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#11: 01-11-2013, 09:47 PM
 
 ScottFW
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Title: Homebrew Vendor
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Quote:
Originally Posted by Max Capacity View Post
I have heard 12-18" from the turbo.
To nitpick, it's not how far the sensor is from the turbo that matters, because the turbo is not the heat source. What counts is how far it is downstream of the exhaust valves. The length of Subie manifolds and uppipes means that anywhere post-turbo is already a good bit downstream, whereas this isn't always the case on inline 4 cyl engines with their typically shorter exhaust manifolds.


Farther is better from a heat standpoint but the tradeoff is slightly longer latency at lower exhaust velocity (idle and low rpm), and if you mount it behind the cat it will read 0.5-1.0 points leaner than before the cat. Any tuner who's charging money should know how to adjust for that though.

Quote:
Originally Posted by Nolmers06LGT View Post
Does this mean the extra bung on a CNT downpipe is a bad location for a wideband?
I have an Innovate LC-1 in my Miata, with sensor mounted in place of the stock narrowband which is less than 18" from the head. No problem on the street but the sensor ocasionally overheated during track sessions. Given that experience, the sensor bung right behind the turbo on CNT downpipes is probably closer than ideal, but I'd run it there for a while and see if I noticed problems with it overheating (don't know how AEMs react but if my LC-1 overheats the gauge will freeze at 15:1 AFR). If it overheats you can try putting a heat sink on the sensor before you commit to pulling the DP and having a new bung welded in. The thick copper sheet versions do pretty well, something like this: http://www.ebay.com/itm/Wideband-O2-Sensor-Heat-Sink-/300590325461?pt=Motors_Car_Truck_Parts_Accessories &hash=item45fc945ed5&vxp=mtr

Last edited by ScottFW; 01-11-2013 at 09:50 PM..