Where did you mount your wideband 02 sensor on your DP? How far back from the turbo?


Thanks Channon

 

Just before the joint with the midpipe.

 

12-18" is ideal, closer and the exhuast pressure waves can screw up the reading according to Tech Edge. Also the EGTs are a little lower. Extremely high EGTs will screw up your readings as well. Carl

 

According to Maximum Boost: Designing, Testing and Installing Turbocharger Systems, by Corky Bell, he writes -

OXYGEN SENSOR POSITION

The oxygen sensor ideally wants to be as close to the combustion chambers as temperature permits. In most cirumstances where a turbo is involved, the oxygen sensor should be immediately aft of the turbo (Bell, 134).

 

According to Bosch, and verified by testing at Tech Edge, and based on the fact that a wideband sensor works by detecting passive diffusion of oxygen, Mr Bell is not correct. Several owners of extreme high HP Supras(a lot less vulnerable than our cars) have verified this fact(the hard way). If you like, take your WB sensor, and place it in the stock location, then switch it to the lower DP location. In general, you will see a slightly richer indication at the top of the DP. This is in part due to the pressure waves in effect pushing o2 against a diffuser designed to detect passive diffusion of O2. The difference is usually only .2-.4 points, but if you are tuning on the ragged edge, that is enough to warrant not second guessing The manufacturer of your WB. The info am quoting is for the Bosch L1H1 /NTK 5 wire sensor. I do not know if it is valid for the new less expensive sensors being used by innovative, and others. Then again, it is easy to access the sensor if it is at the bottom of the DP, so why risk it???

 

I believe accessibility would also be a strong point for your argument. Perhaps Corky Bell was talking about narrow band oxygen sensors. I am not to sure about WB's.

 

I put mine in the stock location, it fit, same windings, and I don''t need the stocker anymore, so why cap a hole or leave a non functioning WB in there, just to drill another.... and I don't want anybody tuning my sh(tuff) to the ragged edge anyhow... since bad gas, or low gas pressure can push you over quickly...

But if you're going that route it might be prudent to ask a race tuner wehere he'd suggest you put it... since he'd be the one to know, and to know what the readings look like at that location.

-DC

 

I read somewhere before I did mine that the sensor should be 30" from exhuast port on engine. That was right at the downpipe to midpipe joint so I just put it as far back on the downpipe as I could (In case I ever decided to switch out to midpipe for track days).

 

Thanks guys, it looks like it will go as far down on the dp as I can get it.

Thanks again