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My personal observation with the center muffler delete on a .2 manual:
It is indeed louder without being too loud and still gives the opportunity to come home quietly. No drone also and
mainly outside racecar-like at WOT. Rev matching is also finally really sharp.
But, there´s one big but, and maybe it´s just me: the sound quality is not enhanced, it actually looses character and
typical flat six notes.
Two examples, compared to stock with blocked exhaust valves:
-below 4000rpm, there is a nice tone/growl that reminds me of the air cooled era. Very Porsche and distinctive.
With cmd-> gone, replaced by louder and unspecific noise
-above 7500rpm, when the induction noise takes over and makes your eyes water, reminds you of e30 m3´s in the early 90s.
With cmd->gone, just loud, so loud the induction noise is no longer heard
Trouble is, even though I really love the stock sound, I´d like it louder, sharper, but without loosing the lovely tones.
How did you guys with side muffler delete experience this?
Peter
Which center section delete are you talking about here?
Below are some real, no BS, same day, independent, no tune/software, before/after dyno of my 997.2 GT3 with complete Akrapovic race system (200 cel cats, headers, and center muffler, no side mufflers). Not the system juanpablo has, but something to go by as to what’s possible with the same Akrapovic full race version. It showed up to 18 HP gains in some areas, and up to 20 TQ gains as well, -57lbs. . I would expect the 991.2 GT2 to show slightly larger gains.
Thats said, this time I’ll be doing Dundon Race headers. Already here in a box waiting for the car to arrive. Same procedure to see what gains they yield.
Below are some real, no BS, same day, independent, no tune/software, before/after dyno of my 997.2 GT3 with complete Akrapovic race system (200 cel cats, headers, and center muffler, no side mufflers). Not the system juanpablo has, but something to go by as to what’s possible with the same Akrapovic full race version. It showed up to 18 HP gains in some areas, and up to 20 TQ gains as well, -57lbs. . I would expect the 991.2 GT2 to show slightly larger gains.
Thats said, this time I’ll be doing Dundon Race headers. Already here in a box waiting for the car to arrive. Same procedure to see what gains they yield.
For that system they offer up to 16hp and 23nm gain. I believe Akrapovic.
why would they lie? do you have any evidence against their claim?
How about the fact that the other companies selling center bypasses don't hype power gains. Most of the others specifically say there are no power gains with a center bypass as a CYA. Let's just say I'm skeptical and I'm able to put two and two together.
Last edited by FourT6and2; 06-30-2018 at 02:57 AM.
Titanium can only do so much to augment a basic design shared by all center box delete sections, which is some variation of an X-pipe. It is not unreasonable or prejudicial to question an outlier’s data regarding gains in HP and torque.
I have had a Sharky on my .1 and an RSS and GRP on my .2 so I can comment
Sharky- no change in tone takes volume up a couple notches. You need to buy the additional 100 MM tips if you want them bigger
RSS- did not like. It felt like it was suffocating the engine
GRP- Louder and changes tone to a deeper growl. Engine feels like it is breathing better. Retains and enhances the German sound you expect from a 911.
I have the bbi/GRP sitting here waiting to go on. But I'm just concerned there will be a reduction in power/torque. Even if I can't feel it, I don't like the idea of paying money to make the car slower. I'm not saying it will reduce power, but not sure I want to even mess with it. Even if it shifts power/torque to a different spot in the rev range, I don't even want that. I think the car is damn near perfect as is. I just wanted a bit more of that banshee scream and the larger exhaust tips. We'll see. I'm going to put more miles on the car in its stock form first.
06-28-2018, 04:08 PM
