I have a 1981 turbo 301 pontiac firebird that is under conversion... the stock location for the O2 sensor was in the Uppipe pre-turbo. From what I'm seeing, you want the sensor to be post turbo? Are standard O2 sensors not as sensitive to the pressures pre-turbo, or did they just not know any better back then?
How much of a difference is it? I'm not looking forward to hacking the down pipe out so I can get the bung welded in. Right now none of the joints want to free up, so it may be angle grinder time. I'll do it if I have to, but if the up-pipe location will get the job done until this is tuned enough to get to an exhaust shop, that would be nice.
Windeband O2 Sensor in uppipe?
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
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Matt Cramer
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Re: Windeband O2 Sensor in uppipe?
You'll want to move it to post-turbo; the sensor readings can be way off due to the excess heat and pressure. I suspect that Pontiac only used the O2 sensor for correction in a limited range at low flow rates that didn't build much heat or pressure in the exhaust.
Re: Windeband O2 Sensor in uppipe?
Thanks for the info... I guess I just needed someone to force me to do it 
.
The only good spot I have to place it now is about 40-50" downstream. I've seen evidence in posts that this is doable, although perhaps not ideal this far away.
My down pipe is a bit mangled, and will ultimately get replaced. For now I'm using a band clamp O2 sensor adapter to put the fitting on the pipe, and the best spot as after the downpipe ends. I just want to get this up and running. When I can get this to the welding shop and have a new down pipe built I'll probably have a bung welded in about 20-24" from the turbo and then retune.
.The only good spot I have to place it now is about 40-50" downstream. I've seen evidence in posts that this is doable, although perhaps not ideal this far away.
My down pipe is a bit mangled, and will ultimately get replaced. For now I'm using a band clamp O2 sensor adapter to put the fitting on the pipe, and the best spot as after the downpipe ends. I just want to get this up and running. When I can get this to the welding shop and have a new down pipe built I'll probably have a bung welded in about 20-24" from the turbo and then retune.