[MrPickles]

Originally Posted by mike@x-ph.com

Done

Took the dive and placed my order! Shame it will have to stay in the box till spring. But then again, it will give me time to properly break the car in before install. I'll just stare at it in the box till then... lol

[mike@x-ph.com]

Originally Posted by MrPickles

Took the dive and placed my order! Shame it will have to stay in the box till spring. But then again, it will give me time to properly break the car in before install. I'll just stare at it in the box till then... lol

Congrats

[Soylent]

Looking at the inside of these downpipes it's amazing that anything flows through them and why catless are so loud.

[dasistato]

Just installed my AA DP today. Loving the sound, burbles and a little more power. Drove around for 20-25mins no CEL, nothing unusual.

Installation is fairly easy. I know there are DIY videos but still some pointers below because I got stuck a few times:

-2x4 wood pieces can be used to drive the front up to ramp(from Harbor freight). I wasn't sure if i'd have enough room under the car so I decided to jack it and put jackstands as well.

-The middle area plate with 4 quarter eclipse seemed to be safe floorjack point to raise the car further. No issues.

-You can losen the bolt on v clamp but DP wont move unless v clamp becomes loose. So after you losen the V clamp bolt, it may not move at all, you need to pry it from the bottom to pop it out, dont be afraid.

-The nut that holds the mid pipe is easy to get off but its fragile, dont over tighten it, it will break. :/

- DP to MP clamp is easy to remove but takes some wiggling to up and down side to side to get the DP off MP.

aside from what i mentioned above, following the BMW fanatic video on this installation for m340i is spot on.

[Rdurty2]

Originally Posted by Vccc34z

I need information on this also

What information exactly. That person was initially incorrect thinking that stock cat is 400. Stock cat is 700. He even updated the post you quoted with the correct info.

So AA has plenty more flow.

[Info@mad-us.com]

Originally Posted by Soylent

Looking at the inside of these downpipes it's amazing that anything flows through them and why catless are so loud.

Agreed/

[Brett_C_F30_G42]

I’m running a MAD catless downpipe for the last couple months and to be fair I don’t mind the smell or sound. To me, it’s better to go catless due to the lower prices and slightly better tq/hp increase. It doesn’t matter if you just want a baseline build but once you start going hardcore modding I suggest catless (thought it can be done with a catted downpipe and even stock downpipe). It’s just, at least to me, there’s only so far you can go catted before you need catless but it’s up to the builder and the builder’s preferences. The only downside to the catless downpipe is the CEL (and no, not even a O2 sensor bung deletes the CEL; the car’s ECU is too smart for it). The only way to get rid of it would be to flash & get rid of the code permanently (with a FEMTO unlock and a BM3 flash).

[XC3LLR8]

Originally Posted by Brett_C_F30_G42

I’m running a MAD catless downpipe for the last couple months and to be fair I don’t mind the smell or sound. To me, it’s better to go catless due to the lower prices and slightly better tq/hp increase. It doesn’t matter if you just want a baseline build but once you start going hardcore modding I suggest catless (thought it can be done with a catted downpipe and even stock downpipe). It’s just, at least to me, there’s only so far you can go catted before you need catless but it’s up to the builder and the builder’s preferences. The only downside to the catless downpipe is the CEL (and no, not even a O2 sensor bung deletes the CEL; the car’s ECU is too smart for it). The only way to get rid of it would be to flash & get rid of the code permanently (with a FEMTO unlock and a BM3 flash).

Pretty sure the AA catted DP exceeds the power rating of the B58's internals. Anyone going into the 700's+ is likely not running a catted DP. Below those numbers I think anyone will be hard pressed to feel a power difference between catted and catless; but you're right, there is a big savings in cost.

[mike@x-ph.com]

Originally Posted by XC3LLR8

Pretty sure the AA catted DP exceeds the power rating of the B58's internals. Anyone going into the 700's+ is likely not running a catted DP. Below those numbers I think anyone will be hard pressed to feel a power difference between catted and catless; but you're right, there is a big savings in cost.

+1


99% of the builds will make the same power with catted downpipes vs. catless.

The catless option will make power once you start making serious power with turbo upgrades; at that point, you are probably not even considering catted.

[johnung]

Originally Posted by mike@x-ph.com

+1


99% of the builds will make the same power with catted downpipes vs. catless.

The catless option will make power once you start making serious power with turbo upgrades; at that point, you are probably not even considering catted.

Fabspeed is the only one as far as I know who actually dyno tested their N55 catless downpipe vs their N55 HJS Catted downpipe.

I don’t recall the numbers (I have them somewhere) but the affect of the cat was negligible on performance, especially considering the advantages of a high quality cat like passing emissions and no gasoline smell!

Fabspeed was touting this as a significant feature. Several of the Fabspeed guys during their open house told me that the N55 HJS Catted downpipe is actually their highest volume product.

It is a handmade welded product combining HJS catalytic converters from Europe with Fabspeed’s custom metal fabrication. (Fabspeed is the North American distributor for HJS.) Fabspeed has actually improved manufacturing process over the years. The same veteran experienced welder makes batches of dozens of HJS DPs at a time and uses heavy custom steel welding jigs to assure that they are all identical. Pretty cool to see the process, but it still comes down to experienced welding skill/craftsmanship.

I definitely would not assume that all brands of catted downpipes flow as well as the HJS catalytic converters, which are widely regarded as the best in the world. I’m pretty sure that’s why Fabspeed touts it as a feature, and also why other downpipe manufacturers don’t publish catted vs catless dyno comparisons.

[XC3LLR8]

I'm embarrassed to admit I still haven't installed my AA DP, but my son installed his yesterday on his '23 Supra. Here's a visual of the density between the AA and OEM...

[Dinosoar]

Much more direct entry flow with AA DP than the OE...assuming the Toyota part is one-and-the same as the BMW part.

Question, what HP/TQ increase is expected? I've been researching and not getting a lot of sources, and those that do list is show a range of increase, and no hard number.

[XC3LLR8]

Originally Posted by Dinosoar

Much more direct entry flow with AA DP than the OE...assuming the Toyota part is one-and-the same as the BMW part.

Question, what HP/TQ increase is expected? I've been researching and not getting a lot of sources, and those that do list is show a range of increase, and no hard number.

I think you're likely seeing a range of increases because the DP will provide more benefit with supporting mods. Just a DP alone may only be 15-20 HP, but with a tune maybe double that. However, just a DP will give you faster spool, so there's more benefit than just higher HP numbers.

I finally got around to installing the DP yesterday, and the density between the AA and OEM looks just like what's pictured above.

[Dinosoar]

Originally Posted by XC3LLR8

I think you're likely seeing a range of increases because the DP will provide more benefit with supporting mods. Just a DP alone may only be 15-20 HP, but with a tune maybe double that. However, just a DP will give you faster spool, so there's more benefit than just higher HP numbers.

I finally got around to installing the DP yesterday, and the density between the AA and OEM looks just like what's pictured above.

For me, I'm just looking to get to 300HP/350TQ in my 230. I only want more power. I only assume a quicker spool pushes that torque curve lower in the RPM, but not sure...would be cool if true. It's a lot of cash for a potential 10-15 HP (in a B48), but I want to keep the mods simple too. And some estimates have it only at 5-10HP bump with the four-banger. An advanced piggy-back tune and a DP would get me there easily, I suspect.

[XC3LLR8]

Originally Posted by Dinosoar

For me, I'm just looking to get to 300HP/350TQ in my 230. I only want more power. I only assume a quicker spool pushes that torque curve lower in the RPM, but not sure...would be cool if true. It's a lot of cash for a potential 10-15 HP (in a B48), but I want to keep the mods simple too. And some estimates have it only at 5-10HP bump with the four-banger. An advanced piggy-back tune and a DP would get me there easily, I suspect.

I’m currently loving my ingredients:

JB4 map 4 with E30
xHP transmission flash
AA downpipe

If those same ingredients are available for the 230 then I think you’ll be very happy.

[Dinosoar]

Originally Posted by XC3LLR8

I’m currently loving my ingredients:

JB4 map 4 with E30
xHP transmission flash
AA downpipe

If those same ingredients are available for the 230 then I think you’ll be very happy.

They are, though I may leave tranny alone. I have a Dinan Sport piggyback which is awesome for the price, but it won't get me to 300/350. I am considering that JB4 with the 93 octane map. That with a charge pipe and DP would get me there, I think. CarBahn has their tunes out for both our cars too, not just the M cars!

[kumizi206]

Originally Posted by XC3LLR8

I called Fabspeed to inquire about their downpipe as they use a 200 cell. However, they did not list the G42, but they were curious if the downpipe for the M340i was the same. I called my BMW dealership and confirmed the downpipe part numbers for a G42 M240i and a 2022 M340i are the same.

Now it looks like the two top-tier downpipes - Fabspeed and Active Autowerke - are the ones I'd like to compare.

OEM = 700 cell
Active Autowerke = 400 cell / $1,500
Fabspeed = 200 cell / $1,996

Both guarantee no CEL.

"This downpipe feature German made HJS 200 cell EURO 6 compliant trimetallic catalytic converters. We use 4 in piping from the engine side to the cat, and 3 in tubing from the cat to the rest of the exhaust. Our larger catalytic converters are better because they allow for more exhaust flow and the increased catalysts surface area allows for better exhaust gas filtering which means emissions compliance that will NOT trigger a check engine light. Our Sport Cat Downpipe are a direct bolt-on replacement for the factory M340i catalytic converter.

When we looked at the factory 12” long 700 cell ceramic core cats we immediately found an opportunity for improvement. The OEM Cats restrict exhaust CFM flow, limit sound and worst of all, rob performance. Replacing the OEM cats for a set of Fabspeed Sport Catalytic converter will net you improved performance with absolutely zero fear of a check engine light."

I'm a little concerned I'd be overpaying for the Fabspeed name, as they're selling a $70 K&N drop-in air filter (labeled BMC F1) for $200. LOL

Fabspeed is the only distributor for HJS cats in the US. They'll last longer than any other aftermarket cat I've run over the years. It's not about more hp necessarily.

On my Alfa, the Fabspeed cats were 3x the cost of other ones. If it's only $500 more, I would definitely go that route.

[XC3LLR8]

Originally Posted by kumizi206

Fabspeed is the only distributor for HJS cats in the US. They'll last longer than any other aftermarket cat I've run over the years. It's not about more hp necessarily.

On my Alfa, the Fabspeed cats were 3x the cost of other ones. If it's only $500 more, I would definitely go that route.

So far I've been 100% happy with the Active Autowerke, and with it being around $1,200 and includes a no CEL guarantee I can see no benefit of paying $500 more for another brand.

[TJZ67201]

Could any kind soul post a video of the exhaust sound with AA downpipe?

There are a couple vids on YT for the M340i and tbh, I’d prefer the stock idle sound over the sound of the AA. Maybe it just doesn’t come across as well through video?

[XC3LLR8]

Originally Posted by TJZ67201

Could any kind soul post a video of the exhaust sound with AA downpipe?

There are a couple vids on YT for the M340i and tbh, I’d prefer the stock idle sound over the sound of the AA. Maybe it just doesn’t come across as well through video?

I’m out of town without my car so can’t post a video but I can’t see how anyone wouldn’t prefer the sound with the AA over stock. The only time it sounds a little odd is the first 10-15 seconds on a cold start it sounds a little like a boat with a V8. After that a valve or something changes and it has a nice deep tone. Even raising the RPM a little like it was on cold start doesn’t duplicate the cold sound, so it must be something other than the muffler valve contributing to the sound.

[Zemzam]

Originally Posted by XC3LLR8

The only time it sounds a little odd is the first 10-15 seconds on a cold start it sounds a little like a boat with a V8.

This is accurate. However other than cold start, it sounds very nice to me. I am unable to start my car at all at the moment but will gladly try to get a video once I can. Its really hard to capture sounds like that with a cell phone, because it will automatically cut the levels of the sound in the video in most cases. But I will try once I get this xHP thing figured out.

[Redbeemer]

Originally Posted by XC3LLR8

I called Fabspeed to inquire about their downpipe as they use a 200 cell. However, they did not list the G42, but they were curious if the downpipe for the M340i was the same. I called my BMW dealership and confirmed the downpipe part numbers for a G42 M240i and a 2022 M340i are the same.

Now it looks like the two top-tier downpipes - Fabspeed and Active Autowerke - are the ones I'd like to compare.

OEM = 700 cell
Active Autowerke = 400 cell / $1,500
Fabspeed = 200 cell / $1,996

Both guarantee no CEL.

"This downpipe feature German made HJS 200 cell EURO 6 compliant trimetallic catalytic converters. We use 4 in piping from the engine side to the cat, and 3 in tubing from the cat to the rest of the exhaust. Our larger catalytic converters are better because they allow for more exhaust flow and the increased catalysts surface area allows for better exhaust gas filtering which means emissions compliance that will NOT trigger a check engine light. Our Sport Cat Downpipe are a direct bolt-on replacement for the factory M340i catalytic converter.

When we looked at the factory 12” long 700 cell ceramic core cats we immediately found an opportunity for improvement. The OEM Cats restrict exhaust CFM flow, limit sound and worst of all, rob performance. Replacing the OEM cats for a set of Fabspeed Sport Catalytic converter will net you improved performance with absolutely zero fear of a check engine light."

I'm a little concerned I'd be overpaying for the Fabspeed name, as they're selling a $70 K&N drop-in air filter (labeled BMC F1) for $200. LOL

I had the Fabspeed catted downpipe on my 2016 M235i and liked it and sounded similar to the AA on my M240i. However, I noticed that the Fabspeed started to smell almost immediately and started throwing a cel around 11k miles. Since I have only recently installed the AA on my M240, I can't say it won't throw a cel later on, but I do believe it will not do so in only 11k miles. Also, there is no smell at all with the AA thus far.