Michael Gibney

Hi, I am still preparing for the big service and am collecting parts etc'. One job is to do away with the cat converter. Please don't tell me it's needed - it's going for weight alone not to mention restriction. The final muffler has already been replaced with a G pipe.

Question 1 - Two types are on offer from porscheshop UK one with oxy sensor and one with with "loop out plug". Which one should I go for and why?

Question 2 - What if any changes can I expect with the change?

As always advice appreciated.

Thanks,

Michael Gibney

Christer

Michael

If you are going to get rid of the CAT then you do not need an O2 sensor, so you can buy the one without. As has been discussed many times, you should get the DME jumpered to work without O2 sensor, and I personally had an altitiude sensor fitted (although in the UK it is not really useful as the highest mountain is barely a molehill...but I dream of the Alps...but then I would be arrested by the Swiss police for noise pollution. Bugger.)

Changes:
You will get more noise.

Michael Gibney

Thanks Christer, that's got me headed in the right direction but as always another Q - as I understood it the O2 sensor allows the computer to fine tune the mixture - thats why it's placed in the outgoing combustion stream - to "measure" the end result - and mixture is very important for power and temperature and economy etc' - so - if there is no sensor how does the computer get the mixture spot on?

Thanks again - Michael Gibney

Christer

I will try not to dig myself a hole here. The O2 sensor is mainly needed for emissions and fine tuning the mixture so that the CAT is protected from harm.

How the system works without an O2 sensor in detail has been discussed before (but don't remember the details) - so a search may yield results. Or someone knowledgeable in this area may chime in of course.

Claude

Michael: My cat bypass has an O2 sensor--got it because my mechanic recommended it. My check engine light comes on once in a while only under hard throttle. I also have the g-pipe. Never had it dynoed so I can't give you real data on HP. The good news is all of this is "bolt on" stuff so if you don't like it you can go back to stock. You will definitely hear the difference, a personal preference but I love it.

Ruairidh

My cat bypass also has an O2 sensor. This is one mod that I highly recommend.

Jeff Curtis

I use the Fabspeed "Euro-Premuffler" which is a high-quality, stainless steel, baffled cat pipe that somewhat resembles a catalytic converter (this is good).

It is a bit quieter than having a full straight-thru bypass, looks great and has the O2 sensor bung in it, which comes with a threaded plug in it in case one decides not to utilize the services of an O2 sensor...so the choice is there.

As for a performance increase?? ...coupled with a chip - OH YEAH.

As often heard from others on this board, I too receive MANY compliments no the sound, which is well below the "annoying threshold" and right smack dab in the middle of the "SWEEEEEEEEEEEEEEET" spectrum.

FWIW, I do NOT have a secondary muffler (right rear quarter) and utilize a factory primary muffler (center muffler) which has a Fabspeed tip welded to it so I don't have to use a secondary bypass either.

I have a friend who uses the Fabspeed Euro-premuffler with a primary bypass and his factory secondary still intact...seems to sound similar...but of course I claim mine is "refined"...read as BETTER.

Michael Gibney

Thanks to those who made suggestions re the de cat pipe - I gave the matter some thought and have ordered a locally made pipe by "monty"

Cost already paid was $220.00 Aus tax included, shipping $20.00 Aus.

Interesting story - I had heard of Monty products but could not locate the manufacturer - somewhere in Melbourne - I rang the local Porsce parts shops and no they did not know a contact number and they all tried to sell me some other product so then "I smelled a rat" and phoned another parts supplier ans did a white lie - I said "I want to complain about this cracked exhaust pipe - its a Monty brand" and presto the same shop that a day befor had said they did not knoe his number gave me his number and told me to be sure I demanded a refund etc'.

So I got Monty's number - that's also his name - and called him - nice guy - makes all product himself - he does it all and he only sels direct because he sais the shops mark up too much ans he is busy selling direct so he does not need them.

Thanks again - I will let you all know how the pipe goes.

Michael Gibney

simonrs

Michael
Could you please let me know Montys number? I have his secondary muffler fitted to my 92RS, and would like to remove the cat using his bypass pipe. I am in Perth WA. Thanks. Simon

Michael Gibney

Simon,

Monty's no is 0427 814 824