Found 2 location options and was looking for opinions on which you think would be best option. debate.  

First pic is a secondary option which measures cyl 1-3 and is supposed to read hotter than the preferred position in the second pic of the rear collector area. In my mind the hotter the temps one sees it is more realistic of what is actually happening.

http://www.dieselmanor.com/diy/CMS3-gauge/CMS-gen3gaugeinstall.htm

 

 

I have mine placed on the top of the manifold similar to picture 1.

 

Picture 2 I think would be a problem if you have a divided port on the manifold.  You would essentially be placing the probe on one side or the other of the divide.

The manifolds all have a divider at the collector area preturbo up until the 6.7 which is open and has no divider like 12v, 24v vp and 24 cr have. But the preferred way on all the older ones was always the rear divider port like the preferred pic #2 but the main reason for that was that cyl. 4-6 were supposedly hotter and that was the reason to monitor there but this site claims cyl. 1-3 in the main manifold pre-collector is hotter which makes no sense as compared to all the other info I have ever seen.

It doesn't matter to me but I would like to see the hotter of the 2 temps myself, I think that would be more ideal but there seems to be a different thought process as which spot is hotter.

           until I get feedback from the masses. I am personally leaning towards the top of the manifold in the 1-3 location closest to the cylinders for a hotter more realistic reading but I want to hear your opinions as I am going to dig into the install in the morning.

Drill and tap both positions. Do some test and find out which one is truly hotter.

Might do that down the road, for today I think I am going to start on top.

Just got done doing the install and put it in the top of the manifold, no broken drill bits or taps or cross threaded adapter fittings either.

If it was me I would been in the collector of the manifold like in your second pick. 

mine is on top.

G-day Bill! after some research i used the lower location... i'm sure both are better then none! my experiance was that the casting drilled much easyer then i expected,..scared me, but it worked! just remember to keep an eye on the road! :woot:and not just watch the TOUCH!   MATTHEW

Either way you are only reading 3 cylinder temps, in the confluence it is seeing the rear 3 cylinders down stream, the top you are reading the front 3 cylinders upstream. Half dozen of one six of the other the way I look at it on this subject now......................I may get bored some day and drill the confluence in the rear section and see what it does in comparison, then I would have a second spot to access for drive pressure readings.

The other thing to keep in mind, Bill, is that the underside option might be boosting temps due to the restriction at the turn.  It might not be a "real" temp but an increased temp due to the sensor itself.  

The other thing to keep in mind, Bill, is that the underside option might be boosting temps due to the restriction at the turn.  It might not be a "real" temp but an increased temp due to the sensor itself.  

Which is why I drilled where I did, I want closer cylinder temps not altered exhaust temp downstream of the cylinders possibly being affected by other things. This is a different animal than the 2nd gen manifold.

I've never heard of 1-3 being hotter. Mine use to be on the 1-3 side and I moved it to the collector of 4-6 and it seemed to go up a little, but not much. The only reason I have ever heard of 1-3 being preferred is ease of install, otherwise everything I have seen is a recommendation to monitor in the collector.

6 is your hottest cylinder, which is why 4-6 in the collector is recommended probe location. 1 is your coolest cylinder, so that alone makes the 1-3 reading lower in addition to the increased surface area on the manifold causing temps to decrease from 1/2. It may not seem like much, but if it wasn't much manifold blankets would make a difference but they make a big one.

Due to the lousy design of the OEM manifold #4 had the worst flow, but 5/6 flow decent.

6 is typically the first piston to melt, followed by 4 with an OEM manifold.

Due to the lousy design of the OEM manifold #4 had the worst flow, but 5/6 flow decent.

 

 

Sound like someone needs to do a porting write up for exhaust manifolds.

Sound like someone needs to do a porting write up for exhaust manifolds.

It's not porting issue but more of a routing/casting issue.

It's not porting issue but more of a routing/casting issue.

 

I remember your write up on that John.

That's sure a weird. I didn't know that. Wow... Cummins/Dodge could of done a better job.