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We have seen the pre production 992 GT3 exhaust and it’s along these lines. Either way we’re ready and plan to be at the forefront of all coming GT models when it comes to exhaust development
Originally Posted by DE-RS2018
Why do you think no Valves will be required?
do you think it’s louder than the non OPF Center Bypass
The OPF serves as a pretty substantial silencer in its own right, it’s possible to create a system which at low RPM / throttle openings is tame while still being raw at the top end / WOT
Originally Posted by EST
Well done JCR! How much it wights or the weight difference compared with stock system?
OEM OPF back system weights 17+ KG. Our silenced system is 4.8KG and our non silenced is 3.5kg so some great weight savings to be had too!
Originally Posted by threers
I'm really curious how the result will be! Thanks JLC
Cant wait to share!
Videos are coming tomorrow all being well, were on the very final stretch right now
When I see dyno plots of exhaust modification of before and after, I always question the "sustainability" of the horsepower gains over time after the ECU adapts. It's hard to quantify the gains because when you do an immediate dyno plot after you put on a free flowing exhaust, you would always see a nice horsepower/torque gain. But what happens when you give the ECU a few hundred miles of adaptation? The new Porsches ECU with the particulate filter is calibrated to recognize a certain amount of back pressure. When the ECU realizes that these back pressure are missing, it will adapt and make changes in its parameters and dial things back.
This concern/question is not just directed at JCR in particular, but I always wonder about the power gain associated with just an exhaust swap without modifying the ECU on a long term basis. Anybody want to chime in?
When I see dyno plots of exhaust modification of before and after, I always question the "sustainability" of the horsepower gains over time after the ECU adapts. It's hard to quantify the gains because when you do an immediate dyno plot after you put on a free flowing exhaust, you would always see a nice horsepower/torque gain. But what happens when you give the ECU a few hundred miles of adaptation? The new Porsches ECU with the particulate filter is calibrated to recognize a certain amount of back pressure. When the ECU realizes that these back pressure are missing, it will adapt and make changes in its parameters and dial things back.
This concern/question is not just directed at JCR in particular, but I always wonder about the power gain associated with just an exhaust swap without modifying the ECU on a long term basis. Anybody want to chime in?
The ECU monitors the pressure differential across the OPF thats correct, however this is not a tuning aid, it's purely to check the correct operation of the OPF and that its working as intended. Think of it as a secondary lambda sensor is to the cats.
We replicate the factory secondary OPF sensor position and as the exhaust changes after this sensor the back pressure is therefore not considered in these readings. The OPF sensor position, size and profile is exactly as per OEM, 3D printed in titanium, see below..
As far as the ECU adaptation, in our experience the dyno figures and general running of the engine only improve over time as the ECU adapts, not the reverse.
Thanks for the reply. Interesting, so your exhaust system does not replace the OPF? Or does it replace it but the secondary OPF sensor is prior to the OPF? I'm just trying to get a clear picture here because I am very interested in getting a good aftermarket exhaust system for my incoming Speedster.
Originally Posted by JCR-Porsche
The ECU monitors the pressure differential across the OPF thats correct, however this is not a tuning aid, it's purely to check the correct operation of the OPF and that its working as intended. Think of it as a secondary lambda sensor is to the cats.
We replicate the factory secondary OPF sensor position and as the exhaust changes after this sensor the back pressure is therefore not considered in these readings. The OPF sensor position, size and profile is exactly as per OEM, 3D printed in titanium, see below..
As far as the ECU adaptation, in our experience the dyno figures and general running of the engine only improve over time as the ECU adapts, not the reverse.
Thanks for the reply. Interesting, so your exhaust system does not replace the OPF? Or does it replace it but the secondary OPF sensor is prior to the OPF? I'm just trying to get a clear picture here because I am very interested in getting a good aftermarket exhaust system for my incoming Speedster.
I asked the same question at Post #4 and was answered at Post #6...
Thanks for the reply. Interesting, so your exhaust system does not replace the OPF? Or does it replace it but the secondary OPF sensor is prior to the OPF? I'm just trying to get a clear picture here because I am very interested in getting a good aftermarket exhaust system for my incoming Speedster.
It's possible to replace the OPF, we're working on the system which will allow this without tuning and/or CEL. Either way we will have a complete solution for this vehicle.
It's possible to replace the OPF, we're working on the system which will allow this without tuning and/or CEL. Either way we will have a complete solution for this vehicle.
The systems above are OPF back.
JC
Great work JC! I'm looking forward for more videos and performance stats. Maybe difficult to hear on your video but the second video with the custom silencer doesn't sound that great (???)
I am also waiting for your OPF delete; this car doesn't deserve an OPF I don't think supercars - with low mileage - will effect environmental Greta Th*nberg
Great work JC! I'm looking forward for more videos and performance stats. Maybe difficult to hear on your video but the second video with the custom silencer doesn't sound that great (???)
I am also waiting for your OPF delete; this car doesn't deserve an OPF I don't think supercars - with low mileage - will effect environmental Greta Th*nberg
Agree this car shouldn't have OPF look forward to seeing what JCR come up with for a solution
Great work JC! I'm looking forward for more videos and performance stats. Maybe difficult to hear on your video but the second video with the custom silencer doesn't sound that great (???)
I am also waiting for your OPF delete; this car doesn't deserve an OPF I don't think supercars - with low mileage - will effect environmental Greta Th*nberg
As ever, its extremely difficult to accurately capture the sound but I can vouch for how great it sounds and im sure once we release driving, track, dyno videos that'll all become a little more apparent.
Dyno testing next week, here's some beauty shots of the two offerings.
We have built both the Non Silenced and Silenced Race Pipes such that the centres are cross compatible between both versions. This means that the 2x sides are common between both versions allowing owners to order an additional centre (non silenced or silenced) if they wish and swap prior to events etc
We have also carried over the tip flange from the 997/991 GT cars which means fitment of all of our existing Titanium Tips and/or any other manufacturers / OEM tips with the same 3-bolt flange design are compatible with this exhaust.
JCR Titanium Race Pipe (OPF)
JCR Titanium Silenced Race Pipe (OPF)
Also some more detailed shots of the sides. A huge machined titanium ring makes for perfect fitment to the factory OPF, mated to sooth radius bends reducing down to the same 70mm diameter as we use on all of our Race Pipe products.
Billet machined titanium secondary OPF bung, positioned in the exact same position as OEM to make fitment simple.
3D printed secondary OPF sensor spout is again positioned in the exact same position as OEM to ensure no chance of fate readings which may lead to CEL for OPF efficiency.
As ever, we make things light weight! Just 1.44kg (3.17lbs) for the pair of sides.
Finally some beauty shots, just because..
Dyno testing data along with noise testing and a ton of videos will be shared next week, in the mean time the system is now open to pre order with first deliveries expected in around 4 weeks time.
Both systems are compatible with the 991.2 GT3 RS (with OPF) and 991.2 Speedster
JCR TITANIUM RACE PIPE (OPF)
3.14KG (6.92LBS) total saving 13.86kg (30.55lbs) vs OEM £3995.00 GBP
JCR TITANIUM SILENCED RACE PIPE (OPF)
4.92KG (10.84LBS) total saving 12.08kg (26.63lbs) vs OEM £4995.00 GBP
We welcome any questions and we're super excited to share more!
10-10-2019, 06:40 PM
(???)
I don't think supercars - with low mileage - will effect environmental 
Greta Th*nberg 
