1st dumb question for 2009

[3chord]

ok so to get a little more power out of it, and to keep things safe, I know we are encouraged to get a custom tune. Here's my question. Never been to a dyno, and don't want to weld in an o2 bung for a wideband. Can they still dyno it using a probe at the tailpipe or will the downstream emissions equipment throw the AFR values off?

[Letxen3]

yes thats how its always done if you dont have your own wideband.

[Mike_Levy]

They can measure at the tailpipe. Or it wouldn't surprise me if they couldn't just pull one of the front O2s, put in a Y-fitting and measure there. Of course I don't know if that would actually work, but it seems like a good idea.

[ZMagnum]

Yeah, not everyone who goes to a dyno for CMR tunes has to have their exhaust modified with an O2 bung.

[Eagle1]

Using a sniffer is not the best way to do it, however, IF you can get steady reading at the pipe, it will suffice. The A/F reading is a starting point, the dyno will let you know what the correct reading is by the HP.

[06MonteSS]

it's always better to have the wideband O2 sensor as close to the upstream as possible...

meaning, either in the front O2 sensor 1 location before the CAT, or ever a little closer...

[~RAM~]

I got a question.
So my cats are falling apart from the inside. An it sounds horrible, but in a couple weeks I'm gonna go get the cats cut out. So when I first put these cats on wich are high flow cats, I bought some 02 simulators so I don't get a cel. My question is, when I get the cats cut, should I put the wideband right after the headers an pipe connect, or after the 02 sensors?
Also should I get the 02 deletes thru cmr tune, or the simulators be fine?

[sfla_srt4]

The wideband needs to be pretty close to the collector but before any cats... You could also get the 02s turned off by the CMR and not have to deal with the 02 sims.

[Mike_Levy]

But don't forget if you turn the O2s off, they won't give a reading, therefore the OBD-2 system will never be "READY", and you will not pass an inspection in CA emissions states (CA, NY, MA, ME, CT, VT, and a couple others).

[~RAM~]

We don't have any emissions inspections or anythin where I'm from.

[Quick]

A wideband after the cats is not all that bad. At the most, your readings might be off by 0.2 AFR. Usually less. The cats will "dampen" changes in a/f. So if there are immediate changes in a/f they would be "smoothed" by the cats with some delay. Optimally your sensors (Bosch) should be at least 24" downstream from the exhaust port at the the block (you can incinerate them) and ideally before the cat. I don't believe having the sensor before the cat is critical to our application; just not ideal. That's my understanding.

The only thing that is not acceptable is any sort of air other than the exhuast coming across the sensor. Clipping a sensor on the tips doesn't work (that's why the sniffers have a long rod on them). Even the smallest air leak at the bung weld doesn't work.

[3chord]

Thanks everyone for your responses