Where to tap EGT probe on stock exhaust?

[SiberianPatrol]

Ok mates, I'm finally to the point where I've got my Patrol GU 2.8 ready for my DIY projects. I've got my EGT gauge and boost gauge to wire up and install, and while I have found some great wiring posts for the gauges, I can't find anything on where to tap the EGT probe.

I've read that pre-turbo is the best place to tap for the most accurate readings, but I know many tap into the dump pipe post turbo. Can anyone give advice on the best place and way to insert the probe?

I don't want to weld a bung in since its factory exhaust and I'll upgrade it later, but it won't be for a couple of years. I'm hoping to just tap a threaded hole and insert the probe.

Open for advice. Thanks.


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)

[SiberianPatrol]

So no one has any input on which is better - pre-turbo or dump pipe installation?

[threedogs]

mine is about 4"-6" after the turbo on the dump pipe.
Mine is a 3 ltr though

[the evil twin]

So no one has any input on which is better - pre-turbo or dump pipe installation?

Pre- turbo is better in every way except one.
That is the difficulty in installing the probe on an assembled engine.
Swarf etc from the drilling ends up in the plumbing.
Post turbo no drama a all so noone cares, pre Turbo causes problems so everyone usually takes the easy option

The biggest reason for pre turbo is that post Turbo EGT's are only a guess as far as combustion temps.
The actual combustion temps are unknown as the delta T across the turbo can vary significantly and be 100 to 250 degrees or more different and it is not a constant either.

[SiberianPatrol]

Pre- turbo is better in every way except one.
That is the difficulty in installing the probe on an assembled engine.
Swarf etc from the drilling ends up in the plumbing.
Post turbo no drama a all so noone cares, pre Turbo causes problems so everyone usually takes the easy option

The biggest reason for pre turbo is that post Turbo EGT's are only a guess as far as combustion temps.
The actual combustion temps are unknown as the delta T across the turbo can vary significantly and be 100 to 250 degrees or more different and it is not a constant either.

So the best option is to pull the manifold and tap the probe there, then reinstall? What temps are considered normal for the 2.8 pre-turbo?


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)

[the evil twin]

So the best option is to pull the manifold and tap the probe there, then reinstall? What temps are considered normal for the 2.8 pre-turbo?


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)

If you are after accuracy then the answer is unreservedly Yes.

Unfortunately I know nothing about the 2.8 engine as I have only ever had 3.3, 4.2's and 3 litre
Maybe 700 C max continuous as a wild guess

Some engines people have tapped into EGR (dunno if 2.8 has it) but try and avoid extremities IE near #1 or # 6,

[SiberianPatrol]

If you are after accuracy then the answer is unreservedly Yes.

Unfortunately I know nothing about the 2.8 engine as I have only ever had 3.3, 4.2's and 3 litre
Maybe 700 C max continuous as a wild guess

Some engines people have tapped into EGR (dunno if 2.8 has it) but try and avoid extremities IE near #1 or # 6,

Thanks. I'll have to look at it to see what I can get to with my limited setup. I may wind up having to do it post-turbo. I'll do a little research on the safe temps for the 2.8


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)