dark321devil

I have not changed my tune since i got it running good. I have been runing my two cars recenlty and they only get up to about 170-190 degrees. The motor seems to run strong and i get a trail of smoke and it runs perfect but i cant see cooler temps hurting the engine becuase the booklet for the engines states to be at around 220 degrees i beleive. I am attributing these temps due to colder weather outside then when i tuned the engines. Just wanted your opinion on it. thanks.

46u

My Feedback: (3)

Tune can change from day to day even hour to hour if there are weather changes. If you are running in real cool weather you might even wrap the head with something to hold the heat in. Running a engine to cool is not good! I recommend 220 to 280.

Argess

I don't think the cold weather makes as much of a difference as one would think. At the cooling fins, "yes", the temp will be lwoer with colder ambient temps, but the source of heat inside the combustion chamber is the same. Therefore, if you measure temperature at the glowplug, you won't see a huge temperature change, even though the outside temp has dropped considerably.

I agree with 46U....lean it out until the temp is up in the 200's. If you run it too cold, the engine will wear to that temp. The piston/sleeve could be then too loose if you tune it leaner at a later date.

slayerphonics

IF your running really cold temps. and having a hard time getting your engine to temp.. start wraping the head download in something like foil or cloth of some type. the engines don't run well at 180 degress and your just cause premature wear IMO

iamnot

46u did not say to lean it out until temps got into the 200's

he said it may need to be retuned daily or more

big, big difference

if he's running in really cold temps, leaning the engine is very bad for the it as there's already more oxygen in the colder, denser air and the engine is already naturally running leaner anyway because of that
that's why you need to wrap the head to keep temps up

Argess

picky, picky, picky.....but you are right. 46U didn't say to lean it out to keep the temp in the 200's. BUT I'll say it. I've run my engines in sub-zero weather many times, and the temp always comes up in the 200's.....at the glowplug. Regardless of the ambient temp, an engine should be able to reach the low 200s. Unless it has an extra-large cooling head, it is most likely rich if running below 200F. If it stays below 200F, it probably needs to be leaned out.

So....sorry for my mis-quote. What I should have said is I agree with 46U where he says, and I quote:

"Running a engine to cool is not good! I recommend 220 to 280."

JB COMP

The engine can be running at 170 and still be running too lean, when its cold out (like 45F or less) you need to wrap the head with alum foil.

Air temp (or temp out side) affects engines a lot (Gas, nitro, ect...)

slayerphonics

+1

hrdcoreglf

I have run a couple of times in the extreme cold ( for me extreme cold ). I use a sock with the bottom cut off. Makes your engine cozy and warm.

Argess

hmmmmm........I guess one reason my engines run hot and never get below 200F in winter weather is the damned fuel I have to use. It's always a fight to keep the temps on my engines down and still get half-decent performance out of them. So my engines are always at a compromise.....hot and rich. Maybe that's why the difference of opinion here.

I have tried other fuels that run way cooler, but they are hard for me to get (200 mile round trip to the hobby store). The LHS that is only 15 miles away only sells one brand.

I don't want to mention which brand, as I don't want any more arguements.......LOL.

Thank-you

JB COMP

Traxxas or blue thunder?

What nitro % are you running?

Argess

LOL......OK......Sidewinder Race 20% nitro. I have found this runs cooler than Sidewinder Backyard Basher. I have also used Blue Thunder Sport, which runs cooler still, but is hard for me to get.

here's an edit.....I forgot to ask....what kind of engine was it that you had running lean at 170F? I have had one engine run under 200F and tuned lean....a Force 26 I was experimenting with. BUT, I had an extra large cooling head on it, cold shorty plug, 1 extra head shim, body off vehicle, and it was below zero ......oops....below 32F, outside.

JB COMP

Sidewinder is a good fuel. That's what I run (but I run the race 30%)

I have not had a engine run 170 and lean (for some reason mine like to run in the 250-300 range, but I don't get to run in the winter, not sure why) but I've seen some and its possible too run one that cool and still lean.

I had a TRX 2.5 that was running 245F and it had a few broken fins so I put a new one on there (not really over size but I think 1/4"-3/8" taller then stock) and the temps dropped to 205-210 with the same settings.

I was breaking one of my engines in on a cool windy day (it was my Force 26 which I no longer own) and I couldn't get the temps up above 150 so I had to wrap the head and that got the temps up to 210

hrdcoreglf

Have you asked your LHS if they will order some for you. If they won't because the order is not big enough, see if you can get a couple of rc buddies to pitch in and buy a case. Most hobby shops will order it if you ask.

dark321devil

great responses. some more info, my two engines are and ofna force 26 in my hyper 7 and the s-25 in the savage. outside temps were around 40 degrees. body off. fuel is 20% duratrax red alert. The engines are easy to start and run strong. I dont want to start messing with the tune becuase i feel they are running great. I have the , if it aint broke dont fix it attitude towards the tune. lol. maybe and probably im wrong about that.

iamnot

yes, you are wrong about that
absolutely wrong

you're running the engines too cold
that will hurt them
so, to fit your theory
it IS broke and needs to be fixed

rc nitro tuning is a fluid thing
and needs to be adjusted to match conditions

try to get past your tuning phobia
and take care of your engines

Argess

That's very interesting JBCOMP. You are getting the same temps I seem to get in a variety of engines I own, and with the same brand of fuel, although different nitro percetnages. That makes me feel better I am tuning OK. Oh, and I thought you stated you had an engine that ran lean at 170F.....guess I misunderstood that. And "wind"....yes "wind chill" seems to affect the engine temp more than the actual ambient temp. The air gets in around that heat sink and just blows the heat out.....LOL.

Well Dark-Devil.......if you feel your engines are running great, then leave the tuning alone. However, if they are used to running great at temps considerably higher than what you are currently experiencing, you may be pre-maturely wearing them out. Sounds too rich to me, but if you are happy with performance and don't want to mess with the needles, maybe try the sock idea to keep the temps up.

Some engines......my son's Ravager with the Force 28.....never seems to need to be re-tuned. Always runs great, and the glow-plug temp measures approximately the same summer or winter. At the other extreme was my Force 26.....very touchy HSN. Always running too rich or too lean.....constant adjustment required. Nitro-star 25.....needed the odd adjustment with major weather changes, but not a lot. The little HPI 18SS and the Team Associated 15 we have never seem to need much adjustment dependant on the weather, but maybe a little tweak and that's it for the day. The OS 30VG we are currently working with runs too hot, but it seems to be consistent with the weather so far, although the weather hasn't changed a lot recently. My best guess is that when an engine compression, timing, etc., is matched with the right fuel, you can get good power at lower temps, and then if things vary from there a bit, you are still in a safe range. Just not too many engines seem to be like that.

JB COMP

Here I don't have to worry about getting too cold. The coldest its gets here is low 45 o so during the day (and those are the days I'm either inside or working) so I don't have to wrap my heads too often. People that live up north where it gets in the 40 and below have to worry about temps being too low.

Wind cools off the engines a lot, but cold will drop the temps too. If you try cooling something that's 250 with (lets say air) that's 100F it will take a while too cool, but if you're trying to it with air that's only 50 it will cool faster and not get as hot.

slayerphonics

Ya nitro hobby in florida is good year round,
And let me tell you my motors love it when its 90+ degrees outside
You can lean the piss out of them and they stay cool with more power and better milage