Chirping / chattering running Redcat XTR

[HueyC]

Hello my follow Rc hobbyist,

I was wondering if someone can tell me what the chirping / chattering noise might be when the car decelerates only. When I squeeze the throttle, it responds great and accelerates no problem but gives me this annoying chirp when decelerates down to idle. I've attach video of me running it this morning on cloudy day in Allentown, pa.
Link to my U tube video below. Taken by my 7 year old son so it's not greatest.

I hope it's just tuning and not the clutch going out on me.... your thoughts appreciated.

 

[nick1oswald]

Hi
There is a good YouTube video on fine tuning LSN and HSN on nitro cars and he also talks about this chirping noise. Please find link below.

Really good video. You can fast forward all the boring bits and watch from the 10 minute mark.

 

[HueyC]

Hi
There is a good YouTube video on fine tuning LSN and HSN on nitro cars and he also talks about this chirping noise. Please find link below.

Really good video. You can fast forward all the boring bits and watch from the 10 minute mark.

My friend, thank you for hooking me up with video. In your opinion, you think that chirp is tuning, right? Nothing wrong with clutch going out on me.... I'll check out video.

 

[nick1oswald]

Hi HueyC

The noise that you are hearing is called pinging. This happens when the engine is starving for fuel in long runs. You can adjust your HSN (High Speed Needle) needle anti-clockwise in small 1 hour turns until the pinging noise is reduced and have a constant stream of blue smoke coming out the exhaust.

If you have a temp gun, this will make your tuning a lot easier. With a temp gun, you will be looking at temperatures between 220 and 230 degrees Fahrenheit or
110 - 120 degrees Celsius.

If you don't have a temp gun, you can use the spit test. After a long speed run, drop a droplet of water or you can use your saliva on the top of your engine, if the droplet sits for a second and then evaporates, HSN (High Speed Needle) is good. If the droplet sizzles and evaporates, you running too lean. If the droplet does not evaporate after a couple seconds, you running too rich.

After you have adjusted the HSN (High Speed needle) needle, i would recommend adjusting the LSN (Low Speed Needle).
There are multiple ways to adjusting the LSN (Low Speed Needle). see below:

Pinch Test:
The pinch test is when you pinch the fuel line with your fingers and count how many seconds your engine takes to die. 3-4 seconds is what you are looking for.

Listening and watching:
This method is done by listening and watching the exhaust doing small bursts. If your engine is too lean at idle, you will hear the engine pinging with very little smoke. Too Rich, your engine has a very deep idling sound, very slow pull off and lots of smoke. Your engine might even cut out at Idle.

I would personally do the pinch test first to get your base idle right and then fine tune from there.

You can also reference this forum for more info:
https://www.rcnitrotalk.com/forum/threads/rc-nitro-engine-performance-tuning.102688/
You can also reference this in depth tuning guide as well:
https://www.rcnitrotalk.com/forum/threads/nitro-tuning-tips-and-tuning-flow-chart.60832/

Good luck and let me know if you come right.

 

[HueyC]

Nick,

Thanks for taking time out explain all this.... much appreciated. The video is very good as well in demonstration. I'll keep you posted how I make out.

 

[cbaker65]

That's a great vid. to show people how to tune & listen for!...

 

[HueyC]

Hi HueyC

The noise that you are hearing is called pinging. This happens when the engine is starving for fuel in long runs. You can adjust your HSN (High Speed Needle) needle anti-clockwise in small 1 hour turns until the pinging noise is reduced and have a constant stream of blue smoke coming out the exhaust.

If you have a temp gun, this will make your tuning a lot easier. With a temp gun, you will be looking at temperatures between 220 and 230 degrees Fahrenheit or
110 - 120 degrees Celsius.

If you don't have a temp gun, you can use the spit test. After a long speed run, drop a droplet of water or you can use your saliva on the top of your engine, if the droplet sits for a second and then evaporates, HSN (High Speed Needle) is good. If the droplet sizzles and evaporates, you running too lean. If the droplet does not evaporate after a couple seconds, you running too rich.

After you have adjusted the HSN (High Speed needle) needle, i would recommend adjusting the LSN (Low Speed Needle).
There are multiple ways to adjusting the LSN (Low Speed Needle). see below:

Pinch Test:
The pinch test is when you pinch the fuel line with your fingers and count how many seconds your engine takes to die. 3-4 seconds is what you are looking for.

Listening and watching:
This method is done by listening and watching the exhaust doing small bursts. If your engine is too lean at idle, you will hear the engine pinging with very little smoke. Too Rich, your engine has a very deep idling sound, very slow pull off and lots of smoke. Your engine might even cut out at Idle.

I would personally do the pinch test first to get your base idle right and then fine tune from there.

You can also reference this forum for more info:
https://www.rcnitrotalk.com/forum/threads/rc-nitro-engine-performance-tuning.102688/
You can also reference this in depth tuning guide as well:
https://www.rcnitrotalk.com/forum/threads/nitro-tuning-tips-and-tuning-flow-chart.60832/

Good luck and let me know if you come right.

Everything worked out per your recommendations, thank you for your help!

Hi
There is a good YouTube video on fine tuning LSN and HSN on nitro cars and he also talks about this chirping noise. Please find link below.

Really good video. You can fast forward all the boring bits and watch from the 10 minute mark.

Awesome video! Thank you... that pinging noise mentioned in video is exactly what is going on with my XTR.

 

[2GMitsubishi]

Mine was doing the same thing today. Leaned the LSN 1/8th turn at a time till it ran right in the cold rainy weather.. Pretty sure il have to retune it for the spring.

 

[Mr.MadfireMoe]

Hello my follow Rc hobbyist,

I was wondering if someone can tell me what the chirping / chattering noise might be when the car decelerates only. When I squeeze the throttle, it responds great and accelerates no problem but gives me this annoying chirp when decelerates down to idle. I've attach video of me running it this morning on cloudy day in Allentown, pa.
Link to my U tube video below. Taken by my 7 year old son so it's not greatest.

I hope it's just tuning and not the clutch going out on me.... your thoughts appreciated.

It's just the tune. What the guy said sounds right. It is a little lean lsn. But your tune in my opinion does not need to be changed