Personally I do not know on the flow on lower boost. My whole build was based on bigger power and higher boost. Personally I just see better flow as a positive in your scenario, you will gain more under the curve ala why the gt3 has the most flow (via manifolds and heads). I could always be wrong lol.


I hate that!! lol. You know what you want and you can picture in your mind but just can't find it lol.

 

I'm thinking the same thing but just trying to get educated on the various options out there. I've pretty much nailed down 80% of this project and just looking at some options on the intake and heads/valve train. I plan on calling Tim after the holidays and picking his brain a bit.

The larger 74mm 997TT TB is also a tempting option but you need to use the IDP plenum with that for which no one has ever been able to supply any solid proof of improvement. If you do a search you will find more guys that claim they have lost power over those that have gained some. I can see why Porsche made the T-design the way they did on the TT as the two banks need to be able to cross talk with one another since they don't have the extra resonance tube like the GT3s The little splitter/diverter in the IDP plenum would seem to interfere with that.

 

do you have the oem t/b? mine came with a 75mm t/b from a n/a car(boxster?) i think and when the motor came out i found a ipd early version plenum! no idea if there were any real gains as i never had the stock setup

 

Yes. RUF uses the standard OEM 68mm TB. My intake manifold past air filter/MAF is bigger and also the turbo intake pipes are larger. Everything after the ICs is stock. The OEM 996TT/GT2 TB is a 986 Boxster part. The 997TT/GT2 uses a 74mm TB.

 

I had 68mm plenum last year and now 82mm competition gt3 style plenum, i can look for some dynos at the same boost and tune, but they are very similar for sure, IPD maybe shifted a bit to the left the power band... I guess where the tb/plenum shines is at high boost allowing more and more air to move faster, again 1.3bar isnt high boost but rather very close of the stock boost

I would see a real benefit of tb together with a complete heads job, not saying that by itself doesnt do some improvements but isnt the most efficient mid for the buck and really counts well above 700hp, just my opinion

 

Car just went in for a gt3 intake. I'll be selling my 997tt intake in like a month or 2 if anyone is interested.

 

i might be interested if it isn't to costly and is complete for the 996 tt

 

Long story here: http://www.renntrack.com/forums/showthread.php?990-Newbie-Q-s

(But you need to be registered to see the pics.)

Short version follows.

I went to complete aluminium 997 GT2 intake system few years back. With proper OEM Y-pipe and all, including standard VGT turbos. And it still has 996 base engine. It produced very healthy peak TQ and HP numbers, but had enormous problems around 5k rpm, a dip in the curve that was impossible to cure with local skills.* Last winter I changed to 997 plastic intake with IPD plenum. (Last one because I got it very cheap... ) Only other change was larger silicone feeders to turbos. No changes to tune. Peak HP and TQ dropped few %, but curves are as they should be so AUC is much larger.

I asked about this tuning issue a lot, and the answer I got was that 997 GT2's ECU has completely different math core and VE calculation base than 996's. Because of that ME7.2 cannot be programmed to handle 997's expansion intake manifold principle. Also 997's higher boost pressure may have something to do with this. Again 1.6 bar is more than ME7.2 can handle. I was -and still am- running 1.3 bar.
So IMO one should try 997 GT2's intake only if they are using a standalone ECU and have a good tuner.

OTH IMO base 997 turbo's intake is an improvement to 996's.

Regarding to non-standard TB sizes vs Y-pipe and silicone transitions, use them only with good t-bar clamps or similars. Make sure that trasition's lenght is correct, or maybe a bit too long than necessary. Even a slightly too short will pop off.

Anyway, if someone wants to try 997 GT2's intakes, I have an extra pair, associated OEM plenum and few different TBs for sale.

* I asked help from a couple of well established tuners abroad, and they also refused. Would have done after switching the intake...

 

like i said pete i might be interested if the pricing is right and complete . I'm standalone with a greta tuner who is familiar with using these setups

 

I'll PM you tomorrow or the day after, when I get back home from holiday. Installed pics in my trhead at renntrack...

 

Good read Pete. You have patience my friend. I would have burned the house down a long time ago, lol. Glad it all worked out in the end. Did you do any work to your head/valve train as part of this?

 

i beg to differ, although i readily defer to your depth of knowledge on the topic, i can only add my barely relevant experience. my experiential and anecdotal results by having simply switched to the 68mm ipd in concert with the oem tb have shown noticeable gain in the low to mid range, and tq was what i was seeking to improve. e.g. more low end grunt.

i'm reasonably certain ( if you a/b the two pieces ( oem vs the ipd design ) together side by side ) that the ipd plenum Y design is an improvement over the T design of the oem plenum and results in an increase and/or less restrictive airflow, and i'm fairly certain, the ipd does not impede "cross talk"? but that is just pure conjecture on my part! but ipd must have made them and sold them successfully for this long for reasons other than results based merely upon conjecture. my point being, i certainly haven't lost any "gain" and in fact may have gained in real terms, beyond even my "seat of the pants" assessment..

..once installed, that became immediately obvious to me, while any gains would ( i believe ) also become immediately obvious to a discerning driver such as yourself.

i cannot imagine that would be any different, by your upgrading to the 74mm w/997tb or possibly even a 78mm? setup? especially if you're about to embark upon the 3.8? ( or is even a 4.0!? re-build which i look forward to following, as you begin and progress ...just my 02

 

How much are stock 997tt intake manifolds selling for?

 

I get it Mark. I'm just going off of a simple google search regarding the plenum. Like I said, there are numerous reports of guys that have installed these on 997.1TT only to take them off after experiencing a power loss. Then you have tons of reports of other Porsche applications where people report they can't honestly tell any difference at all. For obvious reason, I certainly don't believe any dyno numbers provided by the manufacturer. Call me a bit of a skeptic. I have also talked with a number of guys/builders who are way more knowledgeable than myself that have brought up the simple fact that the T-tube arrangement is set up that way for a reason, not simply because Porsche was too cheap or not smart enough to make it like IDP. Allegedly, the reason for the T-style is so that the air can resonate back and forth as the intake valves open and close. The TT does not have a resonance tube to serve this purpose like on the GT3s. I know this is all complex fluid dynamics stuff but bottom line is the simple fact that Porsche likely would have done it differently if there would have been an improvement. They're not stupid. I have a customer that wants to try the plenum/TB on his 6GT3 and we might try it but we will do before and after dyno data to see what we get. I will do the same on the TT to see if there is anything there. Pretty much anyone will tell you that the claimed 35-40 whp improvement claimed by IDP is wishful thinking (marketing). Realistically maaaaby half that on a lucky day. My butt dyno is just is not sensitive enough to discern such a small amount.

Then you have companies like RUF that go to great lengths to make their own post MAF cast intake manifolds (which can't be cheap) and turbo intake pipes, yet they leave the intake plenum untouched. Don't tell me that during development they didn't look at that area as a place to make an improvement? I certainly would. A couple of years ago I spoke with one of the techs in Phaffenhausen and asked why they didn't go with a larger TB/plenum and he basically told me they would have if there was an improvement there.. Both their 550/590 engines retain the stock TB/plenum. All of this makes you go hmmmmm...

I am looking at all options for my rebuild especially if simple bolt ons might add a benefit. I would love for the IDP 74mm plenum/TB to be the magic bullet for the rather modest $900. That would be fantastic. As I said, I'm a bit of a skeptic. I wish it was all that simple but I've learned in most cases that the old saying "if it sounds too good to be true, it probably is", still mostly holds true. My engine rebuild will be a modest hp engine so the question remains what benefit the larger TB would provide at that level. I think I have already pretty much scratched the 997TT intake off the list as there is too much unknown there and I really don't want the deal with rerouting a ton of vacuum lines, etc., for an unknown improvement. I just don't wanna open up a can of worms. I'd rather throw the money into better valve train and bump up the redline a bit.

 

i'm sure you'd be right that ipd's numbers as posted would be optimistic at best, and i'm also of the mindset that porsche *usually* get's it right the first time, but then, we all have some mods or other that we would all consider to be an improvement, and i believe the ipd plenum to be one of them.

i would venture more folks that have replaced with the ipd, whether the 68 or the 74, have kept them, rather than removing them after. but i'm just guessing, i just believe you're on the right track when thinking about how to get more air in and i do believe the way you mentioned, in spite of your doubts might prove to be a good idea. ultimately though, i'm sure your car will continue to be a benchmark for many of us. so,.. was just something to ponder.

ADD: you'd feel +10, i know you would. i do lol