LavaGTS

No knock on the mentality you have going on but you have to see the bigger picture..

Manufacturers almost always leave something on the table for the next generation or refreshed models... Think 992.

I don't think these Porsche Engineers go ***** deep into extracting as much as possible on every engine.

1analguy

I don't get this analogy. Are you saying that Porsche made the 991 engines too big just so they could shrink them down and plaster on some turbos for the 992?

mikex25

Needsdecaf

No, 992. Not 991.2.

///M3THOD

I wanted to re-bump this thread.

Anyone else install the plenum and have any insight? I am interested in putting on my GTS, but Im not completely convinced its going to make that much difference and the fitment/clearance seems to be a commonly complained about issue.

Im running COBB Stg.1, AWE Sport cats and a BMC filter on my GTS. Im assuming there should be more gains now that I am tuned, but maybe theres a place to better spend the money?

LavaGTS

4.0 says it gave him enough gains to pull on cars he wasn't pulling on before.. Its only 800 bucks and you're running a BMC filter anyway.. If you're not sold on it put it towards some intercoolers and comfortably run stage 2/3.

Can you give more insight on your tune? Been patiently waiting for you to post something but I didn't want to ask.

I have same mods as you add headers. I'm eventually gonna buy the plenum.. Through PM I was told by another member that the IPD made a difference at WOT.

PTS-BRG

I asked two guys about doing the plenum before I pulled my ECU for the tune as that was the time to do it. Both guys said don't bother, don't waste your money. One of them, who will remain nameless, actually said that they tested the plenum at COBB on a dyno and there was no discernible improvement. The other guy (also a hot rodder) said that the dimples and design should have zero effect on HP. He actually said "if fuel was going through it I would consider it but, all it does is flow AIR". He also said that the BMC filter should improve airflow more than a plenum could.

I am thinking that maybe the guy who was pulling on guys with the plenum that he wasn't pulling on before, might have also changed the air filter at the same time but, I cant recall.

I am all for cheap HP and I had the OEM plenum on the floor in front of me when I did the ECU pull and Air Filter swap and after looking at it I came to the conclusion not to do it. Believe me I wanted to and the labor was ZERO at that point. I just decided it wasn't proven enough to bother.

If real proof shows it to provide significant dyno gains I would certainly reconsider..

///M3THOD

PM'd you.


Thanks for your insight. I can see why It could flow better, but it picking up 20hp/20tq in the midrange seems optimistic to me... I could be completely wrong though. I wish I had decided whether I wanted to do this when the bumper came off for the filter, but Ill have a chance down the road if I want to do IC's.

4 Point 0

I haven't done the BMC as yet. I was waiting for the full carbon box to come out by aFe? I have seen dyno's of the IPD Plenum and whilst they didn't add anything up top, they did add some delta in the mid range.

So I figure combined with Headers for top end and a tune, they would work in nicely. I roll race frequently. There were a couple of cars that just beat me prior to the IPD, but that was enough to turn the tables and have me in front. So I am a believer it did something. But its not going to be like a Stage 1 tune lol.

I am more sceptical that the BMC would do anything other than Sound. Its great that 991 has MAP and not MAF, so no oil possibility of oiled filters fouling whats not there.

4 Point 0

I wonder if IPD will do the Y pipe for the C, CS and GTS like they did for the TURBO.

4 Point 0

I wouldn't be listening to those two guys. Have you ever heard of turbulence, low pressure or anything to do with air flow at all? The stock piece of plastic is a T intersection. You have air flowing in, then crashing into a DEAD END.

That cannot be good for flow. The air hits it square on and bounces backwards stalling further air coming in. Blind freddy can see that. The IPD design, is a Y. It channels the air to either side without any blockage or back pressure or back flow. As for the dimples, I gather all three of you don't play golf? It will definitely provide smoother better flow.

Now with all of this said, will that amount to much HP? Probably not much on a fully stock engine, but as you mod, it will have greater and greater effect. Similarly like headers. On Stock tune, won't do much, but as you tune more aggressively, it does more.

Changing an AIR filter will not have as much effect as removing a Dead end T intersection from the path of air. An engine is little more than an air pump. You want uninterrupted air flow as much as possible.

As with most air flow mods, they don't usually show much sitting stationary on a dyno. But when the car is moving fast, the better they perform. Such a cheap mod and you want to see SIGNIFICANT gains on a dyno. Doubt that will happen. But they show a dyno with some nice mid range improvement. Every bit helps, its the sum of the parts. Its also a fit once and forget about it, it's there for life. No maintenance. Set and forget and enjoy better flow forever. No moving parts, nothing to lube or tighten or clean or change. Set and forget. It was a no brainier for me. But I am a no stone unturned type of guy.

4 Point 0

991 don't have a MAF, they have MAP.

SeeForce

does replacing the plenum require a tune?

Aatish

If you wanna take advantage of it, yes.

kahane18

It did throw a CEL on my GT4 so I put a tune in it, Dont know on the 991.2's....