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X Pipe question - Odor & Power

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Old May 29, 2017 | 12:44 AM
  #16  
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"Can anyone who's run both the 200 cell and cat bypass pipes comment On a difference in sound? Are the cat less pipes louder than the high flow cat pipes?"

My ear tells me that the 993 with 200 cell cats and sport mufflers, on a scale of 1 to 10, and 1 being super quiet, with 10 being raucous, the car with sport mufflers and cat bypass is an 9 under acceleration....be gentle with the throttle and the car is fairly tame.

The car with the 200 cell cats and sport mufflers is 6....on my personal scale.

My experience? I started with B&B, went to Motorsound, then to the RSR muffs, several iterations of FD Motorsports...then to Fabspeed cross over/under cat bypass pipes with ??? mufflers, then to Maxflows with 200 cell cars and Fabspeed X pipe...then replaced the 200 cell with Fabspeed Cat delete....and finally, went back to stock muffs and a stock cat...why back to stock? To pass bi-aanual emissions testing and annual 91 dB sound at Laguna Seca.

Take a long trip with cat delete, you'll need your hearing checked when you get back home. I drove from San Diego to San Jose with cat delete cross over pipes, planned for it, took along a set of BOSE noise canceling headphone...this really happened.

Stock is tame, but it works for me.

Last edited by Martin S.; May 31, 2017 at 11:03 AM. Reason: Correct Typos
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Old May 29, 2017 | 08:21 AM
  #17  
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Wow, that's a big difference. Thx Martin!
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Old May 31, 2017 | 01:00 AM
  #18  
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Originally Posted by Bill Verburg

2) x pipe- IF properly designed it's possible o see increased performance but that's a big if


The primary benefit of an x connection is noise control

Note that most of the X pipe myth has been translated from V8 experience where the exhaust flow is very different due to the odd fire configuration of most V8s as compared to the even fine architecture of a flat 6
What he said.

The other factor in a 911 is that the only way to fit an X-pipe - well, at least the popular way - has the exhaust from each bank basically ramming into each other. Not conducive to good flow.
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Old May 31, 2017 | 01:45 PM
  #19  
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Originally Posted by vincer77
What he said.

The other factor in a 911 is that the only way to fit an X-pipe - well, at least the popular way - has the exhaust from each bank basically ramming into each other. Not conducive to good flow.
This is exactly why I've never picked up any of the available "x-pipes". The mixing area is too small to effectively combine pulses, without totally ruining scavenging flow. The custom chambered boxes that mix both banks, would be the only acceptable blend, in my humble opinion.
Even had a very well respected exhaust fabricator tell me, x-pipes on flat sixes are counter productive. With their small cross sections (maybe a couple of inches, if that) make it easy to feel they are restrictive.
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Old May 31, 2017 | 05:56 PM
  #20  
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Originally Posted by Martin S.
"Can anyone who's run both the 200 cell and cat bypass pipes comment On a difference in sound? Are the cat less pipes louder than the high flow cat pipes?"

My ear tells me that the 993 with 200 cell cats and sport mufflers, on a scale of 1 to 10, and 1 being super quiet, with 10 being raucous, the car with sport mufflers and cat bypass is an 9 under acceleration....be gentle with the throttle and the car is fairly tame.

The car with the 200 cell cats and sport mufflers is 6....on my personal scale.

My experience? I started with B&B, went to Motorsound, then to the RSR muffs, several iterations of FD Motorsports...then to Fabspeed cross over/under cat bypass pipes with ??? mufflers, then to Maxflows with 200 cell cars and Fabspeed X pipe...then replaced the 200 cell with Fabspeed Cat delete....and finally, went back to stock muffs and a stock cat...why back to stock? To pass bi-aanual emissions testing and annual 91 dB sound at Laguna Seca.

Take a long trip with cat delete, you'll need your hearing checked when you get back home. I drove from San Diego to San Jose with cat delete cross over pipes, planned for it, took along a set of BOSE noise canceling headphone...this really happened.

Stock is tame, but it works for me.
I run crossover by pass w/ turbo mufflers and pass the very stringent LRP noise tests, 88dB
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Old Jun 5, 2017 | 07:42 PM
  #21  
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Originally Posted by jg291446
I know there are lots of threads about this but I can't find an answer.

Please keep in mind my tolerance level is quite high. I know it's going to be loud with my Maxflo but that's what I'm looking for.

I also know it will smell bad. I am ok with a smell at start up... but I have a cab, and sometimes there is traffic on my way to work.

2 questions :

1- will the odor ruin my driving experience?
2- I am looking at a cat bypass x pipe home made. Does just replacing by an x pipe increase power?

BTW if you have something to sell, contact me!
if your tolerance level is high, then no it won't ruin the driving experience. If your tolerance level is low, then yes it would. You say your tolerance level is high, so have some fun and go for it! As Foxman mentions below, if you feel it's a bit much for you you can reuse the X-portion and add cats our system for a nice bit less than buying the whole thing again.

Originally Posted by Foxman
Here's some feedback from the Pelican 964/993 Forum. http://forums.pelicanparts.com/porsc...at-bypass.html

The beauty of the Fabspeed X pipe is that you can easily switch back and forth from sport cats to a cat delete pipe.
True story, thanks for chiming in : )

Originally Posted by pp000830
Smell that? You smell that?
Lance: What?
Kilgore: Hydrocarbons, son. Nothing else in the world smells like that.
[kneels]
Kilgore: I love the smell of hydrocarbons in the morning. You know, one time we had a track day, for 12 hours. When it was all over, I walked up. We didn't find one of 'em, not one stinkin' catalytic converter. The smell, you know that gasoline exhaust smell, the whole track. Smelled like
[sniffing, pondering]
Kilgore: Victory!
Best play on a quote I've read in awhile

Originally Posted by enjoytheride
I just installed a cat-less Fabspeed X-pipe and must admit I was surprised by the smell, which I would describe as 1973 Chevy Pickup-esque. The smell is certainly not unbearable, and the extra ooomph is very nice
Glad the catbypass is not only acceptable in smell for you, but spiced up the performance for you as well! How do you like the sound? : )

Originally Posted by mhm993
Maxflows and bypass pipes on my 993. The smell is great; the sound is great; and I don't have a clue whether the combination does anything beneficial other than weigh 40 lbs less.
Interestingly, I must be under 87db as I've never had issues at lrp.
Now that sounds like a fun time! Any videos of your car in action by any chance? : )

Originally Posted by JZ98-993
Can anyone who's run both the 200 cell and cat bypass pipes comment On a difference in sound? Are the cat less pipes louder than the high flow cat pipes? Thx
Catbypass X-Pipe is definitely louder than the Sport Cat X-Pipe, for sure
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Old Jun 5, 2017 | 09:26 PM
  #22  
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FWIW on my current project I decided against the X-pipe. I've spoken with several tuners and exhaust manufacturers and the consensus is that with Porsche has designed a very good exhaust flow system on the 993, out of the box. So I bought a Dansk 100 cell sport cat which uses the same architecture as the OEM cat, but without the restrictions due to emissions.
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Old Jun 5, 2017 | 09:39 PM
  #23  
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Love the sound with the Fabspeed pipe on our '97 coupe. Smell doesn't really bother me but I've been driving a 914 for 45+ years that never had a cat so guess I'm used to it... for some reason I seem to notice the smell more on my son's Cayman S with cat-deletes.
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