Best place for EGT probe?

[msimmons]

Gentlemen:



I wish to install an EGT gauge on my '03 HO CTD and am undecided on where to locate the EGT probe. My initial thought was to install it in the exhaust manifold just above the exit flange. I saw a drawing in a thread though and it appears that the manifold is divided by a cast "divider" and want to make sure that I don't hit that when drilling/tapping the manifold.



While in a conversation with an engineer from Cummins, I asked him the "best" location and he advised that on their heavies they locate the EGT probe "post turbo". If I do decide to monitor "post turbo" temps, where then should I locate the probe?



What are the pro's/con's about EGT probe location, pre vs post turbo? What are the best locations for probe location for each setup?



I have seen probes located on top of the manifold which would make for ease of drilling/tapping but it appears that that location "may" not give a true indication of the "average" exhaust temp pre turbo.



Any input is appreciated



Mike

 

[Blakers]

Your initial thought is a good one - that's where I put mine. Just choose one side of the webbing or the other. It's easy to see where is good. Folks seem to put them all over the place in different locations - all probably work. Personally I would not go post turbo.



Good luck.



Blake

 

[Buzzer]

Originally posted by Blakers

Your initial thought is a good one - that's where I put mine. Just choose one side of the webbing or the other. It's easy to see where is good. Folks seem to put them all over the place in different locations - all probably work. Personally I would not go post turbo.



Good luck.



Blake

Just curious why not post turbo. Wouldn't that give you a better idea of the true turbo temp?

 

[Don-T]

Post turbo wold give you a better idea of the turbo temp. The big concern on EGT is the temp comming from the combustion chambers. If the temp gets too high (1250 - 1300) from running or towing for example you can cause engine problems such as burned pistons. The time to be concerned with turbo temps is when you want to shut the engine down right after a hard run. You should cool the bearing in the turbo first. If you let it run for a couple of minutes until the pre turbo temp is at 350 or less the turbo will be fine. It is difficult to judge pre turbo temp with a post turbo gauge because when you load the engine the pre turbo temp can climb to danger levels in a few seconds while the post turbo gauge may only show 800 or less. Most people go pre turbo i think.

 

[BRayls]

local shop told me they always put post from fear of having the probe munch the turbo in a bad situation. for the pre,I am told from the guys the best location is the back half of the outlet. I have mine in the cast elbow post turbo.

 

[WStrmiska]

Has any one talked to Cummins about the best place to put the EGT. I would think since they build the engine they would know where the best place is. Just my 2 cents worth.

 

[msimmons]

Yeah, see my original post, the engineer at Cummins that I spoke with said post turbo.



Mike

 

[XJSuperman]

We're still getting 50/50 split. . some say pre... some say post. HEAVY equipment people say POST... but we are not really in the heavy equipment arena... what's a person to do?

 

[Blakers]

I bet 90% of guys on here go pre-turbo. Do a search and you may find a pole regarding that. Or, if you can't find one, start a new pole.

 

[dpuckett]

It's next to useless POST turbo

When I first got my current pickup, I ordered gauges for it, and even tapped the manifold, only to find out they no longer made ISSPRO T-couples with a 1/8"NPT thread; 1/4"NPT was all they had. I figured that post turbo would be better then none at all, so that is where I put it. Never hit 900 deg, decent cooldown, even with my lack of intercooling. A week later, I found an automotive machine shop to drill and retap the manifold, and put the probe in the manifold. GOing up the same hill that I had hit about 875*/ 28psi, I was now nearing 1400, with only 25 psi boost, and a lot of pedal left to go. Point being, I was well into the danger zone, and the post turbo temp showed it all to be just fine, even adding 10 deg per psi boost. Turned out to NOT be the case at all.



RE: chunks hitting the turbo- if you are getting hot enough to melt the tip of your t-couple (which is a type K; good to about 2500*F), or have chunks coming out of the combustion chambers that will knock the tip off, you have MUCH bigger issues to deal with. The old "tip breaking off and taking out the turbo" is a truck stop myth, right along with Ford owning Cummins and ATF making a real good injector cleaner. Everyone knows somebody that has had that happen to through the years. I wouldnt trust most Cummins techs more than I would the DC techs. They seem bent against Dodge trucks, and try to cover their @$$es at all costs.



Daniel

 

[Joseph Donnelly]

How about the turbine wheel coming off the turbo and taking out the $150 Autometer comp probe that was post-turbo

On the 3rd Gen, drill sideways just behind #3 into the log. Most stuff falls off onto the rag you put under the manifold. After tapping with grease on the tap, you will find only a very few shavings inside the manifold, and they are easily removed with a small magnet on a stick.

 

[BrettMiller]

Gentlemen:



I wish to install an EGT gauge on my '03 HO CTD and am undecided on where to locate the EGT probe. My initial thought was to install it in the exhaust manifold just above the exit flange. I saw a drawing in a thread though and it appears that the manifold is divided by a cast "divider" and want to make sure that I don't hit that when drilling/tapping the manifold.



While in a conversation with an engineer from Cummins, I asked him the "best" location and he advised that on their heavies they locate the EGT probe "post turbo". If I do decide to monitor "post turbo" temps, where then should I locate the probe?



What are the pro's/con's about EGT probe location, pre vs post turbo? What are the best locations for probe location for each setup?



I have seen probes located on top of the manifold which would make for ease of drilling/tapping but it appears that that location "may" not give a true indication of the "average" exhaust temp pre turbo.



Any input is appreciated



Mike

I put my EGT probe in on my 01 in the manifold right at the exchange another good way to collect the shavings is to take a good shop vac and have someone help you or set it up so that the hose

stays right close to where you are drilling and as it will have enough suction to pull the shavings out and not let them fall into the manifold! as for my 08 2500 I put the EGT in the block off plate

from the EGR that was pre-drilled and taped not sure thats where i will keep it but was told that cylinder 5&6 are the hottest burning cylinders. As I said I'm not sure if that's where it will stay

 

[Prairie Dog]

I put mine just slightly back from above the opening to the turbo. This way when anything fell I could stick a small mechanics magnet in there and retrieve everything from the bottom of the manifold. It's also a good place because your drill can stand straight up.

 

[Axekicker]

If your as 'concerned' as you sound....do it my way. I have both. One that I drilled in the post-turbo 'elbow' and one in my BD exhaust manifold, which already has a port(s) for an EGT-probe. Look at your '03 exhaust manifold and you'll (probably) see cracks in it...like my '04 had...it's a common problem with those year trucks w/ a 5.9 Cummins. It's time to replace your exhaust manifold now....with an aftermarket pre-tapped exhaust manifold. While the exhaust manifold is out...drill the turbo elbow for the post-turbo egt-probe and Bingo!

Remember....if you put an egt-probe in either spot....your still monitoring a cracked exhaust manifold. Duh?

 

[AH64ID]

Pre-Turbo give more accurate readings thru out the range of operation, where post-turbo will have a variance from pre-turbo that isn't consistent. Depending on load/rpm/etc the difference could be 100°-400°, but how do you know? The small OEM turbine housing makes range large.

 

[JBallou]

Drill it with the truck running. If, that is a big if any very small metal pieces go into the manifold they will be exhausted very easily. I even run the tap in with it running, it blows all of the chips out.

 

[AH64ID]

Drill it with the truck running. If, that is a big if any very small metal pieces go into the manifold they will be exhausted very easily. I even run the tap in with it running, it blows all of the chips out.

But what it doesn't blow out goes right into a turbine wheel that is spinning in the thousands of rpms, good way to damage it. It's also hot, good way to get hurt and what if the bit breaks? Now you get to buy a new turbo.

 

[RVTRKN]

https://www.turbodieselregister.com/threads/243000-Proper-EGT-location?highlight=EGT+location

Check link, same arguements, and what I did.

 

[MLee]

This was not mentioned, When post tubo installed you have to keep in mind a temp difference of approximately 300* cooler than pre tubo. The cooler temp looks cool but you don't want the piston to get above the 1250* and get damaged. A lot of PRO & CON. OTR trucks have them post. They are working harder than ours. And the 5-6 area is your hottest spot.

 

[RVTRKN]

If its critical to the OP, then Mike should install Post and Pre Turbo Thermocouples. My choice was pre turbo, for thats the most critical temperature you need to worry about for the 5.9/6.7 CTD. OTR semi engines are a lot more sophisticated and built to average a Million miles, when the CTD is capable of a million it was designed for 500K miles. Another way to look at it, is a motor built to haul 80K pounds plus, every mile of its life you can bet its engine components are made to handle high EGT's.