M&K 3.2 active exhaust

[freeform911]

Curious if any one has installed this active exhaust on a Carrera?

I'm looking for a little more sound at WOT..
I have a bypass pipe(test pipe) and a dynomax 1 in 2 out muffler..
Wondering if M&K premuffler with a vacuum valve would give more sound at WOT in the higher rpm range..

Would appreciate anyone with first hand experience to give feedback..

TIA Steve

[famoroso]

I have one on order for my '87. I'll post up my thoughts in a couple weeks.

By design, the Active Exhaust will give more sound at WOT ay higher revs... https://mkexhaust.com/active-exhaust-with-pre-muffler/

[darrin]

I have an M&k active cat coupled with a stock muffler (original, with 180k miles) it provides a nice sound boost when I'm "on" the throttle, but quiets back down when cruising. That's with my noise-reducing baffle installed on the active exhaust pipe -- understand it'll get a fair bit louder (with VERY minimal HP improvement) with the baffle off, but haven't had a reason to try yet, as I'm completely satisfied with the transformation it gives with the baffle on.

[freeform911]

darrin...
Would you say with the valve opened it sounds like having a muffler bypass? (which sounds horrible)..
Is there anything you could compare the sound to?
Would you say it's worth the $750?

[freeform911]

famoroso...would love to hear your thoughts when you get it installed...

[darrin]

Originally Posted by freeform911

darrin...
Would you say with the valve opened it sounds like having a muffler bypass? (which sounds horrible)..
Is there anything you could compare the sound to?
Would you say it's worth the $750?

Haven't heard a muffler bypass so can't directly comment on the differences, but mine sounds far from horrible (to me) -- indeed, hearing the bypass open causes me to want more (lizard brain trigger?) and find excuses to open throttle/bypass valve. Keep in mind that only a fraction of the exhaust diverts through the bypass when activated. Also, it's my understanding that Brian at M&K feels the cat compromises the quality of sound produced by the bypass (i.e. the premuffler version sounds "better")

[freeform911]

darrin...
Thanks for the info...interesting that not all gasses go through the valve when open...sounds fun��...I may gamble and pick one up...

Was it difficult to run the vacuum line?
Thanks again...

[RarlyL8]

The Active Exhaust System for SC/Carrera was developed using a dyno to find the optimal flow for creating max horsepower. When the valve is open the exhaust is partially waste gated resulting in a better sound than a straight pipe as some volume still passes through the rear muffler. Final volume is adjustable using the tailpipe baffle, from sport to track mode. Max power is achieved with the baffle in place, no more power is produced with the baffle removed only more sound. It is suggested to change the chip to take full advantage of the extra flow.
Vac line is included and easily connects with a T fitting (also included) to the throttle body vac port.

[freeform911]

Thanks Rarly8...
So even though I already have a semi sporty sounding muffler, I will still get more sound when the valve opens?

I keep going back to your video to listen, Unfortunately my cars louder at idle so hard to picture in how it would sound...

You would happen to have sound clip with 1 of your sport mufflers��

TIA Steve

[RWebb]

hp vs rpm over other options?

[darrin]

Originally Posted by freeform911

Thanks Rarly8...
So even though I already have a semi sporty sounding muffler, I will still get more sound when the valve opens?

I keep going back to your video to listen, Unfortunately my cars louder at idle so hard to picture in how it would sound...

You would happen to have sound clip with 1 of your sport mufflers��

TIA Steve

Steve -- yes, when the valve opens a significant % of the exhaust gas goes straight out the bypass pipe and completely skips the muffler -- very noticeable to me with the bypass pipe's sound arrester in place, suspect it's a LOT louder if arrester is removed. If you're looking for a LOUD setup, keep an eye out for used Bizmoto Pulse Chamber exhaust -- understand those are LOUD

[freeform911]

Steve -- yes, when the valve opens a significant % of the exhaust gas goes straight out the bypass pipe and completely skips the muffler -- very noticeable to me with the bypass pipe's sound arrester in place, suspect it's a LOT louder if arrester is removed. If you're looking for a LOUD setup, keep an eye out for used Bizmoto Pulse Chamber exhaust -- understand those are LOUD

darrin..
the Bizmoto seems like a muffler delete to me...loud all the time...
I ran a muffler delete for a very short period...to loud n was not pleasing to listen to...neighbors didn't like it much either...Hahaha

[RarlyL8]

Yes the sound when the valve is open is adjustable. If you want it track loud then remove the baffle.
Dyno testing was done using a stock OE rear muffler. The object was to allow the enthusiast to keep the stock sound at idle and cruise but have something more sporty and powerful when you get on it. Having a sport muffler in the rear just gives you a louder baseline.

[freeform911]

Thanks RarlyL8...

[famoroso]

Originally Posted by freeform911

famoroso...would love to hear your thoughts when you get it installed...

Fo'sho'!

FWIW, here's a vid of first cold startup with a Dansk pre-muffler and the Bisimoto Pulse Chamber muffler (without sound arrestor). On the one hand, a cool lil' piece of kit and on the other hand... a glorified muffler delete.




And for grins, here's the unit at shutdwown...



It's fun in a super juvenile sorta way and super lightweight, but will only be on until the M&K Active Exhaust pre-muffler arrives. I'll settle on a final muffler choice after I have that installed. I'll initially run it with a Dansk 84mm sport muffler, but want to end up with something lighter than that still. I like the Dansk 84, especially the aesthetics of the tip, but want something one step more aggressive and as light as practicable (I've already lost ~20 pounds between bumperette delete & Euro crush tube swap. I'd like to lose 10 more via the muffler). I'd love to hear different M&Ks (2.5" vs 3") before deciding.

Anyone running a pre-muffler + M&K in SoCal? If so... Hit me up!

To give a sense of how muffler-deletey the Bisi is, check out the vid in this post...

https://www.instagram.com/p/CCrZrtSFGDm/?igshid=v7boov3hwr32

That's with Bisi sound arrestor installed and <2,000 RPM!

[Knight77911]

I know this is an old post, but has anyone compared the sound of the M&K active pre-muffler and the Bisimoto? I love the sound of my Bisimoto, especially at full song,. But I dona lot of interstate driving, and I'd really love something more quiet. This M&K just might be the ticket.

[Showdown]

I have an M&K active exhaust- I switched the vacuum pods to electric gates.

I’d say that it has two states: really loud and a bit droney, and really loud AF, what drone, I can’t hear you!

For me, it’s a bit of a bummer that it’s not quieter in normal mode and I’ll be trying to come up with a solution this winter that’s quiet with the gates closed and loud with them open.

[darrin]

Julian -- I'm using a stock (vacuum-actuated) M&k active cat with my '86 targa's 1 in 1 out factory muffler and have not had the same experiences you are. Specifically, mine's quite quiet in normal mode (part throttle/crurising) -- essentially the same stock muffler exhaust sound I had before adding the active cat, but has a nice deep grunt when under hard(er) acceleration. Have you removed the baffle from the m&k outlet? I've left mine in place. Understand that removing the baffle significantly increases noise but only has a negligible effect on power output.

[edit -- reading through your build post linked in your signature, I see that you added the complete active exhaust system (m&k muffler, etc.) a different beast than the pre muffler/cat component of a 1 in muffler that I purchased and that's discussed above]

[RarlyL8]

I’d say that it has two states: really loud and a bit droney, and really loud AF, what drone, I can’t hear you!

Something is wrong if that is the case.
When the valve is closed the sound level is determined by the final muffler. The AE system uses a pre-muffler. If you have an OE final muffler then the baseline sound is stock. If you have one of our sport mufflers as a final muffler then the baseline sound is a bit louder than stock. When the valve opens the volume is much louder as the final muffler is partially bypassed. Max power is achieved as the flow is optimized.

[Showdown]

The setup I have is a 2.7 with SSI, M&K active exhaust 2-in 2-out baffled “S” type muffler.

With the valves closed it’s loud and a bit droney. Certainly nowhere near stock or the sound level of a 2-in 1-out sport muffler I previously had.