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We've had no emissions or monitor reset issues using Euro Emissions Spec HJS cats on 911s. They pass emissions, make power, and have no issues (from our own product testing) with the monitors resetting. Although, P-cars have monitor reset information (instruction set) that makes it pretty easy, especially on a dyno.

I do have a 2019 STi, making 500whp with an HJS cat without issue, but it was tuned a long while ago and we have no additional testing/tuning on the schedule for that car right now.
 

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We've had no emissions or monitor reset issues using Euro Emissions Spec HJS cats on 911s. They pass emissions, make power, and have no issues (from our own product testing) with the monitors resetting. Although, P-cars have monitor reset information (instruction set) that makes it pretty easy, especially on a dyno.

I do have a 2019 STi, making 500whp with an HJS cat without issue, but it was tuned a long while ago and we have no additional testing/tuning on the schedule for that car right now.
Thanks for your feedback.

Any chance you can procure one of these cats for me? I tried reaching out to fabspeed who is listed as a supplier and they ghosted me after 2 emails so I took that as they aren't interested.
 

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Thanks for your feedback.

Any chance you can procure one of these cats for me? I tried reaching out to fabspeed who is listed as a supplier and they ghosted me after 2 emails so I took that as they aren't interested.
Sorry to say, but they are your best bet. Our next delivery date is out months, and I expect it to be pushed out even more.

Normally I'd have no issue with helping out, but with current conditions I'd be hanging out to dry a customer who has already paid and has been waiting. Crazy world we live in right now :/
 

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Sorry to say, but they are your best bet. Our next delivery date is out months, and I expect it to be pushed out even more.

Normally I'd have no issue with helping out, but with current conditions I'd be hanging out to dry a customer who has already paid and has been waiting. Crazy world we live in right now :/
Yeah, I hear you on that. Thanks anyways, I appreciate your honesty.

Over the weekend I had an idea. The B58 in BMWs and the Supra has a pretty high flowing OEM cat, at least good for 450whp. I'm going to see if I can snag one and weld it into my downpipe and report my results. It should be more efficient than any aftermarket cat I can readily buy, so it might be enough to make the Oxygen sensor monitor happy while also flowing enough that I don't need to swap it out after the emissions test. Time to get creative.
 

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Yeah, I hear you on that. Thanks anyways, I appreciate your honesty.

Over the weekend I had an idea. The B58 in BMWs and the Supra has a pretty high flowing OEM cat, at least good for 450whp. I'm going to see if I can snag one and weld it into my downpipe and report my results. It should be more efficient than any aftermarket cat I can readily buy, so it might be enough to make the Oxygen sensor monitor happy while also flowing enough that I don't need to swap it out after the emissions test. Time to get creative.
Maybe. Those are going to be 600 cel cats, but if they have a higher flow rate (usually dictated by diameter with the same cel count) then there is an opportunity for gains.
 

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We've had no emissions or monitor reset issues using Euro Emissions Spec HJS cats on 911s. They pass emissions, make power, and have no issues (from our own product testing) with the monitors resetting. Although, P-cars have monitor reset information (instruction set) that makes it pretty easy, especially on a dyno.

I do have a 2019 STi, making 500whp with an HJS cat without issue, but it was tuned a long while ago and we have no additional testing/tuning on the schedule for that car right now.
P car you say :unsure:
Under the KillerB brand or something else?
Got anything for the 987.2?
 

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I am also tuned on Green Speed with 20 STI, Cobb GESI DP, 3" Single Out Tomei, Cobb SF, AEM Drop In Pump and also receiving a P0420 code. It has been protuned but I'm willing to seek other e-tuning avenues to get this to stop. I'm super pissed that I didn't know that Cobb discon'd the GESI because it wasn't working as intended - would have just left my stock one in.
 

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I am also tuned on Green Speed with 20 STI, Cobb GESI DP, 3" Single Out Tomei, Cobb SF, AEM Drop In Pump and also receiving a P0420 code. It has been protuned but I'm willing to seek other e-tuning avenues to get this to stop. I'm super pissed that I didn't know that Cobb discon'd the GESI because it wasn't working as intended - would have just left my stock one in.
Go with Mike Botti. He tuned mine and no light after I mentioned it and he scaled the o2 sensors. It's not the dp its cobb green.
 

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Any updates for finding a cat that won’t throw p420 code?
From reading other threads, it looks like it can be tuned out (not suppressing the code).

I ended up just welding in a stock cat and testing my tune with P0420 enabled. I have no CEL, but my catalyst and oxygen sensor monitors both won't get into ready state, even with the stock cat. So looks like all my hardware options have been exhausted at this point, time to revert to green speed compliance and retune.
 

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From reading other threads, it looks like it can be tuned out (not suppressing the code).

I ended up just welding in a stock cat and testing my tune with P0420 enabled. I have no CEL, but my catalyst and oxygen sensor monitors both won't get into ready state, even with the stock cat. So looks like all my hardware options have been exhausted at this point, time to revert to green speed compliance and retune.
Thanks for getting back to me. By chance do you know what the stock cat can handle power wise before it gets damaged?
 

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Thanks for getting back to me. By chance do you know what the stock cat can handle power wise before it gets damaged?
Better to consult a tuner on that one. But in my opinion, if a downpipe is required to run higher boost on stock turbo, then it isn't much. Not sure how much that has to do with the larger downpipe diameter or a higher flowing cat.
 
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