You're welcome. This is a time consuming Mod. The hardest part I found was getting the last bolt out of the intake plenum. I took the Plenum completely out of the way, makes installing the 987 air box easy. I didn't have a hard time at all putting the 987 air box in place. Second hardest thing, making sure you cut the silicone hose to the proper length. Tip on cutting the silicone hose itself, take one of the clamps and tighten it down on the hose were you want to cut it, then just use a box knife cutting right at the clamp, makes a nice straight cut.

No I don't live in a dream world. If you have some documented data on your HP gain post it so we can see.

Here is what I've done in five years of tracking a my car starting with the original 2.7 motor. I can say for some time I've run almost every configuration of air intake on track and have hours of data recording to back them up.

In the 2.7 with an smooth 3-1/4" inlet pipe upgrade plenum and 74mm throttle body stock MAF stock air box desnorkled. My recorded improvement is 19-20 HP

The next year I ran a Agency power box with a cone filter a SLIGHT improvement.

The next year I had the 987 box stock MAF. The rest was the same as above. I had "NO" improvement in HP or Torque. But I wasted an entire weekend getting it installed IHAVE NO PROBLEM SAYING IT WAS JERRY RIGGED. I could only get 2 bolts in it was cockeyed high in the front low in the back and towards the motor in the rear.

Using your prices the straight pipe throttle body and plenum would have been $170 without 4-6hours removing the intake injectors and all the other crap.

This is a fact I can say the 987 air box never was installed right until I removed the 2.7 motor to install the 3.2/3.6 conversion. It's flush to the cover now the flange had vibrated against the top spot Brad had previously mentioned and made a flat spot that was nearly through. It was bad enough I bought another one.

This may be the case on your setup with a 2.7L engine. I've read the stock ECU tune can only compensate up to a 20% increase in air flow. I've also read that the ECU can not correctly read the air volume when using the 987 MAF house without a tune. Sounds like when you put the 987 air box with the 987 MAF house you exceeded the 20% air flow, which would yield the car running lean and with the 987 MAF house a tune was needed. I'm surprised your HP numbers didn't go down.

It's also a known fact that Porsche put the smaller air box on the 986 to keep it's performance down. They cut the nuts off the 986 with that air box.

You do make a good point, in the fact you can get a 20 HP gain with just upgrading the intake from the stock 986 air box.

$170 to get 20 HP increase, hands down the best bang mod for the money. Really makes the UPD for $200 and 5 HP gain look even more silly.

I've always estimated I got a 20 HP increase, but always felt is was more. My brother who has taken many rides and driven my Boxster before the intake and air box upgrade. I took him for a ride after the upgrade and also let him drive it. I then told him about the header, cat delete pipe, Borla muffler, 987 MAF house and larger intake pipping with a tune plans. His exact words were. "Your car is too fast right now, you don't need to do those upgrades". He is 6'-3" at 260lbs, even with the extra weight of him in the car, his impression was the car is too fast already.

For those in the know then, should I look for certain year 987 intake 997 distribution T, and 996 TB? Same for every year? I'd like to start gathering all parts. Thanks.

987 air box are all the same. When looking for the 996 Throttle Body, make sure it came off a 996 model number 99660511501, some people will list them for a 996 and they came off a Boxster. The 997 Distribution T make sure you get one that looks like the one I linked to, the turbo models are different. You probably can't beat that price.

You could also look for a 997 TB model number 99760511501.

Anyone see gains on a 2.5, or is the stock air box 'right sized' for the smaller motor?

Pedro offers a kit.

TechnoPower Kit

You can have this guy bore your TB and do your own thing for the rest of the air intake system.

http://www.maxbore.com/pictures.html

Bang for buck mod
 

Kram, Did you end up shaving off the top of the 997 -T for clearance? I recall you expressing earlier in another thread of a thick ridge hitting starter.

I have not yet. I plan on doing it though. It's not a huge issue and depending on the car's transmission will depend if the starter get's in the way. The trans on the left is a 6 speed and the Tiptronic trans has the starter in the same higher location, so it get's in the way.

http://i60.tinypic.com/vdjz2s.jpg

Just talked with the man at Softronic. He said using the larger 987 MAF Housing will yield no gain with the 996 TB, is could also hurt the cars performance even with a tune. He also said do not go to a larger TB, like a 82mm TB on a stock 3.2L engine (no internal engine changes). It will actually hurt the cars low end performance. The 996 TB he says is what to go with and stick to the 986 MAF housing.

So all I have to do now is get my exhaust upgrades done, forget the larger 987 MAF housing. I will be getting a tune from Softronic as I want every bit of HP I can get out of this engine.

Bang for buck mod
 

Thanks, Thats nice to know we are utilizing the best combo of parts to up our ponies. And I hope you don't mind one more question. Just for clarity, for our 987 intake the only needed part is the unit and flat snorkel? I was concerned about the small rubber elbow for Maf to air but I don't need either.correct? Thanks,

umm ... so what was porsche thinking when they put it on the 550 and added 8 hp? the 550 is basically your engine with the 987 airbox / maf housing and a factory tune.

no gain? not likely. most likely no gain for softronic. you've been upsold. instead of 1/2 hour at your indy getting the spyder tune pushed onto your car, now you're out $800 to ... softronic.

The 996 TB can only move so much air, the 82mm MAF house would do zero good. I told the man I was more then willing to buy the MAF housing and the Maf sensor the 550 Special Edition came out with. He told me it would be a waste of my money, we got into discussing the air velocity and everything, it was quite a long talk. I was really surprised he took that much time with me. The 550 Special Edition only has 6 HP over the standard 2003-2004 Boxster S not 8 HP and that's at WOT. What was Porsche thinking? Save money and make the HP look as good as possible, while the around town drivability is probably not as good as a standard Boxster S. Come on TRK use your head about it.

I called two indy shops and neither could push a 550 Special Edition into my car as they do not have the tune. I asked how much they would charge to push the tune if I got it, $800 to push a tune. At least with Softronic you get the Durametric cable which will work on your car with Durametric software.

Yes, you could just get the 987 air box with the snorkel. Cut your 986 MAF housing off the 986 air box and plumb it to the 987 air box. I think you would still want to get the 75mm Honeycomb air straighter and mount it into the 986 MAF housing. You will have to shave a bit of plastic off the inside of the 986 MAF house to get it to fit (I used a dremel to do that) ,that also holds it in place so it doesn't get sucked into your your intake.

i don't think anyone ever recommended using a gt3 tb on a 3.2.

wiki lists the 2003/04 as 258 and the 550 as 266 - that's 8 hp increase.

as i've stated previously (in this thread, for example) the role of the intake mod is to go from a reducing diameter intake designed to accelerate the air and benefit low rpm power (your "around town drivebility") to an intake that works better at high rpm because it flows more air by reducing the amount of restriction (accelerating air takes work). so, either have an oem reducing diameter intake (did you notice that the oem air pipe on your car is a smaller diameter at the tb than at the maf housing? that the tb is 2.7" ID and the maf housing is 3" ID? - that's reducing diameter - as the air gets drawn in it has to either compress or accelerate as the amount of space available decreases - this accelerating air rushes into the cylinder and increases power. works good when the engine needs help breathing, but just gets in the way when the egnine is trying to breath hard) or mod your intake to move as much air as possible. putting on a big tb, big plenum, and big airbox, then leaving a restrictive pipe in the middle, does neither - it slows the air down instead of accelerating it, and it serves as a restriction to airflow. if you already have the big tb, big plenum and big airbox, then you are already expeneincing any loss of low rpm power you are going to experience - not much, is it? changing that one pipe sitting by your airbox is not going to reduce the amount of hp your car makes.

it took me 5 minutes with a pirate porsche pst2 to do my row flash. it is not an $800 job. the mechanics you checked with probably don't have the tool and are quoting you softronic, giac, pedro, or one of the others.

I suggest getting your 550 Special Edition HP numbers straight from the horse's mouth. It's only 6 HP more at 264 HP.

Special Edition Boxster® S Celebrates 50 Years of the 550 Spyder

"For added performance, the new Boxster S edition is equipped with the most powerful engine ever offered in the Boxster model line. Rated at 264 horsepower (SAE)"

Yes I am looking to increase the size of the piping between the MAF housing and TB. Was looking on eBay earlier today looking for some 74mm I/D pipping. Right now with the stock piping the car has no normal driving issues and when you drop the throttle, she goes like stink. I don't know how the larger piping is going to effect the car's drivability, but once I get it done, I'll share the information.

Bottom line is, the 987 MAF housing is a zero gain using the 996 TB. If a person wanted to use the 987 MAF housing, he would want to use the 82mm TB, but you would need valve work done to the heads. The stock motor just can not take in the extra air without internal engine mods. 996 TB with the 986 MAF house is largest you would want to go on a stock 3.2L, your power band is perfect with that setup, no normal driving issues and will suck all the air she can at WOT.

Got the larger pipe ordered, but it's coming out of China and had to order a fitting for the Tiptronic venturi tube from China too, then will have to have the fitting welded onto the pipe. So it will be a bit before I have any feedback on that.

Kram, Need another clarification, on the Honeycomb 75mm for Maf they come in different ratios for cells. Remember which one? Seems default on website is 4:1 ratio. Gathered most parts and getting jazzed!

The real problem isn't the 987 MAF or the 996, 76mm throttle body. It the stock 996 Plenum. There is a lot of engineering data some in this post.
http://986forum.com/forums/general-discussions/31693-maf-throttle-body-diameter-10.html
That discuss the problem, which is the Plenum design that create a massive turbulent blockage.
Then a spin off where a members was designing a retro plenum, very similar to IPD's design. I don't know where this led after the thread died.
http://986forum.com/forums/diy-project-guides/55966-intake-plenum-911-throttle-body-4.html

The IPD does make this transition but the price is somewhat objectionable to some members.

Pipe
 

KRAM36 where did you order the larger pipe from and what size was it?
I to am wondering if the larger diameter exhaust pipe will give me a pick up in HP
and still provide enough back pressure. My CAT by pass is 40mm.