WR450F'12+ "EPA muffler" interior vs. racing muffer interior?

3 replies to this topic
  • WRF-Rowdy

Posted June 08, 2015 - 11:06 PM


The end caps are interchangable, both come with spark-arrester screens,

there is the pea shooter (~10mm opening) and the racing end cap (~18mm).


But does anybody know the differences inside the mufflers themselves?


I've got the street legal muffler from the previous owner clean and unused, lying in my garage.

It appears to be polished steel or even stainless steel.


Does it have a catalytic converter inside, to match the Lambda sensor in the street legal header?

Does itself restrict airflow or just the pea-shooter end cap?


Anyone go an idea how it sounds?  Maybe someone here is runn his WR street legal :rolleyes:

I'm reluctant to simply try it out as w/o resintalling all die lambda-O2 sensor stuff and

enabling closed loop operation any test would ruin the catalytic converter.



  • Krannie McKranface

Posted June 09, 2015 - 04:59 AM


No O2 sensors on USA models

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  • WRF-Rowdy

Posted June 09, 2015 - 05:18 AM


No O2 sensors on USA models

Oh.  Good to know, thx for the info.

  • boston460

Posted June 10, 2015 - 04:12 AM


No O2 sensor on the Australian model either.


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