Rattling Cat

[tommy583]

Ok 1998 2.5 base with 2000 S crios mod factory muffler, factory exhaust manifolds (with no cats) and factory pipes with cats in them. One of my cats is starting to rattle. I know it's not the heat shield because I removed them.

So I think I have a few choices to cure this problem. First I could get a used cat pipe from Woody. Or second I could get some Ebay headers and pipes with high flow cats. Just replacing the cat with a used one would be the easiest and cheapest for sure, but for less than $500 I could get the headers and cat pipes.

Does anyone on this forum run a 2.5 with headers and high flow cats? If so I'd like to hear your thoughts. And yes I did a search and read about it for hours, but I didn't really find one about the set up I plan on going with.

So to sum it all up. 2.5 liter with headers, high flow cats and factory S muffler with crios mod. What do you think? Any worthwhile performance gains to be had? I'm sure it would sound different, maybe better.

[glenf]

I had same issue with my Box. I ended up replacing with fabspeed headers

[jayspeed999]

Originally Posted by glenf

I had same issue with my Box. I ended up replacing with fabspeed headers

Hi - can you let us know what the car sounds like with this setup compared to the stock setup?

[Boxstard]

Originally Posted by tommy583

So I think I have a few choices to cure this problem. First I could get a used cat pipe from Woody. Or second I could get some Ebay headers and pipes with high flow cats. Just replacing the cat with a used one would be the easiest and cheapest for sure, but for less than $500 I could get the headers and cat pipes.

Really? A pair of high flow CAT pipes and headers for $500? Show me where I can get them!!! And I'd like to hear from those experienced, specifically with 2.5L motor. I got stock header/ CAT plus PSE, wondering further improvement.

[tommy583]

Originally Posted by Boxstard

Really? A pair of high flow CAT pipes and headers for $500? Show me where I can get them!!! And I'd like to hear from those experienced, specifically with 2.5L motor. I got stock header/ CAT plus PSE, wondering further improvement.

Circuit Werks Porsche Boxster 986 2.7L 3.2L High Flow Cats Catalytic Converters | eBay

The price went up since I posted about them. If you email them he will give you a better price. I still haven't bought them yet, I'm too worried about breaking the manifold bolts off in the block. You can find headers for $150 all over the place.

[DrCactus]

My car also has had a rattle for many years now....I have grown to accept them and its a clear reminder that my car is like an old man! haha Im starting to rattle too...

[nieuwhzn]

Hey Tommy. I see you are in upstate NY. NY State has recently adopted the same environmental laws wrt cats as CA. That means that your cats have to be complete factory standard otherwise you could fail emissions inspection.

[tommy583]

Originally Posted by nieuwhzn

Hey Tommy. I see you are in upstate NY. NY State has recently adopted the same environmental laws wrt cats as CA. That means that your cats have to be complete factory standard otherwise you could fail emissions inspection.

In my area as long as you don't have a check engine light you will pass emissions. As for visual checks, lets just say I know a guy who does my NYS inspection.

[joecal]

Mine has that rattle too at start up, then goes away.

[BYprodriver]

So to sum it all up. 2.5 liter with headers, high flow cats and factory S muffler with crios mod. What do you think? Any worthwhile performance gains to be had? I'm sure it would sound different, maybe better.[/QUOTE]



You will lose low RPM torque which I assume is the worst thing about a 2.5L, having never driven one. If I were you I would replace the rear pipes & think about removing the manifolds to "port & polish" them before reinstalling.