[evilcalvin]

Is there any truth that removing the facotory header that has the pre-catalytic converter on it and installing a header will damage the main catalytic converter?

I would love to know if I'm damaging my car with this.

 

[TrevorS]

The only thing that can damage a cat is an overly rich AFR (damages the catalyst). Removal of the pre-cat will possibly raise the exhaust emissions, but it won't damage the primary cat. At worst, you could reinstall the pre-cat and be back to stock !

 

[phobic]

I've never heard of a header causing issues with your main cat. if you're worried about it, you might want to look into a high flow cat some point down the line to replace your main cat.

 

[TrevorS]

I've never heard of a header causing issues with your main cat. if you're worried about it, you might want to look into a high flow cat some point down the line to replace your main cat.

FWIW -- from what I've read, both Toyota OE cats are high flow. However, either way, there's no impact on damage susceptibility. As long as your OE ECU is in control, there's no risk to your cats.