Pic Help: What's between this x pipe and headers?

[dave73chally]

What did this guy put between the x pipe and header? Looks like a small glass pack or something?

[turbostang7]

flexible joint.

[burdar]

They are a stainless mesh type flex pipe.  A lot of 4 cylinders use them off of the exhaust manifold.

[dave73chally]

Are they any good?

[anlauto]

I was going to guess some sort of catalytic converter for emissions  

[WildJones]

I was going to guess some sort of catalytic converter for emissions

That's what I thought it was too as it looks a lot like the catalytic converters on aftermarket downpipes for turbocharged 4 cylinders.

[burdar]

My guess is that you'll find something similar on all engines that are mounted transversely.   Since the engines rock front to back with a load,(not side to side) the exhaust needs to get longer/shorter.  I don't think it's that big of a deal on our cars.  The engines rock side to side so the exhaust system doesn't really need to "grow".  There is enough movement in the system already.  It probably doesn't hurt anything to add them though.  If someone decided to solidly mount their exhaust to the body(not use rubber hangers) then a flex joint would be needed. 

[Cudakiller70]

Wonder if they would help reduce header leaks? Even side to side flexing could help loosen header bolts?

[turbostang7]

They do help, they take a lot of the vibrations out that really don't need to be there.

[Cudakiller70]

They do help, they take a lot of the vibrations out that really don't need to be there.

I think this is a good idea. Wonder how well they hold up and life expectancy is?

[GoodysGotaCuda]

I think this is a good idea. Wounder how well they hold up and life expectancy is?

They should last ok as long as the rest of the exhaust is hung on rubber.

[YellowThumper]

The vast majority of OEM cars have them so I would expect them to last.
I have planned on using them to help handle expansion issues on my TT setup. Would also think they would help mitigate resonance issues throughout the exhaust by isolating vibration.

[burdar]

I've only seen them fail on one car.  It was a on 4-cylinder that had a bad engine mount.  Before the bad mount was discovered, two of those flex pipes failed.  The engine rocked back and forth too much and the material eventually split.

[72bluNblu]

I have a set of flex joints like that on my Challenger, they've been on there for over 50k miles if not longer. No problems with them. I was attempting to extend the amount of time that my header flanges would stay sealed up. Might have helped a little bit, but I've still got flange leaks even using dead soft aluminum gaskets and the flex joints behind the flanges. I've come to the conclusion that header flanges just leak regardless if you put enough miles on your car.

[GoodysGotaCuda]

I've only seen them fail on one car.  It was a on 4-cylinder that had a bad engine mount.  Before the bad mount was discovered, two of those flex pipes failed.  The engine rocked back and forth too much and the material eventually split.

Have to consider the loading in each application and they are not created equally.. From my experience, V-engines in a RWD appication generally do not have them. Inline 4s have them to account for fore-aft movement of the engine in the car. In the configuration shown, the loading through the flexible joint will be torsional, not the same loading.

If the joints are intended for torsional loading, they should last well. If they are not, then they will not last well.