can you verify the date code on your muffler?

 

i wonder if maybe the metal in which it hits can be pushed back some or even cut out or something. maybe find a way to attach steel wool on it but that might be a pain in the ***.

 

I think the problem is the valve is too light and the spring isnt strong enough. But for it to open all the way the spring cant be to strong. I think the whole valve idea is good but it just wont work on a spring type setup like this.

 

I don't think there is a date code on the muffler itself. I verified that the box date code is after the "fix" and it definitely looks different than the first one I got. It is better, but not better enough for me.

The thing is, even if it didn't rattle, it's not that quiet -- which I think the video shows well. The car is WAY louder than my Evo X, which is completely stock.

 

They need to control it with vacuum like the car manufacturers do

 

 

Wow, that sounds like a$$. Congrats, EVO8LTW, your car is just about as loud as mine.

Is there any reason why a machine shop couldn't try to engineer a flap like that (- the rattle) into an exhaust tip? Or maybe something that looks more like the butterfly valve on a throttle body. Heck, you could even tie it to the TPS...

On a separate note, does anyone know approximately how hot the exhaust is at the exhaust tip (not counting shooting flames)?

l8r)

 

Wow!

1st. That rattle is to the extreme. When mine rattled I could not see the flapper bounce at all. It didnt even open.

2nd. That is actually loud and my rattle was not as extreme. Yours actually sounds like a pounding rattle as opposed to mine which is more of a buzz.


Could the loudness and rattle be because you have cams? I could only guess the cams create large exhaust pulses further apart. As each pulse comes and hits it over pushes the valve as the valve flaps open the spring pulls it back closed until the next pulse hits....

I'll make a video of mine as well when I receive it. I only suspect I'll have different results.



Also one thing that you can try doing that might help you. You could possible drill a hole or multiple holes on the larger area of the Valve plate. This way a lot of the exhaust pressure escapes through rather than pushing the plate open.

 

I was fooling around trying to kill the rattle, sticking a rod to wedge it open. Killed the rattle alright but made the exhaust too loud. I can tell you that its plenty hot back at the tip. That rod got hot enough to burn...(me) at idle.

I'm sure the cam is what is causing the trouble. Once over about 2000 rpm the rattle quits and the door stays shut.

The electric door , what is it Varex? or close to that, from Australia looks to be the ticket, but with shipping looks like $4 bills.
At that point you might as well get an electric cut out right ahead of a good muffler and call it a day.

 

Well I just installed the Greddy SP2 and it is so so nice (quiet)...For those of you looking for to quiet your exhaust down a bit I would highly recommend the SP2 over the rattling Dynomax....

 

wow that sucks...

 

tell me again how restricting the exhaust flow by a butterfly valve is good?

 

This thread got me thinking about muffler design, and I think what the ultimate solution would be is a muffler with a built-in bypass valve. In other words, take a very restrictive (aka quiet) muffler and add an internal bypass valve that actuates as the exhaust gas flow reaches the limit of the base mufflers flow rate. That way, you'd end up cruising around with the valve closed most of the time, but as soon as you go WOT, it'll open up the straight path through the muffler.

l8r)

 

It keeps the car quiet during normal driving/idle. Exhaust pressure opens the valve when you get on the throttle more. Keeps the popo's and tickets off your back.

That is what this muffler does. Unless you are talking about something boost actuated.

 

Why not get a muffler for the vw that is vac controlled.