83safari

Hey folks, I bought a new-to-me 1983 SC that came without a catalytic converter. Instead it has a Dansk stainless-steel bypass pipe. I'm looking at putting a catalytic converter back on it, for a bunch of reasons (being a non-annoying neighbor on my quiet street; the reducing emissions thing; sitting in traffic without choking on fumes).

Any advice on how to proceed here? There's a whole bunch of options that I can see online - genuine OEM (or supposedly genuine OEM), or Dansk Sport Catalytic Converter, or Fabspeed's Sport Catalytic Converter, or PartsKlassik's, or MagnaFlow's. Not sure what to pick.

Would be grateful for any advice or experiences that people have had. Thinking about factors like price, performance hit, noise reduction, emissions reduction.

Thank you!

911h20

I used the M&K sport cat. Works very well. My 1987 passed CA smog with flying colors.

parkerfe

If you're choking in fumes while sitting in traffic, you have something else wrong, I would check for leaks in your exhaust system.
I have been running headers and no cat on my 1988 911 for years with no fumes.

Spyerx

Do you need to pass an emissions test (ie CA)?

If you do, there is only 1 option that is EO approved outside of OEM.

If not, any aftermarket cat will reduce the stink and likely work better than the OEM cat given age and technology.

83safari

Thanks for the input! And to answer the question @Spyerx I don't need to pass emissions like in CA, no.

theiceman

i have had my car for 16 years with no cat and never smelled a thing, there may be something else going on. also i dont think it will make much of a difference on noise, sure a little but i dont think much.

SARGEPUG

Ditto! I've had a Fabspeed bypass on since day one / 10 yrs and never smell anything at a standstill, unless the car is idling in the garage (w/ the garage door open of course).

Keith Guidus

OK here guys- Aftr 37 years I am thinking its time to get rid of completely stock exhaust and freeing up the old girls exhaust. We live in Prescott Valley AZ now so NO smog test here. Living in CA was my reasons for staying stock besides other costly hobbies.
WHAT do you all think I should buy?

wildcat077

MK by far ... it is definitely the best cat bypass out there for a start , the rest of the MK exaust system is also nice but pricey !

Cheers
Phil

SARGEPUG

I love my system, Fabspeed Cat bypass w/ duel output exhaust. However, I have a Targa and 99% of the time I have the top off. On long distance runs w/ the top on, the drone can get irritating, but that's few and far between on my end. If you just take her out recreationally like me, you'll be ok regardless of type.

wildcat077

For what it's worth , my 89 has a 3.6 with full Fabspeed headers and two out exaust and the droning between 2000 and 3000 rpm is very annoying ...
I install the Car Chemistry inserts in the exaust tips if i go on a long drive but if find it really chokes the exaust !
Lots of history regarding fitment of Fabspeed systems , but i used their two out muffler and the MK cat bypass when my car was a 3.2 and with the current 3.6 and headers i never had
any fitment issues, it just takes more time to adjust everything correctly.

Cheers
Phil

Keith Guidus

THANKS!

SARGEPUG

Yup, that's the "drone zone", I occasionally downshift when it get's too irritating, but again only on very rare long trips w/ the Targa top on. It' never an issue w/ it off.
As far as the inserts, never heard of that! Which one from this link did you choose or now recommend and is it an easy install?? https://www.carchemistry.com/cc-inserts/

wildcat077

Sarge,
I use the units with two disks , you'd have to measure the diameter of your tail pipes as these install aft of the muffler.
Car Chemistry were really annoying as they kept asking for pictures of their installed inserts ... but the inserts do work and are worth the money.

In my case with the Fabspeed tailpipes it's a simple operation to remove and install.The exaust i had when my car was a 3.2 was with those horrible huge
tailpipes which i never liked from the beginning , the system for the 3.6 has regular normal sized tail pipes.

Cheers
Phil

wildcat077

This ...

I use their 2 inch diameter inserts with my Fabspeed tailpipes , the SKU is 2D102R.
They do work but it changes the sound quite a bit , i just put them in when i go for a long drive !

Cheers
Phil