Pyrometer

[TomC]

Vertually every OEM truck Pyro is mounted after the turbo.  Now the temp for the particulate trap is right on it (replaces the muffler). 

I say (pre 9/11) the generating power plant on Kauai, Hawaii.  They had Wartsilla engines that were straight 8's that were 2 stories tall.  They had an individual pyrometer per cyliner, total pyrometer and a tachometer for the turbocharger!  Now that's neet.  Good Luck, TomC

[Jerry32]

I had a cummins that had the pyro pickup post turbo and it worked quite welll showing temps to 1300 degrees. Jerry

[Tim Strommen]

A pyro is great for dubugging Jakes (finding which side's solenoid is either stuck open or not turning on at all).  One half runs cooler than the other.  Twin pyros also can show a side (assuming a ''v" type engine) running hot due to high fuel injection (like a stuck injector or a slipped rack).

Of course having one behind the turbo makes this impossible as a diagnostic tool (as the different tempurature exhaust gasses would get mixed, and the tempuratures averaged).

I've heard of others using a pyrometer to determine combusion efficiency (over-fueling should have fuel continuing to burn as the exhaust valves open - thereby increasing the temperature in the exhaust manifold).  This temperature increase appears faster than the transfer of heat from the cylider jackets to the cooling water (and thus the water tempurature reading), and roughly the same time as black smoke would be working through the exhaust system.  This should be good if you do a lot of grades - you can tell when it's time to back off the throttle and down shift (this is how the Bank's computer upgrades work supposedly).

-Tim

[JackConrad]

I've heard of others using a pyrometer to determine combusion efficiency (over-fueling should have fuel continuing to burn as the exhaust valves open - thereby increasing the temperature in the exhaust manifold).  This temperature increase appears faster than the transfer of heat from the cylinder jackets to the cooling water (and thus the water temperature reading), and roughly the same time as black smoke would be working through the exhaust system.  This should be good if you do a lot of grades - you can tell when it's time to back off the throttle and down shift (this is how the Bank's computer upgrade work supposedly).

-Tim

This is how we used our pyrometer. When climbing a grade, I watch tach and pyrometer. As RPM drops, EGT rises. When EGT is 750-800 (RPM is usually around 1500), we downshift bringing RPM up to about 2000 and EGT drops to about 500.  Jack

[HB of CJ]

Post turbo pyro senders do have their place and in my opinion, the ideal setup would include 2, the primary in the normal position between the head and the turbo and the secondary placed close to, but outboard from the turbo on the down/out side of the turbine.  A properly marked two position switch would be required next to the boost/pyro gage.

This way you can analyze all sorts of problems within the mill and the turbo itself and also keep an eye on changing conditions with the exhaust back pressure/temperature situation which can explain/indicate muffler or spart arrestor conditions.  I for one enjoy having all that stuff available on the dashboard although 99% of the time it would be ignored. 

[JohnEd]

Henry,

I am with you....I want all the data I can imagine cause it only has to come into play once to justify the expense.

I had a vac gauge that i watched all the time so I would get better MPG and I installed an inclinometer for finding a level patch in the "space dujour" and save me some time setting up.  I saw an inch less of vac than i should have at 55mph and my incl. said dead level.  I stopped to check tires and found a hot rear axle.  25 mph for the remaining 15 miles into Sioux Falls and the shop found a fried bearing.  Mech said that mine was the first rear bearing replacement job he ever saw where the driver "caught" the problem in time to prevent serious damage to the axle and tube.  Yeah, I like all the data I can get.

John

[niles500]

****Of course having one behind the turbo makes this impossible as a diagnostic tool (as the different tempurature exhaust gasses would get mixed, and the tempuratures averaged****

And that is the intent of the pyro in our usage - there are other diagnostics available to measure other parameters of exhaust gases and resulting inefficiencies - FWIW