I have a few questions regarding high flow cats, and to those who’ve installed them. My drivers side cat is rattling and is also throwing the P0430 code. To anyone that’s installed the Magnaflow high flows which one is the go to? The 59975 or the 99675HM. Also how far does the o2 need to be away before and after cat? And do you need the extender for the downstream (post cat) sensor?

 

Ordered 2 Magnaflow 59975 High Flow Catalytic Converters, these specific cats have a bend that actually goes with the factory style for the stock cats, so replacement should be easy for any exhaust shop. Now the research I’ve been doing is both sensors should be a few inches from the cat. Next post I’ll update on how they are on the car and also if any codes come up for cat inefficiency. Just waiting on these cats to come in

 

It’s been almost 2 weeks of daily driving, city and highway miles. No CEL and o2 readings are spot on. For install I’ve used no foulers or any dummy products to fool the o2 sensors into reading a “clean” reading for downstream sensors. I’ve placed the upstream bung into the cat and the downstream is 2in after the cat. The car is smooth and quiet and has plenty of power. All in all I would highly recommend it I went with the Magnaflow 59975 High Flow cats. I hope this helps anyone that is looking to replace their own cats

 

good to hear. Update us if you end up getting a code. Sometimes they take a while to show up.

what year and engine do you have?

 

I will for sure, 2006 4.2 Supercharged V8

 

Awesome same as mine

 

Good to hear, I’ve deleted mine and eventually if I want them back I’ll look into these. My cats went bad so I just ditched them.

 

Still going strong no codes or anything! Strong acceleration and no foul smells from exhaust