[87 HJ60]

I'm going to install my pyro in my HJ60 this weekend. I have a question about where the probe for the EGT gauge should be located.
I heard that I should install it directly on the exhaust manifold by drilling and tapping a hole.
I also heard that it should be located just after the turbo and on the exhaust downpipe but somewhat close to the turbo.
Any thoughts ??

[Gold Boy]

Originally Posted by 87 HJ60

I also heard that it should be located just after the turbo and on the exhaust downpipe but somewhat close to the turbo.

works good for me, that's where mine is located [13bt].

[bvissers]

I had a dual Pyro on my 60, so I had both, in the manifold and in the down pipe 6" below the turbo, there was a good temp difference between the two as well as some what of a lag in the reading of the post turbo probe. That being the case, if I only had the one I would most definetely go for the manifold probe. After all its the exaust temp leaving the head and entering the turbo you are concerned about, If the turbo acts as a heat sink and cools the exaust some, that is of little consern.

[amaurer]

Go pre-turbo. If you go post turbo you'll be using those numbers to try and guess what the pre-turbo numbers are, so why not just measure what you really want to know.

[valdezhilander]

You need to keep in mind that the numbers are relative, your looking for major increases in temp, you will not be counting each degree. I have said it before and I will say it again, ever major truck engine manufacturer puts the EGT probe post turbo, not in the manifold.

[amaurer]

Originally Posted by valdezhilander

You need to keep in mind that the numbers are relative, your looking for major increases in temp, you will not be counting each degree. I have said it before and I will say it again, ever major truck engine manufacturer puts the EGT probe post turbo, not in the manifold.

... because the manufacturer has fully tested the engine in the engineering stages WITH a pre-turbo probe and knows how to correlate pre and post turbo readings.

On these old engines, where everyone's combo of mods, engine age, turbo type, etc, are unique, we have no such data.

Put it in front of the turbo.

[valdezhilander]

What do you base that on? There are plenty of folks on this site that have the probe after the turbo and I am not aware of there being a trend for burn downs? I base what I say off of my personal experience as a diesel mechanic, and I tend to trust the people that design engines that put down 600+ hp and charge upwards of $40,000 for an engine. Here is one more reason, your cast iron mainfold was designed to have certain holes in certain places and expand a certain way, when you start drilling holes in any cast material in a spot not intended to have a hole you weaking that casting and creat a perfect spot for a crack to start. Here's my final comment, you can put that probe where ever you want, but I am going go with where the engineers that actually know what their talking about put it.

There it is...

[Diesel42]

If your using a 13bt exhaust manifold, theres a factory threaded hole just underneath the turbo adapter. You can drill this out and retap with a 1/4"NPT which fits most any EGT probe. I agree with Armuer on the pre-turbo. Why not get the quickest most accurate readings possible. This location is pe turbo as it just enters the turbo. Simple install. Good luck.

[Diesel42]

Sorry, misspelled Amaurer and i meant 1/8"NPT for the probe. Been a long day machining in the shop.

[Garry]

Definately pre-turbo

[onefsatchevy]

Mine is in the top of the manifold, been there for a few years in a hole I drilled, no problems, no leaks or cracks, this is after a fair bit of searching on this site, and the recommendations of the pyro manufacturer I bought. However valdezhilander makes some good points, thus neither is wrong, just make sure you specify where it is when asking questions about heat, and if your readings are good.

[sandcruiser]

I installed mine pre-turbo (hd-t) by drilling/tapping the manifold.
if I were to do it again, I would probably do it the same way.

Post-turbo will not be as accurate, but if the install is easier/safer/faster/cheaper then I would consider that route. Unless you are planning to aggressively tune the motor/fuel delivery/boost, the exact reading of the pyro is not going to make a big difference to you.

[Tapage]

another vote for pre turbo .. ( in both of my Cruisers )

[rick_d]

as sandcruiser said, unless you are going for performance and believe it is critical to know if you are 1201 F pre turbo either position (pre, or post) does not matter. You should use the EGT as a general guide for operation of the engine and limit stress during the high end and allow sufficient cool down when shutting the engine down.

I see more issues with pre turbo vs a post install as far as failure of the probe and destruction of the $$$ turbo. Do put it close the the hot side outlet to get a solid reading.

I'm post, and avoid sustained 1000F operations (I've touched 1000, but less than 10 seconds) try to keep around 900F or less) and cool down I wait until 400 normally to shut the engine down.

The first 100K before I got the engine the owner never once used an EGT...I want to get another 200K without thinking...

[Tapage]

funny and maybe a little paranoic .. but I never shutoff my engine before 350°F ( now running a turbo timer ) and I'm pre turbo ..

[finderscuba]

Originally Posted by Tapage

funny and maybe a little paranoic .. but I never shutoff my engine before 350°F ( now running a turbo timer ) and I'm pre turbo ..

My 1HD-T is always below 350 when idling. It rises with acceleration, and will sustain a higher reading while cruising, but it falls below 350 almost as soon as I stop. According to this, I don't even need my turbo timer. But I idle for at least one minute before every shutdown.

[amaurer]

Originally Posted by finderscuba

My 1HD-T is always below 350 when idling. It rises with acceleration, and will sustain a higher reading while cruising, but it falls below 350 almost as soon as I stop. According to this, I don't even need my turbo timer. But I idle for at least one minute before every shutdown.

After a long highway run I find that my 3B will soak up enough heat that idle will be over 350. It only takes a minute or so to bring it down below 350 though.

Given enough time, it'll idle just above 200.

[Tapage]

Originally Posted by finderscuba

My 1HD-T is always below 350 when idling. It rises with acceleration, and will sustain a higher reading while cruising, but it falls below 350 almost as soon as I stop. According to this, I don't even need my turbo timer. But I idle for at least one minute before every shutdown.

well if I drive gentle mine cools faster .. but if I'm with the AC and usually driving around the City at MD haven't lime to let it idlle ..

it's a matter of weather and outside temp ..

[sandcruiser]

interesting notes about EGTs. Mine us usually at around 400 when I get home, and takes over a minute to get down near 350. I wonder if I should back the fuel off a little?

More importantly, I suspect my injectors aren't very clean/well tuned.

[Tapage]

Originally Posted by sandcruiser

interesting notes about EGTs. Mine us usually at around 400 when I get home, and takes over a minute to get down near 350. I wonder if I should back the fuel off a little?

More importantly, I suspect my injectors aren't very clean/well tuned.

mine cools much more easy and fast now with the manual tranny (without the auto tranny job on the rad )

[jake2far]

Originally Posted by valdezhilander

What do you base that on? There are plenty of folks on this site that have the probe after the turbo and I am not aware of there being a trend for burn downs? I base what I say off of my personal experience as a diesel mechanic, and I tend to trust the people that design engines that put down 600+ hp and charge upwards of $40,000 for an engine. Here is one more reason, your cast iron mainfold was designed to have certain holes in certain places and expand a certain way, when you start drilling holes in any cast material in a spot not intended to have a hole you weaking that casting and creat a perfect spot for a crack to start. Here's my final comment, you can put that probe where ever you want, but I am going go with where the engineers that actually know what their talking about put it.

There it is...

Here is a link to the quote "experts who design the 600+hp"
as far as cracking the exhaust manifold I would like to see a post with pics of someone who has cracked a exhaust manifold thru a hole drilled and tapped for an EGT. If Banks is not big enough of a designer than who would you believe?
Banks Power | Why EGT is Important
Whether the pyrometer thermocouple is mounted before or after the turbine is usually a matter of finding a suitable mounting location, or of convenience. It should be noted that when the EGT is measured after the turbine, the turbine outlet temperature at full throttle or under a heavy load typically would be 200º to 300º F. lower than the EGT measured in the exhaust manifold. The temperature drop after the turbo indicates the amount of heat energy in the total exhaust gas flow that was used to drive the turbocharger. The temperature drop through the turbine is also related to the total flow and speed of the flow through the turbo. At part throttle, under light load, such as cruise conditions, the turbine outlet EGT may be as much as 500º F. lower than the turbine inlet temperature, but the total exhaust flow is much less than at full throttle. At high turbine speeds (under heavy load) the exhaust gases simply don't have time to give up as much heat energy as they speed through the turbine. This variance is why installation of the thermocouple in the exhaust manifold is considered more accurate. The EGTs discussed in the remainder of this article will all be turbine inlet temperatures.


Not my words but I installed my EGT preturbo by drilling a hole and tapping it, knowing what the temp after turbo is a guessing game in my opinon.
BJ70, new frame galvanized, 13BT, warn birfield replacement kit, rear disc conversion, AC installed, Old Man Emu lift kit, anti reverse shackles,


Jim

[87 HJ60]

OK so it seems that pre-turbo is the way to go. As far as drilling and tapping a hole in the exhaust mainfold, should I remove the ehaust manifold from the engine to do this?
My concern is the little bits of metal from the drilling and tapping? If I don't then won't all the metal bits be blown through the turbo and possibly damaging it?
Or is there a way to minimize/prevent this while leaving the mainifold on the engine. Getting the exhaust mainifold is a pain in the buttocks.....
Also is there a particular spot on the mainifold I should install the probe?

[sandcruiser]

when I installed mine on the hd-t, I did it without pulling the turbo and without pulling the manifold. It was .... nerve wracking.

But the way I did it was to put a magnet next to the hole- to pull chips/shavings away from the bit, and to do the work while the motor was on so that there was positive pressure on the exhaust system to blow chips/shavings out.

the downside is that you'll probably have to drill, then wait for things to cool off, then tap. The other downside is that I had a lot of trouble getting the tap handle to move freely in there- very cramped.

All things considered, if I did it again, I would seriously consider pulling the turbo (at least) or pulling the whole manifold (better) to do the work.

[jake2far]

Originally Posted by 87 HJ60

OK so it seems that pre-turbo is the way to go. As far as drilling and tapping a hole in the exhaust mainfold, should I remove the ehaust manifold from the engine to do this?
My concern is the little bits of metal from the drilling and tapping? If I don't then won't all the metal bits be blown through the turbo and possibly damaging it?
Or is there a way to minimize/prevent this while leaving the mainifold on the engine. Getting the exhaust mainifold is a pain in the buttocks.....
Also is there a particular spot on the mainifold I should install the probe?

Take the turbo off, use a vacuum cleaner, when drilling vacuum the chips from the outside to the point of penetration, switch the vacuum to the inside, continue with the vacuum inside until you are finished. Coat your tap with grease to aid in cutting as well to trap the chips, wipe everything with a clean rag. Install the EGT probe, hook up the turbo and you are finished.


Jim

[Dougal]

Originally Posted by rick_d

as sandcruiser said, unless you are going for performance and believe it is critical to know if you are 1201 F pre turbo either position (pre, or post) does not matter. You should use the EGT as a general guide for operation of the engine and limit stress during the high end and allow sufficient cool down when shutting the engine down.

I see more issues with pre turbo vs a post install as far as failure of the probe and destruction of the $$$ turbo. Do put it close the the hot side outlet to get a solid reading.

I'm post, and avoid sustained 1000F operations (I've touched 1000, but less than 10 seconds) try to keep around 900F or less) and cool down I wait until 400 normally to shut the engine down.

The first 100K before I got the engine the owner never once used an EGT...I want to get another 200K without thinking...

Have you seen a pre-turbo probe lunch a turbo or is it just the potential that worries you?

The problem with post turbo is the measurements are a guessing game. Sure it'll work as an idiot light (oh look, it jumped 300 degrees, something is wrong), but as a tuning and diagnostic tool it loses all of it's accuracy.

As for a drilled hole starting a crack. Well drilled and tapped holes aren't a good stress riser. Drilled holes are often used to stop cracks growing.

[valdezhilander]

All right I have to jump in here again. First of all the temps are all relative. You will have slightly different temps at different spots in your exhaust manifold and for that matter in your entire motor. Since there is no specification for what temp your supposed to have, and where, your'e looking for relative increases and decreases. I prefer after turbo because I don't risk an EGT probe going into the turbo, and yes it does happen, especially in high performance cars and I perfer to not drill out the manifold. To me it is much easier to put a small welded boss on the outlet pipe of the turbo. Which is how all heavy duty diesels are set up. Now there are far more Caterpillars, Detroits and Cummins engines in North America than there ever was or ever will be Toyotas, engines that routinely go to 500,000 miles before in inframe and then go another 500,000 before a crank/cam R/R. I am just saying that I think if it were so much better and more important to have the probe pre-turbo then why don't the big trucks run them that way?

[Dougal]

Originally Posted by valdezhilander

All right I have to jump in here again. First of all the temps are all relative. You will have slightly different temps at different spots in your exhaust manifold and for that matter in your entire motor. Since there is no specification for what temp your supposed to have, and where, your'e looking for relative increases and decreases. I prefer after turbo because I don't risk an EGT probe going into the turbo, and yes it does happen, especially in high performance cars and I perfer to not drill out the manifold. To me it is much easier to put a small welded boss on the outlet pipe of the turbo. Which is how all heavy duty diesels are set up. Now there are far more Caterpillars, Detroits and Cummins engines in North America than there ever was or ever will be Toyotas, engines that routinely go to 500,000 miles before in inframe and then go another 500,000 before a crank/cam R/R. I am just saying that I think if it were so much better and more important to have the probe pre-turbo then why don't the big trucks run them that way?

"big trucks" run a completely different state of tune. When you've got an engine you want close to a million km from, you run a leaner mix which gives a cooler exhaust.
The probe on those is primarily a driving aid, lets the driving know how hard the engine is working.

The typical person here putting one in is looking for feedback during engine tuning (often after fitting or changing a turbo) and is getting more than stock power levels from their engines. The other benefits include shutdown temperature.

I have a probe in my exhaust manifold and run EGT's up to 750C (higher accidentally sometimes). For me it allows getting the most performance with the least danger. Something a post-turbo probe can never offer.
There is a specific temperature you shouldn't exceed and that's what we use those probes for. Relative sure is interesting, but not as interesting as exactly how hot it gets under full load.

I haven't seen or heard of a probe failing and taking out a turbo. I'd like to hear from someone who has.

[amaurer]

Originally Posted by valdezhilander

All right I have to jump in here again. First of all the temps are all relative. You will have slightly different temps at different spots in your exhaust manifold and for that matter in your entire motor. Since there is no specification for what temp your supposed to have, and where, your'e looking for relative increases and decreases.

But thats not true! There is a specification given by the melting point of the metals used in the cylinders/pistons. Thats where the 1250 max limit stems from.

Originally Posted by valdezhilander

Now there are far more Caterpillars, Detroits and Cummins engines in North America than there ever was or ever will be Toyotas, engines that routinely go to 500,000 miles before in inframe and then go another 500,000 before a crank/cam R/R. I am just saying that I think if it were so much better and more important to have the probe pre-turbo then why don't the big trucks run them that way?

Because if your manufacturer has gone through the trouble of correlating pre- and post- turbo temperatures over the engine's operating range, then there is no need to take additional preturbo measurements. But since everyone's custom turbo setup is different on this forum, and no one has ever run pre AND post turbo pyros to create such a map for every engine/turbo/exhaust combination, we don't have the luxury of being able to divine the pre turbo temperature from a post turbo measurement.

... which is what I've already said.

[rchalmers3]

Notice the "Exxes" in those horses eyes. Them horses are dead.

Rick

[Tim-HJ61]

I'm with Sandcruiser and the nerve wracking comment

I actually drilled one hole and missed the gas flow chamber Hmm, I recall there was a bit of black smoke coming out this spare hole so I tapped it and put a bolt in it. Not my best moment.....

Second hole went right into the right spot and the probe screwed in very nicely. I put lots of grease onto the drill and the tap and am reasonably confident only a minor amount of debris went down the hole and onto the turbo. I've driven 6 months since installing with no adverse affects.

I run up to 600°C - 1100°F before chickening out but am intrigued by Dougal's comment of their being a temperature not to exceed. What is it?? I'd be highly anxious if I saw 750°C on the gauge. That'd freak me!



This is on a 12H-T.

Tim