ThePartsMan

If you have, or have had one installed, please post performance results.

simsgw

Okay, I'll bite. What is the IPD Plenum? I don't remember that on my order sheet.

Gary

rpilot

Mods made by people who think they can do better than Porsche...

http://www.ipdplenums.com/

Of course, I have no clue what they do, besides voiding the warranty I am sure.

chuckbdc

According to the site, IPD plans to have them available in January. Given what Porsche says is needed to get ~30 more HP, it seems like a stretch that a plenum mod is going to do much.

simsgw

Hmmm. I've heard the name, and sincerely hope they don't sponsor this particular forum because I have to say I would be worried first by their getting the displacement wrong when talking about the base Carrera. People selling aero aids can make that mistake and it's no big deal, but engine mods should be created by people who know the engine.

Never mind. Ascribe it to a website person interning from the local art college.

This bothers me more:

I can't argue the degree of difference in the 3.8 S engines. I haven't looked a the tech specs myself. But if the differences from my 997S to my 991S engine are not in basic changes, changes on which Porsche plan to build higher output versions in coming months, then I am puzzled. That leaves tuning refinements in areas like air flow and my 991S already gained 15 hp over my 997S.

How can a plenum change that yielded about fifteen aftermarket horsepower do the same thing for the original engine and for a version that just got bumped fifteen horsepower by the factory?

The only plausible answer would be "the factory changed areas we don't touch." Which ones I have to wonder? Given the assertion that the engines remain "relatively unchanged". They presumably haven't opened the base engine yet because it would be hard to assert that when the factory reduced the displacement while increasing the output. But we'll stick with the 3.8 S engine and ask again what the factory changed while overlooking intake air flow?

Gary, a grumpy old skeptic if truth be told, so probably best ignored

TTCarrera

I installed an IDP Plenum on my '08 RS60 Spyder, along with the programmable ECU re-map from Softronic.

Oversimplification: The larger plenum allows more air to be sucked into the engine's pre-ignition area faster. The ECU remap permits a more aggressive ignition timing in the 6 cylinders and a slight increase in redline (maybe an extra 300 RPMs I think). Result is more horsepower.

How much? I don't know, I never bothered to spend time & money to have the car dyno'd.

But I was VERY happy with the increased acceleration.

No warranty issues. Never had a CEL, never had the dealer object to the aftermarket plenum, never had Porsche's diagnostic system object to any engine abuse (although I did, as a precaution hook up my laptop and return the ECU map to the factory program before taking it in....then bump it back up after the car returned).

I would imagine that after a year I might be looking for more horsepower for the 991S and I would certainly look at these options closely.

exponential

For N/A engine, ECU shall yield some power but not so much.

However, for the plenum ?????

GSIRM3

Your ECU remap and 300 rpm redline increase also = voided warranty.

TTCarrera

Then Porsche forgot to tell me when they continued to honor it.

But you probably know best.

TTCarrera

Plenum was less.

I installed the plenum first and got a little bump. Then the remap added a bigger bump. It felt like an extra 10 HP, taking the RS60 from 305 HP to what seemed like about 315, which is a little less than they claim for this combination.

I never measured it on a dyno because it wasn't important to me, but my seat-of-the-pants dyno felt like about an extra 10, which is not significant but is material.

My experience is based upon owning and tracking 14 Porsches over the last 36 years. Your experience may be different.

chuckbdc

That small a % increase in power would be inside the variabilty range due to ambient temperature, atmospheric pressure, fuel sample or mixture. So no telling what caused the feeling in the seat of your pants.

neanicu

This thing is a big waste of time and money IMO.
We modify for the sake of doing something to the car,we get bored after a while and think of changing in order to make an already good product into a ' better ' one(I think I'm guilty of this too).That's not always the case.
Do people even realize how hard it is to obtain even 15 HP,real HP to the wheels from a normally aspirated engine? Very hard! Porsche wants 15K$ for measly few HP,but at least you know those are real. 15K $!!!
IMO this plenum won't give 2 HP let alone 15!
As much as I know,the engine is like a lung,in order to get more power,yes,you do need to get more air into the engine,but if you don't do anything to let more exhaust gas out,there's no increase in power. Do the Plenum,tune and exhaust and maybe you'll get 10 HP.

TTCarrera

You're right. It could have just been an exceptionally good second-half tank of gas on the the day of the transition. And the first half-tank that day, not so much.

You know, this setup may not be for you, so don't try it. I was just responding to the inquiry for information in the initial post, about an IDP Plenum?

TTCarrera

We agree. The RS60 Spyder came with the extra exhaust throughput over the standard 981S. That's why I added the plenum and the ECU remap and got the "maybe 10 HP", per your recognition above.

chuck911

Was just wondering, for the sake of argument say, if maybe a lot of us hold the underlying assumption that every motor model Porsche builds is somehow a perfectly optimized example of all that can be done at a given price point- which often seems to be the unspoken assumption- and if maybe that assumption is not so well founded. What I'm getting at is that it very well could also be that Porsche KNOWS it would only take a simple part change to gain 15 hp, BUT that if they did that then it would set ripples in motion that would spread across their entire marketing program where at some point suddenly it becomes VERY EXPENSIVE to keep,say, the GT2 or Turbo S an appropriate number of hp above the model just below.

If this is true it would explain a lot of things. It would explain what Gary just mentioned about an engine being initially overbuilt so as to facilitate future hp gains. They get big economies of scale doing that up front. Then they get big marketing profits by dialing in incremental hp as the years and models go by. Virtually all those gains COULD have been done from the beginning. But that would leave marketing dollars on the table. And, in fairness, they learn a LOT more about reliability taking the incremental approach.