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Discussion Starter #1
Anyone here have done first cat delete?

Want to know if there will be any engine check light out after delete or other problems.
Would like to try del first cat
Currently have deleted second cat, straight through resonator and semi flow exhaust but sound wise still acceptable
 

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If you delete the first cat (the one inside the header), you will eventually get a CEL. This typically happens with the purchase of a non-catted header. When the ECU registers long-term values from O2 sensor #2 (after the cat) that suggest there is no header cat (or a defect in the stock header), the ECU will throw a number of possible errors. You can have a tuner disable all the associated CEL codes through tuning, as long as they know which ones to look for hehe. There is also a non-fouler O2 sensor trick, but this is not always very reliable.

Deleting the cat on the stock 4-2-1 header will give you some power gains, but the biggest would come through widening the header and a tune, as I believe it only has ~1.25" primaries (skyactiv 2.0).
 

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If you delete the first cat, the second one won't hold up and you'll be replacing that. You are better off removing the second cat and resonator.
 
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