Best Exhaust for a 991.2 GT3
03-28-2018, 08:54 PM
#346
Race Director
Originally Posted by Mvez
IMO, there is no con, except cost. This is why people do the Center bypass, because it's typically ~$350 vs ~$1750. But there is a reason that Cup cars don't have side mufflers......
It removes 40lbs from the rear of car
It retains full sport exhaust button function (for street cars)
It makes a little power
It creates better handling
It is a tad quieter than center muffler delete
It offsets the weight gain of a rollbar install
I prefer the TPC design over Fabspeed, because it has the flexible upper tubing, which is same as OE.
It removes 40lbs from the rear of car
It retains full sport exhaust button function (for street cars)
It makes a little power
It creates better handling
It is a tad quieter than center muffler delete
It offsets the weight gain of a rollbar install
I prefer the TPC design over Fabspeed, because it has the flexible upper tubing, which is same as OE.
03-29-2018, 09:39 AM
#347
Rennlist Member
I keep hearing about disabling the valves when doing a bypass exhaust. I'm assuming these are the valves that keep the car quieter until it hits a certain RPM? Is this pretty common thing to do when getting the bypass exhaust done? Easily done? Any real downsides to doing it? I'm deciding on which bypass to get when I get my car but definitely interested in having "loud" exhaust at all times versus over a certain RPM. If anybody has done this I'd love to hear the results of this. Thanks.
03-29-2018, 09:55 AM
#348
Race Director
^ I have disconnected my valves. Best thing I have done. No more transition around 4000 rpm from open to shut(Back and forth). Also - it says in the Manual that you gain more torque with valves open- no reason to have them shut
Last edited by Jimmy-D; 03-29-2018 at 10:12 AM.
03-29-2018, 10:08 AM
#349
Rennlist Member
Just found the link where it's discussed. I skimmed thru it seeing if there is any downside which seems like there is not. I'm all for the noise. Why else would we be looking at the bypass exhaust to begin with?!
https://rennlist.com/forums/991-gt3-...***-valve.html
https://rennlist.com/forums/991-gt3-...***-valve.html
03-29-2018, 06:18 PM
#350
Rennlist Member
Not to mention it decreases heat soak into the rear tires, which is probably the single biggest improvement the side muffler bypass offers. The increases air flow offers better cooling for the rear tires. Another reason Cup cars obviously don't run side mufflers.
Using the in-car performance software, TPC saw gain of ~7hp up top and ~7 lbs/ft tq in midrange, on the 991 GT3.
I personally like that the valves keep some civility if you want it. Long drives, or when you have somebody in the car, it's nice to be able to tone it down a bit if needed.
Using the in-car performance software, TPC saw gain of ~7hp up top and ~7 lbs/ft tq in midrange, on the 991 GT3.
I personally like that the valves keep some civility if you want it. Long drives, or when you have somebody in the car, it's nice to be able to tone it down a bit if needed.
03-29-2018, 06:38 PM
#351
IMO, there is no con, except cost. This is why people do the Center bypass, because it's typically ~$350 vs ~$1750. But there is a reason that Cup cars don't have side mufflers......
It removes 40lbs from the rear of car
It retains full sport exhaust button function (for street cars)
It makes a little power
It creates better handling
It is a tad quieter than center muffler delete
It offsets the weight gain of a rollbar install
I prefer the TPC design over Fabspeed, because it has the flexible upper tubing, which is same as OE.
It removes 40lbs from the rear of car
It retains full sport exhaust button function (for street cars)
It makes a little power
It creates better handling
It is a tad quieter than center muffler delete
It offsets the weight gain of a rollbar install
I prefer the TPC design over Fabspeed, because it has the flexible upper tubing, which is same as OE.
03-29-2018, 06:51 PM
#352
Rennlist Member
TPC side delete on order... agreed this is the best option. weight savings and heat reduction are biggest issue. Did not know this offers an addl 7hp... Mvez blessing too!
Last edited by JCL59; 03-29-2018 at 07:25 PM.
03-29-2018, 08:11 PM
#353
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Here is a Chalk 991.2 GT3 with BMC Air Filter and BBi Center Section Exhaust Installed
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03-30-2018, 09:18 AM
#355
Rennlist Member
03-30-2018, 09:23 AM
#356
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03-30-2018, 10:13 AM
#357
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03-30-2018, 06:19 PM
#358
Rennlist Member
I don't know if anyone is interested, but I'm going to take my Dundon race headers off of my 991.1 RS (about 1000 miles on them) and put on a side delete/mini muffler combination with my stock cats on to change things up. Never got a CEL with this setup and I'll definitely miss the power...but want to change to get a more high pitched sound and don't want to run LT catless headers and a mini muffler/bypass...that would be a little much for me. Anyone interested PM me! (headers would come off the car in a couple weeks depending on when my new exhaust gets in).
04-02-2018, 12:32 PM
#359
While I appreciate many of the center muffler replacement variants, I am with Mvez and consider side muffler delete options by far the best solution, for all the reasons he listed above.
I have done that on 997 4.0 with a Cup system foregoing the valves, and installing the OEM Cup parts, living with the drone.
On the 911R I will install the valved TPC side delete pipes with Akrapovic central muffler (could have just as easily used the standard central muffler, but I suffer from vanity from time to time).
Best, w
04-02-2018, 01:09 PM
#360
Three Wheelin'
Thread Starter
I don't know if anyone is interested, but I'm going to take my Dundon race headers off of my 991.1 RS (about 1000 miles on them) and put on a side delete/mini muffler combination with my stock cats on to change things up. Never got a CEL with this setup and I'll definitely miss the power...but want to change to get a more high pitched sound and don't want to run LT catless headers and a mini muffler/bypass...that would be a little much for me. Anyone interested PM me! (headers would come off the car in a couple weeks depending on when my new exhaust gets in).