jjrho

hi, have a 991.2 gt3 manual coming at the end of the month… i m researching exhaust system…

first question is; on the PSE algorithm, is it true that with the PSE 'ON', the exh. valves are "closed" until the rpm hits 4k ? I don't like that cause the sound level does not really open up until you are above 4k rpm then … does anyone have an algorithm/program to override it so that the PSE button can manually close or open the valve regardless of the rpm ? also, does the pse button do anything else? like change the shift point on pdk or more responsiveness to gas pedal, etc ? if there is no over ride option, i will probably just put my own vacuum pump and ctrl the valves myself manually….

which leads to….

i've read as much as i could on various exhausts and mods…. what i'm looking for is something that is a bit more aggressive/louder sounding than factory oem setting on 'quiet mode' with no drone; so that i can cruise distance with wife and driving around my neighbor…. but on ' open/loud mode', want to essentially have a straight pipe effect…i.e. as loud as it can be…. even if some drone at certain rpm and gear….

for above effect, what has been the best set up ?
1. keep factory side muffler/valves and do a center muffler delete with various ones sold out there by gmg,sharkwerks, awe, fab, etc ?
2. take factory side muffler out and get one of those bypass pipes that retain a 'valve feature' so that i have some control of loudness, and keep the factory center muffler in ?
3. go with full valves systems from various makers….. like AWE, or whom ever ?

i realize this is a huge topic but I'm open to hearing all your suggestions and recommendations….

another options is just fabricate/installl a y -valve in line before the factory oem side mufflers after cats; (which is what i did on my e92 M3, with manual control…which is oem quiet to straight pipe level) but in a gt3, i don't' think there is room for me to do that in that tight space….

thanks for the replies….

james R
'18 gt3 miami blue, manual, pccb, ….
'16 huracan 580-2
'15 Viper T/A
'08 F430
'08 e92 M3
​​​​​​​'95 NSX

erik_plus8

Yes, with PSE ON, the valves close when you roll away from standstill and open again either when you hit 4000 or at a certain car speed. If you want the valves open all the time, just disconnect the vacuum lines to the actuator and plug them. Actuators are spring loaded to default open.

Dalema

AutoQuest MS

Hello James,

I've built plenty of these cars and know the different options quite well. I'll shoot you over a PM now so we can chat and make sure you make an educated decision

Palting

First, congratulations on getting your GT3 and welcome to the forum.

Next, the PSE button opens the valve at idle, closes it when you start rolling, opens it again at about 4K RPM. Claim is that there is better torque at the lower RPMs with the valve closed, better midrange and up with the valve open.

PSE button does nothing to shift points nor responsiveness to the gas pedal. PDK Sport button changes shift points for acceleration as well as engine braking. I find it quite annoying for street driving, to be honest. I use PDK Sport button only at the track. Should not be a factor since you will have manual trans.

For exhausts, there has been a whole slew of threads. There's one referenced by Dalema above, plus lots of others posted by the various manufacturers as well as RL'ers. Search is your friend .

erik_plus8

I am quite positive that the reason for closing the valves when rolling off (with PSE on) is sound regulation fulfilment. A higher static backpressure will never, ever increase performance. Gas dynamics (pressure waves) is a whole other matter...

jjrho

Ok, tnx for the replies so far...

yeah, I d like a valve control where I can have the valves such that it's always "louder" when PSE is ON... from idle to 9k.... not just above 4k....

if I go with IPE exhaust, what I may do is just install a vacuum pump n control the ipe's valves manually... and just for get the PSE button (good going the pse button doesn't change anything else for the car. ...

Money2536

I did a case study on this back in late 2014. I've chased operation without valves quite a bit. I came to the conclusion that they are necessary to eliminate drone. It is a myth they are there for low-end torque. It's just simply for sound.

https://rennlist.com/forums/991-gt3-...st-valves.html

BlazinPond

At least in my 991.2 GT3, valves typically cycle around 3k rpm's depending on how much accelerating I'm doing.

I'm still getting a new exhaust. Miss my full akrapovic system on my last car.

jjrho

Ok... then how about the ipe exh for gt3?

they claim that their valve control is via a remote control n that you can have 3 modes.... valves open all the time, closed all the time. And automatic... which seems to follow the PSE ECU algorithm....

is this true? Any one with ipe exhaust for gt3 that can comment on this ?!??

AutoQuest Motorsports

jjrho just shot you a PM, I'll guide you through this. It's not complicated to accomplish what you are trying to do, you just have to know how to do it

erik_plus8

I agree. Static back pressure never ever will increase performance, as I have stated several times.

Curious to know though, if you have concluded what causes the 2000-3500 rpm drone? I mean what part of the system? I don't know this, but guess that the sides are bypassed with valves open, right? That must mean that it's the center that causes the 2000-3500 drone? So with a center delete, there would be no drone? Or am I completely wrong?