titleist1

I have read about Option M150, no cat material inside stock cats, anyone here have this option, did search but no match.

Kolbjorn S

Yes got it - all "Gulf spec option C32" 993's have option 150. Cats are physically there but there are no O2-sensors to my understanding.
EDIT: There are no emission regulations here in the Gulf countries. Besides, as recently as 1999 no unleaded petrol was sold here. But over the last 5 years it's changed to ONLY unleaded fuel (as a sidenote to that, I suspect the octan to be quite low though). So new Porsches come with the full emission system in place and hence no 150 on those cars.

titleist1

Kolbjorn, thanks for info, anyone else here in USA gone this route with their Cats?

Macca

Hi there. I have M150 option (my car was written up extensively in Adrian Streathers book). My understanding is this: No O2 sensors, OBD1, C02 potentiometer to balance fuel mix and I believe the cats may well be without catalyst cores as my car sounds louder and more hollow than a standard 993 of the same era when put side by side. I cannot verify this as the PET does not show a different part for non core Cat - however M150 was not an official option either - it was an internal factory designation and typically the option was shipped on the Motorsport department Werks1 cars like the 993 Cup of the same era....Porsche were not keen to draw attention to "dirty fuel" cars in the mid 90s.

One thing is for sure - the car responds well to higher octane fuel mixes, has run very strong compared to other 993s I have driven and proved to be 100% reliable after 12 years...

Hope this helps.