Nitro tuning is hard!

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mzanzirc

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I know I know, not ANOTHER tuning thread. But I've come to the conclusion that any tuning guide is merely a very rough guide. Very rough.

After breaking in my engine and with it running pretty sweet, I decided to change all my needles back to "stock", flush, whatever you can call it, to try and tune from scratch. I want to learn this dark art. :cool:

Reading and watching some videos, most of it looked and sounded very simple. Can't be THAT hard now can it? On paper it looks easy enough....

What a ballsup! 😂

I first eyeballed my idle gap where it was. Didn't measure it, but it looked pretty much more than 0.5-1mm. More like 1.5mm? Can't say.
So I set it to just over 1mm. Say around 1.5mm. Which it looked like where it was.

Started the car up and the idle was very high. The clutch would engage and it was smoking like a chimney. Leaning out the LSN made it worse.
My idle gap was probably too high, fuel was too much and that made the car wanna go. Like I'm on the throttle a bit.

I reduced the idle gap down to 1mm. Maybe a pinch below 1mm.
Set both LSN and HSN needle flush with the "housings" again.

Fired it up and now the idle is too low, and the engine dies after a couple of seconds. Basically it won't idle for long, unless I'm giving it a bit of throttle. It goes, but take off is groggy and would die if I give the throttle a little stab. Gently on the throttle and it will pull away and run. This sounds like it's running too rich on the bottom end?

It was late at night, SWAMBO was getting agitated and I left the car.

So, first thought was that I need to lean out the LSN to get the idle a bit higher so that it at least idles good before I go onto the HSN tuning?

The car was running great, so I know it's LSN and HSN needle issue.

Any thoughts on the way forward? At least the car doesn't sound like a banshee trying to kill me. I can work from a low idle. 😂

Edit: So what I will be doing going forward is to record each change, the result of the change and any correction I made and then the result again.
Just so that I can backtrack if I need to.
 
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gandalfnz

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No, never adjust the LSN first, as it will be affected by the overall fuel intake trough the HSN.
Always tune HSN first, then go for LSN.

Leave idle gap at 1 mm approx.
Adjust HSN until top speed is good and smokes.
Once HSN set, keep bringing the car in, let it idle for 5 seconds and listen how it sounds.
If it shuts off and is groggy in take off, keep leaning the LSN until it stays running and you have a good take off after letting it sit for 5 seconds or more.
Adjust until take off is crisp/snappy, then after that, if the idle is too high, lower it down with the idle screw.

good luck!
 

mzanzirc

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No, never adjust the LSN first, as it will be affected by the overall fuel intake trough the HSN.
Always tune HSN first, then go for LSN.

Leave idle gap at 1 mm approx.
Adjust HSN until top speed is good and smokes.
Once HSN set, keep bringing the car in, let it idle for 5 seconds and listen how it sounds.
If it shuts off, keep leaning the LSN until it stays running and you have a good take off after letting it sit for 5 seconds or more.
Adjust until take off is crisp/snappy, then after that, if the idle is too high, lower it down with the idle screw.

good luck!
Great stuff thanks.

So i just need to get the car warmed up and not die and do the HSN. Got it. I'll give it a bash this weekend.

I want to get good at tuning these things. I hate not knowing things. Lol
 

gandalfnz

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Great stuff thanks.

So i just need to get the car warmed up and not die and do the HSN. Got it. I'll give it a bash this weekend.

I want to get good at tuning these things. I hate not knowing things. Lol
Yes, dont let it die, if it wants to, keep applying a bit more throttle, or use throttle trim on the TX to increase the idle gap a bit more.
Get the HSN right, the focus on LSN after that.
To be honest I adjust both at the same time, but for a beginner, I suggest you focus on HSN initially.
 
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mzanzirc

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Yes, dont let it die, if it wants to, keep applying a bit more throttle, or use throttle trim on the TX to increase the idle gap a bit more.
Get the HSN right, the focus on LSN after that.
To be honest I adjust both at the same time, but for a beginner, I suggest you focus on HSN initially.
Awesome thanks man.

I am a bit confused around the idle. You mention that after tuning the LSN (snappy take off) and the idle is high, I need to adjust the idle screw.
But a lot of videos and things, people say to never adjust the idle screw if you have set your idle gap and to adjust the idle with the LSN. Meaning, richen it when the idle is high and lean it if the idle is low.

Won't fiddling with the idle screw mess up the idle gap again? Needing adjustment of the LSN again? :confused:

I don't want to get caught a viscous tuning circle back and forth between the idle screw and LSN. 😂 If this thinking is correct anyway.
 

gandalfnz

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Awesome thanks man.

I am a bit confused around the idle. You mention that after tuning the LSN (snappy take off) and the idle is high, I need to adjust the idle screw.
But a lot of videos and things, people say to never adjust the idle screw if you have set your idle gap and to adjust the idle with the LSN. Meaning, richen it when the idle is high and lean it if the idle is low.

Won't fiddling with the idle screw mess up the idle gap again? Needing adjustment of the LSN again? :confused:

I don't want to get caught a viscous tuning circle back and forth between the idle screw and LSN. 😂 If this thinking is correct anyway.

Those videos are wrong.

When I tune the car for the first time, I set my idle always a bit high, like 1mm is more than enough, usually you end up at 0.5 or even less.
Its simple, adjust for snappy take off with LSN, once satisfactory take off is achieved, and idle IS STILL too high, you then lower the idle down with an idle screw, do not richen LSN more.

When I first got into nitro, I aways used to set the idle gap at 1mm, then adjust the idle with LSN, but this is also not good, as you always compensate for high idle gap with a too rich LSN, hope that make sense.
 
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mzanzirc

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Those videos are wrong.

When I tune the car for the first time, I set my idle always a bit high, like 1mm is more than enough, usually you end up at 0.5 or even less.
Its simple, adjust for snappy take off with LSN, once satisfactory take off is achieved, and idle IS STILL too high, you then lower the idle down with an idle screw, do not richen LSN more.

When I first got into nitro, I aways used to set the idle gap at 1mm, then adjust the idle with LSN, but this is also not good, as you always compensate for high idle with a rich LSN, hope that make sense.
Ok cool. Got it.

I think where I (and maybe other beginners) get confused is when I'm at this setting (groggy low end, idle sucks and car dying), I am under the impression the car should at least idle good. Seeing the idle so crappy and the engine die, I tend to think something is wrong and I need to sort that first and then start turning needles and screws to fix it, before tuning starts.

Maybe some videos and post forget to tell people that hey, look, the idle is crap and the car will probably die without throttle input, but ignore it for now and go onto xyz, and then at the end, adjust the idle if need be.

I might be wrong in my assumption.

But for a beginner, there are just so much variables at play that it's easy to get super confused and confusion leads to chaotic changes.

I am a very impatient person when it comes to things like this. I know it's wrong. But when I start something like this, I feel I need to carry on until it's done. Which makes me anxious. LOL! But I'm going to break it down into stages over a couple of days so that I can gather my thoughts and write stuff down as I go along.

First stage was getting the car calmed down after it tried to keep running away. Check.
Second stage will be tuning the HSN.
Third stage will be LSN tuning.
Fourth stage will be the idle (if it needs adjustment).

I hope it's as straightforward as you explained. :)
Thanks for the input.
 

gandalfnz

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The tuning method I explained was applied in this video and look how the car sounds and runs....
Idle was adjust after HSN and LSN.

Its all good man, took me about 2 years to learn how to tune on a single tank :)

 

mzanzirc

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The tuning method I explained was applied in this video and look how the car sounds and runs....
Idle was adjust after HSN and LSN.

Its all good man, took me about 2 years to learn how to tune on a single tank :)
Tell me about it. I've wasted 2 tanks already trying things out. :doh: That also adds to the anxiousness. I would rather use the fuel for playing than tuning.😂
 

mzanzirc

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Well well well!

Turns out nitro tuning aint THAT hard. 🤣 🤣

I put together this little video to show exactly how I did it. And the tune did not come out bad me thinks. hahaha

 

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I have learned that RTR grade or second hand used engines are prone to airleaks. When i sort out my engines, i use gray motorcycle case sealant, on the backplate, and then once installed and tightened down evenly, i seal the gap around entirely, i also seal off the carb pinch bolt both sides, install rhe carb with fresh orings on the base or the block, depends on which style (some have orings in the block where the carb sits, some don't).

I replace fuel line regularly, as small pinholes that are not visible cause havoc chasing a tune and holding it.

Worst thing to do is turn in all your needles to factory suggested, that is a ballpark, and once broken in, optimal settings are way different.
 

mzanzirc

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Worst thing to do is turn in all your needles to factory suggested, that is a ballpark, and once broken in, optimal settings are way different.
Yeah, start from the factory settings and tune from there as I mentioned.

Why would anyone want to run factory needle settings?

I suggested to anyone running a 2nd hand model that does not know what the factory settings are, to turn them to flush. Like my engine. Try finding factory needle settings for a .21 Go Engine on the internet. 🤣 🤣
 

gandalfnz

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Hey mate, great job, you have made it run good!

You hear, at the end when you stop the car, the idle hangs high, then drops to a second stage idle, this is when the LSN takes over.
Your true idle is actually when you let go of the throttle.
Lean the LSN a bit more, until idle stays high and will be too high, because 1 mm idle gap is too big to stay with, then lower the idle with idle screw.
You should lose that second stage idling.
Then its pretty much 100%.
 

mzanzirc

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Hey mate, great job, you have made it run good!

You hear, at the end when you stop the car, the idle hangs high, then drops to a second stage idle, this is when the LSN takes over.
Your true idle is actually when you let go of the throttle.
Lean the LSN a bit more, until idle stays high and will be too high, because 1 mm idle gap is too big to stay with, then lower the idle with idle screw.
You should lose that second stage idling.
Then its pretty much 100%.
Awesome will do.

Yeah I felt the LSN could go a little more, but I was running out of fuel. lol!

Will lean it a bit more. :)
 
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