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Old 08-18-2009, 10:50 PM   #1
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Default DX3S Temp Sensor

Has anyone had concernes about the accuracy of the DX3S temp sensor?

I have been tuning my 1:8 nitro with a heat gun and usually it sits around the 180 f using the gun. I got the DX3S recently and gor rid of the gun ran it last night (cold night) and it hit 239 and was climbing, I had to shut it down before it did 3/4 tank. It was in a parking lot, flat and sealed.

Any ideas? I followed the instructions on its install and wrapped the sensor where head meets heat sinks.

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Old 08-18-2009, 11:10 PM   #2
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Has anyone had concernes about the accuracy of the DX3S temp sensor?

I have been tuning my 1:8 nitro with a heat gun and usually it sits around the 180 f using the gun. I got the DX3S recently and gor rid of the gun ran it last night (cold night) and it hit 239 and was climbing, I had to shut it down before it did 3/4 tank. It was in a parking lot, flat and sealed.

Any ideas? I followed the instructions on its install and wrapped the sensor where head meets heat sinks.

Put it on the 3rd or 4th fin if you need the temp to go down as far as being accurate.
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Old 08-18-2009, 11:11 PM   #3
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I hope I don't come across as an elitist by saying this, but those DX3S telemetry things are more novelty than useful. The radio is fine, especially for the price, but the temp sensor is notoriously inaccurate. I've read across several forums about people shortening their engine life because they assumed that it works.

You noted a big disparity between your temp gun readings and the DX3S readings. Your temp gun may be inaccurate as well. I own a $300 one (Exergen) and a $50 one (branded as OFNA). The expensive one is always accurate, but the $50 one reads colder and colder (as much as 30ºF) as the sensor gets dirtier. If I clean the sensor (using my t-shirt), the $50 one is more accurate again.

If you're running in a parking lot, avoid the temptation to run it wide-open-throttle very much. The gearing in 1/8 scale buggies and truggies is not for top speed (like a Jato is), it's for meeting the demands of off-road tracks. Your engine temps will run very hot with long runs of wide-open-throttle.

Hope this helps.
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Old 08-18-2009, 11:29 PM   #4
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Put it on the 3rd or 4th fin if you need the temp to go down as far as being accurate.
Would it still be accurate? I was always told the temp of the head is whats important not the heat sinks?
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Old 08-18-2009, 11:41 PM   #5
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Originally Posted by markr04 View Post
I hope I don't come across as an elitist by saying this, but those DX3S telemetry things are more novelty than useful. The radio is fine, especially for the price, but the temp sensor is notoriously inaccurate. I've read across several forums about people shortening their engine life because they assumed that it works.

You noted a big disparity between your temp gun readings and the DX3S readings. Your temp gun may be inaccurate as well. I own a $300 one (Exergen) and a $50 one (branded as OFNA). The expensive one is always accurate, but the $50 one reads colder and colder (as much as 30ºF) as the sensor gets dirtier. If I clean the sensor (using my t-shirt), the $50 one is more accurate again.

If you're running in a parking lot, avoid the temptation to run it wide-open-throttle very much. The gearing in 1/8 scale buggies and truggies is not for top speed (like a Jato is), it's for meeting the demands of off-road tracks. Your engine temps will run very hot with long runs of wide-open-throttle.

Hope this helps.
Thanks for the info, I assumed it would be accurate, these are quite expensive here in oz. I might try and get ahold of the heat gun again and compare them, if its not accurate im going to remove it, its taking voltage and if its not accurate whats the point?

I wasnt driving it that hard, did a few high speed passes but also took it easy for a while as well.
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Old 08-19-2009, 12:01 AM   #6
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i have a $100 temp gun and recently bought a dx3s and it reads the same temp as my expensive temp gun. and its off only a few degrees ever.
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Old 08-19-2009, 03:48 PM   #7
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i have a $100 temp gun and recently bought a dx3s and it reads the same temp as my expensive temp gun. and its off only a few degrees ever.
Can I ask where you have the sensor on your engine? Is it where the manual says to put it, where heat sinks meets engine?

I borrowod a kingchrome heat gun last night off a mate, very expensive one, and compared it. Difference was 5 deg c cooler compared to what the radio was showing.

I am considering putting the sensor on the lowest heat sink instead of it being wrapped around the head as it is now. What do you think?
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Old 08-19-2009, 04:45 PM   #8
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Can I ask where you have the sensor on your engine? Is it where the manual says to put it, where heat sinks meets engine?

I borrowod a kingchrome heat gun last night off a mate, very expensive one, and compared it. Difference was 5 deg c cooler compared to what the radio was showing.

I am considering putting the sensor on the lowest heat sink instead of it being wrapped around the head as it is now. What do you think?
when i got my radio used it came with the electric motor temp sensor only i dident know i put it on my lst and it reads very precise and also with my tc too.
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Old 08-19-2009, 05:29 PM   #9
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when i got my radio used it came with the electric motor temp sensor only i dident know i put it on my lst and it reads very precise and also with my tc too.
Oh so u running electric with the sensor?

I really dont want to richen it more than it already is, judging by sound and smoke its plenty rich. Might have to ingnore the reading for now, just want to get it right considering I paid so much for the radio and receiver kit.
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Old 08-19-2009, 05:40 PM   #10
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I set mine up as described in the manual, on a new car with a new motor. Thought everything was great until my first race. Pit guy temped my car after the race with an exergen at 170 and the DX3S was reading 230. No wonder my car ran like crap. The Temp sensor is not accurate, i would not use it to tune by. I never could get the RPM thing to work. After the first race I ditched all the telemetry junk.
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Old 08-19-2009, 05:44 PM   #11
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I think the telemetry isa joke. I was in a main, the alarm was set at 280, It started going up an up, by the time my pit buddy got to it the dx3s said 370, I was flipping out, he put the temp gun on it and it was 214, needless to say the main was shot and I bought a m11. telemetry is worthless and so is horizon hobbies
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Old 08-19-2009, 06:27 PM   #12
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Wow looks like im getting a few instances where its not even close to accurate. Thats a worry! Wonder how many people out there expect this to be accurate (like myself) and take the reading as accurate and end up de-tuning their set up because of it!

Looks like its time to buy a heat gun, even though the main reason I shelled out the extra money for the DX3S was because of the heat reading!

Live and learn hery.
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Old 08-19-2009, 06:32 PM   #13
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These instances prove that you should NEVER tune by temp. Tune by smoke and sound and of course how it feels!

Temperature is just kind of like a conformation but not something you need!
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Old 08-19-2009, 06:50 PM   #14
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I use the Spektrum sensor in my truggy with great accuracy. At first it was off a bit because I had it in the wrong spot but once I moved it to the right spot mentioned in the manual it has been within 3 degrees of any high cost gun that has been used to check its accuracy. I run mine a lot and would no longer second guess the readings. In the manual it says to put it as close to where the head and cylinder meet, so once i moved mine to the lowest groove on the head it has been on. Try that location and see how it does.
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Old 08-19-2009, 07:42 PM   #15
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dont know if this will work but here is a photo of how I have attached mine, im thinking about putting it up one. Is this the same how you have done yours?

This photo is not of my buggy, found it on the net but same position.
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