Modified OEM Muffler 996TT
#423
11-21-2011, 03:13 PM
Adjustable Valves
Hi,
had already done this mod with the "ajustable" valves:
https://www.6speedonline.com/forums/996-turbo-gt2/78446-modified-oem-muffler-996tt-26.html#post3072976
Like you noticed, you have to drill holes in the exhaust guide plate behind the cat. If you dont, you have a severe "drone"
between 1.200 and 2.500 U/min.
The third pic of my old post show, (thru the open valve) the air guide plate on the second cat. After drilling holes in that part, the drone was nearly gone.
But mutch better with removed second cat (with the guide plate)!
Reg.
Phil
had already done this mod with the "ajustable" valves:
https://www.6speedonline.com/forums/996-turbo-gt2/78446-modified-oem-muffler-996tt-26.html#post3072976
Like you noticed, you have to drill holes in the exhaust guide plate behind the cat. If you dont, you have a severe "drone"
between 1.200 and 2.500 U/min.The third pic of my old post show, (thru the open valve) the air guide plate on the second cat. After drilling holes in that part, the drone was nearly gone.
But mutch better with removed second cat (with the guide plate)!
Reg.
Phil
#424
11-21-2011, 04:56 PM
Registered User
Join Date: Jul 2011
Location: Portland, Oregon
Age: 51
Posts: 38
Rep Power: 14 
Hi,
had already done this mod with the "ajustable" valves:
https://www.6speedonline.com/forums/996-turbo-gt2/78446-modified-oem-muffler-996tt-26.html#post3072976
Like you noticed, you have to drill holes in the exhaust guide plate behind the cat. If you dont, you have a severe "drone" between 1.200 and 2.500 U/min.
The third pic of my old post show, (thru the open valve) the air guide plate on the second cat. After drilling holes in that part, the drone was nearly gone.
But mutch better with removed second cat (with the guide plate)!
Reg.
Phil
had already done this mod with the "ajustable" valves:
https://www.6speedonline.com/forums/996-turbo-gt2/78446-modified-oem-muffler-996tt-26.html#post3072976
Like you noticed, you have to drill holes in the exhaust guide plate behind the cat. If you dont, you have a severe "drone"
between 1.200 and 2.500 U/min.The third pic of my old post show, (thru the open valve) the air guide plate on the second cat. After drilling holes in that part, the drone was nearly gone.
But mutch better with removed second cat (with the guide plate)!
Reg.
Phil
#428
06-01-2012, 02:59 AM
Dear colleagues
Are you still satisfied with the TJW Mod? In europe this mod is not really known and i am thinking about to drill a tjw-hole. Regarding the cuttings wich will come out while drilling and falling down inside: i hope this wil not be problem for the turbo? Last Question: Is there a possibility that the turbo can have a vaccum on opposite direction so that the drillings inside can be "sucked" trough the cats and damage the turbochargers?
Thank you
kind regards from switzerland
Ray
Are you still satisfied with the TJW Mod? In europe this mod is not really known and i am thinking about to drill a tjw-hole. Regarding the cuttings wich will come out while drilling and falling down inside: i hope this wil not be problem for the turbo? Last Question: Is there a possibility that the turbo can have a vaccum on opposite direction so that the drillings inside can be "sucked" trough the cats and damage the turbochargers?
Thank you
kind regards from switzerland
Ray
Last edited by ipower; 06-01-2012 at 03:13 AM. Reason: correction
#430
06-01-2012, 11:07 AM
Dear colleagues
Are you still satisfied with the TJW Mod? In europe this mod is not really known and i am thinking about to drill a tjw-hole. Regarding the cuttings wich will come out while drilling and falling down inside: i hope this wil not be problem for the turbo? Last Question: Is there a possibility that the turbo can have a vaccum on opposite direction so that the drillings inside can be "sucked" trough the cats and damage the turbochargers?
Thank you
kind regards from switzerland
Ray
Are you still satisfied with the TJW Mod? In europe this mod is not really known and i am thinking about to drill a tjw-hole. Regarding the cuttings wich will come out while drilling and falling down inside: i hope this wil not be problem for the turbo? Last Question: Is there a possibility that the turbo can have a vaccum on opposite direction so that the drillings inside can be "sucked" trough the cats and damage the turbochargers?
Thank you
kind regards from switzerland
Ray
#431
06-01-2012, 11:22 AM
thank you for your responses. ist this also correct, that the diameter of this drill-hole is around 2 inches? Is that not too much? Maybe i will begin with 1 inch and will increase to 2 inch if its too silent.
kind regards from switzerland
Ray
kind regards from switzerland
Ray
#433
06-02-2012, 01:48 PM
Registered User
Join Date: Jun 2007
Location: CIR PCA Region
Posts: 2,142
Rep Power: 131 
Wow, this thread has legs.
I had it for a few years and it was superb. I am the "J" in TJW.
jeff
I had it for a few years and it was superb. I am the "J" in TJW.
jeff
#434
06-02-2012, 02:03 PM
i know. It needed a long time to across the atlantic sea to europe
Regarding the TJW Mod:
It would be awesome, with a valve which you can steer to close or open the TJW-Mod / TJW-Hole. But this would be very difficult to solve i think.
Kind regards
#435
07-10-2012, 06:19 AM
Ok finally did this with my mechanic today and put my already modified OEM exhaust (200 cell front cats replaced by 100 cell race cats and 400 cell rear cats completely removed, cost circa +$1,600) put back on (took my Techart off which has been very satisfactory for the last two years, following my prior disastrous purchase of a Cargraphic loud which was resonance city and only lasted a month).
My mechanic wanted to drill rather than use the blow torch as he thought he would make more perfect holes but as noted previously the steel is super hard and so just use blow torch/welder. We made the holes at least circa 2.25" and it truly sounds like a 993 air cooled motor now with NO reasonance, this procedure is HIGHLY HIGHLY RECOMMENDED !! TX
My mechanic wanted to drill rather than use the blow torch as he thought he would make more perfect holes but as noted previously the steel is super hard and so just use blow torch/welder. We made the holes at least circa 2.25" and it truly sounds like a 993 air cooled motor now with NO reasonance, this procedure is HIGHLY HIGHLY RECOMMENDED !! TX
@RichardCH:
Are you still driving in Switzerland with this modifications? Any problems with cops?
@all:
Does anyone has experiences with CARNEWAL's GT Exhaust? They modify the OEM exhaust. But you have to send them yours as a core exchange. After modifiying the exhausts will look just stock from the outside.
kind regards from switzerland
RaY