NoSeeUm

I thought about that one, but it gets up under the cowl some and hard to install / remove especially with the manifold flipped. The 6-5 is hard enough to get to.

The two I am using, one is the 6-5 and other is only 1. I can see allot of temperature difference between these two. I mean like 200-300F.

Jim

jp8819

Found the following information reading up on thermocouples in a faq

"6. Dual probe configurations:

(#2) Q: I only have room for one thermocouple probe in my process, but I want to have both a local readout as well as a remote display in my control room. Can I still do this?

A: Neither thermocouple, RTD, nor thermistor signals can be "split" to go to more than one readout; however, most OMEGA temperature probes can be made in a dual configuration. Dual probes generally hold the exact same outer dimensions as the single version and make retrofitting easy."


and also found this might solve some problems not sure if it would work or not.

http://www.omega.com/pptst/TC-K-NPT_RTD-NPT.html

Looks like a type K thermo couple with dual wires for like what some of you are trying to accomplish and possible me in near future. Keep in mind this was in a machine control and not on a truck but I think all type K thermocouple should be the same.

Cole_56

So would i want the adrenaline to be right at post turbo or in the 5-6 area because it defuels when it hits 1250 whitch one

XLR8R

Good info & points all around guys!

Nice to see such a high % of truth in a thread...

I have an OEM dual circuit Type K in the shop, but I don't see a need to use it unless you want to test a suspect gauge for pass/fail against a known good unit.

Pre & post turbo are fine to measure the actual delta T, but once that's determined, it's just a waste of dash space... take the post-probe and install it into the airhorn or pre-CAC for tuning purposes.

CamperAndy

The only real problem with the OMEGA site is they are trying to sell thermocouples. In an industrial application a dual element probe makes sense in a location where there is not room for 2 separate probes but there are plenty of single element probes that go to a local indicator with a V-I converter and the signal is then sent to a remote control room.

Also you can look at it this way. With a single element thermocouple connected to a gauge or other control device for a single source/single use application and then you take a test instrument to check the operation of the thermocouple, does this compromise the thermocouple signal? No it doesn't and during this check you effectively have 2 reading devices on a single probe. As long as the reading devices have a high impedance input then you can safely stack several reading devices onto the thermocouple with no effect.

justme-

That is a good site.
They are stressing the CLC aspects, which are the most concerning, but the length of wire in any circuit will affect the accuracy- I'll recant and admit the accuracy we need and obtain for our use you're probably right the resistance would have to be a gross error. The last time I was involved with using a TC was (several years ago) controlling temps with precision requirements around the max (1*C) possible and connection resistance did play a factor.

BTW if you want to see pre-post temps, like around a turbo there are multi source gages that can accept multiple TC inputs.

justme-

That can be accomplished the same as the dual input gage systems- the TC leads go to a circuit box which reads and calculates the voltage then separately sends the signal to a display gage, if designed appropriately the "box" could send the signal to 100 different gages with no effect on the TC accuracy because the gages and gage connections are not in the circuit with the TC leads.
The newest generation of gages are micro stepper motor controlled needles and require such a brain box to interpret the sender unit's signal and send a controlling output to the gage.

HOHN

I'm reserving the post-turbo hole in my elbow for one of these someday:

NoSeeUm

If it were me, I would pick the more common location in the common tube just before the turbo flange on the 4-5-6 pipe. The 5-6 location on my truck is mostly because the exhaust manifold is flipped and the T/C can no longer be mounted there. Still it seems like a very hot spot.

If you decide on going with 5-6, be careful where you drill. There is some sort of a director / deflector plate in all the tubes except 3 and 4 (at least on mine OEM). You don't want to hit it.

I wish I could put one in all six so I could compare. I remember seeing a thread by Comp461 over on TDR where he has all six on a data logger. As I recall number 5 was the hottest and number 1 was the coolest on that trace. His drag truck is a CR.

Personally, I would not use post turbo EGT for engine protection. Post turbo is older technology where the T/C's used to break more often. Although, I did have one on my truck for a bit. I was running a Banks brake that had a pre-tapped hole so it was easy. I only had it there mostly for curiousity reasons.

Jim