Best Location For Pyro

[CKruse]

Can anyone post a pic or two of their post turbo pyro install? I'm doing mine in the next few days, and want to go that route for my purposes (towing with a stock motor). Thanks in advance if you can help. CKruse

 

[rbattelle]

I posted a pic in this thread. . To do this, I actually removed the elbow, installed it in a drill press, drilled the hole, tapped, then re-installed the elbow. Probe is about 2" downstream of the turbine exit.



-Ryan

 

[Bertram65]

There is one in my reader rig of a post turbo pyro.

 

[Highfinance97]

Melting point

In the new "diesel power" mag. you can read all about the placement of the probe on pages 155-160. Its titled "Melting Point":-laf

Not to bad of an article

Michael

 

[CKruse]

Thanks guys, that helps. CKruse

 

[RJOL]

This thread is almost as famous as the "oil wars" threads of the past. I'll throw in my 2 cents...



If you want an accurate measure of what the temps are as close to the cylinders as possible, you install the probe pre turbo. I put mine in the 5/6 manifold joint (see readers gallery). I don't have to worry about adding 200-300 to the readings, what the ambient temperature is, or how I'm feeling that day.



I have never seen a single post that a member has shown a failed probe that took out the turbo. If it has happened it is extremely rare or someone has power moded their engine to very high temps.



I think the "shavings in the manifold" issue is over rated. If you are careful, use grease on the bit, stop and clean it off just before you break through the manifold, use a magnet or vacuum out the hole, and then just start the engine and let it idle to blow out any other small chips, you will be alright. I think removing the manifold or turbo is overkill. JMHO... Now on with the war...

 

[DPKetchum]

Been reading diesel forums for like 6 years amost daily. NEVER read a post of a failed probe in any generation. I'll say it ONE more time. Until the 3rd generation trucks it was NEVER posted or hinted to run a probe POST TURBO. Towing,racing or for any reason,.

 

[rbattelle]

I'll say it ONE more time. Until the 3rd generation trucks it was NEVER posted or hinted to run a probe POST TURBO.

I did a search in the 2nd generation forums for "+post +turbo +probe" and came up with 162 threads where it was discussed. Here's a sample from 2002.



Every time this comes up we end up in an argument. Mine is post-turbo for exactly one reason: I want to monitor the turbine exit temperature, NOT the engine exhaust temperature.



-Ryan

 

[RJOL]

Been reading diesel forums for like 6 years amost daily. NEVER read a post of a failed probe in any generation. I'll say it ONE more time. Until the 3rd generation trucks it was NEVER posted or hinted to run a probe POST TURBO. Towing,racing or for any reason,.

This debate was going on (on the forum) when I installed my probe in the manifold of my 2001 and it is still going on today. It will probably still be going on when the 4th, 5th, 6th, 7th, and 8th gens come along...

 

[BTighe]

come on now everyone knows the best place to install the pyro in the tailpipe. youll never peg that thing Oo.

 

[nickleinonen]

Mine is post-turbo for exactly one reason: I want to monitor the turbine exit temperature, NOT the engine exhaust temperature.



-Ryan

and mine is pre turbo as i want to see what kinds of temps the pistons are seeing.



if i cook a turbo from overheating it i don't really care. ~$1000 and i am running again rather quickly. if i cook a cylinder a whole lot more money and more downtime. .



if i had the time/money/skill i would rig up a system with 6 pyrometers with one being in each runner right at the head, and an ecm controling what i see [either show me the highest or average the numbers] and it would be nice if it could be tied into the ecm fueling the engine, to adjust fueling paramaters to balance the combustion temprature in each cylinder [balanced temps = balanced cylinder pressures assuming all flow well/equally in/out]

 

[HerveyD]

I agree with Nick. That is the main reason for monitoring egt. If a piston melts we have big trouble, assuming the possibility of assorted pieces of piston then going through the turbo causing major turbo problems we have a more expensive fix, to say the least.

 

[Bekim]

Been reading diesel forums for like 6 years amost daily. NEVER read a post of a failed probe in any generation. I'll say it ONE more time. Until the 3rd generation trucks it was NEVER posted or hinted to run a probe POST TURBO. Towing,racing or for any reason,.

Exactly what comes to mind! I have never read any thread in the thousands i've read that talked about turbo damage by filings. Broken taps and other such mishaps, but not metal shavings. These EGT probe placement threads are started almost daily on one of the forums I follow and the same stuff about turbo damage gets thrown in every time. I understand that this is why everyone is so concerned. It's like a tiny story made into a huge story by the media hype. Ridiculous!!
Mike
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[BSMcCauley]

The difference in gas temp pre vs post comes not from the difference in distance from the engine. The temp difference is becasue the turbo has extracted energy from the exhaust gas to compress the incoming stream.



The function of the turbo is to expand exhaust gas, therefore lowering the temp (PV/T).

Exactly right. Accuracy of post-turbo temp is not the issue. It is relevance. The turbine exit temp is only relevant to the engine exh temp if you know how much work is being done by the turbo at the time. More work = larger temp drop across the turbine wheel. Principle used in industry all the time to get larger temperature drops in cryogenic processes than are possible by simply dropping the pressure through JT valve like your air conditioner does. The 200-300 degree drop across the turbo's turbine is simply a rule of thumb. If the boost is low, the temp drop across the turbo will be low. When the boost is high, the temp drop will be too. Putting the temp probe upwind of the turbo saves you a lot of mental gymnastics with ESTIMATING what the relevant exhaust temp actually is while accounting for all the variables in that equation. I choose to get a direct reading and that means pre-turbo.



For those worried about burning up a turbine wheel: the turbine inlet temp is the important one. The hottest part of the turbine is going to melt first and if temp is increasing across the turbo, then the laws of thermodynamics are being violated. You want to know if you've got engine problems as soon as they occur, and if you are running in a high EGT situation, you are almost certainly also running high boost as well. High work = large temp drop; therefore, the turbine is dampening out the temperature spike at the post-turbo probe while the pre-turbo probe sees the problem immediately. If you wait to see temp rise at the turbo's outlet, the turbine wheel may already be damaged or destroyed. On the large industrial engines I work with on the job, the pyrometer probe is ALWAYS pre-turbo with many examples of a temp probe in each engine cylinder exhaust port.



Regarding drilling/tapping the manifold while on the engine, try this: pull the air filter and drop it back in with a plastic bag across the outlet (clean) side. Then put a leaf blower or shop vac in the blow mode on the tailpipe. Wear safety glasses because the chips are going to come flying back at ya!Oo. This is a lot nicer than running the engine because not only is it a lot cooler, you don't have to deal with the noise, fumes and vibration either. :-laf Also second the earlier mention of punching through a small pilot hole first before drilling the final size.



Oh, and remember to remove the plastic bag from across the air filter when you're done!:-laf