I will vote for the intake plenum also. I haven't seen 25hp on the dyno but it is a good mod for the money.

 

We've used this well engineered approach on several occasions for race oriented applications. The process has been available for a long time. It definintely has it's substantiated benefits for improving inner wall smoothness and thereby flow, in addition to enlarging certain materials. I do believe that in the case of the street 996TT, it may not offer much in terms of pure HP/TORQUE gains. Once the engines intake is pressurized, the intake valve(s) see basically higher than atmospheric pressure on that side of the combustion chamber, hence there is where the air pressure(boost) is arriving into the combustion chamber. Normally aspirated engines fair better with attention to intake message. havefundriveporschetakechances-Mark

 

I don't mean to be a sceptic, but show me a a base line dyno and then a dyno with the new intake. 25 hp is alot. A slightly larger intake and 25 hp? Is it all across the power band? Does it give you peak horsepower at a certain speed? 140 to 160 mph? I'm sorry, but I find it very hard to believe Porsche engineers left 25 easy horses on the table.

 

The intake plenum is a part made by innovativeprodesign.com (check the website for the dyno sheets and pictures). Basiclly, porsche left this intake plenum as a T shaped air splitter which creates a lot of turbulent air. This upgraded plenum turns it into more of a Y shaped air splitter which increases airflow to the cylinders. I saw Mike(owner of innovative pro design) doing dyno pulls on the GT3 with this plenum and if i remember correctly he was gainig around 11hp. I think he claims more like 13 or 14hp for the turbo cars but check the site for more accurate numbers.

 

 

I notice that is at 1.1 bar. Doesn't seem like a stock program. Was the baseline done with or without the stock program. There are so many variables and information, or lack thereof, to show a clear benefit. How long was the time lapse before each pull? Which pull was done first? Is it the same car? What was the temperature? See what I mean. From what I understand, they are increasing airflow. What is the difference in the airflow from the stock intake vs. the modified intake? How much are these plenums running 1000.00 bucks? I need more proof and information than that.

 

I just posted what was on his website. I think he has air flow diagrams also to go along with the dyno charts(not sure if they are on his site or not though). Ya,you are right, that is not a stock progam if it's at 1.1bar(I agree that it should be a stock program).

 

Eric's info about the T vs. Y design is correct. My dyno runs were done with GIAC programming, exhaust, and K16/24's. One pull with that equip. then installed the plenum, about an hour, then did it again. 24HP midrange gain beween 3500rpm and 5500rpm. I have no reason to lie, if there were no power benefits then I would have taken it off. All these "little" things add up. Thats why I got 500rwhp on these little 16/24's!

 

I also have the Y design and the 76 mm TB.... it's an aluminum piece that goes behind the TB. The other thing most people never change is the intake plenum that goes from the air box to the turbos... I had the FVD one it was great.
now I have this not painted YET. Y pipe and 76 mm TB

 

Sounds as if Mr Blonde and 9eleven understand more that others about what's really going on out there. Every few weeks we get one of those "tricked" out turbo's in with issues. BOOST is EVERYTHING, getting up to boost is reletively minor in terms of orginal performance VS a ton of "little things" that add up. ALL those "little things" cost BIG BOBBY DINERO. Ohh, one item too many enthusiasts leave to their imaginations is the ability to SELL/DUMP the albatrose that they've spent sooo mooocho on!
Nothing more exhaspirating than to see a beautiful GT2 that's been gang raped!-No doubt Mr blonde and 9eleven seem to be in the right lane on decisions. Amazing wizards out there; we're sure Porsche is watching every move they make and tries to emulate them Gotta go-have a date with the disassembly of a cup engine-BTW-in building engines, the MOST important part is the disassembly-Mark-FormulaMotorsports

 

Hey guys I really appreciate all the discussion and opinions.

I'm in the situation where I have a "cost no object" street car already - my beloved BMW M Coupe. My 996 TT is my daily driver, hence I have different goals with modifying it. I want to err on the side of good value for money and retaining good manners and creature comforts.

My choices would be very different if my Porka was my pride and joy. I would be far less concerned about understanding the performance gains for cost (and time) for every little mod.

I don't judge anyone for what they decide to do to their Porka - it's all good. Just a matter of different goals for different people.

It seems to me that the really good value for money path in modifying a 996TT - given that you retain the stock K16 turbos - is to add your muffler and 100 cell cats of choice, then get the corresponding ECU upgrade.

I am convinced the silicone hose kit and billet DVs are non essential. I feel similarly about headers. I want to know more about the EVO MS V Flow intake and what real world gains have been found.