BIG News! The Active Autowerke Catted Downpipes Got Even Better!

[TEH215]

The fact that the secondary cat is removed from the downpipe makes it illegal.

Where is the second cat? Are there 2 in the OEM unit? Honest question.

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[MisterSkiz]

Where is the second cat? Are there 2 in the OEM unit? Honest question.

The OEM downpipe has two catalytic converters built into it - its why its so darn big.

The first cat is before the second oxygen sensor, and then after the sensor there is another one that is not monitored.

The sensor is sandwiched between the two.

 

[TEH215]

Looking back at this thread, I see nowhere that XPH is claiming that the down pipe itself is EPA approved, just the cat (As pictured). So I kinda read it as the converter itself is EPA approved approved but the application is not? I may as well leave the OEM pipe in place since I am not trying to make huge power.

 

[Kracer]

Looking back at this thread, I see nowhere that XPH is claiming that the down pipe itself is EPA approved, just the cat (As pictured). So I kinda read it as the converter itself is EPA approved approved but the application is not? I may as well leave the OEM pipe in place since I am not trying to make huge power.

But since you can't buy the cat alone, you have to replace the whole DP to get it, the EPA claim is kinda misleading, IMO.

 

[razorlab]

I mean, almost everything we do substantial is "not legal".

A tune is def not, yet many do it.

 

[Kracer]

Not saying that you should not do it.

Just saying that honesty counts so the customer knows what they are getting into.

 

[Eastwood]

Hey XPH, you might want to remove this statement from your website, you're setting yourself up for some serious EPA scrutiny:

• Federal law prohibits tampering with emissions control devices; this product is compliant with EPA standards.

Secondary cat is 100% an emissions device. It's been removed from this product and replaced with a straight section of tube (test pipe), that's tampering.

Under federal law, catalytic converters may not be removed
and replaced with "converter replacement pipes' by any person.
The 1990 Clean Air Act Amendments even prohibit private
individuals from installing "converter replacement pipes" on their
own vehicles. Anyone who installs such pipes would violate section
203(a)(3)(A) and (B) of the Clean Air Act (Act).

https://19january2017snapshot.epa.gov/sites/production/files/documents/exhsysrepair.pdf

I get what you're saying here. Catalytic Converter is EPA approved, but is the downpipe with the EPA approved catalytic converter approved? The wording here is important for potential buyers.

Either way, I am in Cali so it doesn't matter to me lol. I know for Cali, people get confused all the time and buy an EPA approved cat for a replacement but will fail smog inspection because CA requires a California compliant EO Carb Number too.

 

[oreobbq]

I can only speak from my experience with 3 AA no CEL guarantee downpipes across 2 different Supras. All three popped CEL errors, although one of them had longer intervals between errors. Part of my troubleshooting also included replacing the o2 sensor. I’ve damn near become an expert on DP and exhaust installation lol.

A reputable vendor counts for a lot and I would even recommend buying the DP as long as your expectations are realistic. I’d guess most people do not have the time or energy to experiment with warranty replacements. The materials and design are solid and a realistic expectation is to have periods of time without a CEL.

 

[Extreme Power House]

I can only speak from my experience with 3 AA no CEL guarantee downpipes across 2 different Supras. All three popped CEL errors, although one of them had longer intervals between errors. Part of my troubleshooting also included replacing the o2 sensor. I’ve damn near become an expert on DP and exhaust installation lol.

A reputable vendor counts for a lot and I would even recommend buying the DP as long as your expectations are realistic. I’d guess most people do not have the time or energy to experiment with warranty replacements. The materials and design are solid and a realistic expectation is to have periods of time without a CEL.

which cats?

 

[Tlminh]

Welp, just got a CEL with the newer AA catted DP

Purchased new from one of the vendors in Nov 2024, installed Nov 15, 2024.

Just popped a p0141 code on Dec 14th 2025 and only 1400 miles. I reached out to the vendor to discuss my options

Oh, btw, i drive like a grandma and definitely dont push it lol

 

[Mad0zodi]

I've had the same thing happen to me twice. The first time, I just disconnected then reconnected the battery and the CEL went away after a few drives. The second time, the light came on after putting load on the engine before the coolant got up to temperature...didn't go past 3K rpm. Rinse and repeat with the battery (for more than 30 seconds this time) and that cleared it.

Since then, I've just stayed out of boost until the coolant gets up to operating temperature and the CEL hasn't come back.

CELs on my N55 drove me insane!

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