Anyone here run without an O2 sensor?
01-17-2008, 11:05 AM
#17
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pat056 ,
When a 964 DME detects full throttle, the O2 sensor signal is ignored ! Sounds like your RSA is underfuelled on full load . No point in playing with the O2 sensor .
Geoff
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KS400200,the oldest 964 on Rennlist,unless you know differently !
When a 964 DME detects full throttle, the O2 sensor signal is ignored ! Sounds like your RSA is underfuelled on full load . No point in playing with the O2 sensor .
Geoff
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KS400200,the oldest 964 on Rennlist,unless you know differently !
01-17-2008, 11:14 AM
#19
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Geoff - Errrmm..
mainly wondering if its safe to run without it for a while whilst I troubleshoot and/or save up the money and energy to persuade the sensor and cat to part company after 19 happy years together...
..also partly whether it might have been one of these things that lots of people get rid of because they are more trouble than they're worth, like.. um, the undertray (ouch, I said the 'u' word. 10 hail marys..) secondary silencer, airbox cover, intensive wash etc. I'm thinking best keep it, tbh.
mainly wondering if its safe to run without it for a while whilst I troubleshoot and/or save up the money and energy to persuade the sensor and cat to part company after 19 happy years together...
..also partly whether it might have been one of these things that lots of people get rid of because they are more trouble than they're worth, like.. um, the undertray (ouch, I said the 'u' word. 10 hail marys..) secondary silencer, airbox cover, intensive wash etc. I'm thinking best keep it, tbh.
01-17-2008, 11:17 AM
#20
Burning Brakes
Gregg,
The O2 sensor is , by a very small fuel amount , taking the idle/low part load
fuelling up and down , around the desired level .
The best move is to adjust the idle tail pipe mixture to around 1.0% CO using the AFM adjuster . This is with the O2 sensor disconnected and no Cat involved . Then connect the O2 sensor and watch the tail pipe mixture . With no Cat you should see somewhere between 0.5% and 1.0% , gently going up and down .
The Cat is there to remove the 0.5 to 1.0 % CO if emission laws demand that .
Years ago Porsche UK used to supply a Non Cat coding plug and a Cat bypass with no provision for an O2 sensor . It brought me a fair amount of " fix it " business !! This DME set up was incorporated by Porsche design to allow the 964 to be sold in countries with no unleaded fuel .
People thought they would get more power but did not realise what the No-Cat
DME calibration was !!!
Geoff
----------------------------------------------------------------
KS400200,the oldest 964 on Rennlist,unless you know differently !
Hope that helps .
The O2 sensor is , by a very small fuel amount , taking the idle/low part load
fuelling up and down , around the desired level .
The best move is to adjust the idle tail pipe mixture to around 1.0% CO using the AFM adjuster . This is with the O2 sensor disconnected and no Cat involved . Then connect the O2 sensor and watch the tail pipe mixture . With no Cat you should see somewhere between 0.5% and 1.0% , gently going up and down .
The Cat is there to remove the 0.5 to 1.0 % CO if emission laws demand that .
Years ago Porsche UK used to supply a Non Cat coding plug and a Cat bypass with no provision for an O2 sensor . It brought me a fair amount of " fix it " business !! This DME set up was incorporated by Porsche design to allow the 964 to be sold in countries with no unleaded fuel .
People thought they would get more power but did not realise what the No-Cat
DME calibration was !!!
Geoff
----------------------------------------------------------------
KS400200,the oldest 964 on Rennlist,unless you know differently !
Hope that helps .
Sorry to threat-jack Johnny! Hope you fix that idle.
01-17-2008, 11:18 AM
#21
Nordschleife Master
I'd run the O2 sensor regardless of whether or not I removed the cat. There is not a performance advantage to removing it and you lose much more that you could ever hope to gain.
01-17-2008, 11:21 AM
#22
Burning Brakes
01-17-2008, 11:38 AM
#23
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Johnny ,
"also partly whether it might have been one of these things that lots of people get rid of because they are more trouble than they're worth, like.. um, the undertray (ouch, I said the 'u' word. 10 hail marys..) secondary silencer, airbox cover, intensive wash etc. I'm thinking best keep it, tbh."
The rear undertray helps to overheat the motor and cut noise levels !! Never found on Factory race cars .Secondary silencer is a good silencer , standard primary silencer is junk .Airbox cover keeps the intake air temperature low - good for performance .
O2 sensor is a good part to have . How many remove the O2 to improve performance , unless you are moving over to Motec junk ( Happy 2008 Colin ! )
I must get some work done !!
Geoff
----------------------------------------------------------------
KS400200,the oldest 964 on Rennlist,unless you know differently !
"also partly whether it might have been one of these things that lots of people get rid of because they are more trouble than they're worth, like.. um, the undertray (ouch, I said the 'u' word. 10 hail marys..) secondary silencer, airbox cover, intensive wash etc. I'm thinking best keep it, tbh."
The rear undertray helps to overheat the motor and cut noise levels !! Never found on Factory race cars .Secondary silencer is a good silencer , standard primary silencer is junk .Airbox cover keeps the intake air temperature low - good for performance .
O2 sensor is a good part to have . How many remove the O2 to improve performance , unless you are moving over to Motec junk ( Happy 2008 Colin ! )
I must get some work done !!
Geoff
----------------------------------------------------------------
KS400200,the oldest 964 on Rennlist,unless you know differently !
01-17-2008, 12:06 PM
#24
Nordschleife Master
unless you are moving over to Motec junk
01-17-2008, 12:15 PM
#25
Nordschleife Master
"Can you qualify why you think that MoTeC is junk?"
I think thats snark .
"I'd run the O2 sensor regardless of whether or not I removed the cat. There is not a performance advantage to removing it and you lose much more that you could ever hope to gain."
Geoffrey said what I would have liked to say . This is what I've always thought , but I never had any proof .
I think thats snark .
"I'd run the O2 sensor regardless of whether or not I removed the cat. There is not a performance advantage to removing it and you lose much more that you could ever hope to gain."
Geoffrey said what I would have liked to say . This is what I've always thought , but I never had any proof .
Last edited by Indycam; 01-17-2008 at 12:33 PM.
01-17-2008, 12:49 PM
#27
...whaaatttt....I am sure I saw a Motec sticker in my engine bay the other day.....and its junk...???? WTF?????? Who put that there??????I knew I should have got the MAF.........I mean there is a hot film thing included ...and if I had known you get a free DVD as part of the product, then I would have settled for 20HP gain......
01-17-2008, 12:52 PM
#28
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Indycam , Geoffrey ,
Following the " Motec junk " comment I wished Colin a happy 2008 .
I have known Colin for a very long time , I used to programme chips for him .
We have had this joke filled Bosch V Motec "debate " for years .
Do not take it seriously !!
Geoff
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KS400200,the oldest 964 on Rennlist,unless you know differently !
Following the " Motec junk " comment I wished Colin a happy 2008 .
I have known Colin for a very long time , I used to programme chips for him .
We have had this joke filled Bosch V Motec "debate " for years .
Do not take it seriously !!
Geoff
----------------------------------------------------------------
KS400200,the oldest 964 on Rennlist,unless you know differently !
01-17-2008, 12:54 PM
#29
Indycam , Geoffrey ,
Following the " Motec junk " comment I wished Colin a happy 2008 .
I have known Colin for a very long time , I used to programme chips for him .
We have had this joke filled Bosch V Motec "debate " for years .
Do not take it seriously !!
Geoff
----------------------------------------------------------------
KS400200,the oldest 964 on Rennlist,unless you know differently !
Following the " Motec junk " comment I wished Colin a happy 2008 .
I have known Colin for a very long time , I used to programme chips for him .
We have had this joke filled Bosch V Motec "debate " for years .
Do not take it seriously !!
Geoff
----------------------------------------------------------------
KS400200,the oldest 964 on Rennlist,unless you know differently !
