# Exhaust valve 2018 Cruze 1.4T



## mean buzzen half dozen (May 13, 2018)

Another sample pic


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## mean buzzen half dozen (May 13, 2018)

I am thinking the most restriction in the exhaust system is the muffler. 
Any thoughts?


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## Blasirl (Mar 31, 2015)

mean buzzen half dozen said:


> I am thinking the most restriction in the exhaust system is the muffler.
> Any thoughts?


The most restrictive part is actually the first cat.


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## mean buzzen half dozen (May 13, 2018)

I looked @ the cat, it looks to be able to flow pretty good, I might get it flow tested to see.
I am looking to be smog legal, that is why I went with the muffler, because it sounds like a restricted vacuum cleaner LOL.


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## mean buzzen half dozen (May 13, 2018)

The cats inlet & outlet are not small.


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## Blasirl (Mar 31, 2015)

I agree about stayin' smog legal, but if they did not restrict flow, no one would take them out. all of the Tuners will tell you the same thing. You could replace the second cat with a high flow ZZP unit. A catback exhaust might help as well.


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## mean buzzen half dozen (May 13, 2018)

That is true, there is a big difference on my Syclone without a cat.
I like the idea of being quiet as stock but a little more rumble @ W.O.T.
I never really looked under my Cruze for the exhaust (middle area). There are two cats? I thought one was a resonator?
If there is a second cat, I'll need to look into that.


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## mean buzzen half dozen (May 13, 2018)

Well, I installed it. Nice & quiet until the valve opens, then it has a decent sound when it opens up around 6-10 PSI range. It has some adjustment.
It seems to help on performance with the turbo spooling up a bit faster. I can see the my boost gauge increase a bit quicker when the valve opens.

I see there are two cats plus a resonator.


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## mean buzzen half dozen (May 13, 2018)

The valve size is approx 2.25" along with the short muffler I installed.


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## snowwy66 (Nov 5, 2017)

The muffler is basically just a hollow shell with a inlet pipe and outlet pipe.


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## WillL84 (Aug 5, 2019)

snowwy66 said:


> The muffler is basically just a hollow shell with a inlet pipe and outlet pipe.


Some are. Factory mufflers and a lot of aftermarket ones use a maze of baffles inside that redirect sound to keep it from coming out. Some aftermarket ones are straight through with a perforated fore wrapped in fiberglass matting that absorbs sound but they still let a lot of sound through. Aftermarket motorcycle mufflers are typically like this. Your typical Cherry Bomb (or generic "glass pack" muffler is a straight-through style with matting.

Flowmaster automotive muffler:



























Yoshimura muffler:









Borla "glass pack" muffler:


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## snowwy66 (Nov 5, 2017)

Find one for semis.

Mine was pretty much hollow when I replaced it for a hi flow muffler. That muffler was almost a waste of money other then it added a low rumble sound.


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## mean buzzen half dozen (May 13, 2018)

So the fat stock muffler is hollow inside? Seems too quiet being hollow.
On my 2018 1.4T I see exhaust soot on the inlet exhaust tube before the muffler so to me that's an indication there must be some back pressure there..

Has anyone taken off their resonator under the car?
Is that hollow?


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