Question about 100 cell cats
Discussion
Hi All,
Quick question about 100 cell cats- I'm tempted by a set from Essential Styling- their going at 450 + vat.
1)Will they add more of a sporty sound without changing the backbox? It's on a 550 special boxster s so the exhaust sound is already quite good. I'm after something just a little louder and throaty. Will this give me the desired effect?
2)I've been told that they won't trigger a CEL. Is this true?
3)How long do 100 cell cats last? I've heard that they have a much shorter life than normal ones.
Any other info from people that have done this sort of thing would be much appreciated.
Cheers,
Aki
Quick question about 100 cell cats- I'm tempted by a set from Essential Styling- their going at 450 + vat.
1)Will they add more of a sporty sound without changing the backbox? It's on a 550 special boxster s so the exhaust sound is already quite good. I'm after something just a little louder and throaty. Will this give me the desired effect?
2)I've been told that they won't trigger a CEL. Is this true?
3)How long do 100 cell cats last? I've heard that they have a much shorter life than normal ones.
Any other info from people that have done this sort of thing would be much appreciated.
Cheers,
Aki
I would never personally go the 100 cells/sq inch cats.
I've done work with OBD (On board diagnostics) and when you see what is
involved in the rigourous testing and what constitutes the emissions OBD mill
light to come on, you could easily sympathise with me! The OBD system
monitors the condition of anything that can effect the exhaust emissions
performance of the engine. It monitors the WHOLE engine as a system. This
means if a car has cam profile switching (like the 996) and there is a
possibility that this system could fail and this failure could adversely
effect emissions- this must be tested for. The standard cat bypasses of a
Ferrari must be tested also therefore. This testing is done for the design
life of the engine- certainly over 100,000 miles.
I don't know of Porsches OBD strategy, but the 993 TT certainly has pre and post
cat sensors which are continually monitoring the condition/emissions
efficiency of the catalyst. The Boxster certainly will. I don't know what strategy is employed but a
certain number of adverse emissions excursions will be overlooked. Using 100
cell cats in place of the 600 cells (I think?) could flag up the OBD warning
system much sooner. How will the closed loop emissions control system of the car
try to compensate when it senses the inferior emissions performance of the
100 cells cats? Will it make the car run leaner or perhaps richer when the
HCs or Noxs are higher than spec? Left alone the system should last well over 120,000 miles (it's been tested and HAS to by
legislation)
So it probably won't trigger the OBD warning mill light- but is likely to do it sooner than the standard factory equipment and package. The same goes for how long they'll last. If you're not likely to keep the car all that long , as I am, then it's not of that much cencern.
As for noise, the 100 cells cats will make a difference. Back pressure itself is a simple form of silencing. Reducing this will liberate a bit more noise.
I've done work with OBD (On board diagnostics) and when you see what is
involved in the rigourous testing and what constitutes the emissions OBD mill
light to come on, you could easily sympathise with me! The OBD system
monitors the condition of anything that can effect the exhaust emissions
performance of the engine. It monitors the WHOLE engine as a system. This
means if a car has cam profile switching (like the 996) and there is a
possibility that this system could fail and this failure could adversely
effect emissions- this must be tested for. The standard cat bypasses of a
Ferrari must be tested also therefore. This testing is done for the design
life of the engine- certainly over 100,000 miles.
I don't know of Porsches OBD strategy, but the 993 TT certainly has pre and post
cat sensors which are continually monitoring the condition/emissions
efficiency of the catalyst. The Boxster certainly will. I don't know what strategy is employed but a
certain number of adverse emissions excursions will be overlooked. Using 100
cell cats in place of the 600 cells (I think?) could flag up the OBD warning
system much sooner. How will the closed loop emissions control system of the car
try to compensate when it senses the inferior emissions performance of the
100 cells cats? Will it make the car run leaner or perhaps richer when the
HCs or Noxs are higher than spec? Left alone the system should last well over 120,000 miles (it's been tested and HAS to by
legislation)
So it probably won't trigger the OBD warning mill light- but is likely to do it sooner than the standard factory equipment and package. The same goes for how long they'll last. If you're not likely to keep the car all that long , as I am, then it's not of that much cencern.
As for noise, the 100 cells cats will make a difference. Back pressure itself is a simple form of silencing. Reducing this will liberate a bit more noise.
Thanks for a very informative reply. You obviously know your stuff! So is that no to changing cats altogether or just not 100 cell- how about 200 cell- would that have the same problems? Please forgive my ignorance!
Would difference would changing the headers make to the emmisions/engine function? Any? Would that liberate some power/noise?
Sorry for all the questions!
Cheers,
Aki
Would difference would changing the headers make to the emmisions/engine function? Any? Would that liberate some power/noise?
Sorry for all the questions!
Cheers,
Aki
Well I didn't say "NO" to 100 cells cats, just be aware that they won't last as long and the OBD catalysts monitoring warning mil light will come on sooner potentially.
The same goes for 200 cells but less so.
Exhaust headers will typically boost your low speed torque and possibly add a little bit of top end power if sized correctly. I doubt headers will effect the OBD monitoring equipment for the catalytic converters, as the headers don't effect the emissions efficiency of the cats.
I don't know if the Boxster has cast iron exhaust manifolds as standard- if it does and your after market headers are fabricated steel- it will certainly liberate some noise- as it has on my Bimmer.
The same goes for 200 cells but less so.
Exhaust headers will typically boost your low speed torque and possibly add a little bit of top end power if sized correctly. I doubt headers will effect the OBD monitoring equipment for the catalytic converters, as the headers don't effect the emissions efficiency of the cats.
I don't know if the Boxster has cast iron exhaust manifolds as standard- if it does and your after market headers are fabricated steel- it will certainly liberate some noise- as it has on my Bimmer.
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