Reading AFRs and Tuning with a DDP

[theKnifeArtist]

I have two downpipes.
I got a BIC DDP and a HKS 3" DP.
I recently took my DDP off my car and installed the HKS so i can get my wideband bung welded to the DDP.
So i was just thinking...because the wastegate is not recirculating back to the exhaust, does this mess with the AFR readings?
I'm going to weld the bung right on the elbow of the downpipe, right by the factory O2 sensor. The HKS DP already has one in that exact spot, so ill do the same for the ddp.

 

[JesseH]

I have two downpipes.
I got a BIC DDP and a HKS 3" DP.
I recently took my DDP off my car and installed the HKS so i can get my wideband bung welded to the DDP.
So i was just thinking...because the wastegate is not recirculating back to the exhaust, does this mess with the AFR readings?
I'm going to weld the bung right on the elbow of the downpipe, right by the factory O2 sensor. The HKS DP already has one in that exact spot, so ill do the same for the ddp.

Putting the WB bung that close to the turbo is going to decrease the life in your sensor, AEM states for turbo'd cars the sensor should be mounted at least 18" downstream from the turbo. I have mine 2 inches after the last bend in the DP.

 

[jdub]

I have two downpipes.
I got a BIC DDP and a HKS 3" DP.
I recently took my DDP off my car and installed the HKS so i can get my wideband bung welded to the DDP.
So i was just thinking...because the wastegate is not recirculating back to the exhaust, does this mess with the AFR readings?
I'm going to weld the bung right on the elbow of the downpipe, right by the factory O2 sensor. The HKS DP already has one in that exact spot, so ill do the same for the ddp.

Think about this for a minute...AFR = Air Fuel Ratio. All the wastegate will do on a DDP is divert exhaust gas to a different path.

 

[theKnifeArtist]

87supra- so i should have the sensor down under the car then?

jdub- right, thats exactly what i'm saying.
wastegate exhaust gas is being diverted to a different path, a path that doesnt cross the wideband o2. this going to be a problem?

 

[jdub]

If you have two samples of the same exhaust gas, is the Air Fuel Ratio going to be different?
(think about what the sensor is measuring)

 

[theKnifeArtist]

ahhhh

works like a narrowband 02? measuring oxygen right?

 

[JesseH]

87supra- so i should have the sensor down under the car then?

jdub- right, thats exactly what i'm saying.
wastegate exhaust gas is being diverted to a different path, a path that doesnt cross the wideband o2. this going to be a problem?

Just further away from the heat source, excessive heat takes away from the sensor's life, the WB sensors are a little more sensitive than the NB. I just personally mounted mine a couple inches right after the last bend.

 

[wardog]

X2 on what X87SUPRAX87 said. I just installed my Lc-1 with my Maft-Pro and i had the bung welded 2 inches from the last bend on the DP.