My 'hybrid' exhaust with 02 sensor

[dascoupeguy]

Have finally got my 72 resto on the road which necessitated fitting an oxy sensor to the m30 engine. As purchased, the car had a tubular header, very crudely attached to the original rusted out center resonato, and PO had not ever hooked up an 02 sensor. (thankfullly the 02 wiring connector was there!) Through Paul Cain, I obtained a set of OEM manifolds and downpipes and needed to fit the 02 sensor somewhere. After consulting with SFDon for proper location the sensor was placed in the welded in cross pipe.

I obtained a 'center resonator' (an ANSA muffler for a 635) which was a 2 in 2 out configuration. After some welding (off the car) the finished product is what you see.

It is fit to a standard rear muffler. Sounds great, actually a bit too quiet!

See pics. DCG

 

[rsporsche]

i like the o2 bung on the cross pipe. that's an interesting idea for a stock exhaust. i might have to consider doing that. i had been considering doing more of a custom resonator and tying into the stock rear.

 

[Stevehose]

One thing to keep in mind is occasionally you'll have to unscrew the sensor in order to recallibrate it with the computer so accessing it without a big hassle will be helpful. And of course mounting it on the upper side of the pipe so condensation doesn't get it but it looks like you have done that.

 

[TodB]

I did something similar when I redid the exhaust on my E28 5 series The header went 2 out into an X pipe straight I added back into the cat back (no cat). The 02 sensor ended up being drilled into the x pipe and has worked out great.

 

[gwittman]

I just installed an O2 sensor in my Austin Healey Sprite race car. The instructions said to recalibrate each race weekend. I guess that is because I run leaded fuel. They recommend N/A aspirated street cars recalibrate about once a year. Why is it O2 sensors from factory built cars don't need to recalibrate?

They do recommend unscrewing the sensor for recalibration but I have been checking the O2 readout in the exhaust after the car has not been started for a week and it gives 22.4 which is what it is suppose to be in free air. I plan to recalibrate without unscrewing the sensor after not starting the car for a week or more. My sensor is not inaccessible but kind of difficult to unscrew.

 

[Nicad]

Wonder how the hole was made on the crossover pipe? Hacksaw at an angle to take out a diamond shaped section??

 

[dascoupeguy]

cross over for 02 sensor

For Nicad...

Here is a pic of the crossover before welding. Did the initial cuts with a saw, then used the very sicentific method of filing the hell out of it till it fit! Slices were then cut to fit on each of the inlet pipes. Inlet pipes had flares pressed accordingly at muffler shop. DCG