OEM Cat's VS Aftermarket
 

Does anybody have any input on purchasing IE Magnaflow vs OEM?

More airflow/HP would be great, but I still want to maintain a quiet sounding car.

Anybody experience different cats? (includes the 2 precats).

I run twin Magnaflow spun metal high flow cats ( Random Technology knockoffs ) in my C124 M103-12V TT.
They don't use the typical brick catalyst like the OEM.
Very small, 4" diameter and about 10" long.

Picked up 11HP on a load dyno over a single SL500 OEM converter.

Inexpensive, about $110.00.

Changing the cat will not effect your exhaust sound.

Awesome :thumbsup: Everything I wanted to hear.

I got it replaced today, but I am a little concerned with the sounds....I hear a distinct "tin clanking type" of noise.

Should this be normal?

He basically drilled through the two precats and threw out the insides and put in a magnaflow cat in place of the old one for the main one. He said this was my best option. He showed me the insides of the precats afterwards and they were just completely trashed.

What model Magnaflow cat did he install?

"Clinking" typically is a noise you get when a catalyst brick rattles in the converter.

The spun metals never give this type of noise due to how they are constructed.

Not sure what you mean by "drilling" through the precats?

Did he like "rota-rooter" them ???

Possibly something left in the precat-exhaust pipe ???

Yes it sounds like debris. I'm not sure what model he installed. They are closed today otherwise I'd call and find out.

He left the precat shells in place -- but instead of putting new precats in, he simply cut through them so its straight through at the front. I essentially have one cat now.

Maybe I should give it a good long Italian tune up on the freeway first to see if I can blow out (possibly) anything left over in there.

Hehe, just make sure no one is behind you when you blow that metal out.

No kidding. In school, we had a 350 blow piston chunks into the brick wall.

any clanking sound isn't right..I'd bring it back in...

Jonathan

Loud clanking or alot of little things....




There could still be precats falling apart and making their way into the cat.

Well we are doing the oil pan gasket and we found a bracket that was loose half way down. Once we are done we will tighten it back up and hopefully the sound is resolved.

Got it! Required to take off a coolant hose at the front, but after that we could jack it up high enough. Fiddly though? Yes.

well you know that the precats have platinum in them and while drilling them pretty much deletes them the guy who did then has a nice amount of platinum now. Oh and another thing, if there are still pieces of the precat in there it can damage the engine alot. When the exhaust stroke scavenges the cylinder it can suck some of the cat up in the cylinder.