harveyf

I know some think that cats are the spawn of the devil. That said, the Porsche engine management system uses the information from both the upstream and downstream O2 sensors to make critical decisions regarding fuel mixture. You especially don't want your engine to be running too lean, which tends to generate excess heat. It has been postulated that high oil temps can aggrevate bore scoring due to visocity issues. And if you ever plan to sell the car, particularly to folks in CA, the cat system will need to be functional. I can only assume that the Softronic race tune uses a fixed fuel map for all modes of driving, allowing the cats to fend for themselves or be removed entirely. Just my 2 cents worth.

Softronic

The primary o2 sensors are what actively monitor the fuel burn and not the secondaries or post CATs in which purpose are to monitor the CAT efficiency. A race tune does not change the primaries use yet just the secondaries so that a CEL is not generated and the race car owner would then know if there was an issue without having the CEL on all the time when the CATs are removed. The Race file will not pass emissions either so properly functioning CATs would have to be used and either an emissions file or the original. The assumption that a fixed fuel map is used is incorrect.


Best,
Scott

Hal

Scott, in my research on this, at one time PCNA was putting on a flash to loosen the monitoring parameters as the system was throwing out false negatives. Cheaper to flash than install new cats and O2 sensors.

Have you ever heard this story?

Softronic

Yes that is correct in some of the Cayman and 997 MY's. Some of the emissions standards that have been around that deal with CAT efficiency or not have progressed other than simply just requiring a cat like back in the 70's in the US even before an O2 sensor was used for fuel control and why they were measured at the tail pipe. Then in its progression a post O2 was added to monitor the efficiency and their main purpose to be checked by the DME and accessed by the port and not the tail pipe.

Best,
Scott

sasilverbullet

UPDATE:
Replaced the crankshaft position sensor, AOS, and put that mini-cat device on the o2 sensor that's before the cat on bank 1.
started car, cleared the codes that were stored, went for a 45 mile, very spirited drive, NO CODES!!!!
Also, I was getting around 13mpg, today it was 19.8mpg!

Thanks everyone for all the help!