Thick flange or thin, O2 sensor or not

[mclmk8d]

My son recently bought a Euro 1983 911 SC 3.0 which came with headers. He wants to go with a "normal" exhaust system with heat, an SSI system.
two questions:
1) Thick flange or thin?
2) Does it need and O2 sensor or not?
Any help is much appreciated...thanks

[theiceman]

im not sure about euro models, you might have to climb under and have a look but N/A models had thick flange and O2 by 83.

[RDM]

My '80 has thick flange, as do the cars after if I remember correctly.

And yes, it will have come from the factory with an O2 sensor. Since 1980!

[edit- what I wrote is true for US models- not Euro. My mistake!]

[HaroldMHedge]

1. I'm not sure if you would use thin or thick flanges but my Dansk catalogue lists 91.911SSI (1623104910) as the SSI exhaust for a 1983 Euro (ROW) 911SC. The Euro model used the same heat exchangers as the 78-79 US 911SC, 930-211-025-01.

Besides the Dansk (SSI) heat exchangers, you might want to check out Eisenmann Exhaust Systems GmbH, website. Their larger system for Carreras is discussed in Bigger "SSI" system.

2. The 1983 Euro (ROW) 911SC did not have an O2 sensor from the factory but one may have been installed during its importation and Federalization. You'll have to check the CIS system.

Harold Hedge
87 Carrera Coupe
82 911SC Coupe Ferry Porsche Edition

[theiceman]

so sounds like thin flange and no O2.. by the above description. Im thinking your going to be crawling under to verify

[HRO]

I have an Euro 1983 SC and am pretty sure it's thin flange. The car came with O2 sensor when I bought it, but it was not hooked up to anything. It was just there. I replaced the heat exchangers with SSI without O2 sensor and it runs fine.

[don gilbert]

Thick or thin will both work, ive done both, and for sure use your 02 sensor if the engine is equipped with one. Will run much smoother, very good milage, and will make your engine last longer.

[HRO]

I’m not sure if thick flange would work on the car equipped with thin flange from the factory because of the length of the studs unless you trim the flanges. I’m pretty sure it works other way around though.

[theiceman]

Originally Posted by HRO

I’m not sure if thick flange would work on the car equipped with thin flange from the factory because of the length of the studs unless you trim the flanges. I’m pretty sure it works other way around though.

unless when you rebuilt your motor you put longer studs in as thick flange stuff is way more available !!

[HRO]

That is true. haha

[SkiVT]

The 83 euro did not have O2 sensor from factory. Some had the sensor added when imported to US. Mine had a sensor added and it tied to an enrichment injector and non-OEM WUR. Factory WUR was vacuum enrichment with no O2 sensor or lamba brain. So if the setup was modified to use an O2 sensor, you would be wise to include. If its factory original, no O2 sensor needed as it would do nothing.