Temp Gun for Exhaust temp check

[katman]

If there is anyone who uses a temp gun for checking chrome header temp there is something you have to do first.
The I.F. guns are not accurate for metal so, you need to paint or use a piece of tape( high temp) for metering. IF your header is painted or ceramic coated you are ok.
My neighbour is an engineer for a company who makes the guns and he saw me using one on my bike. that is what prompted him to let me know about the inaccuracy of the numbers.
I asked him if it could be used for differential purposes and the answer was no.
I like to use it for checking heat from each cylinder for carb balancing.

Also, each gun has a distance to spot ratio. That means if the gun has an 8:1 ratio it measure a 1" square @ 8" away. IF you are 3 feet away it is measring surounding air along with the header so the reading will not be acurate. It will be low.

There you have it. something I did not know. I am sure there are a few others who didn't realize either so I am passing on this tid/bit.

[knowyourenemy66]

Thanks for the info--I was considering using one for the same purpose

[Steve]

Thanks for the info--I was considering using one for the same purpose

I have a small, cheap IR temp unit that I carry along with me. I have used it for many things and have noted that the readings vary wildly on shiny surfaces, not just metal. I also get very different air temperature readings outside, depending on which direction it is pointing. (Pointed straight up, it will read about 50 degrees, even though the air temp is close to 90.)

Personally, I would not use a temp gun to balance the carbs. You would have to be assured that the carbs are all perfectly jettted and working perfectly to have any hope of the temp gun doing an accurate job. Note that a lean mixture will burn hotter, checking that with your temp gun, you would be inclined to open up the richer (cooler) carb a little to add some more heat. I would think it is still better to use vacuum gauges to balance the carbs first. Then, when you are assured that they are all breathing the same amount of air, tweak the mixture screws to get the same temperatures.

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[bwringer]

Just cultivate a nice patch of rust on each header...

[katman]

I balance the carbs with drill bit and am now jetting with an LM-2 wide band o2 sensor/meter.
My temp gun has a probe in conjunction with the IR and is very acurate. I use it for head temp and EGT.
I also have a mini IR temp with no laser light. Acording to my neighbour they are very acurate as well but they need to be almost in contact with heat source to work right.

[gs road racer]

Used to use those in the injection molding business to get mold temps the molding surfaces could not be used always roughed up a patch on the clamping surface to check worked fine....not what you want to do on chrome though.The high heat paint would probably work well....Yamaha used to sell an EGA that worked very well but in recent times I've been looking at new EGA analyzers so much more to be had now for much less money. The Yamaha system I think was $3k in 1984 and some new systems are in the $1-2k range. What system are you using?Where do you put the probe for exhaust gas? Yamaha has a rivet system that could be used for each separate pipe. I don't know if they are available but must be something from the automotive side that would work.There's a local HD dealer that has a dyno with EGA going to see what they offer for tuning...the owner has a GS.....

[katman]

the probe goes in the tail pipe. You can get wide band o2 afr meters from 175.00. wifi to your iPhone or laptop. The Innovate LM-2 I just got is a stand alone hand held which is a couple steps up from what the local speed shop uses with there chasis dyno.
Around here it is 50.00/pull and some of the dynos don't have an analyzer which is fine for hp/tq but useless for tuning.

[posplayr]

Not to hi jack but I started a thread on using thermocouples for CHT and EGT or Header Temp

http://www.thegsresources.com/_forum/showthread.php?t=161402

[posplayr]

You would have to be assured that the carbs are all perfectly jettted and working perfectly to have any hope of the temp gun doing an accurate job. Note that a lean mixture will burn hotter, checking that with your temp gun, you would be inclined to open up the richer (cooler) carb a little to add some more heat. I would think it is still better to use vacuum gauges to balance the carbs first. Then, when you are assured that they are all breathing the same amount of air, tweak the mixture screws to get the same temperatures.

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So you would adjust mixture at idle based on header temperature rather than idle speed? What about at load? (assuming measurement was possible).

[posplayr]

I balance the carbs with drill bit and am now jetting with an LM-2 wide band o2 sensor/meter.

.

Drill bit ; Oh do you mean bench sync.....???

My temp gun has a probe in conjunction with the IR and is very accurate. I use it for head temp and EGT.

.

What are you using? Are you doing tests at idle or under load?

I also have a mini IR temp with no laser light. Acording to my neighbour they are very acurate as well but they need to be almost in contact with heat source to work right.

I started a thread to solicit advice on temperature based tuning. Thinking about how to configure thermocouples.

http://www.thegsresources.com/_forum/showthread.php?t=161402

[katman]

Just get an EGR thermocouple and gauge.

IF the carbs are perfectly jetted and sinked there is no need for a temp measurement. The temp gun was in place of other procedures. Same as the drill bit. You can go out and buy a 100.00 vacuum setup to sink them or... use the drill bit.

I guess hotter EGTs from timing could be detected as well but the first time I used it was to check for a bad cylinder. I had a bad plug and the one hole was quite a bit colder than the three others. Its not perfect but it is helpful in some situations.

My purpose of the thread wasn't to promote or defend its use as a tuning tool.

[Darkstang]

Good thread . In my current job, Ifrared Imaging is one of my responsibilities. We use it to monitor condition of switchgear and electrical cabinets/components.

Remember this and hope it helps.

For heat to be measured by infrared imaging, it is emitted like light from a flashlight. The amount emitted is determined by an objects "emissivity". A perfect emitter will radiate 100% of its heat as infrared light.

An objects rate of emission is determined by 3 things....
transparency,reflectivity, and absorbancy.

A perfect emitter is also a perfect absorber ! (black radiates and absorbs easily.)

A perfect reflector is a mirror! A perfect mirror reflects heat!

A perfect transperancy passes all light (of a certain wavelength)

I have to actually measure an objects emissivity for some of my imaging devices to get true temps. Any amount of reflectivity lessens the amount of infrared light that can be given off in relationship to the temp...




So if it is shiny, those little guns will be off! remember the spot ratio as well.


Katman, I am with you on the tools! my tool box will always have one of the guns in it regardless of it's shortcomings.