EGT Probes - Which & why?

[Dean]

Seems to be several to choose from, and many tout "fast response", yet for the most part give no specifications. (Rather like the claim by most of the gauge manufacturers of a "very accurate" fuel pressure gauge, but with no accuracy specification or guaranty.) I figure the smaller the better, for quicker heat gain/loss and less obstruction, but what do I know. The one I saw quoting a response of 50ms is not intended for prolonged use, only testing due to the degradation of the 0.005" probe wire.

Next is where. I know many put 'em in the DP or by the O2 sensor for aggregate readings, but I'm considering putting bungs in each individual pipe to find out which are actually leanest and track those. I'm presuming #5 & #6, but why not verify? I'm even looking at a 6-EGT selector switch and considering leaving the probes in each pipe, more out of curiosity then necessity. Just kinda seems if there is a single probe in the DP or by the O2 that an aggregate temp of, say, 1550, could include perhaps 4 cylinders at 1475, 1 at 1600, and 1 at 1800. And the 1-3-5 bank will be cooled by some degree, who knows how much, during its travels through the crossover.

Am I over-thinking this?

 

[salvageV6]

Check Omega engineering site for specifications they are usually pretty good with valuable info. on models and options.

I think the 1/8" diameter probes would be in the proper size range for response and durability assuming the ratings are proper for the use.

Not to mention mounting easy and fixturing/fitment.

Make sure you can log all 6 probes at once or in a fast sequence if using a switching device.

Your assessment is pretty dead on as far as I can tell.

6 would be the optimum setup placement would have to be equal however.

 

[Dean]

Thanks, salvageV6.

I won't be able to log all 6 at once, just view, except for whichever two are hooked up to the Power Logger. Though if there was a way, that would be very nice! It could to be separate software, but something needs to correlate the timing of the two files. Or maybe next year Power Logger II will have 10 analog inputs. More, MORE, MORE!!


Yes placement is something I am pondering. I have read that optimal placement is 1/2 the pipe diameter from the flange, but if it is that close seems you would need to know where the higher volumes are coming out of the port. It could be left or right side, or the floor or ceiling. I'm thinking equidistant from the bends at each port.

 

[Chrisk]

Would any of these work???

Low Cost Hollow Tube Thermocouple Probe Model Numbers HHTC36-(*)-116G-(*) Available in J,K,T,E, N Thermocouple

Compact Transition Joint Thermocouple Probes

Super OMEGACLAD® Thermocouple Probes - Quick Disconnect Probes with Miniature Size Connectors

 

[Dean]

Nope. Need NPT mounting (and I notice that first one is rated to just 450º).

 

[salvageV6]

Actually they would work fine excepting ease of mounting and insuring they would all be in the same position.

A clamp type would work, or the NPT mounting type or a compression mounted type fitting.

Those small diameter probes are pretty fast response and well made we used them to measure some temps. on flame sprayed shafts at work.

Occasionally one would melt or break the tip off, severe conditions and we used the braided shielded armored cabling on ours.

Lots of options with Omegas stuff, makes it hard to read the part numbers sometimes since most of the number is important options.

 

[Dean]

But they are 6" probes!

 

[Chuck Leeper]

We use the "K" probes, mounted 1" off the header flange.
Clock location did not seem to make a difference.
I've also used the "K" in the header, just under the turbo.
Installing it in the dp is pretty much useless, as alot of heat has been rejected by the exh housing...
Whatever location you use, DO NOT bend the shaft to get clearance!!

 

[salvageV6]

The reading point on the Omega probes is in the very tip where they are joined/welded together (two wire types). You can bend those a bit further back but mounting again would be an issue with that type.

You only need to get the last 1" or so near the heat to make them work.

JEGS has them in their catalog, about $150 with probe and mounting device each.

Street version is a clamp on which would work nice for the header log area.

They also have a nifty data logger setup with probes for about a grand.

I have a fluke data logger I'd use with 24 inputs that runs on 12 volts but haven't seen the need to use it yet in the car to log stuff. Luckily I found it in the dumpster before the trash guy got there.

 

[Dean]

10-4 Chuck, thanks. Any particular probe you favor? (Side note: all hot links on the CODYMOTORSPORTS home page are dead.)


Salvage, where is that dumpster, and do you keep checking it?

The Electronics International E-6 Digital Six Probe is one setup that caught my eye a while ago, though now I see this:

Sweet. Tad pricey though... and mounting might be, um, interesting.