New SSIs and O2 Sensor

[ROW911SC]

About to pull the trigger on a new set (91.911.SSI thin flange + 2/1 Dansk w/ 60mm tip) and see that they no longer come with the O2 bung. Now my car's old exhaust system consisted of factory HEs with crossover pipe jury-rigged into a factory cat. I believe the original Euro pre-muffler was cut and replaced with a section of pipe that included an O2 bung. Ironically, the sensor was present but apparently never connected. Car ran this way for years and years, and my P shop was aware of it. Can I run the car with SSis and no O2 sensor, or do I have to modify a nice new and expensive set of SSIs to add a bung?

Thanks!

[Jack Stands]

It should run, but not as efficiently as with the O2 sensor connected. I'd wonder if it wouldn't be a good idea to have a bung welded onto the SSI exchangers, just find a good welder that can weld stainless steel properly.

[ROW911SC]

Thanks... What exactly do you mean by efficient? Performance, fuel economy, etc?

[catuck]

I welded a bung to the inlet pipe on my muffler - I don't think you have to put in on SSI.

[ROW911SC]

After reading through quite a few threads on this topic I've found that ROW cars (like mine) never had an O2 sensor, so the logical conclusion seems to be that I don't need one for the car to be set up properly and run as intended. Then again, there seem to be plenty of contrary points of view?

[Bob Kontak]

Originally Posted by LenS

Then again, there seem to be plenty of contrary points of view?

Not really. You don't have one and you don't need one. If you get one, the car will not recognize it.

Do look in the driver's side engine bay near the fuel filter for an O2 connector. Looks something like the one in this pic. The harness where it mounts on the frame appears to be missing/broken?

Also, I don't know if imported ROW cars had to have the Lambda system installed. If so, look for any old floating connector.

Maybe the easiest way is to look under the passenger seat for a Lambda control box. If you ain't got one...............

[Bob Kontak]

oops - Forgot pic. By the "U" in the fuel line.

[Jack Stands]

I was assuming you have a Carrera with Motronic. The thin flanged SSIs should have clued me that it's not one. In that case, the O2 sensor won't be necessary.

[MBAtarga]

I thought all SCs need thick flange SSIs?

[Reiver]

Originally Posted by MBAtarga

I thought all SCs need thick flange SSIs?

Not the ROW's, thin flange.
Later year euro's large intake runners, different fuel head on the CIS, dif dizzy and curve, cr 9.8-1, no o2 sensor or corresponding box under passenger seat...204 hp with the crappy 2 into 1 crossover exhaust....with the SSI's and Dansk about what ....215-220 as a guess.

[anders88]

LenS, the O2 sensor is used by an Engine Control Unit to fine tune the amount of fuel being injected into the engine. If you know a little about controls, it might give you a better idea. O2 sensor basically tells the ECU about the AFR, the ECU then fine-tunes the amount of fuel being injected in order to bring the AFR to 14.7 or 15, as suggested by the configuration. If you don’t have an O2 sensor connected, it won’t be big deal while driving within a city but for a long drive, an O2 sensor can save a lot of fuel since you’ll be driving at a constant speed and an O2 sensor removes the steady state error to give the engine exact amount of fuel required.

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