Where to mount O2 sensor
 

Guys, I am getting a Innovate MTX-L to measure AFR and need some advice on the best location to mount the O2 sensor? My exhaust is a full B&B unit.
Also, will I need a heat sink?

Thanks,

Just before the muffler after the turbo at 10 to 2 a clock. For longevity it's best to use a heatsink but some have seen good sensor life without it also.

Thanks for the quick feedback.
I spoke to Innovate and they were confident that I dont need a heat sink.

I was scared about heat sink and short lived sensors, so chose to mount mine in the tail pipe as close to the muffler as possible (for me, that's about 14 inches from the end of the pipe). I do not believe it's causing any erroneous high (lean) readings due to being so close to ambient air. Plenty of exhaust flow to prevent mixing with free air.

Mine is about a foot from the end of the tailpipe (which isn't fitted in pic).
I fitted a simple heat shield to protect the wiring from heat radiated from the turbo.
It is very easy to access in this location for the occasional calibration.

http://forums.pelicanparts.com/uploa...1334997749.jpg

http://forums.pelicanparts.com/uploa...1334998016.jpg

Jeeze Bill, you need to throw some dirt on that thing or be accused of owning a garage queen! :D
I really like the slotted rear valence...aesthetically and functionally.

So I have a dual exhaust B&B, see pic. Not crazy about mounting in the short pipe between turbo and muffler but if i mount after the muffler which side? and will that provide accurate data?http://forums.pelicanparts.com/uploa...1335384157.jpg

mine is after muffler(single outlet rarlyl8) about 7 inches before tail pipe. when i let of the gas the afrs climb to high 17-19 for a split second.... Is that cause of mixing?? I hope so..............................................

Yep probably so innovate told me to use a 1 inch bung and I put mine in the same location as Billjam did and I also wrapped mine with heat sleeve and have seen no ill effects with stable AFR's

Hey Bill, how do you know if it works or not?

That turbo/exhaust looks like it has never been cranked, as well as the WG muf, the pipe is not even discolored...

Mine works fine.

http://forums.pelicanparts.com/uploa...1335493608.jpghttp://forums.pelicanparts.com/uploa...1335493989.jpg

Here is the response I got from Innovate:
"I suggest welding the bung on the pipe furthest away from the turbo, on the right hand ride after the muffler. Also, if you use a clock as reference, the sensor should be between 10 o'clock and 2 o'clock, with 12 o'clock being the best position.

Since the sensor is going to be right by the end of the tail pipe you will get false lean readings until you put the engine under load and build exhaust pressure.

Regards,
Felipe Saez
Innovate Motorsports"

Same guy that told me where to put mine I really don't think I get any false leans in this position except maybe for an instant when I first let off the throttle

Im really sorry if this is a dumb question - but im not a mechanic and I am just slowly learning - please bear with me...

I have a Fabspeed dual-out very similar to the B&B pic in flat_6 post.

So can you confirm - I need to physically drill a hole in the actual stainless steel pipe?

Is the "bung" then welded into that hole, and then does then the sensor / cable attachment screw into that?

Thanks!

My fabspeed headers have a bung after the turbo, I used that port, seems to work just fine.

Yes to all of the above.

FYI, I now have mine install and it works great in the left tailpipe directly after the muffler. I used the left as the exhaust flows significantly more out of that side. I could tell by hand on a cold start up the temps was much hotter.

Flat_6, can you tell me - did you purchase the data logger box (I forget the model number) to go with the MTX-L gauge? Im wondering exactly what else I really need...

I assume if I dont have one, I'll have to tune with the laptop plugged into it constantly...

IMO, the data logger box is great for the track. If you just need to tune then the laptop is fine as you shouldnt be tuning on a daily basis. Once your car is dialed in, enjoy driving and use the AFR gauge as quick reference to ensure no parts have failed.

Followed instructions
 

I followed the Innovate instructions, had bung welded in just before the Zork tube bent down, did this in 2007, built recommended copper heat sink, sensor has lived through a couple hundred dyno tests and lots of track time at vintage races and Porsche events...
http://forums.pelicanparts.com/uploa...1343393368.jpg

Best,

Steve

Dr. Stephen J. Hummel, P. Eng.

mine is a GHL duel out with no internals i put mine in the passenger side tube. Doesnt work below 2k unless i block off the other outlet. keeps sucking fresh air past it and i have 4 inch tips so to block the other side off i have to put a large soup can over the end and clamp it with hose clamps. When i do my EFI swap i'll be moving it to the spot between the turbo and the muffler.

no when you go efi we will do a real muffler set-up and ditch the tin can. ;)

muffler outlet side
 

I also have my O2 sensor on the muffler outlet side. I think when I install mt new turbo, it will go before the muffler. It works well where it is, but on cold startup it take about 15-20 seconds before I get a good reading. I think this is because it takes longer to heat the sensor. This didn't matter with cis, because the AFR adjustment wasn't there. Now with the efi I can adjust AFR every 250 rpm's and would like to know how rich I am running at startup. http://forums.pelicanparts.com/uploa...1343419577.jpg

Any chance on getting a shot of the back of your car I love the slotted bumper