GAZZ

Silence before mod and very quiet after mod.

Peter_GT4

Not the way to go in my opinion. Disconnect the hoses (I could do it easily by hand with moderate force). Insert grub screw in M6 size and thread it in
with a t-handle allen wrench. Use pliers to hold the hose while doing this. The grub screw should be inserted about 20mm into the hose, so you can
completely re-attach it on the exhaust valve. Same procedure on the other side.

Benefits: Invisible, no open ends to be sealed, cheap and quick. Also easy to undo by screwing the grub back out anytime

Peter

GAZZ

Good method.
Gook luck to any Tech in the future if this mod is forgoten about! haha

Also, what I did in the 80s to bypass power robbing emmisions plumbing.

DocMo

Agreed. I’d like more sound in downshifts (I am still under 4500rpms)

DocMo

Well done. I prefer your approach. Any pics of the grub screws used?

spyderphile

Now, this is NOT good!! This is gonna drive me up the wall! No downshift-blip sound after 4k; and, not enough sound under 4k either! This is pretty f^&*k up!! So, fundamentally, the valve flaps are not the only ones suppressing the sound, during downshift-blipping. Not the GPF or pass-through inert filters because their effects are always present regardless of the RPM. So, even if you delete them, you are not gonna get that sound. Certainly not the exhaust. Is that engine management programming/ECU?

GAZZ

Im devastated as well. But dont worry good Rennlisters, we will solve this "problem" together. Been consulting with tuners today...

DocMo

At this stage, my guess based on other cars I’ve owned with GPF is that once we we replace it by a pipe the downshifting and upshifting sounds should be back. I am confident tuners will make it happen

spyderphile

Counting on ya, GAZZ! Help us out! I NEED that sound! As you're a 981 GT4 driver as well, you know exactly the pain-points!!

Hope you're right, Doc! Guys like you and GAZZ are the pioneers to lead the way! Let's make it happen!!

JCR-Porsche

OPF is only part of the issue. The stock rear silencer is far more of a bottle neck than the OPF and due to no mixing from bank 1-2 with valves open (as per pretty much all of the aftermarket systems) the main cause of the flat and uninteresting sound.

Remember you're hearing 2x 3cyl sound rather than 1x 6cyl sound with this stock exhaust arrangement. Think of it like the exhaust sound is akin to a pair of 2.0 3cyl engines, not really what any Porsche owner is looking for.

See image below for a visual demonstration. Green flow is valves open, the gasses will always take the path of least resistance. Red is valves closed.



Removing the OPF will just accentuate the OEM exhaust note, it gets louder with the OPF removed but louder doesn't always mean better. In many cases, as with the 718 rear silencer arrangement, the sound is even more 'tractor' low frequency tone than ever.

Just a word of warning as to what to expect if you remove the OPF with factory exhaust or swap to any exhaust with no proper merge between bank 1-2 of cylinders.

Making an exhaust loud is easy. Making an exhaust add power, sound great and be quiet / loud when you want it to really isn't.

JC

GAZZ

Fully agree with comments above from JCR.
It will be interesting to see the above system with OPF/GPF bypass pipes. Maybe crazy loud because almost totally straight through with no muffler.

JCR-Porsche

This gives a pretty good illustration too.

2017 RSR (pre LM) had the megaphones straight off the headers. So again 2x 3cyl sound, as per OEM 718 GT4 design.


2017 RSR (LM spec) gathered the tips at the centre so you hear the full 6 together. Note that this still has no merge but just graphically shows just how much difference it makes to the sound. With a merge the sound would be even more in this direction.


The latest gen RSR has side exits so even further accentuates the 2x 3cly sound track.


I'd challenge anyone to find someone who doesn't find the central exit sound the most desirable!

JC

d00d

Good analysis, with no merge it just sounds farty.

jvmax

will report back on disconnecting the vacuum lines this weekend. I am really starting to think the 981 gt4 is the better car. If you just compare price when new, $86,000 for a base car without options including delivery compared to a 718 gt4 at $100,500 without options including delivery. Now you have to add at least $5k to fix quiet exhaust. So far I am really disappointed and wished I kept my stripper 981 GT4 that I sold a few years ago due to the hype the 718 GT4 was getting a 4 liter

718GT4.0

Yup, for what you paid, you should have picked up a used GT3 as you've lived the GT4 lifestyle. I wouldn't have ordered a 718 if I was already in a 981 GT4 I loved.