987 Airbox-Worth it?

[Robert986]

Thanks boys, maybe I´m starting to understand.. So, my car is the 2003s ROW as I understand it it should as standard be sporting a 986.606.125.01 MAF-sensor attached to the narrower housing. The 987.606.125.00 would then be the larger housing complete with a 986.606.125.01 sensor inside.. Did I get that correct?

So do I want the larger or the narrower MAF housing..
I believe that I should strive for a air-path with a smooth but slightly decreasing diameter all the way from the airbox to the plenum. Thus I take it that the larger MAF is the way to go, just ensure that the piping gives a good decrease in diameter downstream, and since I will be using a custom tune I guess the cost won´t be too overwhelming just for the MAF-tune part.

Please enlighten me if I still got it wrong!!!


Some more thoughts.. I am starting to believe that the theoretical dimensioning to strive for should be:
1) Go from wide to narrower in the airbox, MAF, Throttle body, to accelerate air and give good cylinder fill at lower rpm (as stated by TRK). By keeping the whole chain larger than oem, it will still give more flow at WOT, thus more power.
2) Here comes the strange part.. I believe I have read somewhere that the plenum, or (maybe the chamber between the plenum and the intake runners) should be basically as large as possible, to act as a "air-reservoar" with enough air to provide the runners with enough air. (Have I got this 100% wrong???)
3) Then the runners.. I guess the runners must me "wide enough" but not least quite long.. The length to achieve some momentum in the air (more air mass accumulated) to provide cylinder fill at lower rpm:s, thus the 996 intake / runners are preferred.

All in all I´m sure I got at least some part of the above bullets 1-3 wrong. Let´s discuss! :dance:

[maytag]

Originally Posted by The Radium King

.....small gains overall, and not worth the work of modifying the programming on your car when you can just use the original maf housing. i did it for (a) oem look, and (b) i have a pst2 and wanted to run a 996 tune on my car.

So I'm moments shy of buying a PST2 for this same purpose.
I understand from other threads that I'll need a 996 VIN and associated password, in order to load that 986 flash to my 986 DME. (Correct?)
In anticipation of this, I called my dealer today to see what it'd take to get them to help me with that VIN and password. No joy. They basically mocked me, that I'd think they'd just hand that out. They're kinda dicks over there.

So, question: some of y'all who've done this (TRK?) Do you have a VIN and associated pass code you can share? And if not, do you know a dealer who is supportive of this, who I could contact?

I'd sure like to know I've got a clear pathway before I pull the trigger on the PST2.

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[itsnotanova]

Originally Posted by maytag

So I'm moments shy of buying a PST2 for this same purpose.
I understand from other threads that I'll need a 996 VIN and associated password, in order to load that 986 flash to my 986 DME. (Correct?)
In anticipation of this, I called my dealer today to see what it'd take to get them to help me with that VIN and password. No joy. They basically mocked me, that I'd think they'd just hand that out. They're kinda dicks over there.

So, question: some of y'all who've done this (TRK?) Do you have a VIN and associated pass code you can share? And if not, do you know a dealer who is supportive of this, who I could contact?

I'd sure like to know I've got a clear pathway before I pull the trigger on the PST2.

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Your Dealer in Utah is the worst in the country. I've heard multiple stories from 986 owners. I have a 996 ROW tune on my street boxster but my DME and immobilzer came out of a 996. Pretty simple switch, but I'm not sure about putting a 996 tune into a 986 dme. The immobilizer will still know it's a boxster (I think). I just put a 996 intake on my 2.7 rallycross boxster and was going to also switch over to a 996 tune. Give me a few days and I can tell you what happened

[maytag]

Originally Posted by itsnotanova

Your Dealer in Utah is the worst in the country. I've heard multiple stories from 986 owners. Try Porsche of Plano. They're pretty laid back there and might give one to you. I have a 996 ROW tune on my street boxster but my DME and immobilzer came out of a 996. Pretty simple switch, but I'm not sure about putting a 996 tune into a 986 dme. The immobilizer will still know it's a boxster (I think). I just put a 996 intake on my 2.7 rallycross boxster and was going to also switch over to a 996 tune. Give me a few days and I can tell you what happened

Ha! You're a stud.

Yeah, I'm quite disappointed with the dealer options we have in Utah.

I'll watch for your update! Thanks!

[itsnotanova]

LOL. I haven't been called a stud in awhile. Text me your vin at 512-925-9171. I'll get you a code when I get one. I have a source but I normally only ask him for codes for myself. It's a source I don't want to wear out

[Newsguy]

Reflashing to a 996 tune is possible.
I got a ROW done to eliminate the secondary cats and the air pump.
Alas, I never got to experience the result. The replacement engine I bought seized after a mile.

[Nitro V8]

I wonder if a re mapping session on a rolling road can tune for the 987 maf rather than having to get an actual 550se tune put on the DME?

[Robert986]

Originally Posted by Nitro V8

I wonder if a re mapping session on a rolling road can tune for the 987 maf rather than having to get an actual 550se tune put on the DME?

That´s not the way to do it.
What you actually need is a new MAF-table for the larger MAF-tube, thus the DME can understand the MAF-signal again. Then if you really want you may map it on the rolling road, but I think the DME will manage this by it´s own with such small changes.

My tuner made me a new MAF-table just for this, you may inbox me for contact info to my tuner, I´m sure he can help you with this table.

[The Radium King]

sure. you are lucky - your car is a 2003 so the anniversary edition tune will work on it. for a mechanic with a pst2 that knows what he is doing it is a 5 minute job to push the new tune onto your car. you would need the dme programming code for your car but any dealer should be able to provide that. otherwise a custom tune or run w the original maf holder. at a minimum, you can run with the original holder until you can get the new tune. for the cost of a custom tune i'll fly to sweden with my pst2 and tune your car for you (actually, i will be in france in april, perhaps i can do a side trip ...).

1) i think you have this correct.
2) i am not sure about this, but that's my thesis. given that the intake runners (the six legs that descend to each intake valve) should also be of decreasing diameter to accelerate air into the cylinder (look at any car design, even the venturi intake tubes on old itb cars). however, if the air acceleration is happening in the intake runners, what is the need to accelerate air into the intake plenum? i'm not sure, so my intake does both.
3) longer runners mean more acceleration, but also more air resistance (work). so, short fat runners are good for hp (less resistance) while longer ones are good for torque (better cylinder fill). 986 is short and fat, while 996 are longer. unsure why the difference; perhaps engine bay packaging, perhaps efforts to limit performance of the 986 vs 996. nova has 996 runners on his car and swears his 3.2 pulls as hard as his 3.4 with all the above modifications. remember, porsche limited the 986 vs the 996 to avoid one stepping on the other; given heads and internals are the same (only displacement differs, but differences in hp/litre ratios between the two engines indicate more than a difference in displacement is at work) so porsche could only limit the 986 w exhaust, intake, and tuning.

[Robert986]

Originally Posted by The Radium King

sure. you are lucky - your car is a 2003 so the anniversary edition tune will work on it. for a mechanic with a pst2 that knows what he is doing it is a 5 minute job to push the new tune onto your car. you would need the dme programming code for your car but any dealer should be able to provide that. otherwise a custom tune or run w the original maf holder. at a minimum, you can run with the original holder until you can get the new tune. for the cost of a custom tune i'll fly to sweden with my pst2 and tune your car for you (actually, i will be in france in april, perhaps i can do a side trip ...).

1) i think you have this correct.
2) i am not sure about this, but that's my thesis. given that the intake runners (the six legs that descend to each intake valve) should also be of decreasing diameter to accelerate air into the cylinder (look at any car design, even the venturi intake tubes on old itb cars). however, if the air acceleration is happening in the intake runners, what is the need to accelerate air into the intake plenum? i'm not sure, so my intake does both.
3) longer runners mean more acceleration, but also more air resistance (work). so, short fat runners are good for hp (less resistance) while longer ones are good for torque (better cylinder fill). 986 is short and fat, while 996 are longer. unsure why the difference; perhaps engine bay packaging, perhaps efforts to limit performance of the 986 vs 996. nova has 996 runners on his car and swears his 3.2 pulls as hard as his 3.4 with all the above modifications. remember, porsche limited the 986 vs the 996 to avoid one stepping on the other; given heads and internals are the same (only displacement differs, but differences in hp/litre ratios between the two engines indicate more than a difference in displacement is at work) so porsche could only limit the 986 w exhaust, intake, and tuning.

Good input, I agree about the runners, they also are of decreasing diameter, and what would the point be to accelerate air in two stages just to have it "consolidated" before the runners, this is over my competence level. However, this design cannot hurt, so it´s my plan. I plan ta take the car to a specific shop for a custom tune on the dyno, however let´s see how things turn out, the idea of you popping by Sweden is a good one, let´s follow up on that one later on!

[nuvolari]

Any updates in this story? What happened?

[redbox986]

If anyone is still interested in this mod, I have done it and run it successfully on my 2003 986S without any problems for over 2 years.

I used the stock MAF holder and coupled it with larger diameter tube on either side, so there is an unavoidable loss through the MAF if you want it to run properly. I still feel that the flattening of the torque curve and power increase is more than worth it.

[ike84]

Originally Posted by redbox986

If anyone is still interested in this mod, I have done it and run it successfully on my 2003 986S without any problems for over 2 years.

I used the stock MAF holder and coupled it with larger diameter tube on either side, so there is an unavoidable loss through the MAF if you want it to run properly. I still feel that the flattening of the torque curve and power increase is more than worth it.

Do you have comparisons of dyno numbers or LTFT before and after?

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[Newsguy]

What you need to know is that if you go to all this trouble, you may as well put in the 987 airbox. The other thing to know is having done it, I don't see how it is accomplished with the engine in place! I do think you get a better and bigger filter with the 987 airbox if I remember correctly.

[nuvolari]

Originally Posted by redbox986

If anyone is still interested in this mod, I have done it and run it successfully on my 2003 986S without any problems for over 2 years.

I used the stock MAF holder and coupled it with larger diameter tube on either side, so there is an unavoidable loss through the MAF if you want it to run properly. I still feel that the flattening of the torque curve and power increase is more than worth it.

Very interesting, so you say you can definitely feel a difference with only the 987 air box? I might do this while my engine is out, simply because the expense seems fairly low and the possibility of added power/torque is tempting. And then a further upgrade to a larger throttle body and MAF would be very simple, other than required software needed.

How about sound? Does it change the intake sound at all?

And as ike, I would love a dyno test but doubting you have one since that doesn't really make sense for just changing the air box.

But further details on power improvement and feel would be appreciated.

Thanks.

[The Radium King]

most of the power benefits come from the airbox.

i ran with the 986 tube adapted to the 987 airbox for quite a while.

if you fit the 987 tube you will need to get the SE flash. at which point you will have an SE for half the price.

[ike84]

1 - no
2 - no
3 - yes

If you want power, you need everything from the box to the TB to be larger. Plenum geometry making more power is bull****************, but needs to be swapped to fit the larger TB.

She won't run without a tune. The ECU won't be able to interpret flow data with a larger maf housing and run lean (detonation lean)

Also, your next project should be to gut the exhaust. Power gains will be muted if she can't exhale.

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[The Radium King]

the only real difference with the SE tune is the maf table to compensate for the larger tube. dunno what the tuner charges but it's a 15 minute job for anyone with a pst2. but you need the programming codes. not sure if tuners require these codes to get in.

[Robert986]

Originally Posted by The Radium King

the only real difference with the SE tune is the maf table to compensate for the larger tube. dunno what the tuner charges but it's a 15 minute job for anyone with a pst2. but you need the programming codes. not sure if tuners require these codes to get in.

I guess you are correct, I didn"t manage to find a SE tune so my tuner made the updated table.

[redpepperracing]

Originally Posted by NotthatJake

I am new to this so sorry if this is incorrect, but where did you find the 74 mm TB that fits the 986/987 IPD plenum?
I have the original 2.5 tb but am trying to find the upgraded TB and am not having any luck so I am curious if there is a throttle body spacer or adapter that is out there to mate these two? Have you heard of an adapter?

@notthatjake I just saw your question, for the 2.5 as it is a throttle-cable TB, you would have to find an equivalent 996 cable operated TB, and I'm not sure on the sizing of those. I presume they are larger, but your options are much more limited there, none of the 987 ones will work.

In terms of an adapter, the best option is to use the associated "Intermediate Piece" (I think that's what Porsche calls it)