Found an earlier post when it was being introduced and it looked interesting. Was wondering if anybody is actually using one and how its working out.

Dynomax® Performance Exhaust | Mufflers | Dynomax VT™ Muffler

 

seem like only a question of time it that valve fails

 

Ha - thats pretty much true for anything mechanical (or even you and me for that matter - ) The question is - how long?

They give it a lifetime warrenty so it seems to me that every time it fails you end up with a new muffler. As long as it isn't failing on a monthly basis seems like it might be worth a shot from the valve failure standpoint.

Anybody have any experience with sound, performance?

 

Well, lets put it this way. BMW, Audi, and several other european cars have diverter valves as OEM, and they don't seem to fail. I would not suspect the valve would be likely to fail.

From a performance standpoint, the Dynomax design is no good, it uses backpressure to open the valve. From a standpoint of being quiet it is probably great. Because this muffler uses backpressure to control sound levels, it is probably not that different from a stock muffler from a performance standpoint. It uses the oldest trick in the book, and that is that the more backpressure you have, the quieter the exhaust will be. Most of rumble it produces would come from the fact that other than the valve, there is little to the design that would absorb noise.

So from a performance standpoint, I would say this muffler is a no-go. From a quiet standpoint, it would have a performance tone, but have respectable sound levels.

But is it too much to ask for both performance and quiet? Thats precisely why I run WickedFlows on both my rides. On my Aerostar, I get a performance sound and actual measureable performance, but when cruising at 65 it is actually 2 decibels quieter than the stock muffler. From a performance standpoint, I have no dynoed it because it is all time AWD and there are no 4WD dynos here in Salt Lake. But in terms of performance I can feel, well, it more than just feel. I can pull up grades with known loads, and keep it in higher gears a greater part of the time than I could with the stock setup, or with the Flowmaster I had. I actually out run a lot of other cars even when I have a load. So in terms of a solid number, can't tell you, but in terms of experience, I would highly recommend the WickedFlow Max to anyone who wants a quiet performance muffler.

 

I'm having a hard time understanding when you say "from a performance standpoint the Dynomax design is no good" To me, it makes complete sense. Sure, at low RPM the spring pressure is greater than the exhaust pressure, the valve stays closed and the exhaust is quiet - which is what I want. When the RPMs increase, the exhaust pressure increases, overcoming spring pressure. The valve opens and you get straight through (or max) flow resulting in better performance - again what I want.

The biggest mufflerthey offer in the VT series is designed for >4.0 engines. With my 6.8 v10 it seems that the exhaust pressure would be greater and the spring pressure would be overcome earlier resulting in even earlier valve opening than with a 4.0 - seems like a good thing to me.

Can you explain why this wouldn't result in increased performance - at least when you need it?

 

Because it take backpressure to hold the valve open. The valve has to be held open by the pressure of the exhaust, it is not as though it just magically opens because you opened the throttle. Backpressure means lost performance. Sure it comes wide open when you step on it, but it is still robbing performance from the engine to do that.

A simple way to represent this is if you put your thumb over the end of the garden hose, the pressure that builds up pushes your finger off the end, allowing water to pass through. The water now flows, but it requires the pressure to build up to overcome the effort you use to hold it back. And the end result is still reduced flow.

Now obviously the Dynomax VT is designed to open with very little pressure, but still that pressure comes from the exhaust itself.

BMW uses a valve to produce a quieter exhaust note under light load and cruising conditions. But their design provides and alternate path for the exhaust to take, and the valve they implement is controlled by manifold vacuum, not backpressure.

When you use backpressure to control sound levels , the pressure makes it harder for the exhaust to exit the engine, resulting in decreased performance. If Dynomax regulated the valve by vacuum, then the moment you open the throttle, the vacuum would drop, the valve would open, and the full flow would be available, without creating backpressure or requiring backpressure to operate the valve. Furthermore, with the vacuum method, you can alter the flow of the exhaust, so you can divert it elsewhere, rather than stopping it entirely.

I have a valve on my exhaust that is vacuum regulated on my 1996 3.0L Duratec Taurus. I wanted this car to have a performance sound while still being respectable. First off, allow me to to explain how my system is set up.

My car came from the factory with dual mufflers, the exhaust splits in two right after the rear axle. From there it runs to two separate mufflers. The stock system sounded ok, but it was ratty at times. I wanted a deeper rumble. So I ran 2 WickedFlow Max series mufflers, which on single systems tend to be quiet, when you run dual mufflers however, it causes a deeper tone shift which tends to penetrate right through the vehicles interior, especially at idle and cruising speeds. So the solution? Make it only a dual exhuast at wide open throttle. Thats where this valve came in.

I installed the valve on the shorter side of the exhaust. This way, when the valve is closed, it forces the exhaust to flow around to the other side. This results in a quieter tamer sound. I could have had this quieter sound if I had opted to convert to a single exhaust instead of running dual like the factory, these mufflers are normally very quiet. The result of the valve was the sound levels at idle were basically cut in half. At cruising speeds, it gets quiet too. This is important to me too. I like to listen to my stereo without having to turn it up, I like talking to people in the car, I like going on long drives. So I like to keep it quiet at times too.

So can I back up any of what I am saying? Thats what Youtube is for. This is my car.
http://www.youtube.com/watch?v=xt9bXOXirq8

And this is my van
http://www.youtube.com/watch?v=qGn4qNyyKKc
http://www.youtube.com/watch?v=aeBEbjOVWuM&NR

 

Cool idea with the vacuum valve on the Taurus.

Back to the Dynomax, I kind of see what you're talking about, the garden hose analogy worked for me. What I don't seem to understand is the amount of power robbed by opening the valve. I guess a dyno could answer the question but I'm guessing nobody has measured it. So, on a single exhaust at wide open throttle, which muffler- Dynamax VT or Wicked Flow - do you think gives greater performance, all else being equal?

 

WickedFlow hands down. The WickedFlow produces the same performance gains, its nearly identical from a performance standpoint to a race magnum. It is straight through with a mandrel formed inner tube. No restrictions at all.

 

Never been a fan of the gimmicky stuff like that, then again, Dynomax is complete and total crap. That said, they did bring out one muffler that isn't bad. I did the exhaust on my dad's '95 Ram Van with a 360, its true duals, 2.25" from the manifolds to the trans, then 3" from there to 3"(2.5" internal) Hush Thrush Super Turbos out in front of the rear wheels, its very deep, has a hell of a bark...

There is no straight through muffler that will come close for sound. The only downfall to them is that they are just a 2.5" muffler flared out to fit a 3" pipe. I could have gotten the actual super turbo for double the price, but with the flow directors seems to come an ungodly drone and a glasspack type rap in higher rpms.

As for straight thru mufflers, WickedFlow, Magnaflow, Ultraflow, Maxflow etc. all the same S*it, different pile.

 

And what do you KNOW about it? Tell me one reason why any of the mufflers you put in the junk pile are that. Tell me what experience you have had with any of them.

Super turbos are basically just stock mufflers. And I'd like to know by what criteria you determine that Dynomax is crap? I have always considered them to be one of the quality leaders.

 

I'm running them on my 48 F1. I checked out the sound bits on youtube and the manufactures warrenty. Dynomax says they ran the muffler through 1 million openings and the butterfly valve was going strong. I haven't run the motor yet so I can't tell you how it will sound.




______________________________________
46 Ford Tudor - Street Rod
48 Ford F1 - Custom

"It's Steel, not Tupperware"

 

Hey is back pressure actually real? I mean i believe it is kinda but on the f150online forums they say it's just a myth and it's real...

 

IMO, the exhaust system is a place where you do not want any moving parts. Any of you have diverter valves on your stock manifolds? They usually seize up over time. I rest my case.

 

Just an FYI he have tested the spring in over a million cycles without any degradation.
That is why we are so confident in this product we are our 90 day guarantee and our lifetime guarantee.

Dynomax® Performance Exhaust | Warranty / Safe & Sound Guarantee

Hope that answers some questions about this great product.

 

I'm a skeptic when it comes to a manufacturer's claims until third-party, empirical data, and objective results are provided. The reason for my skepticism are as follows:

First, the spring may have been cycled over one million times but that is under controlled conditions; Second, it's not necessarily the spring that may fail since mufflers experience repeated thermal cycles, condensation, corrision, and the constant vibration when the vehicle is in operation. In my opinion, nothing compares to long-term tests under real-world conditions where metal fatigue in the welds, hinge, and spring are exposed to typical usage. Lastly, the entire muffler should be tested on a fleet of vehicles such that they provide wide array of operating conditions. For example, a superbly tuned vehicle with cushy shocks driven on smooth streets and interstates will likely be less abusive than, likely, over 90 percent of the users in this forum who regularly use their vehicles outside on less that table-smooth roads.

The VT muffler piqued my interest when it was released since I was in the market to replace the exhaust system on my vehicle. After much analysis and my personal experience, I opted to go with a more sturdy design. My skepticism was recently validated by Off-Road magazine (February 2011 issue). ORM has a "long-term test" section and the article provided an updated on VT mufflers that were installed on a newer model Chevrolet in the August 2010 issue. The article reads as follows:

".... There has also been a small sound that has developed in the muffler - not an annoying one, our tester insists - but a tiny noise that is, what he says, is 'indescribable'. He believes it might be the butterfly in the muffler."

Respectfully,
~HIO Silver