D-Cat
- Thread starter Guest
- Start date
Yes,
Essential styling do a decat section for s2 and turbo, it is straight forward and no changes to the electronics are required. Some cars were decatted from the factory as an option.
There should be a slight performance increase up to 12BHP with rear section as well.
Tony
Essential styling do a decat section for s2 and turbo, it is straight forward and no changes to the electronics are required. Some cars were decatted from the factory as an option.
There should be a slight performance increase up to 12BHP with rear section as well.
Tony
Chris Goodman
New member
I've just had the cat removed from my Turbo SE and it happened to need MOT a couple of days later so was emission tested and the tester said it appeared to be "running on fresh air" - mixture very weak - so I enquired at Porsche specialist and told that I should really have a part fitted "to tell the ECU that the cat has gone". Sorry for non-technical speak but that was good enough for me! Anyway, whatever it is is being fitted on Monday so I should know a bit more after that if anyone's interested!
Chris Goodman
New member
OK guys - seeing as there is some interest I've just phoned the 'specialists' - PCT in Coventry (workshop attached to Autobahn) - to discover exactly what part they were intending to fit on Monday and they now tell me that in fact there is no part needed as such. Apparently they initially assumed that my engine had the oxygen sensor in the cat in common with some other Porsches but have now discovered that on the 944 turbo the sensor is in front of the cat so apparently all they now intend to do is "plug the diagnostic machine into the car, find out why it's running so weak, and probably just reset the mixture".
I'm sorry to have set unnecessary hare running on this one. Guess it's yet another example of large expensive-looking Porsche dealerships having much less experience with 944 than 911. (They're also fitting new rear shocks on Monday so I hope they get that right!) Still, at least they've got loan cars and / or a good coffee machine!
I'm sorry to have set unnecessary hare running on this one. Guess it's yet another example of large expensive-looking Porsche dealerships having much less experience with 944 than 911. (They're also fitting new rear shocks on Monday so I hope they get that right!) Still, at least they've got loan cars and / or a good coffee machine!
eastendr
New member
Your car should run about .5%CO2 at idle with the lambda sensor installed and working properly.
If you've had your CAT removed and the MOT tester assumes it's a non-cat car, he'll be expecting about 2% CO2 at idle. This could be why he says it's running too lean.
There is an adjustment on the AFM for setting basic idle CO2, but this would only work in open loop mode. When the DME's working in closed loop mode (all except WOT), the lambda sensor will cause the DME to go back to .5% / 14.7 AFR.
The only way to really tell is with a wide band lambda sensor or a 4 way gas analyser.
HTH
If you've had your CAT removed and the MOT tester assumes it's a non-cat car, he'll be expecting about 2% CO2 at idle. This could be why he says it's running too lean.
There is an adjustment on the AFM for setting basic idle CO2, but this would only work in open loop mode. When the DME's working in closed loop mode (all except WOT), the lambda sensor will cause the DME to go back to .5% / 14.7 AFR.
The only way to really tell is with a wide band lambda sensor or a 4 way gas analyser.
HTH
Chris Goodman
New member
Thanks Rick.
You're probably spot on with remark re MOT tester. He didn't give me a print-out from the analyser as the car passed but I think he did say "0.5 or 0.05%".
Frankly I don't understand the terms 'DME' or 'Open Loop' but will now be able to ask more (apparently!) intelligent questions on Monday so less likely to be suckered into unnecessary work. Don't want to start a 'thread-within-a-thread' but subject I'm a little sensitive on at the moment as bills on this car approaching £3k in last few weeks.[
]
To return to original point of this thread, my car seems to run very well without the cat and noise level hasn't increased much if at all - which was a concern of mine re track days. I just got an exhaust place to cut out the cat and weld in replacement pipe. Cost £100. Much less than I was quoted for any 'designed' de-cat front system.
You're probably spot on with remark re MOT tester. He didn't give me a print-out from the analyser as the car passed but I think he did say "0.5 or 0.05%".
Frankly I don't understand the terms 'DME' or 'Open Loop' but will now be able to ask more (apparently!) intelligent questions on Monday so less likely to be suckered into unnecessary work. Don't want to start a 'thread-within-a-thread' but subject I'm a little sensitive on at the moment as bills on this car approaching £3k in last few weeks.[
]To return to original point of this thread, my car seems to run very well without the cat and noise level hasn't increased much if at all - which was a concern of mine re track days. I just got an exhaust place to cut out the cat and weld in replacement pipe. Cost £100. Much less than I was quoted for any 'designed' de-cat front system.
ORIGINAL: eastendr
I'd be interested to know as well [
Cat makes no difference to closed loop running.
It does is the lambda has gone at the same time as the cat. If it hasn't then Chris's lean running is nothing to do with the cat removal at all.
As an aside my mechanic thinks the S2 would perform better with the cat and lambda removed and the ECU switched to suit.
Posts made and opinions expressed are those of the individual forum members
Use of the Forum is subject to the Terms and Conditions
