Plate motors and sound

[TritonJrBluePlate]

I’ve been observing some various plate motor karts that have a very different sounds than others. Its my opinion that plate motors within the same class should have a similar sound. I’m not a tech guy and have very little experience listening to these karts. What am I missing? Why would they have drastic sounds with in a particular bid?

 

[Raging Bull Engines]

Mostly depends on how well or not the kart is rolling.

 

[jaymancds]

It could have something to do with the header shape depending on the rules. Also could be slight differences between NKA vs. AKRA vs. ETC rule set that may be on the track together. The only thing that gets my attention in limited classes is if one kart has considerably more "Chop"/"Pop" from presumably cam swaps.

 

[DynoDon]

How the carb is jetted and the amount of timing plays a role in the sound of the engine

 

[TritonJrBluePlate]

Thanks for the reply’s. I’ve been using video to listen to when my driver is lifting. At one specific track I’ve noticed a that I just can’t hear it because of the louder karts. So I’m just wondering about that.

 

[jaymancds]

Thanks for the reply’s. I’ve been using video to listen to when my driver is lifting. At one specific track I’ve noticed a that I just can’t hear it because of the louder karts. So I’m just wondering about that.

I have lots of videos of myself, can't hear my engine in any of them. Just watch the feet. If you cant see them, get some bright colored tape and wrap a strip or two around them so you can see it.

 

[Big Chris]

How the carb is jetted and the amount of timing plays a role in the sound of the engine

What Don pointed out here is the key. What changes the tone of the engine is the amount of cylinder pressure when the exhaust valve opens. More cylinder pressure, more of a "pop" sound.

 

[Raging Bull Engines]

What Don pointed out here is the key. What changes the tone of the engine is the amount of cylinder pressure when the exhaust valve opens. More cylinder pressure, more of a "pop" sound.

Early exhaust opening.

 

[mike97760]

You mentioned your driver lifting. Are they all lifting? We don't see much of that around here.

 

[TGRRacing32]

Gearing can have a part in that as well

 

[TritonJrBluePlate]

You mentioned your driver lifting. Are they all lifting? We don't see much of that around here.

I mentioned that I was listening closely to see where he was lifting. I’ve just noticed how a couple karts seem considerably louder.

 

[combative hodaka]

I'm sure sure that this explanation is not the case but a 4 stroke engine be it in a car, motorcycle , bus whatever can have partial combustion occuring in the exhaust if the ignition is severely retarded . I doubt this is the case with karts he is hearing because they would be track toad's but i thought i'd put it out there.

 

[racinnut15xm]

I mentioned that I was listening closely to see where he was lifting. I’ve just noticed how a couple karts seem considerably louder.

are you on a small pipe rule or can you run large pipes?

 

[TritonJrBluePlate]

are you on a small pipe rule or can you run large pipes?

We are large pipe.

just clarify. We won the feature. However, I noticed two kids with a what looked like a big advantage. Had it not been for a caution and. Sneaky good clean move on the start we wouldn’t have had a chance.

I just hear a different sound and wondering what it could be.

 

[jhucks03]

Plate motor trick used to be to run the screw in muffler a little on the loose side to create an exhaust “leak”. Pretty sure rules changed to address that.

 

[Big Chris]

Plate motor trick used to be to run the screw in muffler a little on the loose side to create an exhaust “leak”. Pretty sure rules changed to address that.

Myth......busted in 2018.

Go here to this thread and start at post #37. I tested for precisely this.
https://4cycle.com/karting/threads/akra-muffler-rule.101552/page-2

 

[Raging Bull Engines]

Myth......busted in 2018.

Go here to this thread and start at post #37. I tested for precisely this.
https://4cycle.com/karting/threads/akra-muffler-rule.101552/page-2

I had a guy call me and ask if we had any acid treated mufflers for sale. He told me the "big guys" pour acid through the muffler and it makes it flow better without making the holes in the plates any bigger. I told him to call somewhere else.

 

[TGRRacing32]

I had a guy call me and ask if we had any acid treated mufflers for sale. He told me the "big guys" pour acid through the muffler and it makes it flow better without making the holes in the plates any bigger. I told him to call somewhere else.

He was probably talking about a ceramic coated header. That’s perfectly legal.

 

[Raging Bull Engines]

He was probably talking about a ceramic coated header. That’s perfectly legal.

No, he wanted the inside of the silencer eroded with acid to increase flow.

 

[combative hodaka]

No, he wanted the inside of the silencer eroded with acid to increase flow.

Acid dipped body's were common in the 70's Pro Stock cars for weight reduction. some panel's just to the point of " just able to carry paint " Bob Glidden.