pe reivers

It is not the higher temperature that makes it run better. It runs better because the tune is better. A well tuned engine generates more heat and thus has higher temperatures that in turn must be cooled better, If you lower the temperature by cooling, there will again be some performance gain.

Dannn

My 3.3 never ran right... it sat around 280-300... Still ran like crap. My os .18tz runs right at 221 when tuned after a few wot runs. i only checked the temps to make sure i wasnt overheating the motor and not knowing it.

pe reivers

The temp measurement , although not known by many, is a good way to tune your engine. Exhaust gas measurement (EGT) would even be better though it does not take into account the cooling factor, which needs to be checked by cylinder head temperatures (CHT). A peaked engine, tuned for best fuel economy will see 400F CHT max. For our purpose that is too high though. We do not need best fuel economy, so we tune for 300F max. in gas engines.

cenracer1

interesting thread and the only reason I answered the question was because it was asked.. I have several different brand engines and they are all over the place as far as temps... My Traxxas 3.3 runs cooler than my OS 18.. why... I don't know nor do I really care... I only check the temps after a long period of bashing or racing.. I've been doing this a long time and its not hard to tell when something isn't right.. Most of the time the temp gun sits in the pit box... Engine temps are not set in stone and should only be used as a guide.. you don't want to be running in the mid 300's and up, nor do you want to run lower than 200 or so...

DaveG55

Wrong.
Running leaner makes it hotter. Leaner does not necessarraly equal a "better" tune. Hotter temps do not equal a "better" tune. Artifically colling a hot engine that is running lean does not help the engine, it is still lean. Run one of these nitro engines lean too much and all you get is a paperweight not a "better" tuned engine.

That may be true with engines whos lubrication does not depend upon fuel delevery. But, with these two cycle nitro engines, tuning to 300 degrees regardless of any other factor is a sure way to, at best, drastically shorten an engines or at worst, kill it outright.

pe reivers

Read again! The mentioned temps are for gas engines, not glow engines, though I have also seen these numbers published. The baked on castor on/in  engines run with castor fuel confirms this. Castor does not bake at low temperatures. At lower temperatures it just gums.
It is a well known fact that in glow engines it is good practice to back off rpm by tuning too rich. That makes the engine live longer, but is not the setting that provides best power.
How to tune by cht in glow engines I do not know because I never measured these. That iswhy I stated GAS engines. The same principle however applies to all internal combustion engines, be it glow or gas.</p>

DaveG55

Your first post says nothing about gas engines.
Your second only briefly mentions it in the final few words.
Since this has been a discussion on model nitro engines your statements, IMHO, are misleading at best.

You tune a nitro rc engine by leaning until you get no further performance increase then back the tuning off by the last lean adjustment. Since there was no performance improvement seen at that last adjustment there is no loss of rpm, power or performance by making that one detuning adjustment. There is however an advantage to the engine by giving it back that bit of lubriction.
Trying to tune to a particular temp, be it head, exhaust or whatever with these engines is not and will not give you the best tune. Even the rc engine makers say not to tune to a temp but rather to check the temp after tuning to use as a basis for a quick check during a days running. As cenracer1 said though, anyone with experience with these will be able to tell if something is amiss.

animalnut

I like to warm it up first then start rich tune to top speed then back off the hsn 1/8 make a couple test runs THEN CHECK TEMPS just to make sure there are no air leaks or anything funny going on.

pe reivers

Hmm,
THAT's why the car racers use the Venom temp gauge huh?

DaveG55

Find me one of them that is tuning to temp. I'd bet you'll be hard pressed to do that. They are meerly keeping track of temps on an engne that is being stressed to it's limits.
I also seriously doubt that many serious racers want the extra weight of an on board temp guage. The serious ones, if they are even concerned about knowing a temp, are using the telemetry features of a good 2.4ghz radio. The good racers already know, by sound and performance, if they have a good tune. And contrary to what you keep trying to imply, a high temp is not an indicator of a good tune.

pe reivers

Dave G55,
I have better things to do than entering a p* contest with someone who contributes nothing to the original poster's question.
Bye.

DaveG55

Wow Pee, that sure is the pot calling the kettle black. I have directly answered the OP's question 3 times in this thread. You on the other hand have not made a single pertinant comment on RC engine temps in the entire thread. Personally, I'll be glad to see your wrong, misleading and argumentitive answers leave.
Now, I too am done.
Good Day to you