Best place to drill the exhaust manifold for the exhaust temp sender ?

[1951M1078]

Working on my M1078 / Cat 3116 and need some input on installing the exhaust temp sender.

The fitting I have is a 1/4" NPT. But where is the best place to cut the hole ?
Can I use grease to hold the cuttings to the tap ?
Or do I need to pull the header ?

Thanks, Randy

 

[snowtrac nome]

I would rather weld a bung into the down pipe than risk causing a future crack in a cast manifold

 

[1951M1078]

Ok,Snow.

Where would you put it ?

 

[scottmandu]

You want to put it as close to the engine as possible, just before the turbo charger.

 

[1951M1078]

On my Semi it is about 1 1/2" after the turbo ?

 

[snowtrac nome]

the ones I have seen are all right behind the turbocharger usually just before the elbow down or right after it I know a lot of kits say drill the manifold all the oe installation's I have seen are in the pipe

 

[scottmandu]

OEM diesel installations require measuring exhaust gas temps at the inlet to the exhaust gas treatment equipment. This is why many sensors are installed post turbo.

If you want to know true EGT, then you want to measure the temps immediately after the exhaust valve and before the turbo. Turbocharged gas powered Audi/VW/Mercedes/BMW/Porsche etc all have factory EGT's installed between the exhaust valve and the turbine inlet. This is in the event the EGT's get too high the computer can compensate with a reduced power output to cool things off as there can be a significant temperature difference of the exhaust temps pre turbo to post turbo.

 

[coachgeo]

Compromise??? drill hole in Ex Manifold but weld a?? around it for extra strength? or...... do post turbo but calculate how much loss in temp between post and preturbo and compensate for that when you watch your EGT guage?