Quieting Boats down

[AWaddle322]

Fast oval time at the Internats in twin hydro was mac 67's turning 4.8" of cup. So what's with that? Placed a close 2nd it SAW too!

What does that have to with anything? Iknow.....I know since I quite running MAC 67 they have turned into a torque motor not a rpm motor. yea you prop a 67 smaller than a 90 and you prop a mac 67 smaller than cmb 90 to make them run in there respective power bands. Is one faster than the other. My opinion on different days you will get different results. n any giving day anyone may win. If the results were already known why would we race?

Andy, I'm getting the impression that I have offended you in some way as evident that you have had a comment to disprove anything that I have said here lately. If that is the case P>M me and we will see if we cant work thru this in private before the cutting gets much deeper.

Allen Waddle

 

[Roxyflash]

Sometimes you wonder where these thread goes.I guess you race to see who has the quietest pipes now adays.LOL

 

[Roxyflash]

 

[Tim_Duggan]

Getting back on track.

These pipes do not have a second cone rather a series of progressive baffles. The first baffle is 2" behind where the first cone ends (2" band as some would call it). This baffle's opening is only slightly smaller than the pipe i.d. Then an inch down from that is the next baffle which has a slightly smaller hole in it & so on. If you were to lay a straight edge along the holes of these baffles you'd see it follows the taper line that the secondary cone would normally make. The last internal baffle is flat with 2 offset .500" stingers 180 degrees apart from each other then exits the pipe thru a .500" stinger.

Don,

Thats a really interesting approach! Hat's off to whoever thought of that! Very clever.

Are these pipes particularly heavy by having all of those 1" apart baffles that replace the rear cone?

Tim

 

[Lorenzo Martinez]

Brian a couple of questions did you use the set up stated in the Noise rule? Also did you have your DB meter calibrated? If so what was the price to have it calibrated? I'm trying to get ours done at the Cal Lab here on the Arsenal. How far from the shore is your coruse set? Was the meter on a tri pod or table and foam? Just tryuing to get some answers from the other posts.

Not sure if anyone answer your question on the cost of calibrating a DB meter... but here're my two cents...

I worked in a Calibration Lab as a metrologist and I calibrated Namba Distric 9 Db meter to a tolerance of +- .5 Db. The normal cost of calibration will vary from lab to lab and if you want a certificate of calibration, with data before and after calibration, but in average it's about $80.

Hope that answer your question....

 

[AndyBrown]

Fast oval time at the Internats in twin hydro was mac 67's turning 4.8" of cup. So what's with that? Placed a close 2nd it SAW too!

What does that have to with anything? Iknow.....I know since I quite running MAC 67 they have turned into a torque motor not a rpm motor. yea you prop a 67 smaller than a 90 and you prop a mac 67 smaller than cmb 90 to make them run in there respective power bands. Is one faster than the other. My opinion on different days you will get different results. n any giving day anyone may win. If the results were already known why would we race?

Andy, I'm getting the impression that I have offended you in some way as evident that you have had a comment to disprove anything that I have said here lately. If that is the case P>M me and we will see if we cant work thru this in private before the cutting gets much deeper.

Allen Waddle

Allen, you have not offened me at all and I don't base my relationships with other boaters based on their choice of equipment. You just told Don that something was wrong with his 90's if he couldn't turn 8.0". You are putting out "mis-information" to the guys who don't really know.

I was just trying to put things into perspective before five new boaters called me asking for props with 8.0" for their new CMB 91 RS's when in reality those engines work best with 6.0'" or less. Someone may just think I'm not giving them the best prop if I recommend 5.8" for their 91.

You may be surprised how many poeple take little things that are said on here like that as gospel.

 

[Don Ferrette]

Getting back on track.

These pipes do not have a second cone rather a series of progressive baffles. The first baffle is 2" behind where the first cone ends (2" band as some would call it). This baffle's opening is only slightly smaller than the pipe i.d. Then an inch down from that is the next baffle which has a slightly smaller hole in it & so on. If you were to lay a straight edge along the holes of these baffles you'd see it follows the taper line that the secondary cone would normally make. The last internal baffle is flat with 2 offset .500" stingers 180 degrees apart from each other then exits the pipe thru a .500" stinger.

Don,

Thats a really interesting approach! Hat's off to whoever thought of that! Very clever.

Are these pipes particularly heavy by having all of those 1" apart baffles that replace the rear cone?

Tim

Not at all. The pipes I'm testing weigh 6.6 ounces each.

 

[Mark Bullard]

Fast oval time at the Internats in twin hydro was mac 67's turning 4.8" of cup. So what's with that? Placed a close 2nd it SAW too!

What does that have to with anything? Iknow.....I know since I quite running MAC 67 they have turned into a torque motor not a rpm motor. yea you prop a 67 smaller than a 90 and you prop a mac 67 smaller than cmb 90 to make them run in there respective power bands. Is one faster than the other. My opinion on different days you will get different results. n any giving day anyone may win. If the results were already known why would we race?

Andy, I'm getting the impression that I have offended you in some way as evident that you have had a comment to disprove anything that I have said here lately. If that is the case P>M me and we will see if we cant work thru this in private before the cutting gets much deeper.

Allen Waddle

Allen, you have not offened me at all and I don't base my relationships with other boaters based on their choice of equipment. You just told Don that something was wrong with his 90's if he couldn't turn 8.0". You are putting out "mis-information" to the guys who don't really know.

I was just trying to put things into perspective before five new boaters called me asking for props with 8.0" for their new CMB 91 RS's when in reality those engines work best with 6.0'" or less. Someone may just think I'm not giving them the best prop if I recommend 5.8" for their 91.

You may be surprised how many poeple take little things that are said on here like that as gospel.

That is a good statement Andy. Allen maybe able to turn 8.0" of pitch. But no one knows what the boat is or how it is set up. I myself can only run about 6.0" of pitch on my twin with 90's. These are my baseline props and then I cup the tips or remove cup between rounds if the boat needs it.

It is a lot like drag racing, you keep twiking the boat between rounds and by the time you get to the last round you have the boat running pretty good.

Mark

 

[Marty Slater]

AMEN BROTHER ANDY

Marty B)

 

[Swissrigger]

Don, sounds like a dream come true, 82 db pipe that wants more prop, don't keep

us in the dark tooo long. 90 Evo 2002s , right?

Here's a shot of the pipes. 2" inch diameter, .500" stinger i.d., 1" lead ins that will go over a CMB 90 header with .020" machined off the o.d.

Hi Don,

The pipes are using a really interesting concept. May be I missed who is manufacturing them and where are they available. Are smaller sizes also available?

Thank you.

Regards,

Petr

 

[Don Ferrette]

Don, sounds like a dream come true, 82 db pipe that wants more prop, don't keep

us in the dark tooo long. 90 Evo 2002s , right?

Here's a shot of the pipes. 2" inch diameter, .500" stinger i.d., 1" lead ins that will go over a CMB 90 header with .020" machined off the o.d.

Hi Don,

The pipes are using a really interesting concept. May be I missed who is manufacturing them and where are they available. Are smaller sizes also available?

Thank you.

Regards,

Petr

Hi Petr,

Macs will be producing pipes & we have chatted about smaller motor applications. Right now my focus is on the big blocks & then 1/8th scale will be next.

 

[gil sonsino]

Hi Petr

Welcome aboard Intl Waters and we all are looking forward for silent pipes to improve our boats.

greetings from downsouth.

Gill

 

[Don Ferrette]

Guys here is a link to the just updated Macs web site. The new pipes I'm testing are now assigned part numbers & when I talk to them on Monday after this weekend's tests I'm anticipating giving these pipes the thumbs up & according to Macs they will be immediately available at that point-

http://www.macspro.com/marinetunedpipes.asp

Scroll to the bottom of the page, these pipes are called the Double Q pipes. They are not going to be cheap as they are very time consuming to make but they sure are quiet. One thing I've learned is that they are best locked in at a particular length & then prop to that set up, which is what I'm currently doing. The pipes I'm running on my CMB90's have been given a part # of 1402 B)

 

[Jerry Wyss]

Does anybody have any links to where you can get O/B pipe add on silencers? This is for

Mod 20 o/b and the 30 tunnel motor,, the stinger on the 30 is about 7/16ths dia.

The normal add on silencers "Rum and Prather" an such are going to be way too heavy,

anything light that's out there.

Thanks, JW

Also: The silencers are going on carbon pipes.

 

[waltr]

Guys here is a link to the just updated Macs web site. The new pipes I'm testing are now assigned part numbers & when I talk to them on Monday after this weekend's tests I'm anticipating giving these pipes the thumbs up & according to Macs they will be immediately available at that point-

http://www.macspro.com/marinetunedpipes.asp

Scroll to the bottom of the page, these pipes are called the Double Q pipes. They are not going to be cheap as they are very time consuming to make but they sure are quiet. One thing I've learned is that they are best locked in at a particular length & then prop to that set up, which is what I'm currently doing. The pipes I'm running on my CMB90's have been given a part # of 1402 B)

Don,

Any idea which of the Double Q pipes would be the best bet for the 84 SGX?

Does anybody have any links to where you can get O/B pipe add on silencers? This is for

Mod 20 o/b and the 30 tunnel motor,, the stinger on the 30 is about 7/16ths dia.

The normal add on silencers "Rum and Prather" an such are going to be way too heavy,

anything light that's out there.

Thanks, JW

Also: The silencers are going on carbon pipes.

Jerry,

Cooper has em too.Just not sure about the Carbon pipe fit.:

http://www.cooperpipes.com/

 

[Don Ferrette]

Don,

Any idea which of the Double Q pipes would be the best bet for the 84 SGX?

I'm going to say try the 1404 with the 7/8" lead in.

 

[Jerry Wyss]

Hey!, Thanks waltr!,,,, cute little guy's,,them lil' bugs on the end that is

 

[Mike Larson]

Hey Jerry! Woods bro's racing made custom addon silencers a coupla years ago, I ran em on my old school Irwin stamped pipes in 3.5 mod..... Dave (SSP) is down for a refit or such (?) Talked to him a little, and, he's in process of quieter/possibly addon production if I read him right, I run mostly SSP outboard stuff on my mod boats, Id like to quiet them as far as I can, too. He'll be in touch, Im sure.... Mike

 

[Piston1]

Don, I looked at the MAC web page. I noticed that the advertised price tripled ($170.00 for the 15cc pipe). My experience with all MAC pipes (15 and 13ccs) associated with CMB 15cc (EVOs, RSs, etc.) motors is that they all act like your motors are running on "governors" which it's what you have been describing. The only pipe I have found that reacts to pipe length adjustments on the CMB15CCs is the Brown AB67. Therefore with all due respect, if the MAC pipes price is going to "triple", my input to you so that you can tell them, is that "they can stick that pipe were the sun don't shine".

JOSE

 

[Jerry Wyss]

Hey Jerry! Woods bro's racing made custom addon silencers a coupla years ago, I ran em on my old school Irwin stamped pipes in 3.5 mod..... Dave (SSP) is down for a refit or such (?) Talked to him a little, and, he's in process of quieter/possibly addon production if I read him right, I run mostly SSP outboard stuff on my mod boats, Id like to quiet them as far as I can, too. He'll be in touch, Im sure.... Mike

Hi Mike, One of the carbon pipes is a SPP and it did have his method of silencing bonded

right on there, but since it was a "one off" 5cc o/b pipe, I had to open up the stinger.

So cutting off the carbon silencer had to happen.

The other is a Ozzy carbon GadjetCraft pipe, it really doesn't need a silencer unless I go National.

So you think typing in "Woods Bro's" will get me there ,yeah?

JW