Quote:
Originally Posted by FatTony001
thanks AMS for the great info !
One more question:
What's all this Primary cat / Secondary cat all about ?
I've read on the E55, it's best to change the Primary...
is it the same with our AMG NA engine?
And if I change my 2nd cat, is there an O2 sensor or
something in there  |
Your car has 4 cats, two primaries / two secondaries (one per side each).
The primaries have O2 sensors before & after. The secondaries are much further back in the exhaust system (look at picture provided above).
No, its not "best" to change primaries. Changing primaries is a huge headache b/c you have to worry about check engine lights and etc. also the primary cats are actually less restrictive than the secondary cats. Hope that helps. Get the 300-cell secondary cats, they won't disappoint
~AMS~