That is a nice change... The previous design looked like it might have reduced flow vs the new one. I guess the initail design was beta version! This is more in line with JCR and SOUL's offering.

 

Hi, interested in your Valvetronic Exhaust and GPF delete for the 4.0.

Will it create the pops/cracks/gurgles on decel like the PSE on the 981 and 991?
Is that effect prominent with just the GPF delete?

Thank you for doing noble work uncorking these!

 

My OPF delete pipes arrived last weekend and I ventured to install it myself.

It’s a fun task and not so complicated.

Suggestions based on my experience:
1) You will need to take the center diffuser piece out. Remove the 6 screws that hold it in place and slide it towards the back of the car.
2) The studs on the OEM header and on the OEM OPF canister flanges are fixed. 3x 13mm nuts on the header side, and 5x 12mm nuts on the flange, from the muffler side of it. Get some long extensions for a Socket drive to help remove the nuts on the header side. One of them is harder to get an angle so you will need a 13mm ratchet wrench.
3) On the muffler side of the flange, the top and the 2 o clock nut are quite hard to access. It’s possible but there will be some arm contortions to find an angle, and patience and some swear words.
4) after removing all 8 nuts on each side, there is no way you can take the OEM pipes out without sliding the muffler back, as both ends are on fixed studs.
5) this is why you need to remove the center diffuser cover I mentioned before. Now you need to get an E-12mm e-torx socket and remove the two screws holding the rear muffler to the transmission case bracket.
6) one thing I learned the hard way: When I did slide back the muffler, the left vacuum valve hose came off from the T splitter that sits on top of the transmission case. The hoses from this splitter to the valves are fixed to the muffler so pulling it back disconnected the hose there. Needless to say that I only found out when everything was reassembled and I drove off the car. Now to reach that splitter with the two hands and plug the lines back on you need to remove the diffuser and the transmission belly pan. Not fun at all.

so a tip to who will undertake this by themselves, be sure that before you close up everything, and before you put the nuts and screws on the new link pipes flange to the rear muffler, make sure the vacuum lines on the T splitter are connected. Even if you plan to unhook the hoses and plug them, I suggest you do that on the both ends that connect to the muffler because those are very easy to access, plus when you plug them with the screw, you don’t get vacuum leaks.

 

I’m happy with the results. The system even with the OEM muffler got considerably louder/uncorked with the valves open. At 7000 rpm is a sweet singing bird! With the valves open all the time, there is a bit of drone around 2000-2500, so one can find it a bit annoying on a long cruising trip at steady speed. But accelerating and doing the auto blip downshifting it’s really really sweet.

With the valves closed it’s as quiet as with the OEM pipes, with some occasional burbles on decelerations.

I believe most people will be happy with this mod only and won’t bother spend another 3 grand on replacing the rear muffler.

Obviously I can’t compare with the other manufacturers like Soul, JCR or Akra. I would imagine that the pure over axle pipes replacement won’t be materially different as it’s a bent pipe more or less at the same angles. The difference between manufacturers will come on the rear muffler replacements I’d think.

 

The wait is over! Fabspeed Motorsport 718 GT4 Product Suite is live! Take a look at the options available (with more to come) and feel free to PM for forum pricing!

 

I like the OPF delete option and the design looks great but I'm not liking the prices. It's a pipe with a Y and 2 flanges, $200 - $300 would be reasonable, $500 on the outside. $1000 + is absurd IMHO. I'm not naive, I've been in the P-Car community for 4+ decades, I know prices have become nose bleed high for quite a while. That doesn't make it right.

 

Not disagreeing with you but if $1000 scares you have the paddles close by when you see the cost of Titanium pipes!

 

$1000 doesn’t scare me and I’ve had titanium exhaust, never again. I’m actually an Inconel fan.

I’m just saying $500 or so would be more appropriate for a SS bypass pipe. There isn’t really a lot of material or engineering required for this part. I understand the price of the rear section, they are much more complex to develop and build. I guess what surprises me is the significant jump in prices over the last decade. Fabspeed has always been a premier builder with reasonable prices so this was a bit of a surprise.

Then again, I never expected to spend over $100k for a Boxster either

 

To be fair, Akra's OPF pipes (which are both Ti and come with heat shields) are roughly the same price as these stainless versions from both FS and Soul. (and that includes shipping from Europe rather than continental US)

 

My point was that all of the OPF pipes mentioned are far more than $1000, and if you are not located in the US and paying in your 'home' currency the cost is much higher!

 

Dyno For the 718 headers!

 

Is that only with the headers and everything else OEM?

 

Great question TD and yes it is only with our long-tube race headers.

 

What are the gains with headers, OAP and valves rear box??

 

We will be testing this shortly. We have multiple R&D project being completed at the same time.

As for the headers here is the process for how we were able to achieve such fantastic gains.



Our design process started with 3D scanning the entire exhaust system using our CREAFORM 700 HandySCAN so that we could make a complete Solidworks 3D model of the exhaust. We then designed the exhaust and fixtures using that model so that the exhaust fit perfectly to OEM standards. After revisions for sound and dyno testing we settled on using 1 7/8 inch primary's compared to the smaller 1 3/4 inch factory primary's. The primaries are mandrel bent using CAD designed model that allows us to achieve the optimal primary length and bends for best flow and scavenging at the collector.



The headers a T304L Stainless steel