Post turbo egts

[notlimah]

Well guys I finally got my hands on a quad adr so I’ll be joining the V2 tuning addiction soon enough.

 

With the quad I’ll know have the option of doubling up basically all of the gauges I currently have. For the sake of simplicity and laziness, I don’t plan on doing except for the EGTs so I can have the turbo timer. With that, I’d like to try and mount my second egt probe post turbo but haven’t really seen much talk of that done on 2nd gens.

 

Are there recommended places to mount these? Any downpipes that come with a port already welded in place?

[Silverdodge]

Lot of people mount it in the down pipe elbow but egts will be 200 degrees cooler then mounting in manifold

[notlimah]

17 minutes ago, Silverdodge said:

Lot of people mount it in the down pipe elbow but egts will be 200 degrees cooler then mounting in manifold

 

Do you know of any pre-made downpipes like that? Or are they all fabbed up by whoever’s doing that?

[trreed]

I don't know about any pre-made downpipes like that.  But it's just an 1/8" NPT bung that would be welded in there.

[AH64ID]

Post turbo is the best spot for a turbo timer since post temps are generally higher than pre temps until the turbo is fully cooled down. I wait until my post turbo temps are under 350° to shut down on my water cooled turbo, around 300° is probably good for a non-water-cooled turbo. 

 

Welding a bung onto the downpipe is the easiest. You will want it as close to the turbo as possible. 

6 hours ago, Silverdodge said:

Lot of people mount it in the down pipe elbow but egts will be 200 degrees cooler then mounting in manifold

 

There is more to in that just a 200° delta. Post can be higher or lower than pre, and it can also be the same or up to 300°+ different. 

 

On my truck the pre-post difference is pretty close to 10° per psi of boost, so at 28 psi I show about a 280° delta. 

 

On a heat soaked turbo the post temps can remain higher than the pre-temps for a descent period of time in the right driving conditions. 

 

Post can be a great reference if you understand what it's telling you. I only use my post for shutdown temps, and at lower rpms the post is a better indication of exhaust/turbo heat soak. 

[IBMobile]

You can drill and tap the hole if you don't have a welder.  I did mine 13 years ago. 

[notlimah]

51 minutes ago, IBMobile said:

You can drill and tap the hole if you don't have a welder.  I did mine 13 years ago. 

 

Did you drill and tap the same as in the manifold? Just so I’m seeing it correctly that’s the curved piece headed down to marry up with the down pipe correct? Any reason yours is tapped on the side?

[IBMobile]

1 hour ago, notlimah said:

Did you drill and tap the same as in the manifold? Just so I’m seeing it correctly that’s the curved piece headed down to marry up with the down pipe correct? Any reason yours is tapped on the side?

It's done the same as the manifold.

Right, the curved piece is the bent top of the pyrometer thermocouple.

Can't remember why it was drilled on the side but it worked for years.  The thermocouple was relocated to the manifold and that fitting is capped. 

[notlimah]

Gotcha. Well since this’ll be my second egt probe, I’m fine with it being there and should work perfect for my purpose. Thanks for the idea! 

[Dieselfuture]

I have my Quadzilla probe in the manifold to control defueling and monitor in general, and I have my mechanical ss pro gauge in my exhaust brake that is bolted to the backside of the turbo, it came with a port  already  threaded. 

Congratulations on the quad

[notlimah]

Thanks for the input. I think I’m going to tap into the same place IBM did so I can have pre and post turbo temps! I don’t have an exhaust brake