Jimmy-D

I am not a mechanic/engineer nor educated on this topic of deleting the side mufflers with straight pipes either with valves (TPC, Fabspeed) or w/o (BBC, FVD). But, could these cause any potential issues besides driving your neighbors nuts. I have the rear bypass and it just seems insignificant, in comparison, to deleting those big *** side mufflers

Thoughts??

Mike in CA

I've said this before but I know it falls mostly on deaf ears, so TEHO. But the word from the GT3 development team is that the exhaust system is one of the most carefully engineered pieces of the engine package and that the bypass valves and other parts have been optimized with the ECU for the best possible performance. It amazes me that people are willing to replace and remove parts on spec with seemingly little consideration for this fact just so their exhaust will make more noise. I'm sure I'm in the minority, however, so flame away. Just my $.02 and end of rant.

SunnySD

Engineered with what purpose in mind? To meet noise ordinances ? Emissions? Or performance? Maybe I'm wrong, but I don't see PSE systems on cup cars or other motorsport racing. There is no way the PSE can keep up with the wide range of RPM shifts on the track/street to modulate the torque curve.

ipse dixit

May want ask some of the 7.2 GT3 guys.

They delete side mufflers and ended up cracking the OEM third bypass.

Before you go yelling and screaming bloody idiot, yes, I realize that the 7.2 GT3 muffler is a different material from the 1.1 GT3 setup, and that the 7.2 GT3 muffler was prone to cracking even with the stock setup, but swapping out the side mufflers with straight pipes probably hastened whatever failure rate that 3rd bypass may have had.

Just something to think about.

TRAKCAR

Yes you want a cheap center muffler, certainly not the Ti OEM one...

ToyGuyAZ

Factory exhausts are designed for max performance with both loudness and emissions as a major factor. They aren't designed for purely maximum power...

Mike in CA

No, you don't see PSE systems on race cars, but you do see systems that have been specifically engineered and tested for best race performance. I'm fairly certain Porsche Motorsport doesn't slap an exhaust part on a new engine just because it "fits". There were bypass systems available almost literally the day the first 991 GT3 was delivered. They fit, but there's no way they could have been developed for and tested with the new engine.

It may or may not be true that PSE can't keep up with the dynamics of the torque curve, but the ECU certainly can. The ECU is designed to work within the parameters of all the other engine components. Radically change one of those components and you can no longer be sure of the results. That's why I was told by someone within Porsche Motorsport that if one made changes to the exhaust, particularly with the way it worked with the ECU in this car, that an ECU reflash would be required to optimize results.

When I was a kid, I used to get noise by using clothes pins to attach baseball cards to the spokes of my bike (yeah, I'm old ) and make it sound like a motorcycle. Want more noise, use more baseball cards. Sounded cool, but the drag from the cards literally slowed you down. I don't know for sure if doing an exhaust bypass slows you down just to make more noise but then neither do 99% of the people who do exhaust mods because the result hasn't been thoroughly tested. I paid a lot of money for a factory engineered system and I don't have enough information to know whether I can improve on that just by swapping out some pipes, so I won't do it. As I said earlier, though, YMMV.

ChrisSmithRacing

All cars are learners
Pmna the guys at porsche are just protecting there brand. !
The car will learn what exhaust system you put on.
02 sensors read and adapt. So put what every system you want.
If you take the headers and change them. Then a reflash will have to be done.
!
That's all I am saying.
Make it load.
Chris smith.

Jimmy-D

The reason I also ask this question is that at the Porsche Customer event last month we had time to sit with one of their Engineers and they had a GT3 on a lift so you can see every thing underneath. I asked him about the rear delete and he reiterated what Mike had conveyed above. But, after spending 15 min under the car and carefully examining the exhaust, it just seemed to me the side mufflers play a bigger part in the whole system than the rear exhaust. I then asked him about deleting the side mufflers and he looked at me like I was insane. Do not get me wrong; I have the SW rear bypass and love it. Contemplating the side deletes and putting back on stock rear but still questioning would I be changing too much. I think I am just going to stick with the rear bypass anyway but just seeing if anyone has any data either way

NateOZ

I trust very few aftermarket companies, Akrapovic happens to be one that I do trust. Here is what they have to say on their system:

"When installing Akrapovič aftermarket optional link pipes with sports catalytic converters or without catalytic converters, which are developed for use on closed tracks only, remapping the ECU is mandatory. When installing Akrapovič aftermarket exhaust system that was developed for use on closed tracks, we recommend remapping the ECU in order to prevent potential »check engine light« warning signals."

They are always late to market, because they take the time to do the R&D to get the product right.

Mike in CA

Makes one wonder why Porsche goes to all the trouble of engineering and testing exhaust systems when they could just put on any system they want and let the "02 sensors read and adapt".

The engineer primarily responsible for engine development at Porsche Motorsport says an ECU re-flash is required to optimize performance if you change the exhaust configuration. As Jimmy-D points out, the engineer he spoke to at PCNA in Atlanta said the same thing. If they were simply "protecting their brand" they could have just said, "don't ever change the exhaust".

No disrespect intended, but personally I have to believe the engineer's advice.

SamFromTX

I have data. Butt dyno and ear data. Butt dyno says no difference (so did lap times). Ear dyno says car goes faster but that contradicts butt and lap data so I'd say no significant performance difference. Measurable change? I bet there is but not sure that a small fraction of a second up or down means anything to me. I want to enjoy my car and to me, refined louder is more enjoyable. BTW, side muffler delete alone changes the tone more than center muffler delete alone does. The contribution to volume increase is marginally higher with the side muffler delete versus the center muffler bypass when the latter is combined with vacuum plugs. To me, the optimum sound improvement with no significant (albeit not scientific) power drop is a combination of side muffler delete and low flow (200 cell) cats, which provides a fantastic auditory upgrade.
I'm not saying anybody else is wrong to think otherwise. I respect their opinions and as Mike appropriately said, TEHO. Cheers!

vf430

I checked my car recently no signs of any cracking or other issues. I have 3 k miles now with bbi side pipes. I cannot imagine driving this car with stock exhaust .. It's very boring.

Mike in CA

Right on, Sam. Jimmy asked for thoughts and I gave mine, but ultimately everyone has to take the available info and make their own choices.

Gt3Fan

I look forward to the day you break down and put some aftermarket side delete exhaust on. It truly does bring the car to a different level, admitidly I was shocked how much more intense my experience is driving my car after just putting on the side fvd j pipes.

Even just for a few days Mike, it would be worth giving them a shot to see what all the fuss is about

I don't have any delusions of performance increases, nor decreases for that matters but these exhaust don't just make the tone louder, they bring out many tones throughout the rpm range, while not killing the already great stock sound at the higher rpm's. It has me grinning like never before, quite unexpectedly