Hey, has anyone installed an O2 sensor in their CMI Sport Tube exhaust? I've got a 2002 496HO with Sport Tubes and Corsa Quick and Quiet. I've got bungs with EGT sensors in them, but nowhere to install O2 sensors. I'll call CMI in the morning, but was wondering if there was someone out there that has already done it and can offer advice/suggestions
Thanks, Bruce

Sending them back to cmi may be a good option. I am sure a good welder could drill the jackets and tig it if you didnt want to pull them out of the boat. I would think CMI would have good stainless bungs to purchase.

It's easy to weld the 18mm bung about 2" away from the collector to tailpipe flange, in the tailpipe. Easy to get off, easy to weld, easy to reinstall. Just mark it and send it off to CMI, Eddie Marine, Imco, CP, Hardin, etc. can all weld it in for you. Ideally, top is best for sensor life, but looks like crap, so I usually put it on the side, facing the engine, but make sure you have enough room for the sensor to go in and out.

Dustin,
So the bung goes in the tailpipe, not the header - makes it easier to send out. Do I need O2 sensors in both tailpipes or just one? I don't know anything about O2 sensors, ECU's etc. - I've always been old-school carb's, jets, and reading plugs - looking forward to learning new stuff!
Thanks,
Bruce

p.s. Here's a pic of my engine - would the bung be welded in before the Corsa exhaust diverter (kind of hard to see), near the jumper hose on the tailpipe?

You should be able to get away with just one side in a fuel injected motor. Depends how precise you want to be. Sometimes it's best to NOT know every bit of info. ONce you know how badly your engine is really tuned, you'll just spend a lot of time and money trying (in vain) to make it right.

search,Theres a few thread that show the bung welded,ill try and get a pick of mine

So true!!
The whole reason I bought this boat/engine was to be turn-key reliable, which it totally is, but of course I can't leave well enough alone!

Tailpipe is fine but I looked at your pic and you have almost no tailpipe, therefor, just weld in center of tailpipe, should be enough room since you have a 1" hose bung on there for the water.

Just go on the odd side (1,3,5,7). Air fuels on the stock motor are within .5 af between cylinders except for #7 which is leaner so the odd side will show the leanest AF average. I can tune per cylinder, but you need 8 af's and thats a entirely different animal.

Thanks,
Dustin

The odd side has more tailpipe before the exhaust diverter so it should be easier to weld a bung in. I spoke to CMI they said no problem shipping to them and having bung installed. I won't touch anything till boating season is over (won't be long up here!)
Thanks for your help, Dustin. I'll be in touch after I get the bung installed.
Bruce

Who makes the best o2 gauges and sensors.Seems like Livorsi needs to add them to there line.Just added methanol
injection maybe i can lean the fuel and get 1.2 miles per gal.
Thanks 1471