Where to put wideband?

[SilverBullet6.0]

Hey guys! Just ordered a gauge pod for my gmc sierra. It's a 2011 5.3 with a magnacharger, jba headers, 6.2 exhaust and dyno tune. I ordered a wideband to keep an eye on my a/f ratio off the dyno. However, im a lil curious as to the best place to put it since there not much room between the collector and cat. Would it be better to put it after the driver's side collector or in the the #7 primary tube? I've read that the #7 cylinder runs the leanest on ls motors.

[mcm1209]

I have heard to put it on the passenger side.
Can't remember the reasoning though.

[00 Trans Ram]

I don't know if they run the "leanest". Frankly, I'm not sure how you would check that, unless you ran 8 widebands simultaneously, one in each header tube.

But, I do know that #7 and #8 run the "hottest". The main reason for this is because of reduced coolant flow at the back of the heads. At the front of each LS head, there is a steam tube that crosses from one head to the other. It allows steam to escape from the top of the head, and more water to flow. On the back of the heads, this is often either not there (for LS1 and LS6, I think) or removed when going to higher HP mods (my DOD-delete kit capped them off).

When I rebuilt my LS1 for road racing, we noticed that the rear 2 cylinders showed signs of being hotter than the rest. So, we took the stock holes that were in the heads, adapted the threads to AN fittings, then ran a hose across the rear to allow for better cooling.

But, to your question, you might want to try it in both sides. Yes, you'll probably throw a code for not having your stock O2 plugged in, but you can at least get some readings. It may help you decide.

[SilverBullet6.0]

Will having the O2 out not throw of fueling and make the readings pointless?

[04blackgmc]

Have extra bung welded in and just put it in after the headers.

On my personal C6 is right at the xpipe merge which is directly after the headers.

[SilverBullet6.0]

I plan on using a 3rd bung, but i have catalytic converters still and shorty headers, so i have very limited space to put it. I'll prolly have to mark a spot for it and then drop the y-pipe to weld in the bung.

[IJ.]

I plan on using a 3rd bung, but i have catalytic converters still and shorty headers, so i have very limited space to put it. I'll prolly have to mark a spot for it and then drop the y-pipe to weld in the bung.

Good point, what's the expected difference running the WB before/after Cats?

[MMGT1]

There is a % loss after the cat and there is no way to know exactly how much you loose. The exhaust cools so much through the cat I would never trust any values reported after a cat anyway, just my 2 cnts. 12-18" from exhaust flange would be my goal. If you are dealing with shorty headers, install just after the flange. And yea, I would also put it in the drivers side header. Between 12 and 18 inches seems to be the ideal location for most wideband sensors from the exhaust flange

[IJ.]

There is a % loss after the cat and there is no way to know exactly how much you loose. The exhaust cools so much through the cat I would never trust any values reported after a cat anyway, just my 2 cnts. 12-18" from exhaust flange would be my goal. If you are dealing with shorty headers, install just after the flange. And yea, I would also put it in the drivers side header. Between 12 and 18 inches seems to be the ideal location for most wideband sensors from the exhaust flange

Thanks Paul, always ran mine pre cats but have seen many Tuners use a tailpipe sniffer and was wondering just how critical it is, guess if I wasn't so lazy I could pull one of my rear o2's and pop the 2nd WB in there to compare