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Would like to eliminate secondary catalytic converters


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Hi, I have a 2002 Boxster 2.7 2002. Tiptronic and would like to eliminate the secondary catalytic converters and I´m wondering if any one has done this.

I live in Guatemala City, so I don´t have problems with the emissions.

I wonder if eliminating them would make the sound louder or will give me any performance gains due to the air flow gains??

I dont see any sensor after the secondary cat converters, so also don´s spect a check engine light to come on.

Sorry for my English

Thanks in advance for any comments

PD. I´m posting pictures of my car

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Though most posts were about your wheels, if you look around, you can find a set of used cat bypass pipes fairly inexpensive. I bought mine from a forum member a couple years ago (Fabspeed), slightly used, but perfect condition for under $300 shipped. They are easy to install, sound very nice, especially in the mid range and provide a crisper throttle response. Whether there is a measurable HP increase or not, the seat of pants could not tell. My '02 S has the bypass pipes, a sport muffler (ala Pedro) and an Evo Hi-flow air intake. As mentioned earlier, throttle blip lag was almost completely eliminated by this setup. No CEL and emission problems for me...

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Something I've wondered about eliminating a set of cats.

Does it put a bigger load on the remaining set? Do they degrade faster? Anyone running one set ever have problems that required you to replace a set?

What would a complete stock set of 4 cats cost on the used market? From a spec-racer conversion or a wreck perhaps.

Ignoring the implications for the planet as I presume that the one set doesn't do as good a job as two.

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Mike, good questions. Here are my assumumptions, with no backup evidence. I believe the secondary cats were placed for two reasons; initial cold start and EU noise compliance. The car is definately throatier without the cats, as I feel they were really intended as pre-mufflers. Only a sniffer would confirm the first and I haven't bothered to have it tested.

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  • 1 month later...
Mike, good questions. Here are my assumumptions, with no backup evidence. I believe the secondary cats were placed for two reasons; initial cold start and EU noise compliance. The car is definately throatier without the cats, as I feel they were really intended as pre-mufflers. Only a sniffer would confirm the first and I haven't bothered to have it tested.

JMATTA Do you know if eliminating the secondary cat sets, (pre-mufflers) will result in HP gain/lost??

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My car has not been on a dyno, so I can't answer the question. I do know that with the mods I've described, throttle response is far more positive, without hesitation. You are not not going to feel a HP gain of under 10%, so throttle crispness is all can can judge by. It sure does scream when the tach hits 3800 rpms.

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My car has not been on a dyno, so I can't answer the question. I do know that with the mods I've described, throttle response is far more positive, without hesitation. You are not not going to feel a HP gain of under 10%, so throttle crispness is all can can judge by. It sure does scream when the tach hits 3800 rpms.

Thaks Jmatta, seems like i`m going to do the same mod, unless some other member has more information.

Regards

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...

What would a complete stock set of 4 cats cost on the used market? From a spec-racer conversion or a wreck perhaps.

...

Not sure about a complete set of 4 cats. I can tell you from recent personal experience that used cats are highly valuable, even very old ones. Three weeks ago I got home late Friday from a business trip to Northern Virginia. I started my 1988 Toyota pickup and I sounded and ran terrible. Somebody hacked off the original catalytic converter! Toyota dealer estimated it was worth at least $50 scrap value for the platinum and palladium. As the economy has deteriorated, the price of precious metals has skyrocketed in the past few years and catalytic converter theft has become big business.

The good news is anyone removing their cats can get a lot of money for them, and Porsches are low enough to the ground it's extremely difficult for someone to get under there and steal a catalytic converter

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...

What would a complete stock set of 4 cats cost on the used market? From a spec-racer conversion or a wreck perhaps.

...

Not sure about a complete set of 4 cats. I can tell you from recent personal experience that used cats are highly valuable, even very old ones. Three weeks ago I got home late Friday from a business trip to Northern Virginia. I started my 1988 Toyota pickup and I sounded and ran terrible. Somebody hacked off the original catalytic converter! Toyota dealer estimated it was worth at least $50 scrap value for the platinum and palladium. As the economy has deteriorated, the price of precious metals has skyrocketed in the past few years and catalytic converter theft has become big business.

The good news is anyone removing their cats can get a lot of money for them, and Porsches are low enough to the ground it's extremely difficult for someone to get under there and steal a catalytic converter

Thanks for the tip, but i live in Guatemala, so i think is goin to be hard to sell them. Any way I´m thinking in eliminating the secondary one`s (pre muffler)

I have an account on Ebay, so i will try to put them on sale there

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  • 2 months later...
...

What would a complete stock set of 4 cats cost on the used market? From a spec-racer conversion or a wreck perhaps.

...

Not sure about a complete set of 4 cats. I can tell you from recent personal experience that used cats are highly valuable, even very old ones. Three weeks ago I got home late Friday from a business trip to Northern Virginia. I started my 1988 Toyota pickup and I sounded and ran terrible. Somebody hacked off the original catalytic converter! Toyota dealer estimated it was worth at least $50 scrap value for the platinum and palladium. As the economy has deteriorated, the price of precious metals has skyrocketed in the past few years and catalytic converter theft has become big business.

The good news is anyone removing their cats can get a lot of money for them, and Porsches are low enough to the ground it's extremely difficult for someone to get under there and steal a catalytic converter

Thanks for the tip, but i live in Guatemala, so i think is goin to be hard to sell them. Any way I´m thinking in eliminating the secondary one`s (pre muffler)

I have an account on Ebay, so i will try to put them on sale there

Well, good news, I finaly did the job (pay for that), and elimnated the secondary cats.

1. The sound got troatier, its a litter bet more high, nothing anoying. I really like the sound. more sporty

2. HP Gains?? dont think so, maybe 1 o 2, but i think is more the efect of the better sound.

3. For shure, i took out a good 3 lb from the rear of the car.

I also painted the brake calipers in red..... I love the new look

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