IMPBA noise rule & dB meters

[Don Ferrette]

Don.. no mention of the term DB is used..

You're completely missing the point. A particular pipe run on a particular engine when tested may be at a certain dB & gets approved with that particular combination. Now add in a modified motor, higher nitro & guess what? It's louder. And what dB level may be on one brand of a particular motor size will NOT be the same on another. Heck, two of the same motors won't be the same, how can you possibly certify all these possible combinations?? Plus this does ZERO for addressing another large part of total noise- THE BOAT!!! I'll give you all a very good example- take that same approved pipe, even a stock motor on low nitro, put it in a mono hull without a cowl, with no baffling or sound deadening in the nose & a solid motor mount & you will have a boat capable of ear splitting noise levels!!! You MUST consider the whole picture when it comes to noise output. And you guys wonder why an electric boat registered 86dB...........

You must look at the ENTIRE package & that needs to be done by measuring sound levels.

 

[Buddy Benedict]

Ok!!! I guess it is time for some FACTS on the DB Readings at the Nats.

#1 Of the 400+ boats entered at the nats only 17 were given a warning for noise. Of that 17 only 2 didn't make the 92db limit the next round and was DQ'ed according to the rules voted in by the members of this organization.

#2 The DB meters were on tripods, 4 foot off the ground and 2 to 3 foot apart and 27 foot from the edge of the water. Of all the boats the passed by these meters there was only 1DB differance between the readings if there was any differance at all. One of the meters was mine and it is just over one year old and the other meter was purchased the day before open water started. As far as everybody else's meters goes, no one had them on a tripod and they were moving them from one of our meters to the other trying to check their readings. If they wanted to double check the readings then their meters should have been setup just like ours. Moving them around in their hands isn't the same as having them on tripods.

#3 Our pond!!! The Rocks!!! The Buildings!!! I heard all of these excuses. I also had a number of people ask me to get readings on their boats to compare with their own readings from their own lakes. I got the same answer from all of them " It's the same here as my home pond".

If you do the math the percentage of boats over the DB limit was only 4% of the total of boats entered in the race. If 96% are ok then the rule must be working as written. The only improvement needed is better clarification on how the time trials are to be run using the DB meters. If you are over the noise limit during a pass should it count????? This needs to be addressed for the next club that wants to do the Nats.

Buddy Benedict

The unfortunate one running the DB meters.

 

[Grimracer]

Don.. no mention of the term DB is used..

You're completely missing the point. A particular pipe run on a particular engine when tested may be at a certain dB & gets approved with that particular combination. Now add in a modified motor, higher nitro & guess what? It's louder. And what dB level may be on one brand of a particular motor size will NOT be the same on another. Heck, two of the same motors won't be the same, how can you possibly certify all these possible combinations?? Plus this does ZERO for addressing another large part of total noise- THE BOAT!!! I'll give you all a very good example- take that same approved pipe, even a stock motor on low nitro, put it in a mono hull without a cowl, with no baffling or sound deadening in the nose & a solid motor mount & you will have a boat capable of ear splitting noise levels!!! You MUST consider the whole picture when it comes to noise output. And you guys wonder why an electric boat registered 86dB...........

You must look at the ENTIRE package & that needs to be done by measuring sound levels.

don,

Im not discounting the rest of the boat... The exhaust is a start... not an end.

Mike

 

[Don Ferrette]

don,

Im not discounting the rest of the boat... The exhaust is a start... not an end.

Mike

And that puts you right back to measuring sound levels of the boats.

 

[Grimracer]

don,

Im not discounting the rest of the boat... The exhaust is a start... not an end.

Mike

And that puts you right back to measuring sound levels of the boats.

Not at all.. the dark side is strong with you... open your mind young padwad.. What we have now is confusion.. what we would have is BLACK AND WHITE fact...

Im trying the Jedi hand wave over the PC but its not working... .. O well no matter what the outcome I bet more then one of us will always play with in the rules (just like most did this year at the internats).. call out parts like im sugjesting or DBs... CDs.. DVD.. the HEBEGEBEs... i dont care... there is always FE...

ROCK ON

Grimracer

 

[brooks93]

there is always FE

Oh sure mike toss the hand grenade at us.. LOL

 

[steve wood]

i'm with mike. just sell me a pipe that impba says is ok. then no one can refute that

 

[Ron Olson]

The dB limits have finally hit close to home. A guy at work that I used to race trucks with told me today that one of the LHS's had to close down their outdoor track. Wanting to find out the full story, I called and talked to one of the owners, Rex Simpson of hobby-sports.com formerly known as R&L Hobbies. The story was true. Although they do have a Kalamazoo address, the are located in Portage. They are zoned as industrial property yet the land behind the store where their outdoor track is at used to be open land where people used to run dirt bikes and dune buggies that is now a new housing plat. The city of Portage does have a noise ordinance of 66 dB for businesses and 55 dB for residences. The city must have gotten a complaint from one of the new homeowners so they came out with their dB meter while a nitro race was going on. They recorded noise levels of 78 dB so needless to say, the track is now in the process of being torn down. These people put a lot of money into their track, importing clay, an AMB timing system, a PA system which they thought might have been the culprit, underground sprinkler system, fencing and driver's stand that all are being flattened. Fortunately the back of their store is an indoor track. The funny thing is that on each side of them are businesses that produce a lot more noise, an auto body shop on one side and a metal fabricating shop for industrial machinery on the other.

This is why I brought up the previous posting about local ordinances not caring about what the IMPBA or NAMBA says what the dB levels are.

Yes, the dB ordinance is really stupid if you think about it as lawnmowers and leaf blowers are going to be way over their noise limits.

I had a carpet cleaning service at a neighbors house that was really loud. I called the cops to bitch about it and held my dB meter outside and got 104 dB!

 

[Brian_Nelsen]

This is in reply to the post about the AMA testing procedure for motor cycles. I personally race a CRF450R Honda Four stroke motorcycle in the District 23 motocross classes. I have been tested several times at different track and have pasted and failed. My bike is stock with stock exhaust. I have been told it would be inpossible to fail with the stock pipe on the bike. This was not the case at two different tracks. I had to at those tracks change to a US forest service approved muffler. I did so, passes and raced. They also do rechecks of bike that sound louder on the track to make sure that the rider did not change the pipe after inspection.

The tracks I failed at looked at the rule book, and determined that where they "where" doing the testing was at fault and changed the proceedure. My bike now passes at those locations.

The procedure is good but not fool proof, I truly believe we will not get it perfect but we can make it work.

By the way, to fix my bike at those failed races I hade to spend 975.00 to get the pipe I needed.

I think we can come up with a workable system, we just need to want to do it.

Brian Nelsen

 

[Terry Keeley]

Ok!!! I guess it is time for some FACTS on the DB Readings at the Nats.

#1 Of the 400+ boats entered at the nats only 17 were given a warning for noise. Of that 17 only 2 didn't make the 92db limit the next round and was DQ'ed according to the rules voted in by the members of this organization.

#2 The DB meters were on tripods, 4 foot off the ground and 2 to 3 foot apart and 27 foot from the edge of the water. Of all the boats the passed by these meters there was only 1DB differance between the readings if there was any differance at all. One of the meters was mine and it is just over one year old and the other meter was purchased the day before open water started. As far as everybody else's meters goes, no one had them on a tripod and they were moving them from one of our meters to the other trying to check their readings. If they wanted to double check the readings then their meters should have been setup just like ours. Moving them around in their hands isn't the same as having them on tripods.

#3 Our pond!!! The Rocks!!! The Buildings!!! I heard all of these excuses. I also had a number of people ask me to get readings on their boats to compare with their own readings from their own lakes. I got the same answer from all of them " It's the same here as my home pond".

If you do the math the percentage of boats over the DB limit was only 4% of the total of boats entered in the race. If 96% are ok then the rule must be working as written. The only improvement needed is better clarification on how the time trials are to be run using the DB meters. If you are over the noise limit during a pass should it count????? This needs to be addressed for the next club that wants to do the Nats.

Buddy Benedict

The unfortunate one running the DB meters.

There we go, some facts. You did a fantastic job all week Buddy, thank-you!!!

 

[piper_chuck]

If you do the math the percentage of boats over the DB limit was only 4% of the total of boats entered in the race. If 96% are ok then the rule must be working as written. The only improvement needed is better clarification on how the time trials are to be run using the DB meters. If you are over the noise limit during a pass should it count????? This needs to be addressed for the next club that wants to do the Nats.

Buddy Benedict

The unfortunate one running the DB meters.

There we go, some facts. You did a fantastic job all week Buddy, thank-you!!!

Let's get some more facts. What was different about those 4%? Was there something obvious, such as unmuffled pipes, or were they running the same setups that passed for other people?

Something that would be really helpful for the rest of us is to keep posting info on what works. Not just the ones that come in just under the line. What are the truely quiet pipes? What measurements are people getting for some of the more sought after pipes, such as Andy's parabolics?

Edit: I started a new thread for people to post results. Let's help each other make our hobby quieter.

 

[EatMyShortsRacing]

There are 2 guys here in my area who are going to the NAVIGA world champs this year and have been racing locally with pipes that are compliant to 80dB, even though we have a 90dB limit in Oz - and funnily enough - they are just as competitive as before they switched to these extremely quiet pipes, because they did the testing and found a set-up that gave them results.

What pipes? I haven't seen anybody mention a name brand for any particular pipe that will run at the NAVIGA 80db standard.

When we first started using CMB engines over 15 years ago CMB only made fully muffled pipes for European racing. Our first modification to them was to drill the rear baffles out so we could hear our boats while racing because the noise from other boats totally drowned ours out and we couldnt tune them. CMB only started making Nitro pipes for the US market after their original baseball bat pipes did not sell!!!!

I also ran a pipe from Nimrif Models on my SG45 and that boat got the nickname of the "stealth boat" because you could not hear it at all on the back straight in a race.

Getting a boat to run below 90db is relatively simple... 80db is obviously harder, but also obviously possible.

Now that all being said I do believe in noise limits as I have stated clearly before. But with all the fuss recently in IMPBA I think there needs to be a few points to make.

1/ I think it is great that the IMPBA have finally tackled the noise issue and I believe those who have made it happen should be applauded as it really is for the survival of the sport and will benefit all boaters in the long run

2/ It should be a constructive debate on methods of reducing noise, not a slanging match...

3/ Equipment calibration and proper measurement procedures are VITAL if you are going to start disqualifying racers!!!!

4/ Share info on how to reduce noise.

Oh and a little note on sound... a 3db increase in Sound Pressure Level is actually DOUBLE the energy but also the minimum difference in sound level the ear can notice, yet 10db is percieved as twice as loud!!!!

... strange huh? So a twin rigger theoretically will be 3db louder with both engines running that if you only ran one engine in it???? The argument being that the same boat with the same noise reduction will put out double the energy with 2 motors running???? Test this theory and you might be surprised.... or confused as the same boat could do 3 passes at an identical distance from the measuring device with 3 different readings 9db apart!!!! For those interested check into phase cancellation. The noise of one engine at times can cancel noise from the other engine... Very rarely will the engines be so in sync that they will double the noise output of each individual engine (3db)

One other interesting thing to consider is the frequency and direction of the noise being produced by your boat.... This can give clues on how to reduce noise... or which noise you are trying to reduce!!!

EMS Racing More noise on quiet boats

 

[bzubee]

I know one of the ones that got DQed was using the internal stingers on his twin then he tried a couple of other additional items to get down to an acceptable level but failed until his next class with that boat came up and he used some silcone deflectors at right angles to the outside of the course and he passed. His other boat a single 67 hydro also passed with an internal stinger.

As for me changing my mind I have opinions also and my first decision was to go with my opinion not the boards and memberships I was reminded of this by a board member and that is when I changed my mind and stuck with the majority of the board to stick with what the majority of the membership voted on (Granted it wa a very small percentage of members that voted like around 10%). Memebrs do need to cast their votes when sent ballots it can make a big difference. Stating your opinions on IW and Jim's does not count as voting.

Bill Zuber

 

[EatMyShortsRacing]

If you do the math the percentage of boats over the DB limit was only 4% of the total of boats entered in the race. If 96% are ok then the rule must be working as written. The only improvement needed is better clarification on how the time trials are to be run using the DB meters. If you are over the noise limit during a pass should it count????? This needs to be addressed for the next club that wants to do the Nats.

Buddy Benedict

The unfortunate one running the DB meters.

There we go, some facts. You did a fantastic job all week Buddy, thank-you!!!

Let's get some more facts. What was different about those 4%? Was there something obvious, such as unmuffled pipes, or were they running the same setups that passed for other people?

Something that would be really helpful for the rest of us is to keep posting info on what works. Not just the ones that come in just under the line. What are the truely quiet pipes? What measurements are people getting for some of the more sought after pipes, such as Andy's parabolics?

Edit: I started a new thread for people to post results. Let's help each other make our hobby quieter.

Great idea to get some comparison on pipe noise....

But thats not the whole story!!!

For instance HOW your pipe is secured to your boat can make a difference. If it is a very solid mount the the vibration of the pipe gets transmitted into the boat and will be louder. I have seen european boats use rubber isolaters to mount the pipe to reduce the noise transmitted into the hull.

Also, fibreglass cowls are quieter than ABS cowls over engines...

More than one way to skin a cat!!!

EMS Racing - Dont leave your cat with me

I know one of the ones that got DQed was using the internal stingers on his twin then he tried a couple of other additional items to get down to an acceptable level but failed until his next class with that boat came up and he used some silcone deflectors at right angles to the outside of the course and he passed. His other boat a single 67 hydro also passed with an internal stinger.

As for me changing my mind I have opinions also and my first decision was to go with my opinion not the boards and memberships I was reminded of this by a board member and that is when I changed my mind and stuck with the majority of the board to stick with what the majority of the membership voted on (Granted it wa a very small percentage of members that voted like around 10%). Memebrs do need to cast their votes when sent ballots it can make a big difference. Stating your opinions on IW and Jim's does not count as voting.

Bill Zuber

Bill,

Given the noise limitations now bwing enforced, are you trying to get your boats to pass by the smallest possible margin or are you giving it a serious effort to be under the limitations? I think too many people think the 'limit' is where their boat should be, not safely under..... Deflecting the sound away from the meters is not making a boat quieter, it is evading detection. It will still be noisier in general and endangering the viability of the sport....

 

[Don Ferrette]

Given the noise limitations now being enforced, are you trying to get your boats to pass by the smallest possible margin or are you giving it a serious effort to be under the limitations? I think too many people think the 'limit' is where their boat should be, not safely under.....

BINGO!!!! That is a HUGE part of it. This is not rocket science nor is 92dB really that difficult but the line of thinking must change. Over the years I've come to realize that we as racers are some of the most resourceful people I've ever met & capable of thinking way outside the box ... BUT ..... we've also become somewhat lazy. Personally I feel if we spend less effort bitching about it & more effort doing something about it this can & will get done. Also try thinking along the lines of how quiet can I get it rather than what's the least I need to do to get under the limit. I have set myself a personal goal this year to try to get my big boats down in the mid 80's as far as dB range, starting with the twin. I might have to do some serious azz bustin' & alot of testing but I'm goin' for it. B)

 

[bzubee]

All of my boats passed with no problem my 67 hydro had an add on muffler at first but I broke down and bought a Cooper pipe before I even ran the boat at the INTERNATS and it was checked at 86-88 it wasn't the fastest boat but I also had only run it 2 different times prior to the Internats and this was it's first race. I ended up having engine troubles and that knocked me out in the later rounds. I like the way the Cooper pipe souned and the way you could talk while your boat was running in the pits it will take mor ework on my part but I'm sure it will get faster. My sport 40 had no problems noise wise and neither did my 21 mono. It was also under 90 from what I was told.

If you do the math the percentage of boats over the DB limit was only 4% of the total of boats entered in the race. If 96% are ok then the rule must be working as written. The only improvement needed is better clarification on how the time trials are to be run using the DB meters. If you are over the noise limit during a pass should it count????? This needs to be addressed for the next club that wants to do the Nats.

Buddy Benedict

The unfortunate one running the DB meters.

There we go, some facts. You did a fantastic job all week Buddy, thank-you!!!

Let's get some more facts. What was different about those 4%? Was there something obvious, such as unmuffled pipes, or were they running the same setups that passed for other people?

Something that would be really helpful for the rest of us is to keep posting info on what works. Not just the ones that come in just under the line. What are the truely quiet pipes? What measurements are people getting for some of the more sought after pipes, such as Andy's parabolics?

Edit: I started a new thread for people to post results. Let's help each other make our hobby quieter.

Great idea to get some comparison on pipe noise....

But thats not the whole story!!!

For instance HOW your pipe is secured to your boat can make a difference. If it is a very solid mount the the vibration of the pipe gets transmitted into the boat and will be louder. I have seen european boats use rubber isolaters to mount the pipe to reduce the noise transmitted into the hull.

Also, fibreglass cowls are quieter than ABS cowls over engines...

More than one way to skin a cat!!!

EMS Racing - Dont leave your cat with me

I know one of the ones that got DQed was using the internal stingers on his twin then he tried a couple of other additional items to get down to an acceptable level but failed until his next class with that boat came up and he used some silcone deflectors at right angles to the outside of the course and he passed. His other boat a single 67 hydro also passed with an internal stinger.

As for me changing my mind I have opinions also and my first decision was to go with my opinion not the boards and memberships I was reminded of this by a board member and that is when I changed my mind and stuck with the majority of the board to stick with what the majority of the membership voted on (Granted it wa a very small percentage of members that voted like around 10%). Memebrs do need to cast their votes when sent ballots it can make a big difference. Stating your opinions on IW and Jim's does not count as voting.

Bill Zuber

Bill,

Given the noise limitations now bwing enforced, are you trying to get your boats to pass by the smallest possible margin or are you giving it a serious effort to be under the limitations? I think too many people think the 'limit' is where their boat should be, not safely under..... Deflecting the sound away from the meters is not making a boat quieter, it is evading detection. It will still be noisier in general and endangering the viability of the sport....

One thing I have learned with this rule is that it has happened in the past with IMPBA, when they went from Straight pipes to Tuned pipes there were aurguments and fights way back then too. Until eveyone figured out they could overcome the new equipment requirments and actually go faster with the new required equipment. It's just another challenge to over come and I'm sure boaters will do just that and end up even faster than with Tuned pipes.

 

[piper_chuck]

BINGO!!!! That is a HUGE part of it. This is not rocket science nor is 92dB really that difficult but the line of thinking must change. Over the years I've come to realize that we as racers are some of the most resourceful people I've ever met & capable of thinking way outside the box ... BUT ..... we've also become somewhat lazy. Personally I feel if we spend less effort bitching about it & more effort doing something about it this can & will get done. Also try thinking along the lines of how quiet can I get it rather than what's the least I need to do to get under the limit. I have set myself a personal goal this year to try to get my big boats down in the mid 80's as far as dB range, starting with the twin. I might have to do some serious azz bustin' & alot of testing but I'm goin' for it. B)

I'm not sure it's even laziness. I can't count the number of times I've seen people actually looking for the noisiest pipe they can get. It seems that for some, the noise is part of their enjoyment. The same thing happens with R/C planes, and Harley owners. B)

There are also those who will always try to push the limits. Rather than accepting the spirit of the rule, lowering noise to save sites, they grudgingly do what they must to get just under the limit. Unfortunately, being too close to the limit exposes one to occasional failures due to site differences, etc.

 

[Wesleys Custom RC]

OK For those still out there who are more confused than ever about what to do with their boat and who just want to go racing and be "legal" I can tell you (because I was there) that the Cooper quiet pipes were on average the quietist thing to go past the db meter. They also have a cheaper muffler add on that works pretty well too. I would be willing to bet that their pipe or add on would pass ANY 92db test. I think the riggers might need a little more development or testing but for everything else I see this as the cheapest and easyest fix to a noise problem. I personally run these pipes on a scale ,sport 40 and sport 20 and the only problem we have is that we have to put our head right next to the motor to hear if it is fireing durring a race where people are using un muffled pipes. No, we didn't take home any US 1 trophies but I contribute that to many other factors tike stupidity, ignorance etc. et. etc. NOT the pipe.

I have to get this off my chest! Someone made a claim or suggestion that Evansville played "favorites" to a certian club or class of boat. THAT IS WRONG!!! I have been to races in the past where clubs played favorites and Evansville did NOT. They were courtious, fair and consistant with their rules and with everyone. I was found to be "illegal" in a stock tunnel class because of a head button that they said did not come on "that" particular motor. Instead of throwing me out, they helped me find the "correct " button and even installed it with the correct clearance. I bought the motor in a sealed box but if the judge says your "wrong" your wrong! accept it, quit crying, fix it or move on. If your not having fun, then move on to something else!!! To quote a famous philosepher "Quit ruining my life"

 

[Brian_Nelsen]

OK For those still out there who are more confused than ever about what to do with their boat and who just want to go racing and be "legal" I can tell you (because I was there) that the Cooper quiet pipes were on average the quietist thing to go past the db meter. They also have a cheaper muffler add on that works pretty well too. I would be willing to bet that their pipe or add on would pass ANY 92db test. I think the riggers might need a little more development or testing but for everything else I see this as the cheapest and easyest fix to a noise problem. I personally run these pipes on a scale ,sport 40 and sport 20 and the only problem we have is that we have to put our head right next to the motor to hear if it is fireing durring a race where people are using un muffled pipes. No, we didn't take home any US 1 trophies but I contribute that to many other factors tike stupidity, ignorance etc. et. etc. NOT the pipe.

I have to get this off my chest! Someone made a claim or suggestion that Evansville played "favorites" to a certian club or class of boat. THAT IS WRONG!!! I have been to races in the past where clubs played favorites and Evansville did NOT. They were courtious, fair and consistant with their rules and with everyone. I was found to be "illegal" in a stock tunnel class because of a head button that they said did not come on "that" particular motor. Instead of throwing me out, they helped me find the "correct " button and even installed it with the correct clearance. I bought the motor in a sealed box but if the judge says your "wrong" your wrong! accept it, quit crying, fix it or move on. If your not having fun, then move on to something else!!! To quote a famous philosepher "Quit ruining my life"

Very well said, I could not agree more. Instead of just trying to get to 92DB I went the extra and made sure I would be under by testing my boats to 88db.

Brian

 

[JKramer]

Rod, I got a smile from the $200.00 per lap race. Sounds like my RC Drag racing. We have sub two second runs and if you get beat, your done. If you figure actual time racing, the cost is high!!!!!!!