Quieting down a loud PV muffler?

[Grant Eaton]

I've had my 2nd generation PV muffler for about 1 month now. It has 2,000 miles on it, and while it has mellowed considerably, it is still too loud inside the cabin, even with the Dynamat I have on the roof and inside plastic panels! The worst noise is the chassis-rattling drone at around 30 MPH (1,500 - 1,800 rpm). It sounds just like blowing into a beer bottle, only you're stuck inside the bottle!

I really like extra acceleration kick and want to keep this muffler. So, what can I do to quiet it down without robbing too much power? There's a lot of information on the Web, but not much for people trying to quiet down a performance muffler.

Bsically I'm considering the following options:

1. Dual exhaust. I'm getting this for looks-improvement only. Perhaps it will have the side-benefit of channeling the sound out both sides of the rearend, and make things sound more balanced as a result.

2. Resonated tips. Some people claim they absorb noise, others swear they make the exhaust drone louder and more annoying. What's the truth?

3. A noise-control tip. I've only been able to locate one example on the Web. At $80, it's not cheap and it doesn't come with any scientific evidence for decibel control. However, the idea of using perforations or baffles to help absorb sound energy makes sense.
http://www.tmtuning.com/exhaust/ex_images/silencertip.jpg

4. An additional noise control muffler (aka inline resonator). Hopefully this won't rob much performance. Perhaps it would be possible to insert one of these inline between the engine and the PV. Or even after the PV.
http://www.flowmastermufflers.com/web10/IMPTS/Resinator_Muffer_Sm.jpg
http://www.extrememotorsports.com/g2cat/reson3-l.jpg

5. Noise control pipe baffle. This is susposed to be inserted between the PV and the engine. It's designed to reflect sound energy back into the pipe while maintaining air flow.
http://store.summitracing.com/global/images/prod/large/dtc-72.jpg


Any advice on how to get rid of the "beer-bottle effect" and quiet down the overall exhaust would be helpful. Thanks.

[FeatherFoot]

Grant,

sorry your having sound/drone problems, unfortunately sound has a tendancy to react differently to length size and volume and can change from car to car.

A resonated tip should get rid of the drone for you.

6 to 8 inches of perferation of the same size as the tailpipe should do the trick. If you go bigger, chances are you will aggravate the problem and much smaller seems to produce a sound similar to a cornered cat.

John

[Grant Eaton]

Originally posted by FeatherFoot
A resonated tip should get rid of the drone for you.

6 to 8 inches of perferation of the same size as the tailpipe should do the trick. If you go bigger, chances are you will aggravate the problem and much smaller seems to produce a sound similar to a cornered cat.

John

Thanks for the reply, John. So, it sounds like I should get this 3"x12" baffled tailpipe PLUS a 6-8" perforated resonator to put inline between the PV and the engine? The inline resonator should go BEFORE the PV, right?

I figure I might as well as go the extra mile and as long as they're going to be hacking the exhaust system apart to put on the dual tailpipes. Couldn't hurt to put on a noise suppressor tailpipe in addition to an inline resonator... right?

http://www.tmtuning.com/exhaust/ex_images/silencertip.jpg

http://www.extrememotorsports.com/g2cat/reson3-l.jpg

I know what you mean about every car being different depending on pipe length and other factors. You know that sound you get when you blow into an empty beer bottle? That's EXACTLY the way the inside of my cabin sounds at around 1,500 - 1,800 RPM. If I could at least get rid of that beer-bottle resonation effect, I'd be a much happier camper. :)

[WyrreJ]

Ever see the Blue Man Group? Their most performed show is called, "Tubes." And a good portion of it makes use of the fact that the resonance frequency of a tube changes based on the length, like slide trombones, except made out of PVC piping and generally much lower frequencies.

Anyway, the point of the story is that perhaps your muffler just happened to get installed at a nodal point that reinforces the frequencies from your engine such that you get the resonance really bad. Perhaps, all it would take, would be to move the muffler a couple of inches up or down the pipe so as to change the resonate frequency enough so that it no longer reinforces the sound from the engine.

Of course, I'm no mechanic and never took any physics beyond high school (AP level, but high school nonetheless) so I could easily be resonating out my ass here.

[Moncha]

That looks to be a very SOUND therory.. :) Actually, it just may work..
Grant, since the PV2 is shorter than the OEM Muffler, did you put an extender pipe before or after the muffler?

[chumone]

I get the "beer bottle" effect at around the same speed/rpm as Grant. Most annoying.

Let us know how the tip/inline perforator works, Grant. That drone is driving me nuts.

[WyrreJ]

Perhaps it would help if people with PVs installed could post the following three pieces of information:

1) New or Old style PV
2) Noisy or mostly Quiet
3) Extender pipe before or after muffler

Also, do the PV guys themselves have any recommendations for where the extender pipe should be installed?

I'm personally very interested since I have just days away from having my new PV installed. If position makes a difference, I'd like to get it right the first time.

[Grant Eaton]

Originally posted by Moncha
Grant, since the PV2 is shorter than the OEM Muffler, did you put an extender pipe before or after the muffler?

No, I don't believe an extender pipe was put in. I was just down under the VX today. I believe Midas pretty much just installed the PV at the same point where the OEM exhaust connected with the main system, within a few inches of the Y-pipe that unites the two exhaust lines. I will try to take a picture of it next week when the tire shop install my new shoes. It'll be easier to see when it's up on the lift.

[paultvx]

Pictures might not be of much value since it'd be hard to see where the mulffer is/should be placed.

It might be more useful to measure where the new muffler is attached... compared to the stock. Better yet... measure from some stock fixture along the stock exhaust (ahead of the muffler) to the PV. That way we'd all have the same reference point.

Recalling some high school and college physics courses, I think WyrreJ's theory is correct.

I find it hard to believe that they did not weld on an extender pipe. Isn't the PV shorter than the stock muffler? If that is indeed the case, they would have to weld on a pipe somewhere (ahead or aft) to make up for the difference in length.

If you're going to spend the money to have an additional muffler put in... then you might as well have started with a complete custom exahust system. I'd do what WyreeJ suggested before spending that much time and money.

[FeatherFoot]

Grant

Just the tip is needed. The reference to 6 to 8 inches of perferation is referenced to the inside of the tip.

John

[skullcap]

Mine just came the other day, so before I go and have it installed, probably at a friend's Meineke Franchise, are there any special installation pointers?

If the PV2 is shorter than the OEM muffler, to which end are folks having the extension attached?

Also, anyone have ideas for use of the OEM muffler?

I was thinking of maybe getting Martha Stewart to make it into a vase or something clever, since I hear she may soon be doing iron-work. :naughty:

[kpaske]

I too have just become the proud owner of a new PV Muffler! Hopefully by the time I get home from my loooooong deployment overseas, a shiny new muffler and some other toys will be waiting for me. ;Db; If anyone has some tips/advice as to the proper installation of this muffler, please post them for us!

[Dallas4u]

Any muffler shop should be able to just remove the old one and install the new one, whether it needs an extender pipe or not, that's what these shops do... mufflers!m Besides, an extender pipe is just a piece of exhaust piping, no big deal. If they don't think they can do it, or if you can't get out of there for under $50, then I would look elsewhere.

[paultvx]

Question is... where does the extender go... fore or aft. The more I think about it, WyreeJ's theory sounds better and better. Assuming the mufflers themselves were built to the same specs and standards, the placement of the muffler is the only thing that can vary in all the installations. It's the only thing I can think of that could explain why some are having resonance issues.

[Dallas4u]

Well, someone can test putting the extender before of after the muffler, but you may also run into mounting issues if you move the muffler around. I know mine is using the OEM mounting bracket and hole, so I am assuming there was an extender added before my muffler. I have a some-what loud grumble, but I'm happy with it.

[Tone]

Mine is mounted in the middle of the space where the stock muffer went with almost identical lengths of pipe before and after the muffler. John has recommended it be closer to the front with the added pipe going aft of the muffler, i.e. cut off stock muffler, weld new muffler to where pipe was cut going into the stock muff, then add pipe from end of PV to beginning of pipe over axle.

Those who want bolt on could have the muffler shops add pipe and flanges to the PV so it could bolt on in place of the stock muffler.

Realize that the PV2 is significantly smaller and shorter than the PV1 or the stock muffler and as such is much easier to mount.

[ISCE]

My PV2 is almost as close to the front as possible. Looks like only maybe 1" added to the front and a longer piece at the back.

Definitely sounds like having it mounted closer to the front tones down the resonance a bit. I am noticing with mine that the temp and/or humidity outside seems to make quite a bit of difference to the sound. When it is cooler and wetter it seems to be louder.

ISCE

[AnalogVX]

I just had mine installed yesterday. And my first impression was that I had a faulty exhuast. It sounded good at idle, but when I gave it some throttle, it was LOUD. Almost embarrassing. I even crawled under to look for leaks. At 1500-2000 RPM it resonates in the interior. Above 2000RPM at cruise, it is SILENT. Go figure. I really think it will mellow, because it does not sound like the PV that I had heard before, whether PV-1 or PV-2.
It is mounted with equal length extensions on both ends and welded.

[AnalogVX]

I am looking at a resonator too. Am I correct when I measured a 2 inch diameter tailpipe?

[AnalogVX]

Originally posted by SPAZZ
Hey dude, you heard mine. Is it like that? because mine mellowed out a lot from my exhaust beginning to break off at manifold when you heard it in Moab.

Like I told you in those Pm's.....you will not be sneaking up on any one ever again!!!

It's louder. I have to admit, it seems like it's getting mellower, especially after it gets good and warm. Doesn't sound as brash. But the resonation at 1500-2000rpm is gonna take some getting used to or an exhaust resonator tip installed to take the edge off.

Nocturnal got really lucky...his sounds perfect!

[paultvx]

I hate to say it but it's starting to sound like a quality control issue in production. A more noticeable note from outside of the vehicle is acceptable, but interior resonance can be extremely annoying on long trips.

[AlaskaVX]

Just installed mine yesterday and I really don't find it as loud as I thought it was going to be. It sounds a little more ricey than I thought, but it is definateley a lower pitch than a ricey one. Overall I think it sounds good, I think it will sound better later. The noise on mine is no louder than my tire noise (under normal driving, if you step on it it will get loud but not too loud). And if it hits that "beer bottle effect" then just let off the gas for a sec and reapply, it seems to go away 90% of the time. Of course I have only drove one day and I don't think the beer bottle effect happened inside my cab, but I could hear the tone of the muffler that you are describing (I just let off a bit and it went away) I had my muffler mounted up front due to Tones post

I love the sound of it when you start it up, it just puts a smile on your face. :) Track times with this mod coming Monday.

[AnalogVX]

I really don't know what the deal is. It most definately gets a little quieter when it warms up. I am still looking for a tip.

[paultvx]

Starting to sound like the Borla exhaust I had on my Jeep GC few years ago. Man did I get ricers come up and try to race. Funny the first few times but after that it got really annoying. Kinda like how you go camping and the mosquitos won't leave you alone? It's the same feeling.

I suppose from a performance stand point the pv is probably worth it. And the Borla for the Jeep did mellow out alot after a year or so. It also sounded quieter once it got hot. Come to think of it, the Neuspeed exhaust I had for my VW GTI was exactly the same way. Loud at first but mellowed out after a year.

I think I'll order one in two weeks or so... when I get hired. *cross fingers*

[Dallas4u]

I can tell you, and I hope other PV1 owners feel the same, that the PV1 DEFINITELY quieted down after a few months. I've had mine installed for over a year and it is a LOT quieter than when I had it installed. In fact, at some points I wish it were a little louder... although it doesn't really matter. I love the hum it makes while cruising, and the growl it makes when reving.

Supposedly, the PV2 is a bit more open, so it may be a bit louder than the PV1 brand new, but I have no idea. I'm assuming they probably sound very similar and over time will, too.

[skullcap]

It's was a little quieter than I expected, but a bit more than the neighbors were expecting (out of lil ol' humble moi).

To get the idea of how it sounds simply put you lips together and say PPPPPPPPPPPPPPPPPPPPPPPPPPPPPPPower Vault!

[AnalogVX]

I really hope it mellows out as much as everyone says it will. I have mixed emotions right now about it. I love the way it sounds while cruising. But the growl everyone talks about under acceleration sounds like a coffee can. I am going to Car-X tomorrow to discuss some resonator options. At this point if the tips are as expensive as everyone says they are, I could have bought a cat-back.

[skullcap]

The shop that installed it ($40 cash) said that, as with all glass-packs, it should certainly mellow-out after a few weeks of use. Heck! I found that driving it through 6" of rushing water down rain-swollen Atlanta streets mellowed it out only minutes after I left the shop.

The little beast really is almost amphibious! With her new guttoral heartbeat, I think I know the perfect badge for her

[AnalogVX]

I am pretty pleased with how much this muffler has mellowed. I was searching the the old threads on Vmag and found this posted by FeatherFoot. I believe it is John from PV mufflers. I will share this with everyone here if anybody is looking to quiet it down futher.

"...loudness can be reduced by replacing the 3" tip on the stock exhaust with a 2-1/4 tailpipe. That tip actually acts like a megaphone which increases the sound level. Another option is a resonated tip which will reduce the sound even further. Do not go bigger than 3-1/2" for the resonated tip or you begin to megaphone again.

John"

The compliments are starting to roll in so I am going to leave it as is with the stock VX tip. Hope others find this info useful.

:)

[lostemple]

Mine has mellowed quite a bit. I have the first generation PV muffler. By listening to Tone's I think the second generation PV muffler is louder, but it supposedly is more efficiant and provides increased horse power. I would like to eventually Dynomat the whole vehicle, but summer temperatures have that delayed until late fall early winter. Until then I can put up with the low RPM grumble.

[skullcap]

I'm starting to get used to the *lunar-rover on steroids crossed with a Bradley* sound. Big Mike let me listen to his FLowmaster and it's only a few decibles lower.

..one thing I speculate is it will likely deter deer better than those dang-blame whistles (which DO NOT work).

I do hear some rattles when idling that I can't tell if it's from the hangers or an exhaust leak in the welds.

One thing for sure, I've some 'splainin' to do at the dealer's service dept. ;Dr;

[johnnyapollo]

Hey Alex,

Check the front flange as it straddles a cross member. Removing the stock muffler drops the rig slghtly and the front flange could be knocking against the crossmember when the engine torques (mine did this.. had to add a hanger). You may want to add an extra hanger to the front of the muffler to prevent this and keep the weight off the manifold.

-- John

[skullcap]

Thanks John!

I'll take her back over to Meineke and ask for them to have a look.

[SGT.BATGUANO]

How 'bout a potato inserted in the tip:eek:

On a more serious note, I'd like to see documentation / hard facts comparing the PV1 and PV2. Anyone had both?

[skullcap]

I already tried the potato trick.

But I couldn't figure out how to make it stay in place with all that butter and sour cream on it. ;Dy;

[AnalogVX]

Be careful when using a potatoe so Harley-Davidson doesn't come down on you. They supposedly had trademarked the sound of their V-Twin to sound like potato-potato-patato.

[AnalogVX]

After a 4 hour trek to Iowa, I have decided to give the tail pipe fix a try. I thought I would be able to deal with the exhaust note now especially after it had mellowed little, but after 2 hours of interstate wind noise and various boy band pop hits (I was taking my daughter home) I was looking foward to the piece and quiet of a 55mph zone only to be greeted by my PV muffler.
I had the stock tip replaced today with a 2" tail pipe. Nothing fancy. The difference it made was nothing short of REMARKABLE!. The exhast note is low and throaty but the brash, resonation is gone. This is the sound I have been hoping for. The best way to describe it is the exhaust note is now in the background were it belongs. Anyone looking to reduce some decibles without loosing the sound, I recommend this fix.
$10.00 for parts and $20.00 for labor.