Cat bypass with resonator
 

I was seraching ebay for the cicuit werks bypass pipes, and found they also offer a bypass pipe with resonators. Looks like a cat but is a fesonator, was curious what that supposed to do? Does it change the sound, or is it more affective?

In Europe these sections are the cats. I guess it's easy to make from the same tooling but simply not put the cat core inside. Stick some snazzy marketing words in the advert and hey presto a new product line.

Resonator changes the frequency of the sound - Less drone sound. Mufflers makes the car quiet.

I just have resonators on my autox Boxster after the precats and no mufflers at all. My complete exhaust weights just 17lbs including the test pipe section and resonators. It is loud, but not super loud like an uncorked car. I could not daily drive the Boxster due to the heavy drone. Driving the car to the track or autox is bearable since I only do it once or twice a month.

Before my current setup, I had the eBay bypass pipes with no resonators and the eBay muffler. No drone what so ever. I was quite surprised. The only bad thing about the Chinese ebay exhaust stuff is the fit. I had to fab mine a little and make a custom mount to make it fit perfectly. I might be a little picky too....

I don’t think these cut down on sound as much as they ‘look’ like cats so you can pass the visual emissions check in states that inspect the exhaust.

Thanks for the replies. Theses are cat bypass with resonator, so I think they are intended to be used with the muffer in place. Just have not seen these before in this way.

If you are running a muffler that is known to drone, you might consider the test pipes with resonators. I ran the the cheap eBay test pipes (no resonators) and eBay muffler, and I had no droning what do ever. If you running a stock muf, skip the resonators. If you are running something like a GLH muffler that is known to drone, I would consider the test pipes with the resonators.

I live in California and just bought the Top Speed "test" pipes. Called the well respected exhaust shop in the area and he said he cant install them, its illegal to remove even the secondary cats.

There is no way I can burn the existing rusted bolts off without professional help (in more ways than one, ha!)

Any tricks you all could share?

Yeah illegal in cali for sure. Probably wont work but you could try soaking them with wd40 or some type of penetration lube let it sit for a couple of hours, see if that would work.

Look for a not so respectable shop, to cut the bolts for you.

Tell them you need you are installing because you will be tracking the car, so you will be switching in and out. I am sure thats belevable. :D

Myself have not had them installed, so good luck.

Seems I recall the bolts at the triangular plate are splined at the base and pressed in, so inspect yours and if this applies, turn the nut not the bolt.
Pretty sure I replaced with normal non-splined bolts. Was a while back.

Try a welding shop. They can cut off the old bolts in about 2 mins and they usually could care less about what you're doing to your car or why.

Everything after that is a fairly easy DIY.

Thanks all, good advice!

You also should be able to cut them off with a Dremel...

You could just pay them to remove and replace the bolts with fresh ones. Then carry on DIY replacement of the secondary cats.

That is a damn good idea, simple and to the point. Lol

Success, used Gilles Dremel idea for the bottom two bolts and used brute force to break the top bolt with a 13mm socket and a breaker bar. After that, the job was easy. After reading several post on the subject, I got the 2" Easy Clamps and they worked great.

Thanks again to all for the help!

I cut my rusty bolts off with a metal blade in a sawsall.

I have a set of these Circuit Werks secondary resonator pipes on order and incoming to me, arriving probably early next week.

I can take some pictures and post here then, if you wish.

Thanks - DM

Thanks I saw pictures, just curious of what the resonator id for and does to the tone.

I just installed the non-resonator Circuit Werks pipes, and the passenger side stock pipe was a nightmare to get out. I too ended up cutting the clamps to get it apart. However the 2" Easy Clamp was too large and didn't work. How did you get yours to fit? I ended up getting the stock clamp from Pelican.

The driver's side was a breeze, only taking me about half an hour to replace. The clamps and pipes weren't rusted like the passenger side.

It does sound better, but it's pretty subtle. Hardly louder than stock, but the tone is better. I'm not sure why you would need the resonated secondary pipe.

Picture looking up the exhaust end of the resonator. As you can see, it is a straight thru design with no obstructions.

http://986forum.com/forums/uploads02...1524966235.jpg


http://986forum.com/forums/uploads02...1524966272.jpg