Here are some pics of the valve in the muffler that has been talked about.
This peaked my curiosity so I cut my old one open. This is off of an 06 xa.

 

oh thats very nice

have you moved/opened this valve with you hand and how hard/easy is it to be moved open?

 

It's fairly easy to open. You could do it with two fingers no problem. The chamber opposite to the valve is a dead end so when your exhaust comes into the mufler, through the valve and into the second chamber is just builds pressure there till the valve opens. It looks to me like the valve would have to be open anytime the engine is running just at different levels.

 

Say you had a stock exhaust and your engine started running or performing different so you took it to the dealer to look at.

How likely do you think the dealer would suspect the muffler spring might be at fault?

 

heh i really doubt they would know that spring would be at fault

 

I agree, most don't know sqwat. Recent example... What are thoses square things in the bumper? Dealer Di Di Di.ah don't know, never did find out...till I came to Scion Life. They are access covers for the towing/pulling pins.

 

Is there any mention of this valve in the shop manual?

 

no it doesn't and i don't remember where the heck i saw it or read about it at either :?

 

Some goofball started a thread about why the stock/TRD muffler is better than anything in the world.

Also, I think someone opened their tC exhaust as well.

 

Chops:
"Some goofball started a thread about why the stock/TRD muffler is better than anything in the world."( is really nessary to resort to name calling , again?)

Ain't what he said, but not so to start ANOTHER flame war, just read what he did say in his words, not from someone whom read into it what he/she didn't want to hear.

But, the valve is incorporated into the tuning of a basic stock system, for those with many more mods and wanting more in the top end, it might not be the best choice.

 

well ive had this idea, I was searching ebay a while back and found an exhuast servo that was ment for controlling exhaust volume. I had thought since you loose backpressure with aftermarket exhausts u could use it and have it open and close depending on throttle position. you could tune it and have the right amount of backpressure and at WOT have higher flow. Since then i havent found it, all that comes up is one for a ninja type bike, i guess they apply the same concept or something so i guess im not THat far off.

 

actually, there's an oblique reference to the valve in the sticky about the 1NZ-FE engine at the top of the page-

"a two-stage muffler (as debuted in the Lexus range) to improve high rpm engine performance on the 1.5 litre sedan engine"

How else would they get a two-stage muffler?

In the usual scenario, as exhaust volume goes up, so does backpressure... the valve helps prevent that, keeping the actual pressure in the exhaust system more constant at any rpm... with excellent noise control at idle and moderate throttle settings...

Ultimately, the spring will fatigue or break - has to be some remarkable metallurgy involved, considering the temperature range involved...

And people seem befuddled when they can't get much more power out of these things- when you think about it at all, you realize that they're already very highly tuned and optimized in stock form...

 

Exactly! Any increase in performance at a particular RPM range will be detrimental in some other range. If you want more power above 4k RPM, you will lose power below it.

 

if you really want power you would not have gotten a xa or xb. these cars were not ment to go all that fast. even with a turbo you have 150-170 hp!

 

Exactly! I bought a new exhaust to make mine sound a little better, it's mostly for the audible pleasure I will give to folks in Jazzy scooters as I over take them.

 

Yeh, mine has the TRD axleback, for which TRD claims "up to" 3hp... I bought it to give my box a little attitude, and as revenge for the wife putting a GODDESS sticker on the driver's door when her PT Cruiser was new... I definitely didn't drive it any more than necessary, and she hates noisy exhaust, so we're even...

 

Do you know if the TRD exhaust has this spring valve in it?

 

yea it does have the spring thats why they say its soooo good

 

"Do you know if the TRD exhaust has this spring valve in it?"

Dunno... but I doubt it. The one thing I'm sure of is that the TRD is a whole lot heavier than stock. I've not found any details about the interior construction, and I've looked... Maybe someone will crunch one, backing into a curb or something, and then cut it open so we can find out...

 

well i guess realtime adjustment of exhaust flow interests noone.