[ElectroGeek]

Dose anyone make downpipes with cats? Is it worth doing or just stick with factory at that point? I don't want to go through the ordeal of finding a shop that will rubber stamp the inspection.

[carseatsm5]

I saw in classifieds someone selling downpipes from Fabspeed that have cats (since sold). I know nothing about this topic but might be what you’re looking for.

[pbonsalb]

Do you want the cats to pass obd2 plug in without a tune or just to eliminate any smell? For the former, Redstar, Fabspeed or AA at $2500+. For the latter, CTS or MAD at $700. I have a set of CTS that I would sell.

[Dasky_spas]

Originally Posted by pbonsalb

Do you want the cats to pass obd2 plug in without a tune or just to eliminate any smell? For the former, Redstar, Fabspeed or AA at $2500+. For the latter, CTS or MAD at $700. I have a set of CTS that I would sell.

RVG seem to be a good value. I'm awaiting install.

[pbonsalb]

VRSF, RVG, MAD are all around $600 for primaries and secondaries — definitely a good value. I love the low speed turbo whistle.

[mike@x-ph.com]

If you are looking for downpipes that do not trigger the check engine light, get the active autowerke

if that's not a concern, get the MAD.

[Info@mad-us.com]

Op, We have 200 cell catted primary's as well as catless secondaries.

https://mad-us.com/mad-bmw-f90-m5-f9...ownpipes-s63r/

https://mad-us.com/mad-bmw-f90-m5-downpipes-s63r/

[NCRob]

Originally Posted by mike@x-ph.com

If you are looking for downpipes that do not trigger the check engine light, get the active autowerke

if that's not a concern, get the MAD.

Subjective question I know, but if I already have catless secondaries is there “much” gain with the 400 AA primaries over the OEM 400?

[mike@x-ph.com]

Originally Posted by NCRob

Subjective question I know, but if I already have catless secondaries is there “much” gain with the 400 AA primaries over the OEM 400?

The AA downpipes are higher flow than catted; there will be a noticeable advantage regardless of your setup.

[NCRob]

Originally Posted by mike@x-ph.com

The AA downpipes are higher flow than catted; there will be a noticeable advantage regardless of your setup.

Thanks! Guess I should ask too “what” will the gain be: increased HP, louder overall, more pops and bangs, etc? And, will it pass inspection? I’ve got MPE as well.
Wish AA sold the primary separate as I assume it would be pointless to change out my MAD secondaries for these.

[pbonsalb]

AA is using Gesi cats, which are very good, but they are 400 cell just like stock. The stock cats were flow tested by one member here, who said they were the highest flowing cats he had ever tested. I would expect minimal to no gain with the AA cats.

Redstar has an option for 300 cell Gesi cats that should offer a slight improvement over stock. Redstar, Fabspeed, Keller and possibly others offer HJS cats, which most think are the best, with 200 cell cats that should offer a modest gain over stock, but at the highest price point.

All the cheap catless down pipes will throw a CEL if that is a concern. I ran CTS Turbo high flow cats for a while. They definitely added some flow — I could hear a little turbo whistle. No smell, but a CEL. MAD offers something comparable. I am selling my CTS if anyone is interested.

My best guess is that catless primaries and secondaries could add as much as 50 rwhp on a tuned stock motor. 200 cell primaries and catless secondaries, maybe 30-40 rwhp. AA primary cats and catless secondaries, maybe 20-30 rwhp.

Next to impossible to find real dyno data. The stock cats are really good. BMS said gains are so minimal as to not be worthwhile on a near stock car. The bang for the buck is catless secondaries — probably gain 10-20 rwhp and you get a faint turbo whistle at low speed/rpm.

Downpipes are all the same. Should be no difference from one brand to another.

[Davewfo]

Question for anyone running the MAD downpipes primary catted and secondary how often do you get CEL codes without a tune? I have a RaceChip black piggyback tune and don't want to do a full-blown tune. I don't want to deal with having to clear CEL codes all the time as I have done that a previous car.

[pbonsalb]

With the CTS high flow cats that should be comparable to the MAD, the CEL appeared within a day.

[Info@mad-us.com]

Originally Posted by Davewfo

Question for anyone running the MAD downpipes primary catted and secondary how often do you get CEL codes without a tune? I have a RaceChip black piggyback tune and don't want to do a full-blown tune. I don't want to deal with having to clear CEL codes all the time as I have done that a previous car.

Without a spacer or tune our downpipes will throw a light. Your best bet is to run just our secondaries and keep the primary stock.

[mike@x-ph.com]

Originally Posted by Davewfo

Question for anyone running the MAD downpipes primary catted and secondary how often do you get CEL codes without a tune? I have a RaceChip black piggyback tune and don't want to do a full-blown tune. I don't want to deal with having to clear CEL codes all the time as I have done that a previous car.

50-100 miles

[916_M5]

Originally Posted by Info@mad-us.com

Op, We have 200 cell catted primary's as well as catless secondaries.

https://mad-us.com/mad-bmw-f90-m5-f9...ownpipes-s63r/

https://mad-us.com/mad-bmw-f90-m5-downpipes-s63r/

Do you have any sound clips with these CATTED DP's installed?

[916_M5]

Originally Posted by pbonsalb

AA is using Gesi cats, which are very good, but they are 400 cell just like stock. The stock cats were flow tested by one member here, who said they were the highest flowing cats he had ever tested. I would expect minimal to no gain with the AA cats.

Redstar has an option for 300 cell Gesi cats that should offer a slight improvement over stock. Redstar, Fabspeed, Keller and possibly others offer HJS cats, which most think are the best, with 200 cell cats that should offer a modest gain over stock, but at the highest price point.

All the cheap catless down pipes will throw a CEL if that is a concern. I ran CTS Turbo high flow cats for a while. They definitely added some flow — I could hear a little turbo whistle. No smell, but a CEL. MAD offers something comparable. I am selling my CTS if anyone is interested.

My best guess is that catless primaries and secondaries could add as much as 50 rwhp on a tuned stock motor. 200 cell primaries and catless secondaries, maybe 30-40 rwhp. AA primary cats and catless secondaries, maybe 20-30 rwhp.

Next to impossible to find real dyno data. The stock cats are really good. BMS said gains are so minimal as to not be worthwhile on a near stock car. The bang for the buck is catless secondaries — probably gain 10-20 rwhp and you get a faint turbo whistle at low speed/rpm.

Downpipes are all the same. Should be no difference from one brand to another.

Very well explained.

[Dasky_spas]

I get my car back eod Tuesday wth the rvg 200 dp installed. Will see if there's a cel or other issue then, or if they even fit. Hopefully the do since I already heat coated them.

[pbonsalb]

You will get a CEL but will be helping the environment and there won’t be any gas smell. A tune from outside the US can address the CEL.

[Info@mad-us.com]

Originally Posted by 916_M5

Do you have any sound clips with these CATTED DP's installed?

I do but it's a very short clip a customer on instagram. He's supposed to be making some more videos shorty.


He has our catted primary and secondary. https://www.instagram.com/reel/CwanB...RlODBiNWFlZA==

[CLEbmw]

I just picked up a 2022 M5 Comp. Love the car, but the exhaust note leaves something to be desired. I'm going to daily the car, so I'm on the fence about doing a full exhaust. In looking at downpipe, I definitely do not want to deal with CEL issues. From reading the posts Active Autowerke primary catted won't throw a CEL, but what about Evolution Racewerks?

I saw these, wasn't sure if they would be a close competitor to AA.

https://x-ph.com/evolution-racewerks...EaAvUIEALw_wcB

Thank You!

[nitrous_nit]

Originally Posted by CLEbmw

I just picked up a 2022 M5 Comp. Love the car, but the exhaust note leaves something to be desired. I'm going to daily the car, so I'm on the fence about doing a full exhaust. In looking at downpipe, I definitely do not want to deal with CEL issues. From reading the posts Active Autowerke primary catted won't throw a CEL, but what about Evolution Racewerks?

I saw these, wasn't sure if they would be a close competitor to AA.

https://x-ph.com/evolution-racewerks...EaAvUIEALw_wcB

Thank You!

From what I read from this post, a primary non stock cat doesn't seem worth it to gain minimum gains, best bang for buck is catless secondaries:

https://f90.bimmerpost.com/forums/sh...0#post30375330