I've been thinking of getting a temp reader to monitor engine temps so I went to the local electronics store to test some out.

What I found was that even among the more expensive temp guns (RayTek MT4, QuickTemp by Linear Labs) which are $70-120, the temp reading against a fixed object varied by more than 10 degrees.

Question is...how do we figure out the "true" accuracy between these temp readers? I read somewhere about pointing it at boiling water, but was wondering if that was an accurate way to gauge the reading or are there other ways to do that?

If you have a good way of knowing your elevation then
you can pretty accuratley figure out what temp water will
boil where you are. It should vary by less than a few degrees.
You dont need any better accuracy than that for your engine.
+-3 deg isnt a problem.

Thanks. Actually, I wouldn't mind +-3 degrees, but even among the expensive non-contact ones I saw at least +- 10 which made me wonder how good the lower end ones (like the one from Radio Shack), or the ones which loop around the engine head are...if they aren't that much worse, then I would just opt to get a cheap one; however, I was thinking that a good non-contact one would be useful for checking other things around the house.

I have one of the Raytek MT4's, they are really good for the money. A friend of mine has an Exergen precision gauge that is calibrated (Uses it for work). The MT4 was only a couple of degress off consistantly when we compared the two.

I have also compared the loop style mip gauges and while I have read that they are not accurate, I have to disagree with that somewhat.
Let me explain what I mean, the MIP gauges use Thermistor or electronic element that relays the temperature. The element has a rating in response time and range of temperature.
It is known that in the first generation gauges that there was latency in the time it takes to relay the temperature to the display. This could appear as inaccurate because what you see on the screen is not what you see on the head of the motor. Given a short amount of time however and the display will show the correct temperature.
They had this type of technology in the Personal computer temperature probes back then as well. You could monitor CPU for overheating while overclocking, however in some cases your CPU would overheat before you even have a chance to know about it because of the latency.
I now use my raytek to not only temp my Nitro engines but my personal computer projects as well as other things.
Temp probes have improved in the PC electronics as I assume in the MIP gauge also, but I have not used one of the new ones.

Dbow

Thanks for the detailed explanation! I'm leaning towards the MT4 since it's about 1/2 the price of the QuickTemp and from the sounds of it...pretty accurate.

How long have you had the MT4? Any problems with the quality of construction? Is it pretty durable?

I also use a raytek. I t seems like a lot of guys at my local
track do.

I have a Raytek also. Works great. Love it.

Well, my raytek came in. It's sweet! I just love hardware...much to my wife's disappointment. Hehehe

Glad you got one. It makes a big difference.

whats the difference between the mt-2 and the mt-4?

Good question.

The MT4 has a laser dot aiming mechanism, the MT2 doesn't have the laser sight.

Don't laugh but the best way I have found is set it where the beam will shoot inside your ear. You know it should be about 97-98. I have have the small one from Radio Shack and it reads 98 every time. I don't know about the Raytech. You might not be able to get it, but just work with the angle. And again I'm not joking, its a sound procedure.

inside the ear is a great checking method! I just love it when one tells me I'm at over 100 degrees! Then I knew not to get it!

do any of them have an actual "beam that cocmes out or is it just the dot like the laser pointers?

no difference between the 2 and the 4 other than the dot?

It's puts out a little dot like a laser pointer. It's powerful enough to have a hazard warning about pointing at peoples eyes. Although, not powerful enough to blast starships and what not......

The specs seem to be the same otherwise.

One thing to note about these temp gauges is that the distance from the object you are temping makes a difference.
Its best to hold it as close as possible for the best results. The further you pull it away the less accurate it is. This is because the field of view increases as the distance increases.


Dbow