Syvecs Forums

Usually the uego is fitted after the turbo (downpipe), if we fit aftermarket or a new age headers won't be better to fit it before the turbo where all 4 pipes from the exhaust meet?

Cheers

Pedro,

UEGO sensors are oxygen partial pressure measuring devices, and as such they are affected by the pressure of the gas mix they are measuring. If the exhaust backpressure pre-turbo is sufficiently high then it can affect the lambda reading, it would therefore be sensible to place the sensor in a location where it is not subjected to large pressure variations.

NB : The New Age "Wide Range" sensors differ in their operation to both normal Nernst Cell sensors and also UEGO, furthermore whilst they are subject to exhaust pressure when on boost, they are not used for closed loop fuelling on boost so it doesn't matter that they don't read true under those conditions.

Hope this helps,

Pat.

On the contrary. Nowadays OEM's tend to run their turbocharged engines, close to lambda one - under full power situations also. Sensors do have pressure and temperature dependency, but OEM's do model their installations, so the pressure- and possible temperature variations also are taken into account. Quicker sensor lightup and hence lesser pollutions, are benefits to OEM's.

Sensor could be mounted before turbocharger, but it needs substantial amount more measurement and development.

This question is Subaru specific (Newage refers to MY01 onwards) and no subaru installations are as you have described.

The sensor is going on a Syvecs ECU, it therefore should be be put before the turbo with otherwise best accuracy will not be achieved and it will affect the closed loop lambda under full power conditions on the current firmware.

The sensitivity of errors in lambda measurement is vastly reduced when running close to lambda 1, Pedro will most certainly not want to run close to lambda 1 or he will expel his pistons out the exhaust!

Thanks,

In fact, the car is a GC8 but with aftermarket headers so, i can install the uego before the turbo (on the bottom of the up-pipe or after the turbo), at the moment is after the turbo (downpipe) and what i notice is that i can´t run closed loop labda at idle because the engine runs very unstable, was thinking to change it closer to the heads.

P.S. No i don´t Pavlo, it is not a pretty view

In newer stock WRX exhaust system, front oxygen sensor is located before turbocharger.
http://www.scoobytuner.com/tuning/?tuningID=15

Don't know much about 'newage', other than it used to be music genre.

Yes it is, but it's not used for full load lambda correction, and is not accurate at rich AFRs

After the turbo is fine, and the idle fuel correction needs to be tuned, do not expect the default values to work all the time, especially with the newer firmware versions where the control cycle time has a 3d map.

Pedro wrote:Thanks,

In fact, the car is a GC8 but with aftermarket headers so, i can install the uego before the turbo (on the bottom of the up-pipe or after the turbo), at the moment is after the turbo (downpipe) and what i notice is that i can´t run closed loop labda at idle because the engine runs very unstable, was thinking to change it closer to the heads.

P.S. No i don´t Pavlo, it is not a pretty view