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That looks similar to an IPD plenum. They claim that it "provides substantial power increases of an additional 30+ horsepower and 32+ foot pounds of torque".
I'll say upfront that I'm not 100% certain with this specific component/application, but I seriously doubt you'll get any meaningful gain from simply replacing your stock plenum with one of these aftermarket designs. Perhaps if used in conjunction with other carefully selected components, this design might be of benefit in that case.
I base this off decades of experience with bolt-on aftermarket components such as this on many vehicles.
What are those two things bolted to the front of the plenum? They look like they connect to hoses covered in wireloom. They definitely redesigned some stuff under there for 2018.
What the heck are the two devices on the front of it - and where are those hoses wandering off to? Something new in the neighborhood.. odd that Porsche would make a late series change to the engine when the next generation out soon gets an entirely new engine.
BTW - on the IPD one - I have yet to see an independent back to back dyno runs done that shows any improvement. On a forced air system like the turbo it's unlikely that small changes in the diameter of the plumbing are going to make much change once boost kicks in. The up and down pipes to the turbos are small diameter on their ID than the ID of the stock plenum, so if there is a restriction, it's likely there. My WAG - work on making the valves larger is needed to really get significant power due to intake changes. Changes in ECU programming are likely more significant.
I wonder if they're to lessen the vacuum in the intake when the turbos aren't providing boost. Perhaps the square boxes have one-way valves in them, only allowing air to flow toward the intake plenum, and the two hoses go down to openings on the air-filter housing. Eliminating vacuum on the intake under those conditions might provide some boost in performance or mileage, and lessen the lag time for spool up. The one-way valves would work fine just based on air-pressure.
Another WAG so please pardon me if this is totally off but my GTS has those same pipes going into a valve near the air filter box, then passing through the box, coming out the other end and finally terminating in the A-Pillars. Porsche had added a sound symposer into some of their models starting in 2013 I believe so that when you turn on the Sport mode, the interior of the cabin would be fed with some of the noise from the engine compartment to complement the sport exhaust (that year there wasn't a separate button to turn on/off the sport exhaust separate from sport mode). Basically, once you press the button inside, vacuum pressure is created which open or closes the valves to allow sound to pass through the pipe. Looking closely, there is a similar diameter rubber hose to the left of the passenger side plastic hose that looks like it attaches to the housing where I'm guessing a valve resides near the intake.
I know I'm describing the effect based on a naturally aspirated engine and the turbo is different in that respect but curious if this is an attempt to replicate some of that same effect in the cabin.
08-02-2018, 04:39 PM
Plenum question?
