Hi all, new guy here from Oregon. A few months ago I picked up a very lightly used (1,873 miles) 2012 991 C2S PDK with Burmester, Sport Chrono, and some other goodies!




Here's the problem, no PSE!

I love the sound of this flat-6 even without PSE, but I've got the mod bug and I'd love to unleash a bit more sound, and gain some horsepower in the process.

I'm inclined to go with Borla, but have only heard a very short clip of it. It behooves Borla to upload a video of the 991 exhaust. I trust Borla's reputation enough to give them a slight edge over the competition. Borla, if you're reading this, we need videos!

The AWE SwitchPath exhaust sounds phenomenal, the only thing I'm not clear about is how it works on non-PSE cars. They say it reacts to throttle inputs and provides a different tone, but what if I just want to set the valves to be controlled by a switch?

Which leads me to NHP. I don't know much about the company, but I stumbled across a video of their new valved muffler delete x-pipe for the 991 on YouTube. It is by far the cheapest option, and sounds pretty raw when the valves are open.


Can anyone provide some input on which direction to go here?

 

Keep the standard exhaust, so you can enjoy your Burmester.
At least give it some more time, until you get a chance to hear some other exhausts in person.
I have PSE and often wonder if the standard exhaust sounds better.

 

seriously? NO it doesnt!

 

My recommendation is to NOT base your choice on pricing. I am not recommending to go for Akra by default, but a few hundred $$ are not much compared to the price of the car and risking to make your driving experience less enjoyable.

My experience has been that exhaust with a similar design (i.e. valved x-pipe retaining side mufflers) can still have a very different sound or drone level. I recently got the AWE exhaust and have been happy with it. I had tried another valved x-pipe exhaust before that was too loud to my taste, both in quiet and loud mode. I also tried side muffler delete, but this should be reserved to track use only.
As far as starting from a non-PSE system, AWE states that they have a specific design. Still, I think you can easily retrofit a remote control system on the AWE exhaust (like you would have to with the NHP exhaust if I am not wrong) or have your shop wiring a switch. I also know that Akrapovic sells a nice remote control system that should probably work with other brands as it simply controls the vacuum lines. Anyway, I would advise to check this with your vendor.

I can only share feedback on what I have tested myself and maybe other products are just as good, but I found it hard to form a valid opinion based on video clips only. Hence why I had to work through trial and error to find a system I liked

PS: I would take a nice exhaust note above Burmester sound quality any day, but it is just a matter of personal preference.

 

contact us for all major brand exhaust at best pricing for your 991!

undercoverperformanceinc@gmail.com

856-382-7543

 

Congrats on the purchase!

The AWE Tuning SwitchPath™ system on a non-PSE cars uses the same load-based valve control as the stock exhaust. On both the PSE and non-PSE exhaust, the exhaust valves are closed below 3500 rpms when in Normal mode. In Sport or Sport-Plus mode, valves are open all the time, regardless of rpms.

When it's time for the valves to open, the factory fuel injection computer opens them via a vacuum actuator.

The key difference between a PSE and non-PSE equipped car is that PSE gives the operator independent control of the exhaust valves, so you can opt to have the valves open all the time even in Normal mode.

To have full manual control over the valves, you would need to do a PSE retrofit which can get pricey and would have to be activated at a dealership.

 

I had PSE, but if i am not mistaking, it is how my AWE exhaust also works when I am in standard mode (=non-sport) with the PSE. The system only switches to 'loud' when I step on it but remains quiet as long as I am driving in commuting or cruising mode. I think it could still be a practical solution for a 'dual mode' exhaust even if there is no PSE or remote control system installed.

 

That is correct.

A properly designed valved system works well on a PDK car, because open exhaust valves in Normal mode below 3500 rpms would not provide the note that most are after in cruising and stop-and-go conditions. During these situations, PDK transmission programming really puts the engine in a rev range highly susceptible to unwanted frequencies, making the valves extremely important in achieving a balance between civility at lower RPMs and aggressiveness at higher RPMs. Without the valves or the effective side mufflers in place, drone can become a real problem.

 

I totally agree with that statement.

 

A bunch of these systems will work with their own respective valve control. I just installed a CargraphicTS x-pipe, and I'll post a thread on it in a couple of days. I have PSE, so I retained the factory valve control, but Cargraphic also sells their own controller.

Do you care about having control over the valves? If not, then KitW has a nice video that explains how the non-PSE cars function (valves open at idle, valves close above 5mph, valves re-open above ~3,300rpm).

 

I have a very slightly used fab speed primary bypass x pipe available that's perfect for what u are looking for if you are interested pls pm me.

 

Non-PSE means that the valves are open at idle, closed at 5mph, and open at 3200rpm with over 25% throttle. This produces a pretty loud transition at 3200rpm, but keeps drone down. Be aware that you will hear it at idle, though, and reverse, which can make backing out of the garage loud.

PSE, when off, opens by itself at 3500 rpm. When On, it's open as long as you are on the throttle. (and does some weird half close thing when you let off)

 

Thanks for the warm welcome everyone!

It's funny that everyone mentioned hearing the Burmester over the new exhaust, but I can already barely hear it over the tire/wind noise. Don't get me wrong, it sounds amazing, but so many details of music are drowned out by the ambient cabin noise. I think hearing a bit more of an aggressive exhaust note and the Burmester system together would be like a symphony though!

I would like to have control of the valves via a PSE button retrofit, I know there are some exhausts that offer this setup out there, right? Ideally, from the moment I start the car until the moment I turn it off again I'd like to be able have the valve open.

 

Kit, just to clear something up... PSE, when off, still keeps the valves closed above 3500rpm as long as you're not heavy on the throttle. I tested this out during my commute this morning on the freeway; valves remained closed around 4500rpm.


A PSE retrofit, or any other valved system with a controller, will give you just that, King. You'll have control over the valve setting. I believe CargraphicTS, NHP, FVD, and Akrapovic sell valve-control remotes/systems (to name a few).

 

Akrapovic would be an obvious first choice, unfortunately it's currently out of my price range

Now, what I surmise from looking at the Borla exhaust, is that it would eliminate the whole 'valve-closed-under-3500 rpm' thing. Can anyone confirm if that's the case or not?

And on a completely random tangent, does anyone else have the infuriating ambient whistling noise at highway speeds?