I am going to get one of these from Mark Craig for my MBRP exhaust. I was wondering if anyone else has gotten one and what they think about it. My wife says my exhaust is too loud while we are pulling our trailer. Does the install require any cutting or welding?

I purchased the resonator and front pipe from Mark Craig the other day. My plan is to install the resonator in that front pipe for a nice clean look. Mark stated a couple of people have done it, but it is tight. They should be here tomorrow, and I hope to install it on Friday. I have a TTS flange back exhaust and while it is not too loud, I want to settle down the noise between 1600-2000rpms. I will post the results as well as some pics if you want...


Bob

Oh yeah, Mark stated the overall length of the resonator is 18". The can is 12" and the slip joints are ~3" on either side. So you will have to cut an approax 12" section of pipe to fit it up there. Edited by: 4x4man

Nice truck Bob! Mine looks almost just like yours but a Chevy 2002. It is even complete with the Wildwood trailer.


If you get some pictures of your dampener installed post them. I would like to see how it looks. I was thinking of putting there on the downpipe as well.

I have designed a Helmholtz resonator for 3 CTD pickup trucks working with tuned fequencies. So far the results on them have been stellar.


Lower EGT's in the working ranges (higher EGT's until the F(s) frequency is reached though) and a much deeper tone, however the drone is gone.


Been trying to do it on a DMX, but the problem i am running into is quelling the tertiary harmonics of the soundwave above 2200 RPMS!http://www.dieselplace.com/forum/smileys/smiley7.gif


An I-6 is far easier to work with as far as frequency is concerned.


This CTD system i designed utilizes no muffler at all! There is no drone, no louder than stock, and very deep in tone (B series sounds like C series)


The EGT's are reduced as the system reaches F(s) of the tuned frequency and in similar fashion to a 2 stroke starts to self scavenge.


I am getting mad just thinking of all the time i wasted in the DMX design.... might have to try it again this year. Hit the math again, hit the welder and see if i can make a go of it.

I just ordered one of these today. The guy at DPP recommended putting this on the exhaust side of the four bolt flange rather than putting it on the downpipe.

Braz,


That's interesting as Mark stated we need to put this as far forward as possible for the best results. I'll shoot him an email to post here to confirm.


By the way, parts are in and ready for install tomorrow!!
Here are a couple of pics of the resonsator, what a piece!
http://www.dieselplace.com/forum/uploads/4x4man/2004-11-18_154055_P1010194.JPG


http://www.dieselplace.com/forum/uploads/4x4man/2004-11-18_154112_P1010195.JPGEdited by: 4x4man

Braz- I received an email from Mark this morning here is what he said:


Bob,
Putting it as far forward as possible will get you the best possible sound deadening, that's why we say what we do. Putting it behind the flange is a little easier to do is all.
Mark Craig

Well got the resonator installed into the new front pipe. Took about 3 hours total to do the job. I installed the resonator with the louvers pointing towards the front of the truck as this provides the most sound deadening per Mark. Only drove it about 15 minutes, but it doesn't seem that it has decreased the noise much if any. Maybe I need to put some more miles on it and some soot in it or something. I'll update in a couple of days...
Here are some pics:
http://www.dieselplace.com/forum/uploads/4x4man/2004-11-19_171710_P1010198.JPG


http://www.dieselplace.com/forum/uploads/4x4man/2004-11-19_171729_P1010200.JPG Edited by: 4x4man

Bob, anymore observations about how much the resonator helped? Have you been able to tell a difference in the sound?

I got more resonance at lower speeds and low throttle positions and actually more cab noise with the muffler. At heavy throttle or outside the truck(or windos down) its louder muffless though by a long shot........

Its all in the design of the muffler(my mufflers innards looked exactly like your "resonator") notice how if you drive a car with flowmasters you ussually get a deccent amount of resonance but you can run a pair of dynomax or something similar and even though overall loudness may be the same that low throttle cruise at a certian rpm drone may be gone? Try pointing the lovers in the opposite direction and maybe a change in mufflers. The hanging of a weight or clamping a peice of angle iron to your pipe like the dodge guys do may work??? How bout a louder stereo? ;)

Got Juice

I am interested in your work. How is EGT and F(s) related? I am assuming better flow is related to frequency, but I never thought of an exhaust this way.

4x4man,

Any updates on the sound??

Back in the '70s, Olds used to do the same thing on the 98's and 88's with 455s to cut the exhaust sound down, only the resonator was on the tailpipe.
Tom http://dieselplace.com/forum/attachment.php?attachmentid=107&stc=1

Got Juice

I am interested in your work. How is EGT and F(s) related? I am assuming better flow is related to frequency, but I never thought of an exhaust this way.
At the systems ' Excited ' Fs the system self scavenges similar to a 2-stroke.

If you take any sound wave (within reason 1/4 wave minimum to work mind you)
and make a chamber(s) that is tuned to that frequency you get an increase in volume output.

Pipe organs, Exhaust, Intake manifolds, Sound rooms etc

Our truck came factory with a Helmholtz resonator..... it is on the intake to keep turbo noise down.

To work properly the system should be installed in the middle of the system, (depending on which frequency the excited state happens at) and the size of the resonator is important as well. There is also a materials Fs) which has to be factored in to the calculations, Pipe diameter, Pulse frequency/Delta T, as well you need to know the cancellation freq# at the operating range that you wish to enhance or eliminate.

http://physics.kenyon.edu/EarlyApparatus/Acoustics/Helmholtz/Helmholtz.html

http://www.phys.unsw.edu.au/~jw/Helmholtz.html

http://scienceworld.wolfram.com/physics/HelmholtzResonator.html

http://www.physics.ucla.edu/demoweb/demomanual/acoustics/effects_of_sound/helmholtz_resonator.html

http://www.google.ca/search?q=helmholtz+resonator&hl=en&lr=&start=20&sa=N

Is the turbo "hat" designed with wave cancellation in mind?

I am familiar with the mass spring concept, and have designed LF sound systems using some interesting port ideas.

Are present aftermarket exhausts using these concepts to facilitate evacuation? If you know.

Sorry guys for the late response, I've been out for the Holiday's. The resonator has made a noticable difference in sound, it just took a couple of hundred miles I guess. This thing almost sounds as quiet as the stock system now (I have about 2k miles on this setup). The only noise I get out of it is in the 1800-2000 rpm range, but it is much quieter and tolerable now than it used to be. Funny thing is, when towing you can't even hear the exhaust at any rpm now...don't know what to make of that, but with nearly 200 degree drop in EGT's and no sound penalty's I'll take it!!

4x4man,

Thanks for the report; guess it will be time to add that to the system. I like the current sound out the back with the windows open, but would like it nice and quiet in the cab which is what I am looking for.

I just re-did my duals with turn downs strait out the back and that made it even quieter...

Ox

Is the turbo "hat" designed with wave cancellation in mind?

I am familiar with the mass spring concept, and have designed LF sound systems using some interesting port ideas.

Are present aftermarket exhausts using these concepts to facilitate evacuation? If you know.
IIRC nobody is taking it on.... I have a few happy CTD guys out there right now running it.
NO RESONANCE in cab at all.... but the sound outside is similar to a C series CTD.... more BASS Rumble!:ro)

Stupid V-8's ... I have tried to find a workable chamber, location.... nothing yet.

"but would like it nice and quiet in the cab which is what I am looking for."

<!-- / message --><!-- sig -->me too. Could be time for a sound deadening project, and a sound system upgrade.

I am still planning on Dynamating my truck this summer as well. May be over kill, but every little bit in the sound deadening department helps!! I guess we are the few that want lower EGT's and QUIET!! :D

If you haven't tried it, the stuff in Home Depots roofing section is exactly the same, odorless, and you get 4 for 1 dynamat. Save a couple hundred$

Thanks for the tip!! I was looking at the Fatmat stuff as well, but have read people complaining about a tar smell for a few weeks. I will check out the stuff at HD, thanks!!

Tar smell goes good with a new exhaust.

You should submit that to Dynamat's marketing department....

I put my bull haulers on and my little girl hates it when I crack down, so I am gonna try the resanator as well. I also have some new rattles in the cab do to the vibration of the stacks. A car audio place has a spray can of stuff they use, I am gonna try this and let you all know what I found.