Engine Temp

Old 07-26-2012 | 08:51 PM
  #16  
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Originally Posted by GizmoJunkie
In theory, since at sea level the air is denser, meaning more air/volume you would want to run a tad richer than you would at say 3600 ft.

Best way is to still tune for performance and make sure it makes power and some smoke.
ya that does make sense, if you have more air you would need more fuel to have a good a/f ratio.

but the guy that tuned it, after i told him i was at sea level says "With the altitude being so different you will need to lean out the high speed needle since there is more oxygen in the air when you are at sea level"

i dunno? sounds like i have some playing to do tomorrow
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Old 07-26-2012 | 09:05 PM
  #17  
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Originally Posted by KYZAAC
"With the altitude being so different you will need to lean out the high speed needle since there is more oxygen in the air when you are at sea level"
Now im no chemist, physicist or meteorologist, but i would think air is a homogenous mixture. Meaning oxygen is a fairly consistent 20% (roughly) of the makeup of "air". Im pretty certain oxygen content doesn't change, but the overall air density does.

Even then what he said kinda doesnt make any sense lol. You want to keep the same ratio of a/f no matter your altitude.

The higher you go the leaner you need.

If you had a good tune at sea level and didnt change your settings and say you took a trip (higher in altitude) and ran your engine it will seem rich. But this would also be based on the same ambient temp and relative humidity.

Hope i didnt get too carried away lol.
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Old 07-26-2012 | 09:29 PM
  #18  
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Originally Posted by GizmoJunkie
Now im no chemist, physicist or meteorologist, but i would think air is a homogenous mixture. Meaning oxygen is a fairly consistent 20% (roughly) of the makeup of "air". Im pretty certain oxygen content doesn't change, but the overall air density does.

Even then what he said kinda doesnt make any sense lol. You want to keep the same ratio of a/f no matter your altitude.

The higher you go the leaner you need.

If you had a good tune at sea level and didnt change your settings and say you took a trip (higher in altitude) and ran your engine it will seem rich. But this would also be based on the same ambient temp and relative humidity.

Hope i didnt get too carried away lol.
not at all man, i appreciate the advice. i'll take all i can get
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Old 07-26-2012 | 09:54 PM
  #19  
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hey GizmoJunkie, you seem pretty knowledgeable, can you take another look at my thread a few threads below this one named "Gears & Clutch Bell Slipping, Gear Mesh Problems"

i posted some pics and a video link.
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Old 01-01-2020 | 10:01 AM
  #20  
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Default Engine temps vs Reality

I think people get too bogged down in details regarding nitro engines - no wonder people think 'sod that' and go brushless! Lol.

RCtech has some of the best info on the Web, but let's hope that newbies to the world of nitro are not being put off by all this confusion.

Our nitro engines engines are miniature marvels but being small, sometimes they can be cranky. Please bear in mind that our IC 'nitro' engines have been around a very long time - since the 40's - long before radio control was even a thing. Long before people had infrared thermometers.

Whilst keeping an eye on engine temps is no bad thing, our engines' operating temperatures are affected by several things:
  • Ambient conditions ie the weather
  • The load being placed on the engine
  • Air flow
  • Fuel choice ie nitro/oil content
  • Choice of plug
  • Tuning
Getting the carb set correctly does not require a temp gun, infact for newbies, just following the operating manual and watching YouTube tutorial videos is probably more straight forward.

There is a zone where our engines will run perfectly, leaner will reduce lubrication, increase temperature and risk premature failure. Richer will increase lubrication and reduce temperature.

So observing the smoke trail from the exhaust is a really easy visual way of making sure our engines are safe. No smoke = bad.

The sound of an engine is another way of knowing if all is well.

Getting a temp gun gadget is purely as an additional aid to help you achieve a correctly tuned engine. We shouldn't ignore our senses just because we're chasing an entirely arbitrary number with a temp gun.

My engines have run at different temps throughout their lifetime. Some run cooler, others hotter. Whilst I own a temp gun, the tune I arrive at is never derived from a temperature. Rather, once the engine is tuned correctly, I record the running temperature for reference.
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