Best pyro drill location?

[MojaveJoe]

Help Guys,



I must be sick. Only had my truck for 1 week and just bought an XMonitor (EGT/Boost/Trans). The salesman at Piers suggested I drill and tap in the middle of the 5/6 exhaust manifold at about the location marked in the pic below.



He also suggested I remove the turbo first, to be sure I didn't get any filings or pieces in it. Then vacuum the port and/or use a magnet to clean up any unseen metal fragments. I have no idea how big a job this will be, or the easiest way to pull the turbo. So any suggestions would be of great help.



Looking forward to hearing your advice and experiences, all of which will be most appreciated.



Thanks,

Joe



P. S. I hope this won't void my warranty?

 

[C. Harlan]

First and foremost: Do you plan to use the truck for pleasure, or pulling? If pulling, I would advise going post turbo, as all the large diesel motors thermocouples are mounted there. Why drill a hole where you are only monitoring 3 cylinder temps?? There will be lots of replies once I am done with this post, but as a regular puller, I like to see the temps after the turbo, and see what all 6 are doing as a team, not just the hottest 3. if it is for pleasure, you can probably get away with pre turbo, as you will not be showing super high temps all the time being that the motor is not under a consistent load. you will get mixed signals on this topic, but I ask this:



If we are supposed to go Pre Turbo, Why do all the Class 8 truck motors run it POST Turbo?? Obviously for a reason, right??



-Chris-

 

[Turbo Tim 1]

charlan, Got your flame retardant underwear on? You know they'll be coming after you soon... ...

 

[snowracer69]

Well, I'm not going to flame, but will put in my $0. 0175...



The reason I went pre-turbo was pretty easy. I want to know instantaneous and exact temps. I want to know what the hottest part of the engine is doing, and I want to know RIGHT NOW!!!



I can't explain why Class 8's run it post turbo, but don't ya figure that they get pretty warm pre-turbo when they're pulling 85k up a hill?



Tell me this... what's going to tell you something catastrophic is happening first? Post turbo showing 900*F or pre-turbo having the gauge pegged at +1650* for 30 seconds? Personally, I like to know when I'm running 1600*F on the last cylinder, cause for some odd reason if that #6 cylinder loses compression the hole thing shuts down... weired how that works.



Oh, and w/ the Drag Comp, 3's, and KSB1, I hit 1650*F whenever I feel like it... course, I'm at 5000' elevation, but it still gets there WAAAAYYYYYYYY too quick.



Josh



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P. S. I don't recommend putting the 1/4" reducer in like I have either... just a pain cause I can't keep it tight. Will fix my mistake when I have the $$$ for a 3-piece (by then I'll turn it upside down and have two of them turbo-thingy's anyway )

 

[JR2]

I am not going to get into the pre/post turbo debate as it has been hashed out many many times.



As for how to pull the turbo, you really don't have to take it all the way off, just take the nuts in the picture off (and the ones on the other side and let the turbo drop a little. Stick a piece of cardboard in there to catch the filings and all well be good. I did not do any of this on my 01 and I had no problems. I did magnetize my drill and tap and used axel greese on them while drilling/taping.



JR2

 

[MojaveJoe]

Just Help...no flames please

Thanks Guys,



I certainly do not want to start anything negative with this thread. Just looking for your tips on how to simplify the installation of the EGT probe.



I will be using my truck mostly for towing a 10K-12K fiver doing long miles.



I have a couple new questions now:



1. Can I successfully install the probe without the bushing, or will it put the probe too deep into the manifold. (Piers recommends the pre turbo install, perhaps because they wrongfully assume I will bomb my truck soon?)



2. BD (the mfr of XMonitor) recommends installing post turbo in the down pipe elbow. Why would they recommend welding the bushing in vs tapping the hole for it? I see where Snowracer69 is finding his loose occasionally, perhaps that’s the reason?



Many thanks to those who have shared their ideas already, and to those who I hope will offer their thoughts or experiences in the near future.



Joe

 

[Turbo Tim 1]

If you were to do a poll I am sure you would find more people saying put it pre turbo for quicker and more accurate readings. The reason your are watching EGT's is to keep and eye on combustion temperature because we have aluminum pistons and being pre-turbo allows you to see those temperature almost real time and prior to melt down. Post turbo will not really tell you anything more than pre-turbo, it is basically the easier way to do things because you don't have to worry about metal chips getting anywhere they shouldn't. Ideally I would want a pre and post turbo EGT but right now I only have one and it is pre-turbo and that's where I would put it again. People that have had both have said the post turbo one reacts alot slower. Pre-turbo cons would be the possiblity of melting the pyrometer off and landing it in the turbo, at that point I would think you have bigger problems to worry about. Just my 2 cents. Do a search on pre and post turbo EGT's and you will come up with days of reading.

 

[MLee]

pre/post

Joe;

if you are going to put an exhaust brake on, they are usually taped, with a couple of places to put the probe. this might help your decision.

just my penny's worth



Marv.

 

[RustyJC]

The large industrial engines our company builds have an individual thermocouple in each cylinder's exhaust outlet and a pre-turbo thermocouple as standard equipment. The individual cylinder thermocouples are there to find a "dead" cylinder or, at the other end of the spectrum, a "hot" cylinder. The pre-turbo thermocouple is there to protect the turbocharger from excessive turbine inlet temperatures (affectionately abbreviated as TIT - let's see if that makes it through the censoring software! ). Post-turbo thermocouples are available as a customer option, but with the other thermocouples already on the engine, the post-turbo thermocouple is really only useful if:



1. The user is set up to calculate turbocharger efficiencies, or



2. The user has an exhaust post-treatment system to reduce emissions, and the inlet temperature to the catalyst, etc. must be closely controlled.



I tow heavy (36' 5th wheel RV that weighs 13,500 lbs), and I installed my EGT thermocouple pre-turbo.



Rusty

 

[LSMITH]

Originally posted by RustyJC

Post-turbo thermocouples are available as a customer option, but with the other thermocouples already on the engine, the post-turbo thermocouple is really only useful if:



1. The user is set up to calculate turbocharger efficiencies, or



2. The user has an exhaust post-treatment system to reduce emissions, and the inlet temperature to the catalyst, etc. must be closely controlled.



I tow heavy (36' 5th wheel RV that weighs 13,500 lbs), and I installed my EGT thermocouple pre-turbo.



Rusty

Rusty is absolutely right on this one. Put it in PRE-turbo.

 

[illflem]

Joe, since your picture doesn't show the hole location in quite the right place take a look at this.



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[C. Harlan]

Just make sure you get a pyro gauge that reads damn high, being over 1500°, cause its going to be showing super high temps when pulling! Oh well, I guess the large motor builders made a flaw. Just ask them why they dont put their thermocouples in the pre turbo position... . not trying to be a firestarter, but I believe I DO have a point, and still, no one has answered the question,

If we are supposed to go Pre Turbo, Why do all the Class 8 truck motors run it POST Turbo?? Obviously for a reason, right??





-Chris-

 

[snowracer69]

Well what's your reasoning then? Why do they do it? Answer your own question for us that are running it in the wrong place



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[C. Harlan]

alright, smart@ss... First, I did not say y'all were running it in the wrong place. Second, why would you want to monitor just 3 cylinder temps, rather than the 6 we have in these trucks? There is a difference in using your truck to just drive around having it for looks, as opposed to using it for its intended purpose. Since I pull loads on a daily basis, I need it behind the turbo, so I do not see 1200°+ temps constantly. Is that good enough??

 

[snowracer69]

Easy killa... I wasn't trying to come off as 100% smarta$$, just 62. 5%.



I guess I just don't see the difference in seeing 1200*F temps pre-turbo on a regular or constant basis, compared to seeing 850-900*F temps post-turbo on a regular or constant basis. If they're both telling you the same thing (that the engine is running a-ok), then why the big controversy, and why continue to spout the part about the class-8 trucks?



Also, and this is a question, not a slam, what contributes the most to your 900*F temp that you see post turbo? You think it's the #1 cylinder running 1150*F or is it the #6 running 1450*F? Yes, they're all mixed up by the time they get past the turbo, but the laws of thermodynamics still can't be ignored... the hotter air coming from #6 is going to raise, across the board, the temp you see post-turbo, so why not just monitor that hottest part to start with? That's all I'm saying.



Oh, do please take note of my use of smileys to portray the fact that I am in no way engaged in a heated discussion with you. I just want to know your side of the argument, and why you think it's correct. Pretty obvious by now that we're not going to change each others minds, so let the information flow so maybe everyone can gain knowledge.



And beating the dead horse was in jest... this has been hashed out before... I've just never been in on it.



Lastly, my pickup is just for looks and driving it around as a daily driver. I'm a punk kid... what do you want from me? I pick on rice for fun and have the fastest pickup around... . when I get :--) from the kid in the Mercedes or BMW, I just smile and drive on... most don't have a clue.



Josh

 

[illflem]

Originally posted by charlan



If we are supposed to go Pre Turbo, Why do all the Class 8 truck motors run it POST Turbo?? Obviously for a reason, right??

Maybe cuz they have class 8s and we have pickups?

 

[Turbo Tim 1]

Let's look at this pre and post turbo question and let me ask you a question, First why did Dodge decide not to put an EGT gauge in our trucks? Mainly because of cost I am sure but besides that because the engine controls were designed so that you shouldn't be able to run high EGT's in true stock form as long as you towed within its ratings. On top of that most people don't even tow half of the trucks capacity. Now look at a big truck originally designed to drag 80,000 lbs down the road, you have motors that go millions of miles over their life often loaded to capacity or over, I've seen chip trailers come in to a plant I use to work at weighing 145,000 lbs, these units on the road are industrial units that need to run to make money, everything in industry has more monitoring capabilities that is the way buyers want them. So why put them post turbo? Same reason your truck didn't come with one, cost! It is alot cheaper to have a boss welded to exhaust pipe than it is to machine a manifold to accept a probe, plus you get rid of risk, the risk of dropping a probe in the turbo. Now there is alot of reading out there, go to google.com and type in "egt pre post turbo" and you'll come up with some good stuff. I like this one on the first page:

Pre / Post turbo EGT

Like was already said here, real diesels that can mean the difference between life and death usually have probes on every cylinder. I know the ones I worked with did. Everybody has their opinions and that is fine, I suggest doing some reading and deciding for yourself want you want to do. I think this article above says it well.

 

[MojaveJoe]

Thanks Guys

I really appreciate all your input.



Still deciding on location, but has anyone actually had their 1/4" npt bushing welded in, or has the taping method been adequate to keep the probe in place and tight? I will be doing this to the manifold or the elbow, so could use your experiences.



... and TT1... that was an excellent article for a novice to this subject... like me



Regards,

Joe

 

[RustyJC]

Originally posted by charlan

Oh well, I guess the large motor builders made a flaw. Just ask them why they dont put their thermocouples in the pre turbo position.

Chris,



I'm not sure that I'm qualified to comment since our company builds engines, not motors, but here goes anyway.



As evidenced by the following photos, I believe our company qualifies as a large engine builder:

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On both these engines (2-cycle and 4-cycle), we have individual cylinder exhaust thermocouples in each cylinder's exhaust outlet as well as a pre-turbo thermocouple. The later CleanBurn(R) low emissions versions have individual cylinder head temperature thermocouples as well.



Rusty

 

[Turbo Tim 1]

MJ - that is the reason we are here, to help, some people would rather fight but I just try to help people make educated decisions. As far as the drill and tap, mine doesn't have a bushing in there, I just made it the size of the EGT probe fitting and haven't had a problem in 50,000 miles, infact I think snowracer mentions that he doesn't suggest the bushing. There is a site that I will have to look up because I can't remember it right now and have to go ship some springs I sold on E-bay but they have excellent directions on installing guages and I think it's the one illflem got the pictures in his post from. Glad we could all be of some help, let us know what you do.



Tim