2000extremeturbo

iTrader: (1)

OK, I'm wanting to get my turbo LSX build completed this month, and have ran into a question that I can't find a good answer to.

I have Greg Baninsh's book "EFI calibration", and in the section on O2 sensors, it says that they work better and more accurately if you put them in the down pipe. SO, I was going to put two O2 sensors about 6 inches behind the turbo, but common sense tells me that left and right sensors are not going to get accurate left and right inputs if they are in the same pipe.

So my question is what do I do now? Is it possible to send the signal off of ones sensor to both inputs on the computer? Or do I need to move the sensors to a place in front of the turbo where they will get the correct information.

My problem with the second option is that ther is not much room on the passenger side header for a sensor.

1320

iTrader: (6)

imo, it wont matter much either way. Since you were already planning on putting them in the down pipe, I d go that route. You obviously wont be getting good lt and rt info but you will get a good average. I have never seen a side problem anyways, other then a bad o2 sensor. If you choose to go to each side, they will read slightly in accurately due to the pressure. In the real world, it makes no difference since your talking about the narrow band sensor anyways, and all your tuning wil be done with a wide band in the down pipe, either on the road or on a loaded dyno. If you dont mimic the load with that, your tune will be crap once you put it in real world conditions.

Id put bungs in both sides....and one in the down pipe for the wideband.

98Z28CobraKiller

iTrader: (17)

Open loop and throw the stock narrowbands in the garbage.

hellbents10

iTrader: (10)

I would have to agree with the open loop statement.

y2khawk

iTrader: (5)

For most conditions when the narrow bands will be switching due to closed loop control, there shouldn't be enough engine throughput to have significantly more back pressure than a production style exhaust. You can get by with the stock narrowbands pre-turbo, and in the proper location. Unless you want to chase fuel trim issues and dive into the nitty gritty of fuel control, transport delay, gains, etc. you're better off ditching them completely or leaving them where they are normally.

But, for a wideband you should run it after the turbo. O2's work off of differential pressure measurements due to among other things, oxygen content. So any over exaggerated pressure in the exhaust is going to skew your readings. And since most times we are interested in the wideband reading when operating the engine at max throughput, the backpressure will be at its worst and the readings effected the most.

2000extremeturbo

iTrader: (1)

OK, I'll definately try to keep the NBs near the stock location. But my problem comes back to the passenger side header. I'll try to get a picture of just the header by itself.

Photochop

iTrader: (74)

My hiflo kit has one sensor right at the collector of the drivers side header/manifold, and the other o2 is in the crossover pipe before it even reaches the passengers side (NOT in the flow path of the passengers side at all). All its doing is fooling the computer to read the drivers side twice. Not sure if this is ideal, but I was having issues with the o2s recently, so I went ahead and had my tuner put my car back in open loop and problem solved.

calongo_SS

iTrader: (7)

OL here, tuned the car with a wideband and have an in car a/f gauge hooked to it for driving around.

The Fugitive

iTrader: (6)

where did you hook up your power and ground wires for you wb o2?

calongo_SS

iTrader: (7)

I don't remember, power was something ignition switched but I don't recall what. Any solid chassis ground will work, usually a good idea to ground everything to the same place to avoid offsets.