Exhaust Temps

[killer]

On Tuesday I stopped at a diesel shop in Calgary to get a hole drilled and tapped in my exhaust manifold for my Juice/Attitude. I made sure and asked the guy if he knew how and where to do it. He said he did. I paid for it, went out and popped the hood. Where's the hole? 8-10" past the turbo, on the downpipe is where. I went in and asked why they put it there, and the explanation I got:

"We find that if we put the thermocouple in the manifold it hits 1600F right away, and the chip defuels. So we put it where we did so that it doesn't read as high."

Now, I've proven countless times that I'm not the smartest kid around, but doesn't that defeat the purpose of putting in a pyro? One of the reasons I went with the chip is because of the safety features built in. Now one of those safety features may have been removed. I was never informed that this would occur, and I wasn't given any reason to believe that they would deviate from Edge's instructions.

Now, with a cold air intake, no cat, no muffler, the highest I can get my EGTs to go is about 700F. I can't imagine the airflow mods I've made allow the temps to stay that low, but I can't imagine there's a difference of 5-600 degrees between where the thermocouple is and where it should have been.

Does anybody know how to adjust the EGT readings so that the chip defuels when it's supposed to? I think until someone tells me otherwise I'm dropping the limit to 700F. I've got to try pretty hard to get it that hot, so maybe that's where it should be.

 

[Whit]

Killer, the post reading of 700 is prolly equal to a 1500-1600* on pre-turbo, if I were you I would move it to pre-turbo so you can get an accurate and faster temp reading, how they have it now kinna defeats the purpose of monitoring IMHO

 

[MUDDY]

move it asap. these guys are idiots.

the local places here do the same. drill a hole in downpipe and even hold the thrmcouple on with a hoseclamp

then they fail to tell the customer the proper temp to run with it like that. one local ******* shop told a customer he can run 1350 with it in the dwnpipe and the customer was b4 i warned him of the danger

some say 200 degres diff tween manifld and dp. false.... especially if ya run higher than stock boost. it really more like 500 diff

 

[RKOCH]

I always put my thermocouples in the downpipe mit is much safer for the turbo.

 

[Whit]

Our local Cummins shop owner loves my truck and always wants to know what I been doin under the hood, several years ago he was snoopin around under there and asked my why I have the pyro pre-turbo, I explained all my teasons and he agreed with me and then told me if the pyrp tip comes off it will destroy the turbo, I agreed with him on that but I sure aint never heard of it happening before, I think the odds are deffinatly in my favor here and I opt to keep it pre-turbo so I can further protect my Cummins from high EGT as well as prpper cool down before shutting it off. There is risks with every thing we do when it comes to bombing and IMHO the pre-turbo pyro is way way in our favor for protection

Cheers, Kevin

 

[rubberfish]

I opt to keep it pre-turbo so I can further protect my Cummins from high EGT as well as prpper cool down before shutting it off. There is risks with every thing we do when it comes to bombing and IMHO the pre-turbo pyro is way way in our favor for protection

Good points Kevin.
The same reasons mine is pre as well.

 

[RKOCH]

You can do the same thing post turbo you just have to know what the lower egt reading will be.

 

[LIPD]

the question has always been what is the difference here is a video of a pre and post top is pre middle is post. I stole this off TDS it's not 200 degrees. http://media.putfile.com/pyrogauges

 

[div7racer]

After I got my 2005,I put on a pyrometer and boost guage to get some baselines for future modifications.With some guidance from discussions on this board,I decided to put the probe pre turbo,even though it meant removing the exhaust manifold to be sure no debri from the installation process would get into the turbo.I also did the same for the intake manifold when drilling the hole for the boost guage.While they were off,I got out the die grinder and did a minor amount of de-burring and general clean up work to the castings.To be honest I didnt notice any improvement in performance or gas mileage from the grinding and polishing.The highest I have been able to get the exh temp is 1400 deg.That is with a 30 ft fully loaded race car trailer,heading to Las Vegas on the grade after Baker.The truck wouldnt go any faster,or get any hotter,my guess is the factory has some failsafes built in.I was thinking of putting another pyro post turbo,but I am no longer curious what the post temp is.I have read the post turbo temp can be anywhere from 300-500 deg less than the pre temp.(ps-the boost seems to be limited to 30 lbs,thats the most I can get it to make,at least for now)

 

[killer]

the question has always been what is the difference here is a video of a pre and post top is pre middle is post. I stole this off TDS it's not 200 degrees. http://media.putfile.com/pyrogauges

Do those gauges read 1200-1400 on the top and 1000 on the bottom? It's kind of hard to tell, but if they do, and they're on a truck similar to mine, then I'll be alright. I would have preferred to do it the right way, but now that the hole is drilled I'd rather learn how to interpret the data I get than drill another hole.

At about 70mph and 2000rpm, I'm cruising on level ground at about 550 degrees. That's on level 3 (+60hp), with a cold air intake, no muffler and no cat. What temps are you seeing in that situation?

 

[RKOCH]

Post turbo you do not want to go over 900 if you can help it. 600 is optimum for post turbo. There is nothing wrong with post turbo reading it will just be a lower number and adjust accordingly. I have seem the tip of the thermocouple break and go through the turbo by the way.

 

[JimmyDee]

You can do the same thing post turbo you just have to know what the lower egt reading will be.

Not entirely true. There is a temperature spread between the pre and post turbo points. The temperature spread is a range not a fixed point. That range can be as much as 300 degrees. Smokey from TDS had a post and pre probe in and eventually determined the post was worthless because one kind of driving condition he would read 200 difference and another kind of driving he would read 450 difference. Doesn't matter much except when you get into the 1200+ range, then it becomes critical.
If you are concerned about the probe breaking off, change it if it ever quits working because it will clearly quit working way before it will break off.
Jim

 

[killer]

What is a safe shut down temperature? I've been shutting my truck off at 350, though I know we let the farm tractors idle until they get down to 300.

 

[rubberfish]

I run mine done to anything under 350.
I find I can wait quite a lomg time if I
wait for it to fall all the way to 300,
if it even makes it all the way.

 

[Wyatt Earp]

Killer et all, some companies don't get it while others do. A shop that might place it down the pipe is likely got experience with draggsters and race cars - not that I do. Now of course you have another benifit to this ordeal, you could run a pre and post turbo pyro now! I agree pre is better but to each his own.