X pipe
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
I live in California, so removing the secondary cats makes me nervous even if it's hard to see that they are missing.
Question: Are there any CA residents here who can share their experience with x-pipes and not having the secondary cats?
Another question: Will the NPP in Touring mode still make the exhaust quiet? (asking on behalf of my neighbors
)
Thanks!
Question: Are there any CA residents here who can share their experience with x-pipes and not having the secondary cats?
Another question: Will the NPP in Touring mode still make the exhaust quiet? (asking on behalf of my neighbors
)Thanks!
Yes it's still quiet in Touring mode. The tone changes more than the volume. I'll wager the car is 5% louder.
Whole lotta hand-wringing about nothing. Yes I lived in Los Angeles and yes I swapped the OEM x-pipe.
Intermediate
Joined: Jun 2018
Posts: 48
Likes: 17
From: Brisbane CA
And if so, rather than replace the entire exhaust, couldn't the same thing be achieved by just eliminating the secondary cats?
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
I have never seen the underside of my car so I feel like a bit of a moron: Based on what you say and how it looks, the stock exhaust includes an x-pipe?!?
And if so, rather than replace the entire exhaust, couldn't the same thing be achieved by just eliminating the secondary cats?
And if so, rather than replace the entire exhaust, couldn't the same thing be achieved by just eliminating the secondary cats?
Racer
Joined: Mar 2017
Posts: 297
Likes: 67
From: Coweta, OK
I have never seen the underside of my car so I feel like a bit of a moron: Based on what you say and how it looks, the stock exhaust includes an x-pipe?!?
And if so, rather than replace the entire exhaust, couldn't the same thing be achieved by just eliminating the secondary cats?
And if so, rather than replace the entire exhaust, couldn't the same thing be achieved by just eliminating the secondary cats?
The aftermarket X-Pipe from Speed Engineering is a double X design that gives better sound than a single X.
Intermediate
Joined: Jun 2018
Posts: 48
Likes: 17
From: Brisbane CA
Le Mans Master
Joined: Jun 2016
Posts: 5,431
Likes: 3,982
From: Cincinnati, OH
IMO, I would have just found a shop to cut out the secondary cats and put in a section of pipe. Stock midpipe is an X pipe and you swap in another X pipe.
Any proof these seemingly double x pipe gimmicks actually picks up power worth the purchase price?
Any proof these seemingly double x pipe gimmicks actually picks up power worth the purchase price?
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Le Mans Master
Joined: Jun 2019
Posts: 5,479
Likes: 2,190
From: Loveland
It would be interesting how much it would cost. I did the same thing on a different car. Can hardly beat an X-pipe for $250.
It is possible a shop wouldn't cut out the cats.
The EOS sounds great, not to stupid loud, and a great price.
It is possible a shop wouldn't cut out the cats.
The EOS sounds great, not to stupid loud, and a great price.
Last edited by kodpkd; Apr 3, 2025 at 11:19 AM.
Racer
Joined: Mar 2017
Posts: 297
Likes: 67
From: Coweta, OK
1) Most exhaust shops will not cut out EPA required items to replace with straight pipe. So that could make it difficult.
2) If you do Find one to do it I bet it's more than 250 for the removal/cut/weld/replace.
3) even if the double-X doesn't pick up power it DEFINITELY cleans up sound and changes tone quite a bit. which is why people started designing them versus a Single X.
4) I believe Corsa claimed 10-15hp gain with their Double Helix X. But I don't think it's the Double X so much as the secondary Cat removal that picks up power.
Le Mans Master
Joined: Jun 2016
Posts: 5,431
Likes: 3,982
From: Cincinnati, OH
Few problems here:
1) Most exhaust shops will not cut out EPA required items to replace with straight pipe. So that could make it difficult.
2) If you do Find one to do it I bet it's more than 250 for the removal/cut/weld/replace.
3) even if the double-X doesn't pick up power it DEFINITELY cleans up sound and changes tone quite a bit. which is why people started designing them versus a Single X.
4) I believe Corsa claimed 10-15hp gain with their Double Helix X. But I don't think it's the Double X so much as the secondary Cat removal that picks up power.
1) Most exhaust shops will not cut out EPA required items to replace with straight pipe. So that could make it difficult.
2) If you do Find one to do it I bet it's more than 250 for the removal/cut/weld/replace.
3) even if the double-X doesn't pick up power it DEFINITELY cleans up sound and changes tone quite a bit. which is why people started designing them versus a Single X.
4) I believe Corsa claimed 10-15hp gain with their Double Helix X. But I don't think it's the Double X so much as the secondary Cat removal that picks up power.
Supporting Vendor
Joined: Nov 2015
Posts: 1,263
Likes: 280
From: Orange County, NY
I do have one last brand new made in USA Corsa double helix xpipe if you want the real deal Corsa option and not a Chinese copycat. I won't ship to California btw but for anyone looking here's a link to them on my website:
https://www.corvetteexhaustsystems.c...a-performance/
https://www.corvetteexhaustsystems.c...a-performance/
Le Mans Master
Joined: Jun 2016
Posts: 5,431
Likes: 3,982
From: Cincinnati, OH
I do have one last brand new made in USA Corsa double helix xpipe if you want the real deal Corsa option and not a Chinese copycat. I won't ship to California btw but for anyone looking here's a link to them on my website:
https://www.corvetteexhaustsystems.c...a-performance/
https://www.corvetteexhaustsystems.c...a-performance/
I'll pay for Corsa (and I did on my C5Z) when it comes to something actually engineered like their mufflers, but not for some simple bent midpipe...
