Quote:
Originally Posted by B1gB0x
No that dont work with the sensors but downpipes with only 400dpi
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400 cpi is pretty standard for cats, although I don't know what BMW uses. If you need a cat for sensor readings most performance cats used are a less dense 200 or 300 cpi. Are yours ceramic or metal matrix? Did your tuner tell you what cpi the stock BMW cat was?