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bcfromfl · 10-23-2017, 07:59 PM

Thanks both of you for the input. While researching this a bit more, I came up with this interesting tidbit I'd never heard of before:

How to Break in Your Cat

A replacement catalytic converter needs to undergo a proper break-in procedure to ensure that it will continue to work as it should, and deliver the required emissions reliability and long service life. If the converter is not warmed-up properly (broken-in), the substrate inside could be adversely affected and eventually cause the converter to fail prematurely.

A problem typically occurs when a shop installs the converter and immediately returns the vehicle to the customer without breaking in the cat. The customer drives away and runs the car for a long distance or lets the vehicle idle for an extended period of time. Under these conditions, the matting, which is intended to secure the substrate, will not expand properly and hold it in place.

Converter matting is made from a mineral called vermiculite, which is held together by a fiber mat and an organic binder. This matting is wrapped around the converter’s ceramic brick. The matting is installed in the converter in an unexpanded state. During the first heat up, the fiber mat and binder burn off, and the matting actually gets looser before it expands to fill the converter cavity and hold the ceramic brick in place. If that warm-up is not done properly, the brick can come loose and get damaged. That rattle you might hear inside the converter shell is a sure telltale sign of this problem.

Warm Up That Cat First

The best way to avoid this service issue and potential warranty problems is to include the warm-up period as a key part of your overall converter installation procedure. This heating cycle will allow for correct matting expansion.

Here are suggested steps for a proper break-in or warm-up:
• Start the engine but do not touch the accelerator pedal.
• Idle the engine and allow it to warm up slowly.
• After five minutes, increase engine speed to 2,500 rpm.
• Hold engine speed at 2,500 rpm for two minutes.
• Allow the engine to cool down.
• Road-test the vehicle to confirm correct installation.

Hmmm. Could it be possible that folks upgrading didn't properly break-in the HFCs after replacing?

10-23-2017, 07:59 PM	#33 (permalink)
bcfromfl Enthusiast Member Join Date: Nov 2016 Location: Youngstown, FL Posts: 256 Drives: 2015 PW Nismo 6MT Rep Power: 9	Thanks both of you for the input. While researching this a bit more, I came up with this interesting tidbit I'd never heard of before: How to Break in Your Cat A replacement catalytic converter needs to undergo a proper break-in procedure to ensure that it will continue to work as it should, and deliver the required emissions reliability and long service life. If the converter is not warmed-up properly (broken-in), the substrate inside could be adversely affected and eventually cause the converter to fail prematurely. A problem typically occurs when a shop installs the converter and immediately returns the vehicle to the customer without breaking in the cat. The customer drives away and runs the car for a long distance or lets the vehicle idle for an extended period of time. Under these conditions, the matting, which is intended to secure the substrate, will not expand properly and hold it in place. Converter matting is made from a mineral called vermiculite, which is held together by a fiber mat and an organic binder. This matting is wrapped around the converter’s ceramic brick. The matting is installed in the converter in an unexpanded state. During the first heat up, the fiber mat and binder burn off, and the matting actually gets looser before it expands to fill the converter cavity and hold the ceramic brick in place. If that warm-up is not done properly, the brick can come loose and get damaged. That rattle you might hear inside the converter shell is a sure telltale sign of this problem. Warm Up That Cat First The best way to avoid this service issue and potential warranty problems is to include the warm-up period as a key part of your overall converter installation procedure. This heating cycle will allow for correct matting expansion. Here are suggested steps for a proper break-in or warm-up: • Start the engine but do not touch the accelerator pedal. • Idle the engine and allow it to warm up slowly. • After five minutes, increase engine speed to 2,500 rpm. • Hold engine speed at 2,500 rpm for two minutes. • Allow the engine to cool down. • Road-test the vehicle to confirm correct installation. Hmmm. Could it be possible that folks upgrading didn't properly break-in the HFCs after replacing?