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Tuning the REVO

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J

jsu0234m

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What would a REVO run like with the LSN lean? If anyone knows, thanks. As far as idling, top end, etc.
 
Leaning the HSN Improves the high speed passes.
Leaning the LSN effects the idle and make the engine have better take off.
 
How lean is lean in your question? You can lean out your tune for power after the break-in, but you need to be mindful of engine temperatures as you do.
 
if its too lean you will get detonation after you let off from a high speed pass. it will sound funny. almost sounds like the engine is missing. Also the idle will be too high and will more than likely fluctuate up and down quite a bit.
 
I have never heard "detonation" in a nitro two stroke. Motorcycles, yes. But, there is no timing involved with a RC mill. I guess you are only referring to engine temps???
 
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I am gonna have to think about that one. Again--motorcycles I agree. They have an ignition (not an always glowing glow plug like an RC two stroke). I just don't see it, but I may be dumb...
 
listen to this truck when he lets off the throttle. this is detonation and a sign that the LSN is waay too lean

Timing is affected by the way the ports are configured. Has nothing to do with the glow plug or the ignition. Port spacing differences will affect timing.

here is some reading for you to read.
http://www.rcboat.com/timing.htm
 
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You have better ears than I. All I hear is a lean engine that has its idle set too high. The idle stays up. Surges. But detonation? Not the definition of detonation that I grew up with.

And yes, I could tell the minute he fired it up that is was way lean. But detonation? I dunno...
 
detonation/preignition. Does not matter. If the engine is too lean no matter what it is it will detonate.
You may not believe me but that's what that sound is. Listen to that engine really closely especially towards the end of the video. You will hear the flutter just about everytime he lets off the throttle. The Flutter is detonation.
 
I guess my mind just can't understand how there can be pre-ignition in a system where the ignition source (the GP) is always hot? Wouldn't there always be pre-ignition? Like I said, I can be dumb...
 
Well, I am going to do some reading. Thanks for opening my eye, lifted. I found a site about glow plugs that talks about detonation and pre-ignition in RC mills. I hope they explain how this can be so when the plug is always "on".
 
It is a hard thing to understand. But now you know it does exist and you also now know what it sounds like so you can avoid it.

Also remember, the Glow plug is not "always on"

The glow plug is only on when the air fuel mixture is compressed. It is compressed so hard that it will ignite the air/fuel mixture. This in turn will make the glow plug burn.

The only way the glow plug could be on all the time is if it were wired up to be "always on"

So on that note if the glow plug were always on then the air/fuel mixture would ignite before it is supposed too. So you would have detonation all the time. And if you think about detonation. Remember detonation occurs in 4 stroke engines by either too much timing or running too lean. Running too lean causes the cylinder temperatures to be extremely hotter than normal. The temperatures will get so high that it will "pre-Ignite" the glow plug causing detonation.


So to anyone that is reading this take this with a grain of salt. Listen to the video i posted. Listen to the flutter that the engine makes after a high speed pass. This is detonation. If this is not solved you will ruin the engine. Fuel is supposed to burn not explode. Detonation is when the fuel explodes instead of burning. it will break rods and in a 4 stroke engine will rip the ring lands right off the piston.
 
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No. richen it. HSN and LSN--if you are referring to the engine in the vid. That thing was all out of wack. The high idle was due to the LSN being too lean (and the idle is up cranked up to compensate). The heat and detonation is due to the HSN being lean.
 
My exp with lean idle setting in my 3,3 Revo (TRX 3,3 engine) it will idle radically at higher rpms even try to creep off sort of speak.

Before I realized this I tried to reduce the idle speed with the idle speed screw but this did not reduce the idle rpms. Richen the LSN and remember to run the truck a bit before re checking.. You must not have any leaks either, had a bad exp with my header leaking and causing a lean mixture and extreme temps.

Anyway that’s my 2-cents hope it helps.
 

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