Pyrometer Question
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From: Rural Central Ohio
Pyrometer Question
I've been looking online for awhile and I have noticed that a lot of people are tapping for the pyrometer probe as close to the engine as possible (exhaust manifold) but read the autometer instructions and they said that the most accurate would be in the exhaust piping 2-3 inches before it hits the turbo.... Which one will actually give me the most accurate reading?
Thanks again....
Thanks again....
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Well here is what I know. My PSD had a pyro in the down pipe just after the turbo when I bought the rig. It would never read over 800 degrees and the needle swept over the dial very slow. I'm guessing because a lot of the heat was lost thru the turbo by then.
I installed a pyro in the drivers side manifold just before the flange. Now the needle goes up very fast as I give it fuel. And it will show higher temps instantly.
I installed a pyro in the drivers side manifold just before the flange. Now the needle goes up very fast as I give it fuel. And it will show higher temps instantly.
Last edited by vancouverpower; Mar 20, 2005 at 05:26 PM.
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From: Cabot, Arkansas
Which one will actually give me the most accurate reading?
Highboy. I'd be interested in what the circumstances were when a thermocouple probe burned off. The thermocouple probe used in aerospace and automotive applications that I've seen are made of Inconel, and would require a sustained temp of nearly 2000*F to melt.
I've pulled many melted t-couples from jet engines, but even the few pulling trucks I've been around only get temps that high for a few seconds at a time.
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Originally Posted by cookie88
Pre-turbo. Either in the exhaust manifold or in the up pipe right behnd the manifold.
Highboy. I'd be interested in what the circumstances were when a thermocouple probe burned off. The thermocouple probe used in aerospace and automotive applications that I've seen are made of Inconel, and would require a sustained temp of nearly 2000*F to melt.
I've pulled many melted t-couples from jet engines, but even the few pulling trucks I've been around only get temps that high for a few seconds at a time.
Highboy. I'd be interested in what the circumstances were when a thermocouple probe burned off. The thermocouple probe used in aerospace and automotive applications that I've seen are made of Inconel, and would require a sustained temp of nearly 2000*F to melt.
I've pulled many melted t-couples from jet engines, but even the few pulling trucks I've been around only get temps that high for a few seconds at a time.
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Neither method is any more "inaccurate" than the other. Just the turbo outlet side generally shows about 2-300 degrees cooler than if the same thermocouple were on the inlet side. Basically your turbo is converting heat and velocity of flow into energy (which is then imparted to the inlet turbine, then the air, end result is now pressure) at a rate of 2-300 degrees per pass through. The slower action of the dial is likely caused by the turbines change in state (spooling up or down). I find that when I'm at max boost the needle is very responsive, as no further change in state is possible. And when I'm slow around town it is sluggish as the turbo has a very wide range it must go through while absorbing energy.
Either inlet or outlet is fine but on the outlet side pipes are readily available with a pre drilled bung for easy install. You could drill your own if you wanted with less likely hood of metal flakes entering your turbo. The pyro runs cooler and has extended life. And there is NO chance of the pyro eating the turbo in the event of failure. On the inlet side you have none of these benefits. But it's cool if you like to watch the needle move.
Either inlet or outlet is fine but on the outlet side pipes are readily available with a pre drilled bung for easy install. You could drill your own if you wanted with less likely hood of metal flakes entering your turbo. The pyro runs cooler and has extended life. And there is NO chance of the pyro eating the turbo in the event of failure. On the inlet side you have none of these benefits. But it's cool if you like to watch the needle move.
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Postmaster
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From: STEPHENVILLE,TX!!!!!
go pre turbo
ive melted holes in pistons and burned off exaust valves but never had a problem with a autometer probe
(long story big turbo bigger injectors) h20 meth didnt get mixed, peg a 1500 degree pyro before you can get your foot out of it.
ive melted holes in pistons and burned off exaust valves but never had a problem with a autometer probe
(long story big turbo bigger injectors) h20 meth didnt get mixed, peg a 1500 degree pyro before you can get your foot out of it.
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On the Allison 501 K34 Model 140RF Turbine Generator I used to do maintenance on they were after the HP turbine and we used what was called "Calculated Turbine Inlet Temp, (CTIT), Other models of the same engine used were before the HP turbine and just used TIT, The reason was extended life of the couple and risk of turbine damage in the event of failure.
Melted pistons and valves from doing experimental hot rodding (I apologize bareback...My truck is destined for the track too) is a whole lot different than making sure your turbo is cooled before shut down to prevent coking and bearing failure. I always make sure my turbo has cooled to 300 degrees...350 if I'm in a super hurry.
What would be really cool is get one of each
but whatever.
Melted pistons and valves from doing experimental hot rodding (I apologize bareback...My truck is destined for the track too) is a whole lot different than making sure your turbo is cooled before shut down to prevent coking and bearing failure. I always make sure my turbo has cooled to 300 degrees...350 if I'm in a super hurry.
What would be really cool is get one of each
but whatever.
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From: STEPHENVILLE,TX!!!!!
pucko, yeah we will all miss him, i met him at a rodeo in st george utah 5 years ago, signed the back of my buckle i won that weekend ridin saddle bronc. just a timed event guy now. it was getting hard paying the bills ridin roughstock.
i would still go pre turbo cause on theese diesels the estimated pre turbo temps arnt reliable. on the other truck i had one on both sides and alot of the time the numbers just didnt correlate to what was going on.
i would still go pre turbo cause on theese diesels the estimated pre turbo temps arnt reliable. on the other truck i had one on both sides and alot of the time the numbers just didnt correlate to what was going on.
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