big things with these engines especially if you are going to work it hard is to be sure the injectors are in good shape and set at the right POP pressure and have a good spray pattern.
A poor set of injectors can burn a piston real quick.
Low pops and a crappy spray pattern and maybe some dribblers to boot will really add some fire when and where you dont need it.

A poorly contoled turbo that is not boosting enough will allow a lot of fuel to be burning as it goes out the stack and this results in some nasty heat you dont need.

Its better to have a little too much boost rather than not enough.
Extra air helps cool the engine out.

If your getting black smoke coming out the stack with your boot on it you are getting heat you dont want.

best

Robyn

[MarkMorissette]

No black smoke (ever), and new injectors are going in before the trip - I just ordered them tonight, actually. Boost is comfortably high, within spec.

The TT in question is actually a very aerodynamic trailer and weighs only about 8500# loaded, so despite it's length, it's not a huge lug to haul around, nor is it a fifth wheel with all sorts of air resistance to pull against. Regardless, even with the 4.10 rears I know it'll work in the mountains.

I just looked around this evening and found surprisingly high prices for Pyro kits...anyone have any deals to share?

[d.h.]

Well.....towing season is quickly approaching and i've installed my pyro-pre-turbo already and my boost gauge will be in by next weekend. My question is about the so called crispy zone where one shouldn't let the egt's go past a certain point. I've seen different opinions on this ranging from 1050 -1200 degrees. Remember i'm pre-turbo. My thermo-couple is installed about 8 inches down from the flange on the crossover pipe driver side. After test driving up some local hills in the neighborhood without a trailer with very cool ambient (40-50 f)temps i was able to reach 1000 -1050 degrees. It scares me to think what i might reach while pulling my 24 ft TT up the Coquihalla in the summer. My rad was cleaned in the spring of 06 and also flushed and replaced dex-cool with regular antifreeze 50/50. The truck doesn't get that many miles on her so the rad should be ok. Looks to me like she's gonna cook bad this summer . I was hoping to install a chip also but now i'm worried about it. What do you guys think of my temps? Any thoughts much appreciated.



Like you I,ve gone through these cooling issues.I found best bang for buck was mounting intercooler.My fifth wheel is 34ft and 13000lbs.Pulling the "coke" last summer I was down to 50km going by the snow shed towards toll booth.As long as I ,m careful so far it,s been ok.My pyro is post turbo in downpipe.I,ve run at 1100 for 10 or so minutes with no problem ....BUT I will sometimes slow it down to bring temps down a bit.
I run 10-15lbs quite a bit on hills (15 being very beief) and always find elevation plays a role on how much boost is generated.


The guages,especially the pyro is a must. Does tour truck have the dual stats as that also helps. I find water temp to be a problem on longer pulls in summer.I think a change in fan/cluch in order.
I,m getting new penisular 18/1 engine insalled right now and will be going over the "coke" again this summer so it will be interesting to see the differance.:D Good luck

[GMC Hauler]

Assuming a bone stock 6.5 (except for a K&N and remote PMD with cooler) wih fresh injectors, should I be worrying? Is it only those with tons of mods and chips that need to worry about this?

Should I be worried? I hate to spend the money on a pyro if it's really wasted in my situation.

If I remember correctly, Ronniejoe damaged up his first engine because of high EGT's. It was bone stock. That's what drew him to the Diesel Page.

[MarkMorissette]

If I remember correctly, Ronniejoe damaged up his first engine because of high EGT's. It was bone stock. That's what drew him to the Diesel Page.

Interesting.

15 years of driving class-8 diesels that are built and setup so that they're virtually indestructible has jaded my views on these little diesels, despite owning one myself.

For example, on the majority of class 8 tractors nowadays the pyrometer is a thing of the past. You'll really only still see them on really high horsepower tractors, and even then they're usually not standard unless spec'd...the computers make sure that the engine can't hurt itself.

If I put a full set of guages on my 6.5TD truck, taking away the air guages on the class 8 tractor I drive everyday, I'd officially have more guages on my pickup then my tractor.

[Robyn]

My Western Star with the 3406E Cat will generally run at around 700-800 degrees on a hard pull and it just wont budge over that.
The computers have things very well under control.
The Older A and B models could really get toasty of you had them turned up some and pulled them down on a grade too far.

1100 to 1300 was an easy trick with the old A model I had in an 84 Pete. :eek:

There is just no real comparison of the little pickup engines to the monsters we have in our class 8 trucks except they burn the same fuel.

These 14 liter beasts are built to run a million miles and take just about anything you can toss at them as long as you give them some reasonable maintenance along the way.

My Cat has about 550K on the clock now and given good service.
Just last week was the first time I have had any real headaches with it.
The O rings on the injector cups started leaking and this allowed coolant and diesel to mix. :eek:

Made a mess and caused some grief. Had to get the o rings replaced as well as the injectors.

Truck runs better now than it has since I can remember.

Mileage is up about 1 MPG and the power is noticeably better too.
A full gear on some grades.

Anyway
I can relate to your feelings of difference between the little 6.5 and the larger engines.

Robyn

[More Power]

Up till the last decade or so, the various diesel engine manufacturers rated (emissions & power) their diesel engines (OTR mostly) to be relatively smoke-free at 1100 degrees F pre-turbo.

You can safely run your 6.5TD at 1250 degrees F pre-turbo for the time it takes to pull the factory GCVWR up the longest grade on any US Interstate highway. I've run the 6.5 at higher EGTs than this for short periods of time. The time variable is important. The hotter the temp, the shorter the time interval before the pistons can be damaged.

For comparison's sake, the Duramax is rated for 1350 degrees EGT, and the Dodge 5.9L Cummins is rated for 1275 degrees as a safe upper limit while towing. The 6.5TD is 1250.

Without incorporating some cooling mods, running the 6.5 at 1250 EGT for some length of time will likely push ECT into the crispy zone before you'd need to worry about EGT.

Some years ago, I heard from a 6.2L diesel owner who was in a hurry while towing, and reported 1100-1150 degrees F EGT for several hours. ECT was near the redline the whole time. There was no apparent long-term damage to his engine. Where the 6.5 is rated for 1250, Banks rates the 6.2 for 1100 (non-coated pistons).

Jim