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Discussion Starter #1
Hi, all,


I have a pyrometer and a trans temp guage to install in my 98 Sierra 6.5. What is the general concencus regarding location of the thermocouple. Pre-Turbo, Post-Turbo, or "doesn't really matter"?


Also, what temperature ranges (pre or post, and trans) should I expect?


(Forgive me if this has been hashed out already here, I don't see any postings on this topic and I'm fairly new here
)


Thanks!
 

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You can "Ask" one of the tech's or Kennedy...........


Click here ---> Ask the Tech's


or


here ---> Kennedy


at the "PLACE"


The short answer is:


The pre turbo location will tell you the temps out of the cylinders....the post turbo is good if you want to see the turbo "COOL DOWN" before shutting down the truck


Tranny temp can be monitored in the "SUMP" by inserting the sending unit in the tranny pan or possibly "T-ing" the line.


BTW-welcome to the Forum.......





T
NYEdited by: GMC-2002-Dmax
 

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Discussion Starter #3
Thanks for the input! I've decided that the pyro will go pre-turbo, just below the turbo as per John Kennedy's site (looks like a good location for measurement, easy to reach and inspect, and looks like it's practically made to have a sensor installed).


The trans temp is likely going in the sump. The gauge I ordered comes with a fitting to braze into the pan, rather than tee into the line to the cooler, and I haven't found a convincing reason not to put it there, (yet).


thewoz
 

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I have it post turbo and wish I would have put it pre and not been so lazy.


I have always heard that the transmission temperature will normally be real close to the coolant temperature saince it is cooled/heated in the radiator by the coolant.


I have the isspro gauge with the colors on it so I don't have to think about the temperature. If it gets close to the yellow, I usually back off a little.
 

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Is there any concern about the pyro tip breaking off and going thru the turbo? It might be very rare but you are taking a chance with your turbo. But I do believe that pre is the best temp reading. post is "safer". Can one get a good reading on cylinder temp by going post?
 

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Pyrometer tips do not break off - without some prior abuse.


EGT probes are encased in 1/4" stainless tubing, sealed. If an engine damages that probe, to point of breakability, the engine has also become damaged at that point.


The only tale I heard about, was some question concerning probe someone had 'inherited', using it instead of real, and more expensive, EGT probe for automotive use.


My probe is in the driver's-side exhaust manifold at the rear where it turns down toward the flange.


Easy to drill and tap for 1/8" pipe fitting there. 1/8" fitting can be safely drilled out to 1/4" bore for probe.


My secondary probe is in the downpipe, 1" below flange, used for comparo readings for interpreting forum posts.


Theres a 'boss' in the turbo-side exhaust manifold, below the flange, suitable for drilling and tapping.


However - always follow directions in gage package, whether pre- or post-turbo installation.
 

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Take a look at all the big diesel trucks and tractors. Every one I have ever seen has been installed post turbo. That should tell you something.
 

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At 1100cuin and up, 18-wheeler engines are capable of more intensive, rapid EGT changes.


Welding a pyro probe fitting into a steel downpipe prevents stress cracking of cast manifolding, where required boss would be tapped for pipe fitting.


Also, pre-turbo probes react more quickly, and can be 'worrisome' - takes some getting used to, compared to post-turbo probe.


K-type pre- and post- probes are identical, gages differ in range numerics and colored graphics.
 

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Regardless of location guys, WHAT about the metal drillings and tapping shavings?? Pre-turbo you get to blow shavings through the turbine inlet and post-turbo you get to blow shavings into the intake and into the combustion chambers.


I guess you can remove the downpipe or exhaust manifold casting, but I'd hate to mess with that . . .


Thanks!
 

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If you go post turbo, the only thing thing they could get into is the cat ot muffler.
 

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My Bad. Don't know why I was thinking along INTAKE tract post-turbo. I'm an idiot, need coffee. Thanks!
 

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Whichever you decide for sure here is the article on how to do a pre-turbo install in the exhaust manifold.

Of all the people who have drilled and tapped the exhaust manifold, 99 percent did not remove any parts when following my directions and no one as far as I know has ever had a stress fracture in the manifold.

There is another method that can be used. A very few have drilled the small 90deg bed that bolts to the back of the exhaust manifold. It's SS tubing. You then use a special clamp that is a SS hose clamp with a hole in it that the thermocouple goes into. No tapping required.

Edited by: hoot
 

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mine is post turbo in the downpipe and running 10psi of boost i rarely see over 600deg. i think you're supposed to be okay up to 1200. still running conservative but until i get more fuel delivery this is where i am.
 

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lupey6.5 said:
mine is post turbo in the downpipe and running 10psi of boost i rarely see over 600deg. i think you're supposed to be okay up to 1200. still running conservative but until i get more fuel delivery this is where i am.
Since you are post turbo you need to add about 300 deg to your 600 and that's only an estimate. If you see 1200 post turbo you are really into danger territory of 1500 that could do damage if you sustain it for a long period.

For those that would like to monitor turbo temp, an egt probe post turbo is really no the way to go. A thermocouple neds to be bolted to the cast housing as this is the culprit as far as overheating your engine oil is concerned. You will find that after a very hard run the turbo actually gets hotter and hold it for a while after you shut down. If your probe is in the exhaust stream it will show a major temp drop while your housing is still hotter than hell and rising slightly. The LB7 water cooled turbo pretty much removes the need for monitoring turbo temps but the LLY is a different animal. Not alot known about it's operating characteristics.

OOOOOPS... just noticed this is the 6.5 forum..

Well some of what I said pertainsEdited by: hoot
 

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OK HOOT


All forgiven for being in the wrong place at the right time. Thanks for the info, I found it to be what I was looking for BUT now how much does pertains to our 6.5's also. Pre or Post my Autometer EGT kit said to install in the down pipe which would be post turbo so does it matter much for the 6.5. And what temps should I see as normal ?
 

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This is a good question for John Kennedy or others that have more experience with the 6.5. I had a few of them but never did any engine mods.
 

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Hoot,

What happens to the hot water the turbo makes on the LB7?
I've been thinking that you could generate steam with all the heat coming off the turbo.
 

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quantum mechanic said:
Hoot,

What happens to the hot water the turbo makes on the LB7?
I've been thinking that you could generate steam with all the heat coming off the turbo.
Lot's of people have asked that question. My guess is there is a certain amount of convection current that moves heat away when she's shut down. A natural "rolling" of coolant. Cooling systems suppress steam with pressure and chemicals.Edited by: hoot
 

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It occured to me that steam formation is natural and could be harnessed to further the effiecency of the diesel engine.
Steam turbines power america, why couldn't it add to the power of your rig while keeping it cool?
 

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its all energy brother. think on!
 
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