Well I just got my DP tuner in and took it for a test run, and well it is just unbelievable. Makes the bully dog I had look really bad. Anyways to the point, I got the tuner mostly for hauling because that is what i use the truck for, but when i put it on the 80 or 120 setting I cant keep my foot in it for my more than say 5 to 8 seconds the egt's are allready at 1150. I have a 6637, 4 inch turbo back exhaust, what are the other options for keeping the egts down. Like I said I got this for pulling, I dont want to be pulling hills and have to back out of it to let it cool down, I might as well have left it stock.
What are your guys thoughts on this?
Thanks

 

your not supposed to use it on the high setting for towing.
as for the egt getting that high, thats normal. when you put it on
that high of a setting your getting alot of fuel in the motor. you just dont want
it to get to 1300 that is the danger point.

 

Dumping fuel actually cools the cylinders. It's just when the intake charge catches up and surpases the ammount of fuel do EGT's start going nuts.
Basically you are going from a rich scenario to a lean one real quick.

And definately do not tow on the highest setting.

 

Those EGT's seem rather HI to me. I have never seen my temps go above 950 w/out a trailer, even when on the 140 setting haulin *** up a hill rollin black smoke! My pyro is right in the bend of the downpipe, however, maybe yours is pre-turbo? Anyone else see temps this high?

 

Not even when I have the 22' gooseneck on, going uphill, through fire. Something is definately amiss.

4" exhaust.....maybe a dumb question, but how big is the downpipe? I know it says 4" turbo back, but I have seen 4" systems with stock DP's.

 

Is yours a clamp-on? Your post turbo pyro will read less regardless, and if it's a clamp on I think that would reduce it further. Mine will get to 1k in no time flat even on the stock setting if I nail it real hard. On the higher settings, it gets up around 1200s but never above, and that's obviously pre-turbo.

I know from the installation that there is a whole lot of probe in that pipe absorbing heat. Also, there are the differences between probe manufacturers, materials, and even gauges, and the amount of sending wire etc, etc.

I guess this is all relative. That is why we get the gauges and bigger pipes. The temp is going to go up. We just don't want it to go any farther than 1300, or stay there for too long when it does. While mine does go up quick at any setting above 50 hp, it peaks out in the upper liveable range and goes no further. Rest assured I watch it closely.

IMHO, if you are not getting higher EGTs, you are not making as much power as you should. There is a reason tuners recommend gauges and larger exhausts. Now I will await responses to this comment with my asbestos smoking jacket on.

 

Tenn, I think you're right on the money. No need for the asbestos.

Wideopen, I'd be curious to see what happens to your temps if you keep your foot in it a little longer. Like Tenn, I find that my EGTs can climb that high pretty quickly, but then level off. It takes quite a bit for me to get them over the 1250 danger zone. You can even go a bit higher for a little bit and still be safe. But, you can hold it at 1250 for a while without much concern.

Yellow, your temps under 950 sound right for a post turbo pyro. However, I wouldn't run anything over 900 in a post turbo application. This comes directly from my personal observations. I have probes in both pre and post turbo locations. This last weekend while on a road trip pulling a trailer, I made some EGT observations about the differences between the two. Most of the time, the variance is around 200-250 degrees, occasionally bumping to around 300 degrees difference when accelerating while already at freeway speeds. Pre turbo EGTs stayed under 1200 during that time.

However, the noticeable difference came under hard acceleration from a stop or very low speeds. We went through several toll booths, so I had more than one chance to check this. I bumped the chip up to the 100 HP setting in order to get EGTs to climb fast, purely for testing these differences, as EGTs don't climb fast enough on lower settings to test what I wanted to. What I was after was to see what post turbo read when the pre turbo probe showed 1300 degrees. What I found was a huge difference of around 400 degrees. On one acceleration run in particular, the pre turbo EGT hit just over 1300 degrees and the post turbo had not yet hit 900 degrees, but it was almost there. A couple other runs showed similar resulsts, pre turbo at 1300, post turbo right around 900.

So, the conclusion of what I found was that while the temperature difference is typically between 200-300 degrees, when you are under hard acceleration, which is where EGTs tend to climb quickly, the difference is greater. I suggest that if you only have a post turbo probe, don't run it over 900 degrees, and I'd keep it under 850 to be safe.

I've also posted a new thread with these findings.

 

sorry, but i think i need to comment on this. fuel actually creates the heat, it is not the surplus of intake air. these engines are throttled by fuel, so naturally it means that these can take in all the air possible. if you look, there is no restriction other than the turbocharger. like when you're goign down a hill and you let off the pedal, the EGT's drop to around 300-400. it is still pumping air in and out of the cylinders, and the reason you can barely hear the engine is because the fuel is shut off and is not being put in the cylinder. to slow the engine down, you take it's fuel away, and it tries to stop moving, and only becomes an air pump. but the weight of the truck/trailer maybe keeps pushing the motor over. it's a weak type of compression braking. when you want to speed up, you get into the pedal, the engine sound comes back, and the EGT's start to rise again. this is because you are adding fuel to keep the engine running, and the fuel makes heat.

another example of this is when you're on a hot chip program, the EGT's climb ALOT faster, because there is ALOT more fuel in there and most of the time not enough air to burn the mix efficiently. if you turn the chip off or down some, it will give less fuel, which means less heat.

 

My Pyro is a probe that is installed right at the neck of the downpipe. Like I said, I,ve never let my temps go above really 900, and that number is even high. I probably could if I was trying, but the point was that WIDEOPEN23 seems to have really high EGTS for 5-8 seconds into the throttle. Something is not right for him to be seeing those temps that fast! I tow an enclosed 16ft trailer loaded with mowers around town and on the 60hp tow, I never let the temps go over 800-850, but I don't have to try, they simply stay under this range.

 

On a GAS engine, dumping fuel will lower EGT's a lot. That's a very old trick on high flying turbo-charged aircraft engines. Some of the flight procedures you must go through is to adjust fuel mix by EGT. The correct way of doing it is to either go on the lean side or the rich side of peak EGT.
.

 

Strokin,


I believe you, problem is I tend to believe our mechanics too. I tend to sway in your favor because you are currently in school learning this stuff. Some of these guys barely have enough teeth to eat soup and with age comes wisdom?

Anyway, I don't mind being corrected....especially from a young'n like yourself. I think you have proved your weight here on FTE. I have been able to repair/modify my truck because of some of your suggestions, so I thank you.

That being said, could you get to work on the quadrupel compound turbo system? I'm getting impatient.

 

For the sake of conversation, and because I think it's good information for others whom might scan over what's being said here, where does safe EGT end and bad EGT begin? And futhermore how long can one stay on the border of that line?

How long is a while? Can you pull a 6% grade for 15 minutes holding 1250?

I'm under the assumption based on my chemistry in HS and college that aluminium melts at roughly 1250. I believe our pistons to be made of an alloy of some sort. When can bad things start happening? I'd hate to see a noob(newbie) come on here and do a bunch of mods based on our thousands of conversations, and then see a thread about said noob melting a piston because of lack of knowledge. In the end, it's up to each of us to determine when to let off the go pedal, as to not cause damage. Anyone know what Navistar has for EGT operation ranges for our 99-03 7.3's?

I've seen 1400, and immediately let off the throttle. I commonly see between 1300-1350 pulling the Vail Pass & Eisenhower Tunnel grades on I-70 around here. I usually just back out enough to get back down just below 1250.

I would love to see what everyone's opinions and beliefs are on this topic, especially the long time 7.3 tuners and folks like Strokin whom are in schooling or have completed such work. Certainly not ranting here, just trying to put more info in to complete the package....

 

Here's my personal thoughts. You can hold 1250 all day long if you wanted to, by a while, I meant a long time, as long as you want. If I recall correctly, that is what Navistar has rated the engine to run at as well.

True that pure aluminum melts right around 1250 degrees, but you are also correct that they are made of an alloy, and that alloy has a higher melting point than 1250.

Temps over 1250 I've been told are ok for up to 30 seconds, just depending on how much over 1250 it is. However, a melting piston is not your only concern with high EGT temps. The piston can expand at a rate faster than the cylinder itself and cause some scoring on both the piston and the cylinder.

I am not a tech, and don't claim to be, these are just what I can recall that I have gathered as the correct information.

 

I agree with JTHARVEY, I remember something about IH/Navistar stating you can run 1250 all day long just don't go over that. I think you can go over that but just for seconds. Sled pullers get up to 1500+ during their pulls.

 

Jody warned me that my EGTs would climb up higher than I have the capacity to cool it so he set me up with a programmed ECM for about 60HP Tow tune. Hit 1150 on WOT up a slight hill with an 01 Excursion