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If it is a 'dummy GPF' - which I am not questioning - then why would Porsche not simply leave the structure empty? I assume it requires more time and resources ($$$) to fill it up with a ceramic matrix, rather than simply leave it empty?
Does the ceramic 'filler' serve a resonator purpose? Based on OP's results, this does seem to be the case.
Regardless, I still do not understand why Porsche would include the ceramic because, as far as I know, everyone in Europe hates having GPFs - they rob the cars of exhaust acoustics. In other words, I am under the impression the GPFs were placed by Porsche ONLY because they were required to include them? If not required in the U.S., then why fill them with ceramic?
Oversimplifying but it's easier to produce one part for everyone than to have several parts depending on the region.
Originally Posted by Avera
If it is a 'dummy GPF' - which I am not questioning - then why would Porsche not simply leave the structure empty? I assume it requires more time and resources ($$$) to fill it up with a ceramic matrix, rather than simply leave it empty?
Does the ceramic 'filler' serve a resonator purpose? Based on OP's results, this does seem to be the case.
Regardless, I still do not understand why Porsche would include the ceramic because, as far as I know, everyone in Europe hates having GPFs - they rob the cars of exhaust acoustics. In other words, I am under the impression the GPFs were placed by Porsche ONLY because they were required to include them? If not required in the U.S., then why fill them with ceramic?
Oversimplifying but it's easier to produce one part for everyone than to have several parts depending on the region.
Yup. One "with" and one "without" becomes two separate parts to track. Two separate manufacturing processes. And manufacturing is always discounted by the quantity of one part. It's cheaper to make 2x the more expensive part, than 2x the parts at half quantity each.
Because that's a different part to track (one "with" and one "without" the ceramic) and a different assembly process. They have to track and know which pipe coming down the line gets the ceramic and fiberglass inserted into the can, and which doesn't. Even assuming it's just a robot that does it all (vs. having to train a human - which would undoubtedly make mistakes) that's extra programming of the machines, etc. And the risk of a mistake... shipping a car that was supposed to have them, but didn't.... especially from VW/Audi/Porsche after the $22bn Dieselgate fine? Would be bad.
Because that's a different part to track (one "with" and one "without" the ceramic) and a different assembly process. They have to track and know which pipe coming down the line gets the ceramic and fiberglass inserted into the can, and which doesn't. Even assuming it's just a robot that does it all (vs. having to train a human - which would undoubtedly make mistakes) that's extra programming of the machines, etc. And the risk of a mistake... shipping a car that was supposed to have them, but didn't.... especially from VW/Audi/Porsche after the $22bn Dieselgate fine? Would be bad.
Very possible I am missing something here, so bear with me as I try to understand what I am missing. . . .
You indicate Porsche tracks true GPF filters and 'dummy' GPF filters with CERAMIC/FIBERGLASS. I get that. Makes perfect sense.
What I am suggesting is, would it not be simpler and less expensive to track true GPF filters and 'dummy' GPF filters that are EMPTY (NO ceramic/fiberglass filler)?
Very possible I am missing something here, so bear with me as I try to understand what I am missing. . . .
You indicate Porsche tracks true GPF filters and 'dummy' GPF filters with CERAMIC/FIBERGLASS. I get that. Makes perfect sense.
What I am suggesting is, would it not be simpler and less expensive to track true GPF filters and 'dummy' GPF filters that are EMPTY (NO ceramic/fiberglass filler)?
Aha!! So that might be the part I have been missing . . . you are saying even the 'true' GPF (e.g., Europe) have the exact same ceramic/fiberglass as the 'dummy' GPF (e.g., U.S. deliveries)? The difference being the presence vs absence of sensors?
If true, then why would people state the European deliveries have their sound muted compared to U.S. deliveries? Is that a fallacy?
Aha!! So that might be the part I have been missing . . . you are saying even the 'true' GPF (e.g., Europe) have the exact same ceramic/fiberglass as the 'dummy' GPF (e.g., U.S. deliveries)? The difference being the presence vs absence of sensors?
If true, then why would people state the European deliveries have their sound muted compared to U.S. deliveries? Is that a fallacy?
I have to tell you, this is quite an eye-opener to me . . .
Universally, across makes and models, it is routinely stated in the usual places (forums, YT, etc) that the European models suffer compromised acoustics BECAUSE of the GPFs.
Based on what you state - and I cannot discredit - it is basically all b.s. . . . I wonder when this started and how it continues to be propagated?
The monitored and un-monitored GPF are not the same, and there is more than one part number for them, Un-monitored GPF units do not have the active metal coating applied to the ceramic matrix and do not have the sensor mounting in GPF body.
About the only thing you can say is that from an exhaust sound perspective they sound the same.
10-03-2022, 07:03 PM
