Mufflers

[Samuel Hagan JR]

Wasn't there a noise rule passed? If so, why isn't it enforced?

92 db is the current IMPBA rule, but 92 db is loud. An open piped .20 mono will run 93 db. I am actually looking forward to getting my boats to the European level. That way I can talk over boats running,instead of waiting for it to stop running. I hope others will follow in D1. I'm surprised Elmira puts up with the noise one bad apple makes with his boats. He ran at my only race, and I kick myself for not running a stricter sound rule. Times are changing guys. Step in the other person's shoes and see how it is best to make our boats as quiet as possible.

Me too. I'm trying to buy a pipe from a guy in Europe but he's not budging!

 

[Greg Hahn]

You really don't have to go to Europe for pipes. There are some really effective pipes available here in the US the new 21 and 45 CMB quiet pipes do a really good job but are hard to run not for speed but when heat racing you literally can't hear your boat over the others and it's hard to get a needle. I ran and had great speed on my B hydro with the CMB 21 quiet pipe but went back to the 3280 just so I could hear my boat. If everyone was quiet it wouldn't be a problem. We as a group just have to buckle down and do it or face the music one day.

 

[Joe Warren]

Wasn't there a noise rule passed? If so, why isn't it enforced?

92 db is the current IMPBA rule, but 92 db is loud. An open piped .20 mono will run 93 db. I am actually looking forward to getting my boats to the European level. That way I can talk over boats running,instead of waiting for it to stop running. I hope others will follow in D1. I'm surprised Elmira puts up with the noise one bad apple makes with his boats. He ran at my only race, and I kick myself for not running a stricter sound rule. Times are changing guys. Step in the other person's shoes and see how it is best to make our boats as quiet as possible.

Craig if it is a problem in your area? HANDLE IT...... IMPBA has a noise level...

 

[Andy Greene]

I run a Cooper QHP on my 40 Mono and frankly if more than 2 other boats are running, I cant hear mine. No idea of the true DB - but if I need to find the needle on the water- I need to go in first............

Andy

 

[Al Hobbs]

At a race in Europe my 90 boat registered 81 db. I was given a warning to get to 80db by the next heat or I was DQ'd.

At 80 db you can hear the carburetors open up in an 8 boat 15cc heat race. You can hear the water splashing off the sponsons during an 8 boat 15cc hydro race.

Even with how quiet they enforce at NAVIGA events, people there still complain about the noise levels at their races. I was at a race in Slovenia, 80db rule, and people 1/2 mile away complained about the noise.

The standard muffled pipes we have in the USA will not get you to 80db. You need to add another chamber to your pipe. You need a full cowl over the engine and the cowl must have soundproofing, like thin foam on the inside.

If you want to race at 80db, there is a lot of preparation required.

Al Hobbs

 

[Ian Webster]

Me too. I'm trying to buy a pipe from a guy in Europe but he's not budging!

Try Dave Marles at Prestwich.

 

[JimZaremski]

Wasn't there a noise rule passed? If so, why isn't it enforced?

92 db is the current IMPBA rule, but 92 db is loud. An open piped .20 mono will run 93 db. I am actually looking forward to getting my boats to the European level. That way I can talk over boats running,instead of waiting for it to stop running. I hope others will follow in D1. I'm surprised Elmira puts up with the noise one bad apple makes with his boats. He ran at my only race, and I kick myself for not running a stricter sound rule. Times are changing guys. Step in the other person's shoes and see how it is best to make our boats as quiet as possible.

It's worse than that; just saying "92 dB" doesn't tell you all that much. You need to consider the frequency content of the sound as well. 92 dB of broadband noise is loud but not nearly as annoying as 92 dB of a screeching .21.

 

[Geraghty]

Wasn't there a noise rule passed? If so, why isn't it enforced?

92 db is the current IMPBA rule, but 92 db is loud. An open piped .20 mono will run 93 db. I am actually looking forward to getting my boats to the European level. That way I can talk over boats running,instead of waiting for it to stop running. I hope others will follow in D1. I'm surprised Elmira puts up with the noise one bad apple makes with his boats. He ran at my only race, and I kick myself for not running a stricter sound rule. Times are changing guys. Step in the other person's shoes and see how it is best to make our boats as quiet as possible.

here is how you do it.........The rest of the world [NAVIGA] has been accomplishing this for as long as I can remember......Prestwich Models also has a big selection of quiet pipes that work.......

http://www.prestwich.ndirect.co.uk/silencin.htm

WWW.prestwichmodels.com

 

[Samuel Hagan JR]

Me too. I'm trying to buy a pipe from a guy in Europe but he's not budging!

Try Dave Marles at Prestwich.

Thanks. How does it compare to the CMB Quite Pipe.

 

[Leon Morgan]

I have always used Dave's pipes on my cmb90/91s but recently tested the lastest cmb pipes. Dave's sound slightly noiser than the cmb pipes but they always under the 82db. better peak rpm than cmb, but more critical on pipe length. Just my opinions

 

[Duck899]

I like the pic of the tether car the most,nice boat muffler though...it is a shame that it only takes ONE person to stop the sound of a Mod. Nitro engine,but that is the world we live in today. The people here in Fl. are very lucky to have a drag strip in Gainsville where we are "BLESSED" to have the Gator Nats where you can still HEAR and FEEL the Horse Power of a non DB regulated racing event...a true HP racing experience that you can only appreciate in person.

P.S. are the lower pans of your tether cars made out of Magnesium...

Mmmmmm, pickles

 

[dr gary turner]

The issue is really not the dB, it is because the sound that is heard is DIFFERENT than the AMBIENT SOUND. If you measure the increase in dB's at the location of those complaining when you have 6-8 of the biggest gas boats or the Blown Nitro motor a block away there will be no change in dB's from the ambient dB readings . It is because it can heard as a different sound. The physics of sound dictate this occurance.

 

[Blackout]

My closest neighbor could tell the 89 db boats from the 85 db boats. It makes a difference.

 

[JimZaremski]

not surprising, a 4 dB increase represents more than a doubling of sound power.

 

[Samuel Hagan JR]

How do you determine which boat is loader then the rest when there's 6 boats on the water?

 

[Tim Kish]

Guys, Tom is asking because I am having problems with sound at my pond. Just came back from a town meeting last night and I had to promise that we would quiet our boats down to 82 db like the Europeans. Do you guys think it would be best to just switch to a CMB Quiet Pipe to get the db's down? I question the effectiveness of add on mufflers. I have a CMB 45 Quiet pipe for my rigger that I will be testing, but it won't be for a couple weeks. I assume the CMB Quiet Pipe will get the engines at or below the European 82 db limit. Am I assuming wrong?? I know I have sound tested .21 boats with the NR .21 Quiet Pipe at 77db. That looks to be the same design as the CMB.

My neighbors are complaining with our gas sport hydros at around 87-90 db. So we are already well under the IMPBA 92 db limit.

Thanks!

Craig

Do what ever you have to do to keep your pond open .

Set a db level that you and your neighbours can live with and simply tell anyone that wants to use YOUR pond that they have to conform.

People get very creative when they are under the gun and Im sure with a little effort from everyone you will reach your goal .

Tim K

 

[Blackout]

How do you determine which boat is loader then the rest when there's 6 boats on the water?

It's easy to tell with your own ears if the boats are spread out by at least 20 feet. With the meter it can be a problem. But that's why you have the option to make a single boat run by itself under IMPBA rules. For my pond, I'm adopting a visual inspection as well, so boats are known ahead of time if they will be quiet, unless the person decides to gut a CMB Quiet pipe. From my experience with full size car racing, the visual inspection will be much easier to enforce. For example, some drivers could let off throttle as they pass sound meter. We used to move the sound meter around for our car racing to combat that.

 

[Blackout]

Guys, Tom is asking because I am having problems with sound at my pond. Just came back from a town meeting last night and I had to promise that we would quiet our boats down to 82 db like the Europeans. Do you guys think it would be best to just switch to a CMB Quiet Pipe to get the db's down? I question the effectiveness of add on mufflers. I have a CMB 45 Quiet pipe for my rigger that I will be testing, but it won't be for a couple weeks. I assume the CMB Quiet Pipe will get the engines at or below the European 82 db limit. Am I assuming wrong?? I know I have sound tested .21 boats with the NR .21 Quiet Pipe at 77db. That looks to be the same design as the CMB.

My neighbors are complaining with our gas sport hydros at around 87-90 db. So we are already well under the IMPBA 92 db limit.

Thanks!

Craig

Do what ever you have to do to keep your pond open .

Set a db level that you and your neighbours can live with and simply tell anyone that wants to use YOUR pond that they have to conform.

People get very creative when they are under the gun and Im sure with a little effort from everyone you will reach your goal .

Tim K

Thanks for your support Tim!

I have already started setting the rules. It's very doable, people will just have to spend some extra $$$ this winter for some good Quiet Pipes. I already have myself. For nitro, it sounds like CMB Quiet Pipes are the way to go and for gas there is Prestwich pipes. In the long run, I feel the add-on mufflers will be just a band aid fix. A purpose built quiet pipe is the way to go as it's designed from the ground up to be both quiet and increase power.

 

[andre holster]

I like the pic of the tether car the most,nice boat muffler though...it is a shame that it only takes ONE person to stop the sound of a Mod. Nitro engine,but that is the world we live in today. The people here in Fl. are very lucky to have a drag strip in Gainsville where we are "BLESSED" to have the Gator Nats where you can still HEAR and FEEL the Horse Power of a non DB regulated racing event...a true HP racing experience that you can only appreciate in person.

P.S. are the lower pans of your tether cars made out of Magnesium...

I was wrong, Navigas sound limit rule is 80 dB! and with the extra muffler it is is very hard to hear (tune) my engine when I run with other boats.

From Navigas rulebook:

The competitor must be advised immediately if their boat exceeds 80 dB/A. If the second

measurement also exceed the noise level they will receive a warning and if the third

measurement exceed thenoise level they will be immediately disqualified.

No the lower pans on the tether car (F10) is made of cast aluminum. I eat the pickles along with beer on late nights when I need to stay awake.

//André

 

[Mark Grannis]

This thread started out as an inquiry and is turning down an unwanted avenue.

One choosing to run boats near a residential area or retirment assisted living community is begging for problems. You don't run your r/c cars in a congested parking lot at quitting time, or fly your planes downtown amongst the tall buildings...right?

All noise problems are more about boaters infringing on unsuspecting citizens than the opposite. The ultimate quiet pipe is a sail!

MG