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I don't think the comparison with the Cup car is relevant here. Cup cars spend most of their time in the higher RPM range,so less back pressure is beneficial.
The GT3 on the other hand spends quite a bit of time in the lower range where back pressure is beneficial to the lower end torque.
Just my 2 c...
I agree. That's part of the reason I took my "cup" version of the exhaust off the car. It was too much for driving around town. I was showing that the Akra Sport Cup version of their exhaust loses some low-end power.
I would agree with Evan that it is probably not worth testing as loss in torque is low; however I am anel and been looking at this with interest.
The car is fine through town with valves open & on the high way at the 2 K figure but my testing does show a difference. Personal testing has been done on a given grade using time and distance in 7 th gear at 2 K accelerating, valve on and off & in car power meter.
The valves are never open at 2,000 RPMs with or without the PSE button ON when the car is moving.
I may add : from driving the car and reading quite a bit about it-I am fairly certain to say that the Porsche exhaust system is extremely well designed and it is very hard to improve! The only thing you can do is what Sharkwerks and others have done : and that's to eliminate the 3rd muffler to get more sound. Other than that,it's just a waste of time and money IMO.
Word.
Porsche itself has said that the exhaust system "is one of the MOST highly developed/studied parts of the car...change the exhaust only for emotional reasons, but at the expense of performance."
Right GTEE3?
Dear Matt, I am presenting are Vittorio an Italian boy very fond of sports cars, in particular of Porsche. I had a 997 mk1 targa, mk2 a 997 GTS, and now finally the legendary 991 GT3. I read with real interest in your posts and seen your videos, really useful for me as a fan of change. Also I have made the change to the original exhaust by removing side mufflers putting a by-pass of the tubi-style with valve. I immediately used without connecting them, the sound really cool and exciting, but after many hours of use can become annoying especially between 2000-3200 rpm. Another annoyance is that I feel the vibrations when the machine speed falls especially around 3000 rpm. I tried to connect valves, less annoying but I do not like how the valves work, and then they connected with the vibrations are more pronounced. I think eventually return to original side mufflers with center muffler bypass, SW or cargraphics, where we have cost much less than sw, and I think it is equally a good product. Reading your post I understand that too with the by-pass of fvd and original central muffler sound alerts the annoying vibrations. One last thing, I noticed that in the 991 gt3 '15 I think they have changed some steps inside the silencers, attractive photo and then to point out the differences. Very happy to be entered in this fantastic forum I salute you and I apologize for my bad English.
I'm sure you guys are getting tired of me screwing with this. After I took the FVD j-pipes off, I decided I was going to stick with the Sharkwerks. It really is great.
Well...that lasted about three days. I called Chris Smith in Atlanta just to talk to him about his bypass solution. About 5 minutes later, they had my credit card, and one was in the mail.
Since I don't let anyone else drive my car, the best way for me to compare the sound is to make a video. Plus I need to get my money's worth out of the Rode Stereo Video Mic X that I bought.
I really like the way it sounds. I wasn't sure about it, but the single "butthole" look is growing on me.
Man, clearly you have taken this machine apart ........I can definitely hear the difference, but it's all preference now as they both sound good. Don't think you can go wrong with either sound, but that one holer is no looker in my opinion. I think your car is great as is, but it's cool you have the time and patience to tinker. I give your wife credit that she has not locked you out of the garage yet?
I am glad you gave the CSR exhaust a try. We helped Chris Smith develope the exhaust and the half cage on our Sapphire Blue GT3! I think the build quality, sound, and look ( though single "butt hole" not for everyone) is spot on. Here is the exhaust at VIR Warp 10 Motorsports 991 GT3 at VIR:
The back-2-back exhaust comparison is awesome. It must take you quite a while to finish the shooting. Based on the video, I can't judge which bypass is better. Perhaps I will admit they are both good.
after testing of center bypass and side bypass. When can we read your review of testing of header and sport cat? lol
06-12-2015, 01:05 PM
Thankfully you can't see the exhaust from the driver's seat.
