Another exhaust sound data point
#226
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Our system uses inline silencers, they're 50mm internal diameter which is sufficient for flow and also effective enough from a silencing point of view. It would be possible to force the valves closed and run in this mode however its not something that we would recommend, the OPF already creates a significant amount of back pressure due to the design of the flange. It wouldn't be wise to add any restrictions as this would only exacerbate the issues. Hence why we ditched the OEM tips as that's like running a fire hose with a domestic sprinkler attachment fitted to the end.
Neither our silenced or non silenced system drones and neither is what I would consider to be loud. Our non silenced system is still below the max dB of a 100% stock 981 GT4 at WOT. The OPF is a very effective silencer in its own right.
JC
Neither our silenced or non silenced system drones and neither is what I would consider to be loud. Our non silenced system is still below the max dB of a 100% stock 981 GT4 at WOT. The OPF is a very effective silencer in its own right.
JC
what’s the expected delivery time for the non silenced version?
#227
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Our system uses inline silencers, they're 50mm internal diameter which is sufficient for flow and also effective enough from a silencing point of view. It would be possible to force the valves closed and run in this mode however its not something that we would recommend, the OPF already creates a significant amount of back pressure due to the design of the flange. It wouldn't be wise to add any restrictions as this would only exacerbate the issues. Hence why we ditched the OEM tips as that's like running a fire hose with a domestic sprinkler attachment fitted to the end.
Neither our silenced or non silenced system drones and neither is what I would consider to be loud. Our non silenced system is still below the max dB of a 100% stock 981 GT4 at WOT. The OPF is a very effective silencer in its own right.
JC
Neither our silenced or non silenced system drones and neither is what I would consider to be loud. Our non silenced system is still below the max dB of a 100% stock 981 GT4 at WOT. The OPF is a very effective silencer in its own right.
JC
If one is keeping the OEM headers and the OPF in place this would make complete sense.
What I should have mentioned is Im considering replacing the entire system with catless headers, and having the cats located where the OPF is. So in open mode it would be completely straight through and extremely loud.
#228
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
From point of order to delivery currently is around 8 weeks for both silenced and non silenced systems. We have been inundated with orders on this system.
Thanks for the reply.
If one is keeping the OEM headers and the OPF in place this would make complete sense.
What I should have mentioned is Im considering replacing the entire system with catless headers, and having the cats located where the OPF is. So in open mode it would be completely straight through and extremely loud.
If one is keeping the OEM headers and the OPF in place this would make complete sense.
What I should have mentioned is Im considering replacing the entire system with catless headers, and having the cats located where the OPF is. So in open mode it would be completely straight through and extremely loud.
JC
__________________
WE'RE NO LONGER ACTIVE ON THE RENNLIST FORUMS - FOR ALL ENQUIRIES PLEASE CONTACT US VIA THE JCR WEBSITE BELOW
/ / / JCR PORSCHE \ \ \
contact@jcr-developments.com
Facebook | Instagram | Youtube
/ / / JCR PORSCHE \ \ \
contact@jcr-developments.com
Facebook | Instagram | Youtube
#229
RL Community Team
Rennlist Member
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Our system uses inline silencers, they're 50mm internal diameter which is sufficient for flow and also effective enough from a silencing point of view. It would be possible to force the valves closed and run in this mode however its not something that we would recommend, the OPF already creates a significant amount of back pressure due to the design of the flange. It wouldn't be wise to add any restrictions as this would only exacerbate the issues. Hence why we ditched the OEM tips as that's like running a fire hose with a domestic sprinkler attachment fitted to the end.
Neither our silenced or non silenced system drones and neither is what I would consider to be loud. Our non silenced system is still below the max dB of a 100% stock 981 GT4 at WOT. The OPF is a very effective silencer in its own right.
JC
Neither our silenced or non silenced system drones and neither is what I would consider to be loud. Our non silenced system is still below the max dB of a 100% stock 981 GT4 at WOT. The OPF is a very effective silencer in its own right.
JC
#230
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
JC
The following users liked this post:
Westcoast (05-12-2020)
#231
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
[QUOTE=JCR-Porsche;16619864]Volume is the difference, the non silenced sounds very very slightly sharper in pitch but thats just due to the nature of a silencer and its effect and tendency to soften the tone a touch.
From point of order to delivery currently is around 8 weeks for both silenced and non silenced systems. We have been inundated with orders on this system.
Thanks JC! Your openness is appreciated. I am hoping you’ll offer the Rennlist community a Group Buy...I am sure many others would jump on the opportunity
From point of order to delivery currently is around 8 weeks for both silenced and non silenced systems. We have been inundated with orders on this system.
Thanks JC! Your openness is appreciated. I am hoping you’ll offer the Rennlist community a Group Buy...I am sure many others would jump on the opportunity
#232
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Thanks!
#233
Burning Brakes
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I cant wait to get my car to start playing with it!
What could be useful to help us choose the perfect setup for our needs would be a table with dB comparo of silenced vs non-silenced race pipe alone and in combination with OPF delete pipes (and maybe with the stock 981 GT4 in the table for comparison). I want it loud but dont want to be above approved dB level at local track (I know a stock 981 GT4 is OK). Ideally I dont want to add the silenced tips!
What could be useful to help us choose the perfect setup for our needs would be a table with dB comparo of silenced vs non-silenced race pipe alone and in combination with OPF delete pipes (and maybe with the stock 981 GT4 in the table for comparison). I want it loud but dont want to be above approved dB level at local track (I know a stock 981 GT4 is OK). Ideally I dont want to add the silenced tips!
#234
Burning Brakes
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I may be wrong but it seems most of these designs may inhabit the rear diffuser from working properly.
#235
RL Community Team
Rennlist Member
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Anything that does would be a non-starter on these cars.
#236
Burning Brakes
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
With the huge size of the stock system I’m sure there is a lot of free space back there once JCR system is installed for a family of cats to reside!
#237
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
#238
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
I cant wait to get my car to start playing with it!
What could be useful to help us choose the perfect setup for our needs would be a table with dB comparo of silenced vs non-silenced race pipe alone and in combination with OPF delete pipes (and maybe with the stock 981 GT4 in the table for comparison). I want it loud but dont want to be above approved dB level at local track (I know a stock 981 GT4 is OK). Ideally I dont want to add the silenced tips!
What could be useful to help us choose the perfect setup for our needs would be a table with dB comparo of silenced vs non-silenced race pipe alone and in combination with OPF delete pipes (and maybe with the stock 981 GT4 in the table for comparison). I want it loud but dont want to be above approved dB level at local track (I know a stock 981 GT4 is OK). Ideally I dont want to add the silenced tips!
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
JC
#239
Basic Sponsor
Rennlist
Site Sponsor
Rennlist
Site Sponsor
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
The complete OPF section is replaced with a Titanium OPF Delete. We will have three versions of our OPF delete, again all modular. Non silenced, Silenced & Race Catted (for use with our Inconel Race Manifolds which delete their factory cats
JC
The following users liked this post:
nhnguy12 (05-13-2020)
#240