Well there is the answer. It’s just not comparable to use your experience on the 3.0L in a 991 to draw conclusions about IPD parts on the 3.8L 991, much less the 3.8L on the 992. Apples and Oranges.

 

Whatever you say. Enjoy the plenum.

 

I picked up 2 mph in 1/4 mile trap speed. It was worth it.

 

Sorry, but I don't buy that IPD Plenums achieve a single thing except to part one from their money.

I have never seen any independent third party (that doesn't stand to gain from their sale) show any gains from them. In fact, some time ago I started a thread in the regular 992 forum about this topic asking about this and I got crickets.

The only information I could find was a video that I posted where a 997 with an IPD plenum was run on a dyno. Compared to stock, no gain. I'd love to be proven wrong, but I still keep hearing crickets.

 

intake restrictions should show up on a dyno as choking the area of highest volume of flow which would be at the peak of the HP curve towards redline. Reducing restrictions should show gains in the upper rpms. The engine is an air pump. Exhaust restrictions lead to dimished turbo spool, which then robs lower end power and torque. Removing exhaust restrictions should result in faster spool and more power earlier.

 

I try not to argue too much on the forums anymore, I learned my lesson

Everyone will have their opinions on parts and they are entitled to them. As far as picking up 2mph on a trap, it could be tire pressure, track conditions, tail winds, better fuel, cooler air and maybe a dozen other reasons, but again if you are happy with your purchase then the only person that needs to care is you.

 

Totally agree there are dozens of factors that could have contributed to the trap speed increase - after all, I didn't run the car, install the plenum then do another run all at once - it was a week apart and a lot can change. I felt a difference driving the car before versus after, but a seat dyno is hardly objective. Still, I believe the customer dynos I've seen, the tuner recommendations I've gotten and the anecdotes I've heard from others with my same platform - and they were collectively enough to convince me to spend the $1K for an IPD Plenum. I see a lot of local 992 TTS builds with the IPD plenum as well... probably not every 992 TTS owner is wasting their time and money on this.