Active Autowerke F8x BMW M2C / M3 / M4 Downpipes w GESI G-Sport Cats

[GuyLedouche]

Originally Posted by DeathBear

Any update on passing emissions? Interested in the down pipes but not if it's not gonna pass emission. Are the down pipes the issue or is it related to something else?

Thanks!

Fitment is spot on now. I still have 3 not ready emission sensors but working on it.

[mike@x-ph.com]

Originally Posted by GuyLedouche

Fitment is spot on now. I still have 3 not ready emission sensors but working on it.

[TR930]

Originally Posted by GuyLedouche

Fitment is spot on now. I still have 3 not ready emission sensors but working on it.

Is this a one off occurrence or are people having trouble with emissions?

[mike@x-ph.com]

Originally Posted by TR930

Is this a one off occurrence or are people having trouble with emissions?

no issues I'm aware of and I used their downpipes on my G82

[hellokitty]

Originally Posted by TR930

Is this a one off occurrence or are people having trouble with emissions?

No issues with emissions here. Never once experienced a CEL.

[mike@x-ph.com]

Originally Posted by hellokitty

No issues with emissions here. Never once experienced a CEL.

[GuyLedouche]

Originally Posted by TR930

Is this a one off occurrence or are people having trouble with emissions?

No issues anymore after the initial fitment problems. Passed emissions with no problem.

[mike@x-ph.com]

Originally Posted by GuyLedouche

No issues anymore after the initial fitment problems. Passed emissions with no problem.

[TR930]

Looking forward to getting these soon.

[mike@x-ph.com]

Originally Posted by TR930

Looking forward to getting these soon.

In stock

[Mikeymymo]

Has anyone tried to run these AA DPs with the new AWE Switchpath? Could that potentially be a fully emission passable setup?

[mike@x-ph.com]

Originally Posted by Mikeymymo

Has anyone tried to run these AA DPs with the new AWE Switchpath? Could that potentially be a fully emission passable setup?

Emission depends on your state; CA is the trickiest.

[Mikeymymo]

Originally Posted by mike@x-ph.com

Emission depends on your state; CA is the trickiest.

That's what I unfortunately have to deal with I wonder how those two together would sound together

[hellokitty]

Originally Posted by Mikeymymo

That's what I unfortunately have to deal with I wonder how those two together would sound together

Honestly the only variable would be the exhaust as opposed to both exhaust and downpipe.

A catted downpipe will make any exhaust sound pretty darn good. The reason why exhausts sound like crap is due to catless downpipes.

That's why exhaust manufacturers add resonators etc. to factor in the rasp of a catless setup.

AA paired up with my Akra Evo setup is pretty much the perfect combination. No rasp, deep, drone free and it screams when you get on it hehe

[mike@x-ph.com]

Originally Posted by hellokitty

A catted downpipe will make any exhaust sound pretty darn good. The reason why exhausts sound like crap is due to catless downpipes.

Agree!

The catted downpipes transformed my setup of resonated equal length W/ REMUS axle-back from okay to absolutely amazing!

[TR930]

Originally Posted by mike@x-ph.com

Agree!

The catted downpipes transformed my setup of resonated equal length W/ REMUS axle-back from okay to absolutely amazing!

How much are those resonated equal length mid pipes? Shoot me a PM.

[mike@x-ph.com]

Originally Posted by TR930

How much are those resonated equal length mid pipes? Shoot me a PM.

Done

[PandaxF82]

Originally Posted by mike@x-ph.com

Agree!

The catted downpipes transformed my setup of resonated equal length W/ REMUS axle-back from okay to absolutely amazing!

Shoot me a DM as well including shipping to 91709.

[mike@x-ph.com]

Originally Posted by PandaxF82

Shoot me a DM as well including shipping to 91709.

Done

[Bettertomorrow]

Originally Posted by hellokitty

No issues with emissions here. Never once experienced a CEL.

I've been contemplating DP options (want to go stage 2 or 2+ and call it a day). From my search (correct me if I am wrong), AA GESI downpipe has 400 cell. And stock downpipe also has 400 cell, and this is probably why there would be no CEL.

So the obvious question is this. Putting potentially different material aside, 400 cell per square inch is, 400 cell per square inch, physical barrier does not change. Does $3000 AA GESI flow so much better than stock?

Another question is this. AA Single Midpipe advertises 18+ WHP over stock & 30+ LB-FT over stock (when paired with exhaust, although I think it is marketing, stock exhaust flows just fine, just doesn't sound great). If single MP is free flowing as the following video, is stock downpipe good enough for Stage 2 or Stage 2+ with Single MP? (I asked MHD and MHD told me to use Stage 1, appreciated their candid response).

So here is what I gather so far.
Stage 2 or Stage 2+ would benefit from DP if DP is 200 cell or straight. But there is no proven & convenient way to work around emission (other than reverting to stock DP, stock tune, so forth).

Stock DP probably flows similar to AA GESI DP. Meaning I could get AA GESI. run Stage 2, and be able to say, "I am stage 2 with DP"! But the performance may be similar to running Stage 2 with stock DP.

Single MP is freer flowing (perhaps in the realm of having 200 cell DP with stock MP?), could support Stage 2, and still keep emission happy as long as I don't disable 2nd O2s. (I think I am emission ready with Stage 1 according to MHD scan).

[TR930]

Originally Posted by Bettertomorrow

I've been contemplating DP options (want to go stage 2 or 2+ and call it a day). From my search (correct me if I am wrong), AA GESI downpipe has 400 cell. And stock downpipe also has 400 cell, and this is probably why there would be no CEL.

So the obvious question is this. Putting potentially different material aside, 400 cell per square inch is, 400 cell per square inch, physical barrier does not change. Does $3000 AA GESI flow so much better than stock?

Another question is this. AA Single Midpipe advertises 18+ WHP over stock & 30+ LB-FT over stock (when paired with exhaust, although I think it is marketing, stock exhaust flows just fine, just doesn't sound great). If single MP is free flowing as the following video, is stock downpipe good enough for Stage 2 or Stage 2+ with Single MP? (I asked MHD and MHD told me to use Stage 1, appreciated their candid response).

So here is what I gather so far.
Stage 2 or Stage 2+ would benefit from DP if DP is 200 cell or straight. But there is no proven & convenient way to work around emission (other than reverting to stock DP, stock tune, so forth).

Stock DP probably flows similar to AA GESI DP. Meaning I could get AA GESI. run Stage 2, and be able to say, "I am stage 2 with DP"! But the performance may be similar to running Stage 2 with stock DP.

Single MP is freer flowing (perhaps in the realm of having 200 cell DP with stock MP?), could support Stage 2, and still keep emission happy as long as I don't disable 2nd O2s. (I think I am emission ready with Stage 1 according to MHD scan).

This might help. http://speed.academy/how-catalytic-converters-work/

[Bettertomorrow]

That is a great link!!! Very informative, thanks!

Two quotes from that article.

In fact, independent dyno testing has repeatedly proven that most engines produce just as much power when equipped with properly sized high efficiency catalytic converters as they do when running through straight pipes.

Would love to see some dyno charts? Better yet, flow test charts? Just hard to imagine straight pipe flow the same as partially blocked pipe?

"In fact, metal cores experience 15-30 percent less backpressure than a ceramic core of the same size and cell density."
Again, I would like to see some flow charts. I would assume stock M cat may not be as restrictive as wide variety of other cats that this article refers to?

So, my question remains,
someone has free flowing mid-pipe and exhaust (perhaps 15-30 percent) with stock DP
vs
someone has AA GESI DP with stock mid-pipe and stock exhaust (15-30 percent)

Just about the same overall flow? Not trying to cause noise, just trying to gather all the info into one place so another person does not have to spend as much time as I did.