Dansk sport muffler tip welding

[belling]

Has anybody tried to weld a bung in to a Dansk Sport muffler exhaust tip? Is the metal chromed steel or stainless steel?

Jeff

[Trackrash]

Stainless. Even if the muffler is not stainless. The 70 mm tip from my Dansk sport is stainless.

You can test by using a magnet. No stick = stainless.

[turbo nut]

Regular steel welds fine with stainless filler rod.

['76 911S 3.0]

I would move that sensor as close to the muffler as possible, you will see false lean reports at idle with it that close to the exhaust outlet

[tocobill]

Honestly most O2 sensors need to be before the exhaust. Usually after the header but no more then 3 feet to get a consistent reading. I would put the bung in the header right after the merge collector.

[Dpmulvan]

Originally Posted by '76 911S 3.0

I would move that sensor as close to the muffler as possible, you will see false lean reports at idle with it that close to the exhaust outlet

can you explain this theory in more detail.

[tocobill]

O2 sensors are very sensitive to exhaust leaks. If you put the sensor to far away from the source or at the end of an exhaust tip it will get false readings caused by fresh air reversion. Similarity if you have a collecter manifold leak it will suck air and give you false readings. That’s is why most efi systems state they want the o2 sensor no more then 3 feet from the header/merge collector on the engine exhaust bank and to be absolutely sure you don’t have any leaks.

[panzerfaust]

Originally Posted by Dpmulvan

can you explain this theory in more detail.

it will read lean due to reversion if its too near the exhaust exit. prong sniffers read a .5 or up a full point vs a bung closer to header merge pipe.

[Trackrash]

FWIW I mounted my O2 sensor in the tail pipe of my muffler. Very close the the muffler which is about 9" from the tip. There are times when the readings go off, especially when lifting off the throttle. Otherwise I have not noticed problems. I have used an extension on my tail pipe and it has not made a difference in my readings. YMMV. On the other hand if you mount it on one of the muffler inlets, you will only be reading one bank of cylinders. It might be best to mount it to the top of the muffler.....

[tocobill]

FWIW if you do some research into aftermarket efi systems a lot of the only use one O2 sensor on one bank to monitor and make fuel corrections based on afr. If everything is set up correctly then both banks should have the same effective O2 readings. My 427 cobra has a Fast XFI system that runs this way. My sensor is set up to monitor the right bank of the engine. The sensor is less then 3 feet away from the engine right after the header next to the merge collector before the sidepipe.

I’m not sure how your using the O2 sensor, wether it’s to monitor or used by an ecu system for efi. I have seen bad readings from reversions and header/exhaust leaks. It’s especially bad for self learning efi systems which will allow the engine to run extremely rich.