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Old 12-27-2010, 09:22 PM   #1
tobylazur
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Default Dynomax VT Mufflers....

has anyone had any direct experience with one? I need to quiet my exhaust down for the new apartment complex I live in, but driving around with the plug in my muffler is lame.

I'd like to figure out a system for quiet when I want it, and performance when I want it Without having to get out of the car and deal with pulling a plug out of the muffler.
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Old 12-27-2010, 09:32 PM   #2
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a few guys tried them on the evo forum. if you dont have cams or just small ones it works great. if you have a lopey idle then the flapper will rattle.
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Old 12-28-2010, 12:26 AM   #3
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interesting. cant really tell how it knows to open.

if you want more control check out the waldron dce. its a little more expensive though.
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Old 12-28-2010, 02:08 PM   #4
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its just a spring loaded plate. when there is enough pressure in the system, it opens. like i said in the other post, if you have a fairly smooth idle and want the quietest exhaust possible during normal driving, this is a great choice. if you have a lopey idle, dont bother.
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Old 12-29-2010, 05:45 PM   #5
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i have one. never put it on (and seriously need to return the thing!) but when holding it up in the muffler cavity there really is no good way of mounting it and having it look good.

instead i made a stealth back out of an ebay exhaust my buddy was trashing, cut and welded it up using a 2.5inch vibrant flange on the rear and a 3inch to 2.5inch reducer. the vibrant flange bolts flawlessly to the sti muffler. cut the 3inch flange off the back of the mid pipe and welded it to the front of the pipe to remove the "doughnut" flange that was there.
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Old 12-31-2010, 12:08 AM   #6
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Quote:
Originally Posted by classicaddict View Post
i have one. never put it on (and seriously need to return the thing!) but when holding it up in the muffler cavity there really is no good way of mounting it and having it look good.

instead i made a stealth back out of an ebay exhaust my buddy was trashing, cut and welded it up using a 2.5inch vibrant flange on the rear and a 3inch to 2.5inch reducer. the vibrant flange bolts flawlessly to the sti muffler. cut the 3inch flange off the back of the mid pipe and welded it to the front of the pipe to remove the "doughnut" flange that was there.

How come it didn't look good? was it just too big?
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Old 01-01-2011, 05:28 PM   #7
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Old 01-01-2011, 07:11 PM   #8
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Hm, I wonder if that doesn't drone in our wagons. As much as I love my exhaust, I wish it didn't drone. On the flipside, I don't think I could live with hearing all the creaks and rattles my interior makes now.
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Old 01-05-2011, 11:03 PM   #9
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the muffler should be here tomorrow. Hopefully I can get it on sometime next week.
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Old 01-06-2011, 04:22 PM   #10
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I haven't read that full thread over on the Evo forum, but from looking at Dynomax's site I'm not sure I understand the flowpath through the muffler. The info on their webpage says that when the flapper is closed flow is diverted, but to where? There cutaway diagram doesn't have any flow arrows on it, and I don't see any way for the flow to go around the closed flapper (through some other, more tortuous path).

And why is this in the Custom Fabrication, Welding & Tools forum?
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Old 01-06-2011, 05:03 PM   #11
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Quote:
Originally Posted by Patrick Olsen View Post
I haven't read that full thread over on the Evo forum, but from looking at Dynomax's site I'm not sure I understand the flowpath through the muffler. The info on their webpage says that when the flapper is closed flow is diverted, but to where? There cutaway diagram doesn't have any flow arrows on it, and I don't see any way for the flow to go around the closed flapper (through some other, more tortuous path).

And why is this in the Custom Fabrication, Welding & Tools forum?
X2

I think it's that second opening on the Left in this picture from that thread

http://www.neiu.edu/~asaakian/Exhaus...0VT%20case.JPG
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Old 01-06-2011, 07:47 PM   #12
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Quote:
Originally Posted by Patrick Olsen View Post
I haven't read that full thread over on the Evo forum, but from looking at Dynomax's site I'm not sure I understand the flowpath through the muffler. The info on their webpage says that when the flapper is closed flow is diverted, but to where? There cutaway diagram doesn't have any flow arrows on it, and I don't see any way for the flow to go around the closed flapper (through some other, more tortuous path).

And why is this in the Custom Fabrication, Welding & Tools forum?
I put it in here because I originally asked in the custom exhaust thread about using one in a side exit exhaust. I got no response in that thread. I figured I'd get better answers here. Seems like if it doesn't bolt directly in place the normal forums don't seem to care too much about it.

Anyway. From the looks of it. The exhaust flow isn't 'diverted' anywhere. The flapper has space around it for the exhaust to flow past. Seems like the flapper just 'bounces' most of the sound back into the muffler until it's opened up.

Quote:
Originally Posted by ScoobNJ View Post
X2

I think it's that second opening on the Left in this picture from that thread

http://www.neiu.edu/~asaakian/Exhaust/Project%20Valve%20Technology%20Muffler/Dynomax%20VT%20case.JPG
ha, that is a picture of the exhaust sitting on the box. The 'second opening' is from the picture on the box.
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Old 01-06-2011, 11:57 PM   #13
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Quote:
Originally Posted by tobylazur View Post
The exhaust flow isn't 'diverted' anywhere. The flapper has space around it for the exhaust to flow past. Seems like the flapper just 'bounces' most of the sound back into the muffler until it's opened up.
I guess you're right. I just think it's strange/misleading that the info on their site says "DynoMax Valve Technology Mufflers feature an exclusive, precisely calibrated internal valve that redirects exhaust flow, during cruising conditions, to provide Drone-Free Performance™." [my bolding]

I guess when you're just cruising at highway speed you're only using ~40hp, so the restriction of having the flapper covering most of the pipe diameter doesn't really matter.
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Old 01-07-2011, 12:07 AM   #14
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Quote:
Originally Posted by Patrick Olsen View Post
I guess you're right. I just think it's strange/misleading that the info on their site says "DynoMax Valve Technology Mufflers feature an exclusive, precisely calibrated internal valve that redirects exhaust flow, during cruising conditions, to provide Drone-Free Performance™." [my bolding]

I guess when you're just cruising at highway speed you're only using ~40hp, so the restriction of having the flapper covering most of the pipe diameter doesn't really matter.
Yea. Unfortunately it's a compromise. I'm hoping the flapper valve isn't too restrictive. If it doesn't work, then I'm gonna have to come up with some type of cut out or something.
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Old 01-14-2011, 09:24 AM   #15
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Quote:
Originally Posted by tobylazur View Post
ha, that is a picture of the exhaust sitting on the box. The 'second opening' is from the picture on the box.
Feels dumb...
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Old 01-28-2011, 04:16 PM   #16
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Originally Posted by ScoobNJ View Post
Feels dumb...
Same here!!

Oh well. tabylazur, maybe you should just go wth an electronically actuated dump and a stock STi muffler? Careful where you put the dump though, With no muffling in front of it it will probably sound pretty nasty. A guy came to our Eastside meet last week with downpipe only, and it sounded like pure ass.
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Old 02-01-2011, 06:32 PM   #17
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Originally Posted by madmax_087 View Post
Same here!!

Oh well. tabylazur, maybe you should just go wth an electronically actuated dump and a stock STi muffler? Careful where you put the dump though, With no muffling in front of it it will probably sound pretty nasty. A guy came to our Eastside meet last week with downpipe only, and it sounded like pure ass.
I finally got the time to play with the new muffler. The result: the muffler doesn't work. Actually, it may work while cruising but it doesn't quiet the car down enough at idle. Seemed to be as loud at idle as the 3" can I have on there currently.

I might go with that type of set-up above. ^^ Only problem I have with that is I hear that electronic cutouts aren't very reliable from what I hear.

Off to do some more research I guess...
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Old 02-02-2011, 10:11 PM   #18
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Quote:
Originally Posted by Patrick Olsen View Post
I guess you're right. I just think it's strange/misleading that the info on their site says "DynoMax Valve Technology Mufflers feature an exclusive, precisely calibrated internal valve that redirects exhaust flow, during cruising conditions, to provide Drone-Free Performance™." [my bolding]
It's not misleading, just a bit confusing with the pictures they have up there. If you goto the dynomax website and enlarge the picture of the muffler it works like this:



During idle or low power usage:
- exhaust flows in on the left side
- the valve is closed so the flow is directed thru the perferated pattern, thru the e-glass, thru the metal partition, then out the muffler thru another perferated patch. The e-glass handles the high frequency noise that is the typical droning.

During high power or high flow:
- the exhaust flows in the left side, the valve is open and it runs as if it's a straight thru design.
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Old 02-02-2011, 10:22 PM   #19
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Quote:
Originally Posted by tobylazur View Post
I finally got the time to play with the new muffler. The result: the muffler doesn't work. Actually, it may work while cruising but it doesn't quiet the car down enough at idle. Seemed to be as loud at idle as the 3" can I have on there currently.

I might go with that type of set-up above. ^^ Only problem I have with that is I hear that electronic cutouts aren't very reliable from what I hear.

Off to do some more research I guess...
What size did you end up buying? The way the unit works you might have had too much flow at idle and had the flapper partially activated. Just curious.
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Old 02-03-2011, 12:38 AM   #20
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What size did you end up buying? The way the unit works you might have had too much flow at idle and had the flapper partially activated. Just curious.
I got the 4.0L and bigger model that was recommended by the Evo guys.
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Old 02-04-2011, 12:09 AM   #21
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here is my dynomax vt setup

it rattles a buch at higher idle (warm up) but goes away when warmed up. rattles on engine braking deceleration, and when taking off from a stand still.

stock on the left dynomax setup on the right
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Old 02-04-2011, 08:17 AM   #22
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Man that sounds HORRIBLE I say ditch that for a chambered Thrush/DynaMax or other chambered muffler
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Old 02-04-2011, 02:59 PM   #23
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ehh i guess im used to it now. it doesnt really bug me. if i wanted to i can take it off in 2 min and slip on the turn down piece and be wicked loud. its just on for "stock" looking and low key.

(the turn down wasnt made when i took the vid)
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Old 05-10-2011, 01:11 AM   #24
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I've been running one for about 6 months, and I couldnt stang the rattle anymore.

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Old 05-10-2011, 12:13 PM   #25
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HAAHHA that is rad!!!! I too am running one. I planned on doing a review and write up of the product, then on day 2 the flap started rattling. ABSOLUTLEY LOVE the sound while on the highway and cruising but now at idle and parking lot pimpin it sounds like a ratteling P.O.S. I've spent way to much energy trying to get it to sound good to have this BS when I start it and roll away. Granted, Dynamax was awesome, they sent me a replacement muffler without the VT in it. Super quick, no questions asked. Im still choosing to go with the maddad whisper now. Funny, I cannot for the life of me find a muffler can that is extra large that I can fab with, thats why I'm giving in and going maddad. This is attempt 3 on exhausts and tired of wasting R&d money. DO NOT PURCHASE DYNAMAX VT-- rattaling at idle WILL make you hate it.
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