Had occasion to look inside the dual mode 20AE muffler for another forum, figured it might be of interest here as well.

Yellow arrows are the low flow/quiet mode, Red is supposed to be louder. You pretty much have to have a dual outlet muffler, and the quiet outlet may very well be smaller than the louder outlet like they are in this one. With the same size tips, hardly anybody would notice unless they knew to look for it.

There is a second picture showing the opening for the quiet flow path through the bulkhead not visible in the main picture.

The spring on the valve was so damn stiff I seriously wonder if it ever did open in the dozen years we've had the car. Dunno, powering the valve open under external control like Chevrolet does with the dual mode exhaust system in the Camaro and Corvette might let the spring be softer, definitely if it is powered closed. It's also easy to see how you could open the louder path at low flow such as idle once you don't need exhaust system backpressure for valve opening.




Norm

 

Neat to see thanks

 

Nice

 

Looks like the time tunermax cut one up for us.Strange!

 

I have an AE model with a stock exhaust system. Would it be safe to say my exhaust is more restrictive due to the age and wear on the muffler with the spring most likely being stuck closed? also any way to check if the spring is closed.

 

Only a little.

IIRC, the claimed HP difference between the AE and the non-AE engines was only 5 HP, so likely only a fraction of a psi difference in backpressure.


Norm

 

I remember somebody doing that also, thought was same till seen date and post, but guess it can't hurt to see another...

 

Looks cool inside.

I know that the system works pretty well. I bought a new muffler for my pathfinder recently from dynomax that use a valve also now.

http://www.dynomax.com/mufflers.php?muffler=vt



Also corvette use a valve also but there valve is external on the exhaust.

 

who's the girl in the pic, she cute!

its cool but it seems over engineered especially for a stock muffler, might as well make it flap-less.

 

most OEM's use something like this now. Have for some time. Great design.

And it wasn't me that did this previously, but it has been done. It's always nice to see though, thanks for posting it dude! great pictures and description!

 

Here's more pics of an '02 from another thread.
http://forums.maxima.org/5th-generat...r-exposed.html

 

I need to find those flappers for my custom muffler that i bought parts to build

 

It makes for good advertising in cars with a bit of sport about them.

Good enough that many people within the 5th gen Camaro community will gladly pay $895 for it as an option. It's interesting to note that the dual mode is not available with the variable displacement V8 models - apparently the V4 operating mode has a really crappy sound that you want kept as quiet as possible.


I wasn't aware of this - never saw mention of it either of the last two times we went car shopping (2008, 2010), and we don't ever buy cars as mere transportation appliances. You'd think it'd get wider mention, never mind that the OEs probably have more reasons for doing it than people have for buying it.


Norm

 

Wife. damn her playing in my account!

 

Serious? U lucky ****, I love black girls :-P

 

V4 sounds awesome, Chevy is lying. They sound like mini v8... YouTube some exhaust vids of vfr750 and yamaha vmax

 

Well go get you one there not rare you know.and they do like white folks too

 

 

 

lol I'm on it bro, Believe me!

 

I think it would be interesting to cut one of these open and mod the internals a bit just out of curiosity to see how much of a difference it would make in sound and possible hp/tq improvements.

 

After seeing where it is, I'll be hacking my flap out.

 

Doesn't matter what Chevy's official position is when it's the people with V8's that hate the sound when it goes into V4 mode. I'm sure that a relatively smallbore V4 with 4-valve heads wailing at 8000 rpm sounds a whole lot better than half of a pushrod V8 chugging along at 1500 - 2000.


Norm

 

I think what you'd want the most would be more volume in the end chambers so that the exhaust flow wouldn't be making all those sharp right-angle turns. I don't see anywhere near enough room to insert any elbows or even curved flow-directing plates.


Norm

 

There's guys who have removed the whole flap and say it increases HP at higher flow, but it's not a mods worth chasing if you ask me. Even if there is an actual benefit it's probably 95% placebo effect.

 

I would say 100%. It's only a flap inside a stock muffler. even if you replaced he whole unit with a straight through muffler you still wouldnt feel ****