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      05-26-2020, 12:39 PM   #1
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Best high flow downpipes

Hey everyone,
I am in the market for a new downpipe. I think I am leaning towards a high flow cat instead of catless. Anyone have any good suggestions on the best high flow cats? I heard VRSF is good but I haven't done too much research yet. Thanks!
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      05-26-2020, 12:56 PM   #2
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Quote:
Originally Posted by Baggs805 View Post
Hey everyone,
I am in the market for a new downpipe. I think I am leaning towards a high flow cat instead of catless. Anyone have any good suggestions on the best high flow cats? I heard VRSF is good but I haven't done too much research yet. Thanks!
Best in terms of what? Power, CEL, sound?
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      05-26-2020, 12:56 PM   #3
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you're way off. better do more research.

Fabspeed, Active Autowerke, CG Precision DS-1

Personally, I'd do Active Autowerke

Last edited by alohasurftoad; 05-26-2020 at 02:07 PM..
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      05-26-2020, 12:59 PM   #4
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Quote:
Originally Posted by Baggs805 View Post
Hey everyone,
I am in the market for a new downpipe. I think I am leaning towards a high flow cat instead of catless. Anyone have any good suggestions on the best high flow cats? I heard VRSF is good but I haven't done too much research yet. Thanks!
I have the Fabspeed Sport Cat and it is lovely. One of the closest options you can get to having catless while still retaining the cats. Excellent quality and customer service from them as well. One of the higher priced options for sure but the product you receive is excellent and performs excellent.
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      05-26-2020, 01:07 PM   #5
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Best in terms of what? Power, CEL, sound?
I would say sound probably, power woulod be nice too but sound is my priority I think.
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      05-26-2020, 01:23 PM   #6
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Quote:
Originally Posted by Baggs805 View Post
I would say sound probably, power woulod be nice too but sound is my priority I think.
Power is the same with any proven brand

Sound is subjective if you are looking for a deeper tone. Wagner is a good option. If you are looking for a higher pitch more aggressive sound, VRSF is my go-to choice
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      05-26-2020, 02:33 PM   #7
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Quote:
Originally Posted by Baggs805 View Post
I would say sound probably, power woulod be nice too but sound is my priority I think.
Honestly the catted are all going to be very similar and nearly negligible differences in power for a stock turbo application. More important IMO is the fitment and quality (assuming you do not have emissions considerations).

Sound will vary slightly between catted depending on cell county/density and the shape of the DP, but with a stock exhaust, they are all going to sound the same and nearly no change from stock. If you have a aftermarket exhaust, the change from OEM to aftermarket catted will be more pronounced, as will the difference between the catted options.

Quote:
you're way off. better do more research.

Fabspeed, Active Autowerke, CG Precision DS-1

Personally, I'd do Active Autowerke
+1. And not to be "that guy" but you are supposed to do research first, then post on the forum with a question. Not the other way around.

Also a +1 for fabspeed since that's what i have, but any of the 3 listed above are high quality pieces.
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      05-26-2020, 03:07 PM   #8
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go vrsf catless with the dinan freeflow everyone says my car sounds really good sounds a lot better than my buddies m sport exhaust, and performance-wise I keep up with him hes fbo mhd 2+ and I have Intake, catless dp, dinan s1, and xhp transmission tune with a passenger in the car he only starts pulling away around 100. Btw if you just started modding your car buy the transmission tune worth every penny if I knew how good it was that would have been the first thing I would install, whole different car after that tune.
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      05-26-2020, 11:22 PM   #9
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I bought a $200 cat-less dp off eBay, quality was good, all welds are good. Its been half a year and no issues. If ur going catless its hard to justify paying way more for the same thing.
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      05-26-2020, 11:30 PM   #10
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VRSF quality is questionable- for Catless, it’s fine, but for Catted, I would go with a more reputable brand, especially at the cost you’re paying.
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      05-27-2020, 02:14 AM   #11
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Best high flow cats? I'm assuming you don't want a CEL light either. If so, these are the best catted downpipes you can get

HJS Euro 6 downpipe with both a 200 and 100 cell HJS cat. Best on the market cats available. OEM looks and fitment. $1500. I have this. It's exceptional in terms of quality, sound, and performance.

Fabspeed downpipe with single 200 cell HJS. $1400.

Active Autowerkes catted DP with GESI cat. Don't know the cell count, not reported by AA.
Reportedly good cats. $1000.

You get what you pay for when it comes to catted DPs.
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      05-27-2020, 09:47 AM   #12
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VRSF was the "best" for me due to price. Install was difficult on ramps but it works great. I just can't see spending $1000+
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      05-27-2020, 11:18 AM   #13
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Quote:
Originally Posted by Baggs805 View Post
Hey everyone,
I am in the market for a new downpipe. I think I am leaning towards a high flow cat instead of catless. Anyone have any good suggestions on the best high flow cats? I heard VRSF is good but I haven't done too much research yet. Thanks!
Just installed my VRSF Catted DP paired with MPE I love the sound especially when in Sport its sounds very refined and just enhanced the MPE, the cold starts were awesome (wife wasn't a fan neighbors either I imagine)

As far as quality go's I can't really say its seems good so far but i've only driven with it for 1k miles (No Check engine light but i'm also tuned with MHD Stage 2+ so i'm sure that helps) I can definitely feel the difference in tq. and whp.

Price wise you cant beat it but then again you get what you paid for but so far I love it, it's probably my favorite mod thus far. I'll post if anything go's wrong for sure.
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      05-27-2020, 11:29 AM   #14
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Quote:
Originally Posted by XutvJet View Post
Best high flow cats? I'm assuming you don't want a CEL light either. If so, these are the best catted downpipes you can get

HJS Euro 6 downpipe with both a 200 and 100 cell HJS cat. Best on the market cats available. OEM looks and fitment. $1500. I have this. It's exceptional in terms of quality, sound, and performance.

Fabspeed downpipe with single 200 cell HJS. $1400.

Active Autowerkes catted DP with GESI cat. Don't know the cell count, not reported by AA.
Reportedly good cats. $1000.

You get what you pay for when it comes to catted DPs.
I wouldn’t go with anything but named brand for Catted - but what proof do we have that HJS cats are ‘high quality’ what are we substantiating this on?
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      05-27-2020, 11:45 AM   #15
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Quote:
Originally Posted by Randy Johnson View Post
VRSF was the "best" for me due to price. Install was difficult on ramps but it works great. I just can't see spending $1000+
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      05-27-2020, 11:47 AM   #16
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I'm running an AWE full catback exhaust and the the next thing I do is a fabspeed catted downpipe. I have one friend who has had it and has NEVER seen a CEL and always passes emissions out here in PA. The cat give 93% of the power gains as a catless one would.

+1 for Fabspeed
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      05-27-2020, 02:58 PM   #17
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Quote:
Originally Posted by AmuroRay View Post
I wouldn’t go with anything but named brand for Catted - but what proof do we have that HJS cats are ‘high quality’ what are we substantiating this on?
HJS, a German company, is pretty well known in Europe and their cats pass MOT and related European inspection and emissions requirements as well as being well known in the motorsport industry where cats are required for racing events. They also have a good track record with the BMW crowd for the lack of failures of the catalyst in tuned BMWs.

Cheaper catted DPs come with cheaper cats. Those cats usually can't handle the heat of a tuned turbo over the long term and they can and do fail, with either the catalyst breaking a part or simply melting.

The HJS Euro 6 (and Akrapovic; same DP, just rebranded), Fabspeed, and AA are the only ones that won't throw a CEL in most cars. They also use name brand cats that have good track records.

I've had my HJS Euro 6 for nearly 2 years and it's never thrown a CEL and I don't have a flash tune, just the Dinan S2 piggyback. The Dinan doesn't have the ability to clear codes.


For me, I'd steer clear of VRSF. Their track record with fitment and quality has been hit and miss. I'd also question the cats their using. Wagner also has reported issues of fitment with the O2 sensors. Both Wagner and VRSF tend to throw CELs as well.
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      05-27-2020, 03:04 PM   #18
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Quote:
Originally Posted by XutvJet View Post
HJS, a German company, is pretty well known in Europe and their cats pass MOT and related European inspection and emissions requirements as well as being well known in the motorsport industry where cats are required for racing events. They also have a good track record with the BMW crowd for the lack of failures of the catalyst in tuned BMWs.

Cheaper catted DPs come with cheaper cats. Those cats usually can't handle the heat of a tuned turbo over the long term and they can and do fail, with either the catalyst breaking a part or simply melting.

The HJS Euro 6 (and Akrapovic; same DP, just rebranded), Fabspeed, and AA are the only ones that won't throw a CEL in most cars. They also use name brand cats that have good track records.

I've had my HJS Euro 6 for nearly 2 years and it's never thrown a CEL and I don't have a flash tune, just the Dinan S2 piggyback. The Dinan doesn't have the ability to clear codes.


For me, I'd steer clear of VRSF. Their track record with fitment and quality has been hit and miss. I'd also question the cats their using. Wagner also has reported issues of fitment with the O2 sensors. Both Wagner and VRSF tend to throw CELs as well.
Everything in this post is correct. You get what you pay for, not only in quality of catalyst material, but in fitment and quality of the DP itself. I would add as FYI that users reported CEL from ER catted as well.
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      05-28-2020, 08:47 PM   #19
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If you are going catted to stay emissions ready you will need to follow the above advice and pay $1000+. If you are going catted just to balance your want of performance and exhaust note while still being semi earth friendly than vrsf or any catted Dp sub-$1k will be your friend.

I'm in the second boat. Plan to throw in a vrsf cat, but I'm currently chasing an oil leak lol. Maintenance first.
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      05-28-2020, 09:35 PM   #20
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Quote:
Originally Posted by Baggs805 View Post
Hey everyone,
I am in the market for a new downpipe. I think I am leaning towards a high flow cat instead of catless. Anyone have any good suggestions on the best high flow cats? I heard VRSF is good but I haven't done too much research yet. Thanks!
I have a Fabspeed HJS catted downpipe. Very high quality and perfect fitment. Amazing sound coupled with my axle-back M Performance exhaust. It sounds so great that I used BootMod3 to completely turn off the burbles and pops in my tune. Now when I step on it I can hear the pure sound of the exhaust system. It's not a noise maker. It's a performance sports sedan!

Fabspeed has an amazing facility outside of Philadelphia where BMW is on the low end of the brands for which they do custom fabrications. Fabspeed is the big North American distributor of European HJS cats. They build HJS cats into custom exhausts for Ferrari, Lamborghini, McLaren, Porsche, etc. They have an awd dyno to test and fine tune all of their work.

No emissions worries and no performance issues. Fabspeed dyno tested their catted downpipe versus their catless and got 93% of the performance of catless. I have my doubts about the performance of other catted downpipes because I haven't heard of any others dyno testing. I assume that if their performance numbers were any good then it would be part of their product marketing.

Guys often point at the list price of the Fabspeed HJS catted downpipe. The cost was a big stretch for me. I ultimately justified the purchase three ways.

1) Throughout the year Fabspeed has sales up to 15% off.

2) Without emissions concerns, I was able to sell my stock catted downpipe and put the money to offsetting the cost of the Fabspeed.

3) Finally, I read multiple accounts of guys in my state and neighboring states who were paying labor and dealing with the hassle of swapping their stock catted downpipe back on and then off again every time they needed to pass emissions. That wasn't a regular expense or hassle that I wanted. I just want to drive my car and enjoy it!

Those three totaled up to justify the expense to me. It was a great decision.

Hope this helps!
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      05-28-2020, 09:39 PM   #21
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Quote:
Originally Posted by Baggs805 View Post
Hey everyone,
I am in the market for a new downpipe. I think I am leaning towards a high flow cat instead of catless. Anyone have any good suggestions on the best high flow cats? I heard VRSF is good but I haven't done too much research yet. Thanks!
Fabspeed HJS Catted Downpipe
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      05-29-2020, 03:33 PM   #22
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Don't own a Fabspeed or an HJS, but if price isn't too big of an issue, I recommend making the jump to either of those brands. I'd avoid the VRSF catted downpipe - I'm sure most of their products are fine, but I've read one too many complaints/red flags regarding their build quality/fitment issues that I'd avoid them altogether. Ironically, I have their FMIC, so take it for what it is.

I personally have the Wagner catted DP - it was on sale and I've heard Wagner is a reputable brand. From a technical standpoint, so far so good, but need to play around with it a bit more. First impressions, the sound is very underwhelming, but that's most likely due to being spoiled by my previous catless setup.

And as someone else has mentioned, you may run into O2 sensor fitment issues. The location of the lower O2 sensor is highly questionable. The O2 sensor placement alone (assuming no logical explanation for their design choice - it's not like it deletes the CEL lol) makes me question the brand. I know that comes off a bit harsh/pretentious, but when you see the sensor cable being bent over 90 degrees while touching the exhaust manifold just so it can BARELY connect to the other end, you have to wonder why they haven't made any revisions (unless they already have and I'm unaware - I bought mine a month back in April).
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