3.2 cat options
12-26-2016, 10:34 PM
#17
I haddah Google dat
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There is no adjustment, apart from changing the chip. And most performance chips will just richen it more. When you "adjust" the afr, you do it open loop, and it is just re-setting the baseline closer to the lean side of lambda.
12-27-2016, 11:38 AM
#18
Team Owner
Much will depend on emissions law where you live. I have a cat bypass on a stock muffler and it has a nice low rumble.
I have a targa and never have the roof in. I don't smell a thing. Then again I'm not following me.
😉
I have a targa and never have the roof in. I don't smell a thing. Then again I'm not following me.
😉
12-27-2016, 10:01 PM
#19
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No problem glad to help. The high flow cats are more popular with the 993/996/997 crowd and I've never heard them say anything about the smell. Personally I've been right up in the tail pipe of a 993 Turbo with 200 cell cats and no mufflers (recording because it sounded so awesome) and there was no foul odor.
12-28-2016, 12:38 PM
#20
Addict
No problem glad to help. The high flow cats are more popular with the 993/996/997 crowd and I've never heard them say anything about the smell. Personally I've been right up in the tail pipe of a 993 Turbo with 200 cell cats and no mufflers (recording because it sounded so awesome) and there was no foul odor.
I live in Southern California in the town I grew up in. As a young child I had no idea there were mountains just a mile north of here. As a teenager an hour of outdoor fun and my lungs burned from the smog. Today the sky is crystal clear year round. It sucks to think how much freedom/industry/wealth we had to give up, but I do enjoy the clear air and don't miss the smell. Cats are one area I am semi-OK with when it comes to big government oversight.
12-28-2016, 02:37 PM
#21
I haddah Google dat
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The cats will scrub some unburnt fumes, but really if it's that bad, then he's running rich. That's why I said to change the O2 sensor. Might as well check the plugs too. He's either running in open loop or the voltage is just too low coming out of it. The only adjustment is at idle, and only affects open loop running. If you did not have an O2 sensor, then that would be the logical move.
01-03-2017, 12:46 AM
#22
Track Day
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I have an 86 with an M&K premuffler and a Steve Wong chip. I smell 'fumes' when I crank it up, but it seems to go away after it's cranked. I don't have an AFR on it, unfortunately, so I can't say whether it's running rich or not (but it probably is). Nobody complains about the smell but, I admit the garage smells like...well, a garage.
01-03-2017, 03:50 PM
#23
I haddah Google dat
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If your O2 sensor is working, then you won't be running rich. I installed a second bung into my Fabspeed test pipe, and monitored running at idle and under load while driving. Once warmed up (that is the key), the system goes into "closed loop", and you notice that the DME will adjust fuel pulses so that you run from .98 to 1.2 lambda. If you have a bad O2 sensor wire, then the system will go into open loop and run a map basically that will limp along with a rich mixture. If the O2 sensor is old, or "lazy" then it will not adjust as quickly and you can run both lean and rich.
01-05-2017, 08:52 AM
#24
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Fastdiablo
The M and K pre-muffler and my Dansk replacement muffler are minimally louder than stock. There's a slight low frequency resonance around idle speed but I can't tell the difference driving. The sound and performance difference are similarly underwhelming.
Unfortunately, otherwise I won't be of much help. I chose option E, none of the above. My dad (who bought the car with me in 1991) agreed to put the car in his garage for the winter at least. This way, the minivan goes back in our garage and my wife stops complaining. No need to do anything else for the moment. I'll let you know what happens in the spring time.
The M and K pre-muffler and my Dansk replacement muffler are minimally louder than stock. There's a slight low frequency resonance around idle speed but I can't tell the difference driving. The sound and performance difference are similarly underwhelming.
Unfortunately, otherwise I won't be of much help. I chose option E, none of the above. My dad (who bought the car with me in 1991) agreed to put the car in his garage for the winter at least. This way, the minivan goes back in our garage and my wife stops complaining. No need to do anything else for the moment. I'll let you know what happens in the spring time.
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Porsche Performance Specialist
John@Fabspeed.com
215-618-9796
Fabspeed Motorsport USA
155 Commerce Drive Fort Washington, PA 19034
www.Fabspeed.com
01-16-2017, 04:08 PM
#26
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01-24-2017, 11:39 AM
#27
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Several years back I replaced the stock cat/muffler on a 3.2 with a GHL 100-cell sport cat and muffler. The sound was excellent but there was definitely a sulfur smell associated with the sport cat. After a few thousand miles, though, the smell went away. It could be that most (all?) new cats smell nastly until they're broken in. Just a guess.