Downpipe Dilemma.... Pro & Cons.... Help needed!!!! (edited)
05-11-2003, 03:49 PM
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Downpipe Dilemma.... Pro & Cons.... Help needed!!!! (edited)
Yes the mention of downpipes will always spark some big debate here on AW. I am currently looking to replace my 1st gen APR DP's with something better suited to my K04's. I have narrowed it down to 3 choices. I have listed the pros and cons of each. Any further input would be helpfull.
AutoSpeed
Pros: Large 3" DP's with 3" inlet and outlet on the cats. Nice smooth bends thruout the DP's. Test pipes available
Cons: Some report install clearance issues. Extra $250 for test pipes
AWE
Pros: Nice large 3" chamber coming off the turbos & tapers down to 2.5". Smooth flex joint. Test pipes available. Fastest K04 kit car running AWE Dp's (R1eater 12.2). APR & AMS (same softwear I have)both using 2.5" DP's when creating the software.
Cons: Bends/welded sections on DP's not as smooth as the auto speeds
LeBree/Tantrumwerks
Pros: Totally new design idea. Smooth bends on DP's. test pipes available.
Cons: Totally new unproven design. 02 sensor located on the turbine side of the DP's. How does the car know the AF ratio when off boost. Dyno runs all done on K03 car. Small 1 3/4" pipe off of the turbine side.
AutoSpeed
Pros: Large 3" DP's with 3" inlet and outlet on the cats. Nice smooth bends thruout the DP's. Test pipes available
Cons: Some report install clearance issues. Extra $250 for test pipes
AWE
Pros: Nice large 3" chamber coming off the turbos & tapers down to 2.5". Smooth flex joint. Test pipes available. Fastest K04 kit car running AWE Dp's (R1eater 12.2). APR & AMS (same softwear I have)both using 2.5" DP's when creating the software.
Cons: Bends/welded sections on DP's not as smooth as the auto speeds
LeBree/Tantrumwerks
Pros: Totally new design idea. Smooth bends on DP's. test pipes available.
Cons: Totally new unproven design. 02 sensor located on the turbine side of the DP's. How does the car know the AF ratio when off boost. Dyno runs all done on K03 car. Small 1 3/4" pipe off of the turbine side.
05-11-2003, 03:56 PM
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Question about your question on the LeBree DP's
What would the issue be having the O2 sensor behind the turbine? Exhaust gas ALWAYS flows through the turbine (On or off boost).
The wastegate side would be an issue since it is only open when boost is achieved.
The wastegate side would be an issue since it is only open when boost is achieved.
05-11-2003, 04:03 PM
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I don't know for sure. I just know that all of the exhaust gases....
are not passing the O2 sensor when the waste gate is open. How this affect the ECU's abilty to control AF ratios I am not sure.
05-11-2003, 04:16 PM
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I think it's a non-issue since the O2 content in the exhaust gas
doesn't change once the fuel is burned up.
Once the three pipes in the manifold merge, it's the same composition, even if it is split again downstream (unless there is combustion or a source of oxygen after they split in the turbo housing...not likely).
Once the three pipes in the manifold merge, it's the same composition, even if it is split again downstream (unless there is combustion or a source of oxygen after they split in the turbo housing...not likely).
05-11-2003, 04:16 PM
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Doe the O2 sensor monitor an absolute or relative level of oxygen? If it's absolute, then you might
have problems because its not "seeing" all the exhaust gas. However, if it's relative (which I think it is), it just needs to measure the amount in relation to other exhaust gases, thus it wouldn't matter how much of the flow it sees, as long as it sees something.
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05-11-2003, 04:27 PM
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The question remains if when the waste gate opens is
there anough gases passing thru the turbine side to get a proper sampling. I understood that when the wastegate opens that most of the gases exit the side without the o2 sensor. Then you would rely on a very small sample to determine the AF ratio. This can't be how the O2 sensor was designed to work.
