Can they be made quieter?

[MarkL]

Hi all,

I’m in the market for a custom freeride ski to chase boat wakes and handle a few trips to the surf.
Ive seen 2 used skis, but neither are for me. And now my search seems in jeopardy. See I’m on a small lake here where people have come to retire. I know I’m asking for trouble buying either of those with their current exhaust system. I’m assuming it’s a cheap way to add power, but do the HAVE to sound like this? Honestly, I must be getting old because it’s annoying to me too.

So I’m willing to go the custom build route on a sub-Krash type budget. The goal is to stuff as much reliable power into the ski as I can, but sound like a stock Superjet. Might sound stupid, but I appreciate any thoughts on whether this Goal is feasible.

Cheers

 

[Big Kahuna]

Only way to sound like a Stock Superjet is to use the Stock Exhaust and Waterbox.

 

[MarkL]

Thanks for the reply! so I’m assuming I’m stuck with a stock Superjet 701 cc block in order for that stock manifold to fit?

 

[SXIPro]

You could run a JM 781BB with the stock manifold.

 

[Storbeck]

Most aftermarket pipes that use a stock waterbox are not much louder than a stock superjet, and you can get up to pretty high power levels with your typical b-pipe and stock waterbox.

 

[aboarder]

I made a small muffler for a past ski using PVC pipe and stainless mesh to pack it. It worked fairly well. Put it in the middle of the rubber hose.

 

[Storbeck]

I would guess, but I don't know for sure, that if you are REALLY concerned about noise some of the beefier cast pipes (Riva Red, Pro-Tech) might be a little big quieter than a B-pipe. Lots of mass and lots of water jacket would probably contribute to noise reduction.

 

[WaveDemon]

you could try injecting water into the exhaust after the waterbox to quiet it down some more too.

 

[Storbeck]

Hi all,

I’m in the market for a custom freeride ski to chase boat wakes and handle a few trips to the surf.
Ive seen 2 used skis, but neither are for me. And now my search seems in jeopardy. See I’m on a small lake here where people have come to retire. I know I’m asking for trouble buying either of those with their current exhaust system. I’m assuming it’s a cheap way to add power, but do the HAVE to sound like this? Honestly, I must be getting old because it’s annoying to me too.

So I’m willing to go the custom build route on a sub-Krash type budget. The goal is to stuff as much reliable power into the ski as I can, but sound like a stock Superjet. Might sound stupid, but I appreciate any thoughts on whether this Goal is feasible.

Cheers

What exhaust was on the skis that you found to be too loud?

 

[Christian_83]

there is a big diffrence in waterboxes and also wether you run you pipe wet of dry.
im also trying to make a water box with extra injection to quiet it down.
I also thought about make a tube for after the waterbox to flood with water

 

[MarkL]

Unfortunately, I actually think it was a B-pipe, but do not know the waterbox.

But this is all very promising. It seems like the key is the waterbox plus injecting water.
Curious about the Riva Red or Protec pipe + stock waterbox and whether it would be a large performance difference over the stock manifold and waterbox for in theory marginal? increase in sound. Wish I could compare.

Seems the smartest thing is to stick with the JM781BB motor mentioned above and stock exhaust system... then try a different pipes with the same waterbox later if I’m in need for more power.

 

[Storbeck]

To be clear, there is the pipe, then there is the waterbox.

Any aftermarket pipe is going to be a huge increase in power over the stock pipe, with relatively minimal affect on sound, especially a wet pipe which is the sort of thing you've been discussing.

Any aftermarket waterbox is going to be an increase in noise (some more than others) with most likely no affect or a slight decrease in actual power.

So for evaluating sound knowing what waterbox was in the ski you are referencing is key.

 

[MarkL]

Thanks, I’m with you. Didnt realize how terrible the stock superjet manifold is for power. All those engineers creating something just to rob power/save cost. Oh well

ill see if I can find out what he had in there for someone to judge.

appreciate everyone’s comments.

 

[WaveDemon]

Thanks, I’m with you. Didnt realize how terrible the stock superjet manifold is for power. All those engineers creating something just to rob power/save cost. Oh well

ill see if I can find out what he had in there for someone to judge.

appreciate everyone’s comments.

the stock exhaust has a very low failure rate and is quieter. No one is designing a system to rob power.

 

[E350]

You could run a JM 781BB with the stock manifold.

Is the @JetManiac 781cc Big Bore engine based on the Yamaha 760 engine?

 

[SXIPro]

Is the @JetManiac 781cc Big Bore engine based on the Yamaha 760 engine?

No. Off the 701 thankfully.

 

[Quinc]

Run the stock RN waterbox with a bpipe and it will keep the ski fairly quiet. You might also play with puting a snorkle/elbow on the rear to force the exhaust into the water? Or change it so the exhaust dumps into the pump area like a waveblaster.

 

[MarkL]

Or change it so the exhaust dumps into the pump area like a waveblaster.

that’s creative! Are there any issues doing this?

 

[Vumad]

the stock exhaust has a very low failure rate and is quieter. No one is designing a system to rob power.

Pretty sure that's all the EPA does.

 

[Vumad]

that’s creative! Are there any issues doing this?

It makes a mess of your pump and it causes cavitation during tail stands. Worth it to some people.