Need full PSE explained
12-07-2018, 05:48 PM
#1
Rennlist Member
Thread Starter
Need full PSE explained
Evidently the GT3 Sports Exhaust is not a simple function of pushing the console button. I've searched but cannot find a detailed explanation of the PSE in my 2018 GT3. It appears that the valves are normally open so at startup exhaust is loud but as soon as vacuum builds they close as vacuum is sent to the valves by an electric solenoid. I've also been told that regardless of position of console button valves open above a certain RPM and even with console button pushed valves may open and close until certain rpm or speed is reached. Has anyone run across a definitive explanation of how this system operates.
12-07-2018, 06:01 PM
#3
Race Director
Seems to me all the PSE on my 2018 does is keep the valves open at idle... after that PSE valves close up to around 3500rpm then at full throttle the open again after that...no matter if PSE button is pushed or not.
I can't hear much of a sound difference with PSE on or off.
I can't hear much of a sound difference with PSE on or off.
12-07-2018, 07:20 PM
#4
Racer
Looking forward to informed answers!!! Was starting to think I was the only one confused about this 
My understanding was no difference between 0-4000RPM then opens above that if PSE button activated.
My understanding was no difference between 0-4000RPM then opens above that if PSE button activated.
12-07-2018, 07:23 PM
#5
Rennlist Member
I believe
on start-up, the exhaust valves are always closed, and they stay that way (unless you press the sport exhaust button) until about 3,500 (or whatever) RPM, and then the valves open and the engine screams all the way to redline.
The reason the exhaust is loud for the first 10 or 20 seconds on cold start-up is because the motor electronics default to a rich fuel/air mixture to rapidly heat-up the cats. The purpose of which is to decrease initial emissions because cold cats don't work.
The reason the exhaust is loud for the first 10 or 20 seconds on cold start-up is because the motor electronics default to a rich fuel/air mixture to rapidly heat-up the cats. The purpose of which is to decrease initial emissions because cold cats don't work.
12-07-2018, 07:24 PM
#6
Rennlist Member
Evidently the GT3 Sports Exhaust is not a simple function of pushing the console button. I've searched but cannot find a detailed explanation of the PSE in my 2018 GT3. It appears that the valves are normally open so at startup exhaust is loud but as soon as vacuum builds they close as vacuum is sent to the valves by an electric solenoid. I've also been told that regardless of position of console button valves open above a certain RPM and even with console button pushed valves may open and close until certain rpm or speed is reached. Has anyone run across a definitive explanation of how this system operates.
gwt side muffler delete and it’s a non issue.
none of the other buttons do anything either btw
12-07-2018, 07:40 PM
#7
Rennlist Member
Thread Starter
so if I'm reading the posts correctly at some rpm (3800, 4800??) valves will open and stay open to redline regardless of console button position. Below that RPM?? pushing the console button will open the valves so you can drive around at slow speeds and irritate your neighbors or impress the throngs around your car at cars and coffee.
Thanks for the replies
Thanks for the replies
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12-07-2018, 09:08 PM
#8
Drifting
so if I'm reading the posts correctly at some rpm (3800, 4800??) valves will open and stay open to redline regardless of console button position. Below that RPM?? pushing the console button will open the valves so you can drive around at slow speeds and irritate your neighbors or impress the throngs around your car at cars and coffee.
Thanks for the replies
Thanks for the replies
Button off = valves closed at idle while stationary. Valves closed up until like 4K RPM or something like that. Valves open after that.
Button on = valves open at idle while stationary. Valves closed when you start to move. Valves closed up until about 3,800 RPM. Valves open after that.
So the only difference between PSE on and off is the sound at idle and keeping the car quiet for an additional few hundred RPM. Really... it's for cruising on the highway so the valves aren't open when you're just putzing around.
12-07-2018, 09:18 PM
#9
Intermediate
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No.
Button off = valves closed at idle while stationary. Valves closed up until like 4K RPM or something like that. Valves open after that.
Button on = valves open at idle while stationary. Valves closed when you start to move. Valves closed up until about 3,800 RPM. Valves open after that.
So the only difference between PSE on and off is the sound at idle and keeping the car quiet for an additional few hundred RPM. Really... it's for cruising on the highway so the valves aren't open when you're just putzing around.
Button off = valves closed at idle while stationary. Valves closed up until like 4K RPM or something like that. Valves open after that.
Button on = valves open at idle while stationary. Valves closed when you start to move. Valves closed up until about 3,800 RPM. Valves open after that.
So the only difference between PSE on and off is the sound at idle and keeping the car quiet for an additional few hundred RPM. Really... it's for cruising on the highway so the valves aren't open when you're just putzing around.
12-08-2018, 12:21 AM
#10
Drifting
Yeah that makes sense, thanks!
12-08-2018, 01:32 AM
#11
Manual on p. 213 says...
"When the sports exhaust system is switched on, the exhaust gas back pressure in the lower and middle engine speed ranges is reduced in the the variable exhaust system. This produces a noticeable increase in torque in the engine speed range up to approx. 4000 rpm." It doesn't say anything about the exhaust note, so maybe we should pay attention to the difference in torque delivery instead of listen for the exhaust note difference.
"When the sports exhaust system is switched on, the exhaust gas back pressure in the lower and middle engine speed ranges is reduced in the the variable exhaust system. This produces a noticeable increase in torque in the engine speed range up to approx. 4000 rpm." It doesn't say anything about the exhaust note, so maybe we should pay attention to the difference in torque delivery instead of listen for the exhaust note difference.
12-09-2018, 08:43 AM
#13
Instructor
There was a really good explanation of this a few years ago. I tried searching for it, but PSE is mentioned so often that it was going to take some hunting...
With the button not pushed, the valves close as soon as there's enough vacuum build up to do so and stay closed.
With the button pushed, the valves are open except in a mid-RPM range. The old thread had the numbers. It's something a little above idle to something like 3600 RPM. The purpose of that was to pass a European drive-by noise limit. So, it covers "normal driving" RPMs.
With the button not pushed, the valves close as soon as there's enough vacuum build up to do so and stay closed.
With the button pushed, the valves are open except in a mid-RPM range. The old thread had the numbers. It's something a little above idle to something like 3600 RPM. The purpose of that was to pass a European drive-by noise limit. So, it covers "normal driving" RPMs.
12-09-2018, 10:22 AM
#14
Rennlist Member
is that if going above 3800rpm in top gear on the highway (88mph or so with 7-speed PDK) the exhaust valves are open REGARDLESS of throttle position when the PSE is on and you hear the exhaust going 88-110+ even if steady throttle. Other cars hear you too.If PSE is off and cruising steady or light throttle even above 3800rpm, valves stay closed and exhaust sound is noticeably subdued. A little more stealth when zipping around other cars and cartel Suburbans, donkey karts, etc.
In short, PSE seems to affect PART THROTTLE behavior above 3800rpm more than anything else. For me, at least.
12-09-2018, 03:54 PM
#15
Manual on p. 213 says...
"When the sports exhaust system is switched on, the exhaust gas back pressure in the lower and middle engine speed ranges is reduced in the the variable exhaust system. This produces a noticeable increase in torque in the engine speed range up to approx. 4000 rpm." It doesn't say anything about the exhaust note, so maybe we should pay attention to the difference in torque delivery instead of listen for the exhaust note difference.
"When the sports exhaust system is switched on, the exhaust gas back pressure in the lower and middle engine speed ranges is reduced in the the variable exhaust system. This produces a noticeable increase in torque in the engine speed range up to approx. 4000 rpm." It doesn't say anything about the exhaust note, so maybe we should pay attention to the difference in torque delivery instead of listen for the exhaust note difference.