Mike D'Silva Posted 30April, 2019 Report Share Posted 30April, 2019 I know that the GT3 muffler has been used on the older aircooled cars. But I came across both a 997 muffler and also a 991 muffler. I'm wondering if it is worth trying either of the 997 or 991 mufflers? Here is the inside of a GT3: Here is the inside of the 997 And here are pics of the 991.. I have not found any cutaway photos of a 991 muffler yet? firstone 1 Quote Link to comment Share on other sites More sharing options...
clutch-monkey Posted 30April, 2019 Report Share Posted 30April, 2019 991 muffler looks thick- would it fit? Quote Link to comment Share on other sites More sharing options...
Raven Posted 30April, 2019 Report Share Posted 30April, 2019 I have seen the rear GT3 mufflers fitted to earlier cars eg G series and 964 ,,dont know about the 991 carrera mufflers ,,but like clutch monkey said will it fit ..??? Quote Link to comment Share on other sites More sharing options...
Mike D'Silva Posted 30April, 2019 Author Report Share Posted 30April, 2019 When I get a chance, I'll pull the current muffler off and offer the 991 up to the recess... the stock bananas are pretty big but yes, this 991 looks even fatter doesn't it. Quote Link to comment Share on other sites More sharing options...
Mike D'Silva Posted 10May, 2019 Author Report Share Posted 10May, 2019 Here is a short clip.. got the stock 997 muffler fitted up.. seems to flow well. But just a tad loud! Quote Link to comment Share on other sites More sharing options...
Raven Posted 10May, 2019 Report Share Posted 10May, 2019 good work sound good Quote Link to comment Share on other sites More sharing options...
sydr Posted 10May, 2019 Report Share Posted 10May, 2019 LOUD is Good, no problem with that. But what about BOOM inside the car? The droning can drive you daft. Quote Link to comment Share on other sites More sharing options...
Raven Posted 10May, 2019 Report Share Posted 10May, 2019 I followed the build of this car on Rennlist 75 with 3.6 Varo and GT3 center muffler fitted ,,,,sounds great to me and proof the latter water cooled mufflers work well on Air cooled cars .. https://rennlist.com/forums/911-forum/860687-75-carrera-with-3-6-vario-ram-it-s-alive.html LeeM 1 Quote Link to comment Share on other sites More sharing options...
Mike D'Silva Posted 17May, 2019 Author Report Share Posted 17May, 2019 Here is a real short clip... going in for resonators to knock off the harshness at higher rpm. Raven 1 Quote Link to comment Share on other sites More sharing options...
Raven Posted 17May, 2019 Report Share Posted 17May, 2019 Sounds good to me ,,not overly loud and a refined sound ........ Quote Link to comment Share on other sites More sharing options...
Mike D'Silva Posted 17May, 2019 Author Report Share Posted 17May, 2019 1 minute ago, Raven said: Sounds good to me ,,not overly loud and a refined sound ........ No, it is actually pretty obnoxious . Youtube makes it sound nice, but in person it is crazy loud. The above video, is without resonators.. just the rear muffler. Resonators are now fitted... but I am not so crazy about the sound now.. They have taken the rasp away unfortunately. Raven and clutch-monkey 2 Quote Link to comment Share on other sites More sharing options...
LukasM Posted 18April, 2023 Report Share Posted 18April, 2023 Hi Mike, This is an old thread but are you still running the GT3 muffler, and were you able to find a good compromise between sound/power/torque/droning etc? I think you said that the big inlets were too loud and lost torque, but the quiet inlet fell a bit flat? Cheers, Lukas Quote Link to comment Share on other sites More sharing options...
Mike D'Silva Posted 18April, 2023 Author Report Share Posted 18April, 2023 hi Lukas the car is sold and now in Melbourne but I believe it's still running the GT3 muff. From the Euro headers, at first I tried a 2 inch pipe to feed the "quiet" ports on the GT3 muff, since that was the diameter of the ports. Torque was amazing and it felt like a turbo with zero lag. Top end was breathless thou.. Then I tried 2.5inch pipes from the Euro headers, straight to the "loud" ports on the GT3 muff. Was a but loud for me, but it was a "nice" sound.. just too much volume. Also, very low torque down low. Then tried 2.25inch from Euro headers and fed to the quiet ports. Best compromise. Almost all the torque down low from the first set of 2 inch adapter pipes. And it just kept pumping all the way to redline with no drop off in urgency. At least, that was my recollection. Volume = subjective. To me, it was not that loud.. but when it was WOT and the rpm were up there, it sounded fantastic. However, might be a tad too loud to live with on a daily basis. I didn't mind so much, as it was a car to drive on occasion and enjoy, not for going to work every day or doing school runs etc etc Quote Link to comment Share on other sites More sharing options...
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