zafeirop

Am I blind or what?

According to Tamiya, when you set the carb needle to 1 and 1/4 turns counter clock-wise, the mixture should be rich and blue rich smoke should be present from the exhaust.

Well this is not the case for me guys! I can see no smoke at all! Just fuel coming out from the exhaust which makes the parking lot very meshy and my RC very slow to respond to throttle.

I can realize that the mixture is fuel but smoke is not there! Maybe it's gone with the wind?!?!

Any ideas?

I'm using 16% nitro, very good quality Viper brand and my stock .12 engine is FS12SS (OS)

Thank you all

cardriverx

is the motor bogging at high speeds?

zafeirop

Nope. It feels smooth but not responsive. It sounds like not breathing but I couldnt say that it's bogging.

Does it have to do with the fuel that I use? In general, this is my first nitro RC and all my experience is obtained from this site and especially from the vids. Well, every single one that I've seen, I realize that RC nitro cars ARE smoking. Mine not! That's the game.

I'm out for a smoke ... [X(]

napalm_Fire

you dont want it to be spitting out fuel from the exhaust... then its too rich and you probably wont be able to smoke because so much fuel isnt being burned. Tune for preformance, under 250f, and you should be fine...

Qlone

what Napalm fire says is right. Oil needs a certain temperature for it to burn, and if you're running too rich the engine does not come to a temperature to burn it, so you see the raw oil coming from the exhaust instead of smoke.
Also, keep in mind that some types of fuel burn very clean and produce less smoke than others.

zafeirop

In my case I think that the fuel is of high quality, thats why i paid for 1 lt $20 [&o]

So some fuels produce less smoke than others - interesting.[&:]

napalm_Fire

i remember i used traxxas top fuel, that stuff burned clean, but verry hot, and i had trouble getting a consistent tune out of the engine. I bought byron 20% 12% and now it smokes great, and i can get a good tune out of my engine.

It depends on the type of oil in the fuel, and the ratio of castor to synthetic oils that they use to mix in the fuel

Philster

Any setting on any needle provided by anyone is a GUIDELINE. There is NO WAY you will use the same setting all the time. Air temp, humidity, barometric pressure, altitude, condition of glow plug, engine temp, etc will cause some tuning issue, meaning you will always need to tweak the hi-speed.

When running a nitro car, you should be carrying a screw driver for those needle adjustments. Heck, on some cars, the amount of fuel in the tank affects the tune.

An engine that is TOO TOO RICH will run...but not scream like it is really loose and ready to zoom. Doubt that it can make smoke, because a nitro engine can make smoke when it really lites up, like coming out of a turn, or opening up on a stretch. "Bogging" is tough to describe...so stick with this: Too rich means it can open up...but it will never stall. Can't open it up and feel it screaming, then no chance to make smoke (esp since the engine ain't hot).

Lean it out 1/12 of a turn and try and repeat if necessary.

coolguy234

Synthetic oil produce very little to no smoke! That's why they are called clean oil!


Usually high quality fule uses synthetic oil, they offer performance and cleanliness but no engine propection.

iacolb12

This whole discussion is why you tune by temperature. Scrounge up the $25 and get a Temp Gun. You won't regret it.

coolguy234

Temp gun are not accurate! They make no physical contact.

Why tune by temp or by smoke? To get your car tuned properly just richen the mixture, then lean it little by little until it runs right! Most modelers including myself, tune by looking how the car runs and by sound the engine makes! It's the best way to tune and make your engine last long!

Philster

Temp guns are accurate. The difference between a infrared temp gun and a probe that makes physical contact is that the user of the temp gun must understand the types of errors they might make as the user, and avoid those mistakes. Otherwise, an infrared device, commonly refered to as a temp gun, is accurate.

You could tune you engine like a champ and discover that you don't have enough airflow. A temp gun would reveal this.

Since listening to, and feeling, engine response comes with tons of experience, a basher who wants a temp gun to insure his/her investment is wise to get one.

fastlane2285

My Feedback: (1)

It is also good to have an on board temp gage to help you adjust the temp of your truck they are pretty accurate within about 5 degrees, and they are very helpful. I have one on my TNX and it has helped to get my temp down to 220 - 225 degrees.

iacolb12

I disagree with coolguy234 to an point. Yes you can get to where you can tune your car by sound, with experience. But you should still have a temp gun.

Your car may sound and run great and be running at 300 degrees! Especially in hot weather where there is LESS oxygen and you want to run your mixture leaner. But leaner = less fuel = hotter.

As far as tuning by smoke, I notice zafeirop is in Greece. I don't know what the humidity is like there but the more humid the less visible smoke will be. As expended gases bond with the moisture in the air and become heavier the less they rise and dissipate.

dbow

My Feedback: (1)

Sounds like you are running to rich (raw fuel all over) , lean it a bit and see what you get. Should start to see some smoke and should be seeing some additional acceleration. do it with very very slight 1/8 the turns on the needle.
If you are still on break-in then keep your break in settings in mind.


As for the temp gun, it is good have one, there is no excuse not to have one these days since they are so cheap.

Goodluck

Dbow

zafeirop

Gentlemen! Start your engines

To all: The main concept of having a temp gun is convenience of measurement. You dont have to put any sensor in contact with the material that you want to measure. In our case, it is not theideal solution, but it still remains convenient. It is a good way to obtain temp values of heated up motors with a relative accuracy (tolerance).

To iacolb12: Maybe you are right pal!
Greece has the disadvantage of high humidity during any sesion of the year, especialy at the offshore places. Values of 70 to 85 % are very common for Greece and hot weather in combination with high humidity maybe makes smoke non visible.

My question: Why synthetic oil do not protect the engine? as coolguy234 said. I thought that synthetic oils are the edge of mech technology. For full scale cars, I know that if you use full synthetic oil then you can extend the life of your engine and your next pit stop ... uhhhmmmmm sorry, your next oil change service

Best Regards from Greece

coolguy234

Ok, it's useless that i try to argue with you. I never used a temp gun and had like 10 gallons (not US gallons, UK gallons that is 4.55 lts) in most of my engines before rebuild. I use only pure castor.

Synthetic will burn very quickly, that is why it will give performance. But since it already burnt before it exit the combustion chamber, it does not protect the engine. Castor on the other hand does not burn completely, there will still be a little oil left before the gas exits the compression chamber. That's why it protects your engine better and is not as clean as synthetic.

coolguy234

In full scale cars you have a radiator cooling the engine, here you have only air acting as coolant. The unburnt castor oil will take heat away. Synthetic is burnt, it gives off heat instead of taking it away.

I'm 20, I'm in RC since I was 7, so I think I'm experienced enough to know what I'm talking about. But this is just my opinion and my personal experience.

iacolb12

The only real advantage Synthetic has is that it burns cleaner and leaves less of that gummy mess. In the end, as coolguy234 said, the castor is a better chioice. The castor has a higher flashpoint and will be around longer. More messy though.

Though I'm not sure how much heat dissipation castor oil really has, that's more to do with the methynol.

zafeirop

I respect your experience and nobody said that I have a different opinion from yours.

I'm just asking.

Anyway, thanks for the info

coolguy234

Sorry if I seemed to be rude or anything, I'm not! I was only giving my opinion from what I have seen over the years.



Once I read on RCU about an experiment to show that Castor was a better choice concerning heat dissipation.

I think it was a s follows (I'm not 100% sure):

The author took a thin metal plate and put it over a bunsen burner, then put a few drops of castor. The castor remained there.
He then repeated with synthetic. The oil either evaporated or moved away from the heated piont.


Once again I'm not sure about the experiment, but I'm sure castor is a better choice in every aspect (compared to synthetic) for model fuel application.

Castor will protect your engine if you happed to have a lean run, at least it will protect your engine better. It also protects your engine from rust.