Engine/Transmission (1998.5 - 2002) egt probe

[BVFD ED]

where can I mount the egt probe besides in the exhaust manifold? I was thinking in the elbow that exits the turbo.

 

[telliott]

yeah you can put it there, but your temps will not be as acurate. they will read significantly cooler than the actual exhaust temps leaving the cylinders. most people will recommend putting it in the exhaust manifold pre-turbo but its really up to you.

 

[aircop]

Just remember that if you run the probe post turbo at times pre-turbo could be anywhere from 300-500* higher temp. I'd run it pre turbo, egt gauge reacts much faster.

 

[BSMcCauley]

Placing the pyro's temp probe post-turbo is better than nothing, but creates some mental gymnastics to estimate the pre-turbo temperature -- and that's the one you really want for an indication of engine system performance and power application level (so you can choose to lift your foot before burning a hole through through a piston or melting away the turbine wheel).



Some folks mentally add 350°F or so to the post-turbo temp to estimate the pre-turbo conditions. However, this is only accurate at a very specific set of operating conditions. For example, the pre & post turbo temperature difference is very small sitting at idle at less than 1 psi boost while quite large when pulling a load of hay up a 6% grade pushing 25 psi boost. This is because of the work (energy) extracted from the exhaust gasses by the turbine wheel to drive the compressor side and generate the boost. While it is true that a small amount of force against the turbine wheel is pressure from air being pumped through the engine, the by far largest force against the turbine wheel is the hot exhaust gasses expanding upon leaving the constraints of the cylinder and exhaust manifold. As they expand while pushing through the turbine, they also cool at a rate proportional with the work expended.



I drilled & tapped my exhaust manifold for the temperature probe for reasons detailed above. However, if this will be done in place, it looks to me like that was actually much easier as well when compared to the shape and position of the turbo's exhaust elbow. I kept the chips from falling down into the manifold by dropping a wal-mart bag over the air cleaner element and stuffing rags around the shop-vac's hose to seal it into the tailpipe and apply a positive pressure to the exhaust manifold. (wear safety glasses 'cause the metal chips are going to be flying back at ya!) And don't forget to remove the shopping bag from the air cleaner before cranking back up after the job's done.



View attachment 68602

 

[litespeed]

Put it in the manifold. It is much easier than it looks and you will get better readings "coming from the head".

I drilled mine with the engine running and used lots of grease. No need to worry about the shavings. They blow right out as you are drilling.

Edit: Pics in my readers rigs gallery.

 

[telliott]

you could always get 2 pyro's and put one at each location. Then you have accurate readings of both egt's and turbo temps. thats something i would like to do one of these days

 

[TboneMan]

I need to replace my thermalcouple on mine. I really dread trying to get the old one out.



I just hope I can get it out without messing up my manifold.