1999 996C4

I recently put on a new exhaust with newer (Dual) tips. From inside the car, when I start to rev in gear, it sounds like there is a major rattle on the right side of the car. I was told by a local Indy shop that it is just because the muffler pipes are so tight and bendy in the back end - anyone else experience this?

I can only hear it when the windows are down, and I guess outside the car it sounds ok- but I am the one driving and I am inside the car - I would like to enjoy how the exhaust sounds too!

I am wondering if it has to do with the dual, oval style tips I put on it - anyone with these tips have a similar problem? It sounds like the noise comes from the dual tip and not anywhere else - and the problem wasn't there when I had the stock round (one hole) tips.

I have ensured that everything is bolted on and secure - the tips were welded heavily and no movement whatsoever.

Any suggestions? Or anyone have similar issues? Maybe I am just being overly concerned.

juankimalo

I don't know what could be, but I recommend to do the bypass and get the sport sound. you can deal with Darin (FisterD)

https://rennlist.com/forums/showthre...&highlight=pse

1999 996C4

Thanks, but just threw in some Fabspeeds and love the sound.

juankimalo

OK, I didn't know
Fabspeed are great mufflers

1999 996C4

After doing the malet test, one sounds like a how a light bulb sounds when broken (very minimal noise coming from inside) and the other sounds like something is inside - although it could just be hitting the rear panel. Will have to try again when I can get underneath it more.

I guess I was just wondering how the dual tip affects the sound coming out, if any - it certainly seems like it "brips" a lot more...to the point that it sounds like a high RATTLE!

1999 996C4

Car is a 1999 and no longer under warranty but I have read that cats should be replaced free of charge (if this is my problem) since the emissions require it - is this true? Perhaps only state to state? I am in MN.

Zookie

Does your Fabspeed Mufflers have a Rattle or your OEM Cat-Pipes?

redridge

bang on the pipes with a rubber mallet.... trace where its coming from. My guess would be... from your $85 tips.

1999 996C4

sorry - the cat has a bit of a rattle inside it.

Also, the tips are the Schnell ones - I traded the $85 muffler mall ones - I do not recommend those. The Schnell ones look and feel great - much nicer quality.

I had a neighbor come over and say that it sounds very "crackly" - this would describe it very well...to the point that it is annoying crackly. Definitely the passenger side area - I am thinking I either have a leak or a bad cat.

Zookie

If your Cats are Rattling... Call some Dogs Over, lolz JK... Do you have CEL coz of it? Anyways contact your Local Dealer and see if you can get it replaced under Emmisions Warranty...

gota911

As Zookie stated, if it is a bad CAT you can get it replaced at no cost to you under the emissions warranty which is a federal, not state, emissions law. The emissions warranty covers the CATS for 8 years/80,000 miles.

However, the dealer won't replace the CAT under the emissions warranty until you get a CEL caused by the bad CAT. Be patient, and drive it like you stole it. If it is a bad CAT, it will trigger a CEL soon enough.

Patrick E

+1. I've been through this twice and both times the CEL came on soon after the rattling started. The rattle you're describing sounds very much like a cat problem.

1999 996C4

Thanks for the help guys - however, my car is a '99, so unfortunately I am outside of the 8 yr warranty period. Maybe I should start looking for a used cat!

Zookie

you might as well contact the Dealer and ask... If not your probaly better of goign to your local Porsche Tuner and picking up a used set of OEM Cat-Pipes... or you can Contact Fabspeed or EVOM and ask them if they have any OEM Cats sitting around... Unless you wanna spend money of Sport-Cats...

htny

Just had my cats done under federal emissions warranty at dealer. Best warranty work ever, car sounds better than ever and feels torquier at low rpm (I guess backpressure is back up to spec?)

on my car it was 8 years /80k miles coverage, but it does vary so look in your owner's manual, it will tell you the exact emissions warranty for your vehicle.

If I didn't have warranty cover, I definitely would have sprung for sport cats or just bypass until my next smog check, but I like it LOUD.