Driving without a catalytic converter!
08-06-2003, 03:34 AM
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Driving without a catalytic converter!
Having brought my 95 993 used the prior owner actually informed me that the cat conv has been removed from the car!!
After buying it I understood that he had not actually removed the catalytic conv BUT he had it emptied from the inside and then rewelded it .
Is there any mechanical problem I might encounter if I keep it this way, It is too costly to buy a new one(2000 USD) that I would want to spend elswhere.... I love the sound though especially with the perforated air box...It sounds a bit like a high grumble especially when I remove the gas pedal on high rev..
Is there an Oxygen sensor on the car as I understand from the previous owner that it did not exist on a 1995 model!!!
Thanks for your help.
After buying it I understood that he had not actually removed the catalytic conv BUT he had it emptied from the inside and then rewelded it .
Is there any mechanical problem I might encounter if I keep it this way, It is too costly to buy a new one(2000 USD) that I would want to spend elswhere.... I love the sound though especially with the perforated air box...It sounds a bit like a high grumble especially when I remove the gas pedal on high rev..
Is there an Oxygen sensor on the car as I understand from the previous owner that it did not exist on a 1995 model!!!
Thanks for your help.
08-06-2003, 05:42 AM
#2
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I don't think this would cause a mechanical problem, but you blow about 20-30 times as many toxic fumes into the air as a car that has a functioning catalytic converter. I'd watch out for a used replacement cat.
08-06-2003, 06:13 AM
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The catalytic converter eliminates up to 90% of benzene emitted from a petrol car exhaust, among many other things. Benzene is really nasty stuff and can cause myeloid leukemia. Try installing at least a sports cat.
08-06-2003, 08:46 AM
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YOU'RE IN LUCK!!
08-06-2003, 01:38 PM
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I am Happy that almost everybody is environmentally friendly..
Is there actually an increase in HP for the car and does the oxygen sensor transmit false info to the computer ?
Is there actually an increase in HP for the car and does the oxygen sensor transmit false info to the computer ?
08-06-2003, 01:59 PM
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Georges,
Do you have to pass an exhaust emissions test in Lebanon? The catalytic converter's only purpose is to reduce emissions.
The oxygen sensor is 'usually' before the cat, I'm not 100% sure if this is true for Porsche, but it should be, so the cat doesn't effect the reading to the oxygen sensor. The oxygen sensor just tests the exhaust and tells the computer to adjust the fuel. If there is too much oxygen in the exhaust then the air/fuel mixture is lean. The only problem you get into is in highly modified cars, like adding a supercharger, you are putting so much air into the motor that the O2 sensor is saying send more fuel, but the fuel injectors are already at their limit and can't supply enough fuel to combine with the oxygen, so at wide open throttle the mixture will still be lean.
Removing the cat decreases back pressure in the exhaust system resulting in higher HP, just like using less restrictive mufflers. In each case the result of the "free" increase in HP is more noise. Ever been near a race car, like a C5R Corvette? Deafening.
Do you have to pass an exhaust emissions test in Lebanon? The catalytic converter's only purpose is to reduce emissions.
The oxygen sensor is 'usually' before the cat, I'm not 100% sure if this is true for Porsche, but it should be, so the cat doesn't effect the reading to the oxygen sensor. The oxygen sensor just tests the exhaust and tells the computer to adjust the fuel. If there is too much oxygen in the exhaust then the air/fuel mixture is lean. The only problem you get into is in highly modified cars, like adding a supercharger, you are putting so much air into the motor that the O2 sensor is saying send more fuel, but the fuel injectors are already at their limit and can't supply enough fuel to combine with the oxygen, so at wide open throttle the mixture will still be lean.
Removing the cat decreases back pressure in the exhaust system resulting in higher HP, just like using less restrictive mufflers. In each case the result of the "free" increase in HP is more noise. Ever been near a race car, like a C5R Corvette? Deafening.
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08-06-2003, 02:00 PM
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Georges
Most of the used P Cars in our part of the world have either removed Cats or emptied cats, being a cheap alternative for some little hp gains and torque I believe, as well as for sound improvement...In my opinion, and I could be wrong, since there is no noise or db limitations in the Middle East and until a few years back there was no unleaded fuel, and unfortunately no control on emissions, this has never been an issue.
On a turbo, the turbo lag gets reduced considerably, starting boost from about 800 rpms earlier than the standard setup, I understand that N/A engines get a little better low end torque as well.
Jean
Most of the used P Cars in our part of the world have either removed Cats or emptied cats, being a cheap alternative for some little hp gains and torque I believe, as well as for sound improvement...In my opinion, and I could be wrong, since there is no noise or db limitations in the Middle East and until a few years back there was no unleaded fuel, and unfortunately no control on emissions, this has never been an issue.
On a turbo, the turbo lag gets reduced considerably, starting boost from about 800 rpms earlier than the standard setup, I understand that N/A engines get a little better low end torque as well.
Jean
