When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Are they basing the dimensions off your calculations or they doing the math themselves. You can increase diameter to shorten length no? It's a matter of volume?
They are using my calcs. Paul said that he's somewhat familiar with the concept of QW and helmholtz resonators, but he's never fabbed or installed one before. You may be able to increase diameter and shorten length for the same volume on a true helmholtz resonator, but not on a quarter wave resonator. The QW resonator is simply a pipe of consistent diameterthat is tee'd into the exhaust and capped on one end. You calculate the full wavelength of the offending resonance (2000 rpm on a V8 gives off a resonance of 133hz), and then build the QW resonator at a length that equals 1/4 of the full offending wavelength. No exhaust flows through the QW resonator, but soundwaves do enter the res, travel to the end, reflect back off the capped end and if the length of the resonator is truly 1/4 of the offending wavelength, it re-enters the exhaust 180 degrees out of phase, effectively offsetting or canceling out the offending wavelength. Because of this, the length is a crucial calculation, and if it is modified, it will attenuate (quiet) a different wavelength, and thus will effect the exhaust sound at a different rpm than you are trying to target. The diameter of a QW resonator is not as critical to the calculation, although the larger the diameter of the QW res, the more attenuation of the offending wavelength. I'm not aware of any benefit to using a QW res diameter larger than the exhaust pipe it's tee'd into, but you can use a pipe diameter smaller than the exhaust and the overall effect of the resonator will be reduced by some degree.
I think you are talking about true helmholtz resonators (like those on the HKS SSK exhaust) - they use a short pipe of smaller diameter (the neck) tee'd into the exhaust, with a chamber (usually bottle-shaped) of certain calculated size attached to the end of the neck. The chamber is sealed on the far end. The two types of resonators have similar effect on the exhaust, but helmholtz resonators work differently - they deal with the "spring" effect of the column of air in the neck and chamber somehow. And with that, I've already told you more than I know about true helmholtz resonators. The math for them is more complicated as well...
Ahh gotcha. Yeah I was referring to a helmholtz chamber. Interested to see the results of your QW setup.
Prompted me to read up on the difference. Looks like the QW is a pretty simple solution. Question is, do you need one per pipe and where do you place a 2' pipe haha. Teed off and above the initial mid pipe?
Edit: Found what I had stumbled upon years ago. You could chop the length and then add a band clamp to make it adjustable?
Ahh gotcha. Yeah I was referring to a helmholtz chamber. Interested to see the results of your QW setup.
Prompted me to read up on the difference. Looks like the QW is a pretty simple solution. Question is, do you need one per pipe and where do you place a 2' pipe haha. Teed off and above the initial mid pipe?
Edit: Found what I had stumbled upon years ago. You could chop the length and then add a band clamp to make it adjustable?
Yep, you need one resonator per exhaust pipe on a dual exhaust setup. As far as WHERE to put the resonators - that's the biggest challenge. On mine, I think we'll have to snake them around the back and side of my magnaflow mufflers. Fortunately, the QW resonator can have bends in it, because I don't think I could fit 2 straight 27" long resonators anywhere under my car. And yes, ideally you'd make it adjustable for length so it can be fine tuned. Some guys have used a trombone slide concept and then band clamped or welded the resonator to a fixed length after fine tuning. I'm not sure if I'll have room for adjustability or not. I think 26" - 27" resonators will be about right for my setup, so if I have the room, I'll go 27" and I can always remove an inch later if needed...
Good call, sounds like there is a small window in which you can be off and still target the resonance. Thanks for prompting the research, I spent all last night reading up on it now haha. Once I get headers and have to deal with this issue, I will hopefully be well prepared.
No, nothing yet. I currently am scheduled to take the car to PPE on January 26 to have quarter wave resonators installed - PPE is swamped right now and they are moving they shop in a few weeks, so they couldn't get me in for a month.
However, I just got back from a 300 mile road trip over the last 2 days with multiple passengers, and with the ISS DES exhaust and newly installed headers, the drone is crazy loud and annoying. After that trip, I'm wondering if the QW resonators are going to reduce it enough across my drone range (I'm droning loudly from 1,400 to 2,300 rpm). I'm going to do some more research on adding quieter mufflers (stock?, Dynomax VT?, etc) and then see if I have any drone left. I just cringe at the thought of paying PPE prices to have QW resonators built and then decide they didn't do enough only to swap mufflers and then maybe adding new QW resonators on the new system. I'm not sure what I'm going to do, but I'll update this thread (or start a new one) either way.
I've started to look into this also, I have PPE headers and Borla catback with hi-flow cats and I have the drone in the same RPM range. Mine isn't unbearable but I'd like to eliminate it if possible. From what I've read, its recommended that the resonators be placed as close to to the cabin as possible to cancel out the drone. Do you have any idea where you will be installing your resonators or will PPE be doing all the calculations and placement of the pipes? A muffler shop recommended replacing the mufflers on my car but I don't want to chop up my Borla system and the ISS DES looks too nice to replace.
I've started to look into this also, I have PPE headers and Borla catback with hi-flow cats and I have the drone in the same RPM range. Mine isn't unbearable but I'd like to eliminate it if possible. From what I've read, its recommended that the resonators be placed as close to to the cabin as possible to cancel out the drone. Do you have any idea where you will be installing your resonators or will PPE be doing all the calculations and placement of the pipes? A muffler shop recommended replacing the mufflers on my car but I don't want to chop up my Borla system and the ISS DES looks too nice to replace.
I've started to look into this also, I have PPE headers and Borla catback with hi-flow cats and I have the drone in the same RPM range. Mine isn't unbearable but I'd like to eliminate it if possible. From what I've read, its recommended that the resonators be placed as close to to the cabin as possible to cancel out the drone. Do you have any idea where you will be installing your resonators or will PPE be doing all the calculations and placement of the pipes? A muffler shop recommended replacing the mufflers on my car but I don't want to chop up my Borla system and the ISS DES looks too nice to replace.
I'm not aware of a requirement to keep the QW resonators close to the cabin - that may make them more effective (?), I've just not come across that in my research. I know several mustang guys have had success putting them in their tailpipe area behind the rear axle. And in the F, it may be a moot point anyway, because I'm not sure that there is any room for them under the middle of the car. When I stopped by PPE to make my appointment, their lift was not available, but Paul and I laid under the back of the car and looked at options. The only thing we could come up with was to attach them right before the Magnaflow mufflers and wrap them around the back and beside the outside of the mufflers. I need to get the car in the air and see if there are any options near the X-pipe area (doubtful). I also wonder if the rear center under-car tray that lives between the mufflers has a void above it that could be used...
Yeah it would be nice to be able to hide them behind the bumper if possible. Don't really wanna see them and I concur, I haven't seen anywhere in the mid section you could hide something that long.
Diesel350 - The exhaust shop made different muffler reccomendations but I wasn't interested. If I wanted to change out the mufflers, I'm better off selling off my current exhaust system and getting something else.
Tom2769- I found this video regarding J-pipes, which is supposed to work similar to a resonator:
I'm not saying its going to work, just saying what I've found so far on the internet. And, I agree, i don't want any extra pipes to be visible from the rear nor do I want it to hang any lower than my current exhaust piping. All this research has been interesting, if nothing else will work to reduce drone, I'm not opposed to going to the PPE exhaust and EL header set-up, It just seems like a waste of money so far because I've only had my headers and exhaust for less than a year and 5k miles.
Diesel350 - The exhaust shop made different muffler reccomendations but I wasn't interested. If I wanted to change out the mufflers, I'm better off selling off my current exhaust system and getting something else.
.
Oh ok, they were probably recommending a bigger chambered muffler than what the borla has in order to tone down the drone. That would probably be a more expensive option than adding J-pipes to the exhaust. If the J-pipes don't work out I think your only option would be to change out your mufflers to bigger reactive mufflers or look into a twin loop type muffler.
Good call, sounds like there is a small window in which you can be off and still target the resonance. Thanks for prompting the research, I spent all last night reading up on it now haha. Once I get headers and have to deal with this issue, I will hopefully be well prepared.
Good luck!
FFM did you ever get a price quote on those Thunder mufflers? Just curious how much they wanted.
FFM did you ever get a price quote on those Thunder mufflers? Just curious how much they wanted.
Yeah I did. No vendors would take on the order and CL brown holed my thread to gauge interest so that killed those dreams.
The more you order the bigger the discount, unfortunately I didn't feel like ordering up 5 sets for myself so gave up on it. It ranged from 500-400 a set depending on how big of a batch.
Yeah I did. No vendors would take on the order and CL brown holed my thread to gauge interest so that killed those dreams.
The more you order the bigger the discount, unfortunately I didn't feel like ordering up 5 sets for myself so gave up on it. It ranged from 500-400 a set depending on how big of a batch.
12-22-16, 07:06 PM
