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De-Snorkling


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The air tube is there for a purpose, it directs and controls air into the air box, and reduces the possibility of water being sucked in. Porsche has changed the original design and came up with a reftofit kit so that the air tube can do it's thing, yet people want to yank them out.

I spoke to Peter about this a while back and he though you would also suck in air that is warmer which could reduce hp. A guy on the UK board asked his mechanic and his mechanic said the same thing.

It does increase the induction sound and I don't think it will harm your motor. You can also increase the induction noise by going with one of the oiled filters if you want to risk the air flow sensor contamination issue. The "best" way I know to increase the sound with no risk is to simply remove the black foam covering from the stock air filter. Several Boxster owners have done this and they like the sound increase.

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Each year Porsche publishes a technical introduction booklet. It tells you if there have been changes or improvements to the current model year. I have them from 1997-2003 and I am waiting for the 2004 to come out. There is no mention of a change to the air box in the 2003 edition.

The part number for a 1998-2004 air box is 996 110 121 06. There is no special part number for a 2003/4 air box. I have not to remove the air vent from a 2003/4 to see with my own eyes, but I think the reports are wrong.

If you really want to increase the induction sound then go with the EVO unit since the entire stock air box and tube are removed from the car. When the local owners get together I can tell who has it. But one of our local owners go tired of chasing check engine lights and he removed it, while another local owner just had one put in her car and no light so far.

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  • 2 weeks later...
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An article was posted yesterday on the technical section site of PCA.

"The side intake snorkel is functional. The main purpose of it is to flow cooler ambient air to the engine. Should this be removed you would be drawing hotter air from the engine compartment than outside of it. These temps are much higher in the engine compartment than the 996. Basically the cooler the intake air the better. Much like the purpose of an intercooler on a turbo. It cools down the hot intake air that gets heated from the turbo itself. Granted the side intake is not actually cooling the air, it draws in cooler air.

Scott Slauson - PCA WebSite - 7/3/2004"

Peter was the Boxster technical advisor up until a few months ago. Scott took over because Peter did not have the time to answer all the questions. I do not know Scott, but I have known Peter for 5 years since he works at my local dealer. What Scott states is what Peter told me in person when this snork fad started.

Link to the complete article.

http://www.pca.org/tech/tech_qa_question.a...5-29D580E29AE9}

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  • 10 months later...

I've searched without any luck...... is the air filter in the 987 the same as in the 986? i.e. when my car arrives in two weeks will I be able to remove the foam from the filter to improve the sound or is the 987 already louder because Porsche changed the filter?

Porsche claimed some of the improved power in the 987 to be the result of changes to the air intake...... but they didn't go into much detail in the info I've seen!

Edited by Wads
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I've searched without any luck...... is the air filter in the 987 the same as in the 986? i.e. when my car arrives in two weeks will I be able to remove the foam from the filter to improve the sound or is the 987 already louder because Porsche changed the filter?

Porsche claimed some of the improved power in the 987 to be the result of changes to the air intake...... but they didn't go into much detail in the info I've seen!

Not even close.

986 Intake

post-2-1116261349_thumb.jpg

987 Intake

post-2-1116261375_thumb.jpg

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You might want to order the 987 tech intro booklet. The part number is PNA 488 521 05 and it is about $25. When the mechanics go to training school for a new model this is given to them.

The 987 intake is a new design. There are drawings of it in the booklet.

At the local 987 tech session last month I wanted to take the filter out to see how it changed but Peter said it was a pain to get out. I went to the parts department but they did not have one in stock. The drawing of the filter on the parts list shows it as a round filter. The 986 is flat. Loren has the drawings. I do not know if the 987 filter has foam on it like the 986.

What is interesting is that the part number for the 987 filter is the same as the 986 special edition, unless there is a mistake on the 986 parts list. One of these days a special edition and 987 will show up at our work on cars days so we can check it out.

post-4-1116261605_thumb.jpg

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  • 1 month later...
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Another article on the PCA tech site was just published on this subject:

Question:

Could you please give me your opinion on removing the snorkel from a stock 2000 Boxster S? I understand the engine sounds better, but will this cause reliability issues with the car? Also, is there any performance gain from this? Thanks

Answer:

I would not suggest it. While it may improve the sound it will increase the intake air temperature. The intake air should always be as cool as possible for optimal fuel to air mixture and performance. Removing the intake from the cooler outside air intake would only cause a reduction in performance.

Scott Slauson - PCA WebSite - 7/8/2005

http://www.pca.org/tech/tech_qa_question.a...0-E9F524E0718F}

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i have a 2004 550 SE

i tried to change the air filter and use the BMC that i got from MMD for my 2002S

the air filter is indeed different

i didn't try and get the air filter out, because it was obviously round (like in the 987 drawing), so i cannot comment on the difficulty of removal

aloha

steve

You might want to order the 987 tech intro booklet.  The part number is PNA 488 521 05 and it is about $25.  When the mechanics go to training school for a new model this is given to them.

The 987 intake is a new design.  There are drawings of it in the booklet.

At the local 987 tech session last month I wanted to take the filter out to see how it changed but Peter said it was a pain to get out.  I went to the parts department but they did not have one in stock.  The drawing of the filter on the parts list shows it as a round filter.  The 986 is flat.  Loren has the drawings.  I do not know if the 987 filter has foam on it like the 986.

What is interesting is that the part number for the 987 filter is the same as the 986 special edition, unless there is a mistake on the 986 parts list.  One of these days a special edition and 987 will show up at our work on cars days so we can check it out.

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  • 3 weeks later...

Having de-snorkeled, and seen what the inside looks like, I would really like to know the rationale of saying that your intake temps would be higher.

The same air is coming from the same place... outside of your car. Removing the snorkel does nothing to alter this.

Thanks from Connecticut

Edited by Skibum
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Agree with Skibum. The intake air is sealed from the engine compartment in either case. Now, removing the air box entirely or putting in a poorly-designed "warm" air intake would be a different story.

macsak, do you have a picture of your 550 air box or recall if it is similar to the normal 986 air box? Obviously, the "door" to replace the filter must be different. I'm wondering if the MAF, air-tube, etc., are the same.

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I also agree with Skibum. There is no way that removing the snorkel is going to increase intake air temps. Not unless the air is cooler at the upper middle of the side intake than it is an inch lower at the middle of the side intake. Air is not being pulled from inside the engine compartment, with or without the snorkel.

To be clear, the snorkel is part 13 in the picture, not the tube leading up to part 13. My guess is that it is there to decrease noise.

post-6427-1123472920_thumb.jpg

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Actually I removed 1 and 13. 

There is still no way for engine compartment air to enter. It is sealed. (I just took mine apart again to check for sure)

I stand corrected; I removed 1 and 13 as well. It's been a while so I guess I'd forgotten. I agree that the compartment is still sealed and does not pull air from the engine compartment at all. Given the volume of air that passes through that tube, the incremental temperature rise would be minimal, even if it has a slightly higher surface temperature than the snorkel would have.

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OK. I did my first mod by taking the foam off the air filter. Whoa-ho! Can't say as I have noticed any difference. Except that I then went on the freeway to go home from work and the car sagged. I hit the gas and the car acted like it hit a pool of water. I thought, Oh no! I screwed something up and now it can't breathe. After a couple of test engine revs in neutral it returned to form. Maybe the computer had to take in what I had done or something. Anyway, all is well.

I'd like to de-snorkle my machine (MY99 non-S). What is the best way to get at it? Are there any tricks/tips to removing the side vent grille? I did a stereo install in the past on a different car and ended up a some broken panel clips/tabs and would like to avoid it with this car. Any input is appreciated. Thanks in advance.

Later,

-pvaughan

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I'd like to de-snorkle my machine (MY99 non-S).  What is the best way to get at it?  Are there any tricks/tips to removing the side vent grille?  I did a stereo install in the past on a different car and ended up a some broken panel clips/tabs and would like to avoid it with this car.  Any input is appreciated.  Thanks in advance.

Here is a guide to de-snorkleing: 986 De-Snorkle -- from the PPBB Archives

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Pay careful attention to the section about pushing the grill IN to release the clips. I think it is the best way. The force required is more than you feel you should give it....but only just.

When reinstalling the cowl be sure to get the bottom front to engage the groove by pushing back and up as you reinstall. If you get all done, and find that the cowling is able to be pulled out on the bottom you have not engaged the groove.

Edited by Skibum
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I "desnorked" my '97 and after about a week put it back in. I did believe I lost a bit of low-end torque.

However, I do not believe it has anything to do with intake air temperature. I believe it has to do with harmonics and resonance of the intake track. Just like in a Trombone, when the tube length changes, so does the natural frequency of the air column that resonates in it. This resonance can be used to benefit engine power. The longer effective intake track length can be used to create the minimum pressure drop in the intake at a particular engine RPM.

If you want to see this practice taken to an extreme, look at the Helmholz resonator that is fitted to Buell bikes (at least it used to be, don't know if Erik still does this).

Dougman

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I "desnorked" my '97 and after about a week put it back in.  I did believe I lost a bit of low-end torque.

However, I do not believe it has anything to do with intake air temperature.  I believe it has to do with harmonics and resonance of the intake track.  Just like in a Trombone, when the tube length changes, so does the natural frequency of the air column that resonates in it.  This resonance can be used to benefit engine power.  The longer effective intake track length can be used to create the minimum pressure drop in the intake at a particular engine RPM.

If you want to see this practice taken to an extreme, look at the Helmholz resonator that is fitted to Buell bikes (at least it used to be, don't know if Erik still does this).

Dougman

Dougman,

As a Trombone player who reread a Scientific American article on the Horn Function several times in the 80s, I choose to disagree with your theory on harmonic resonance.

Your basic thought is good but it seems to ignore two issues:

1) the air filter placed in the middle of the relevant airstream totally mucks up the harmonics,

2) the open cup at the end of the tube (in the ah position of the wa-wa sound of a hat mute) radically disrupts the Bernoulli effect of the flared end of the tube.

After the air filter, there is 'an effective length to the intake track' that could favor certain RPM ranges. De-snorking doesn't affect this length.

PS. I have no direct knowledge as I have never de-snorked.

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FYI, i should add that i had been de-snorked for about a year until the hottest days of summer came around. i noticed the engine temp creeping up around 195+. i prompty re-installed the air tube and immediately noticed normal (185-190) temps again. of course, i'm not talking about too much of a temperature difference, but a difference nevertheless.

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I "desnorked" my '97 and after about a week put it back in.  I did believe I lost a bit of low-end torque.

However, I do not believe it has anything to do with intake air temperature.  I believe it has to do with harmonics and resonance of the intake track.  Just like in a Trombone, when the tube length changes, so does the natural frequency of the air column that resonates in it.  This resonance can be used to benefit engine power.  The longer effective intake track length can be used to create the minimum pressure drop in the intake at a particular engine RPM.

If you want to see this practice taken to an extreme, look at the Helmholz resonator that is fitted to Buell bikes (at least it used to be, don't know if Erik still does this).

Dougman

Dougman,

As a Trombone player who reread a Scientific American article on the Horn Function several times in the 80s, I choose to disagree with your theory on harmonic resonance.

Your basic thought is good but it seems to ignore two issues:

1) the air filter placed in the middle of the relevant airstream totally mucks up the harmonics,

2) the open cup at the end of the tube (in the ah position of the wa-wa sound of a hat mute) radically disrupts the Bernoulli effect of the flared end of the tube.

After the air filter, there is 'an effective length to the intake track' that could favor certain RPM ranges. De-snorking doesn't affect this length.

PS. I have no direct knowledge as I have never de-snorked.

Hmmm, interesting. There may be something to this discussion. I have no answers, but rather can share an experience. Long ago I had a motorcycle. I was looking at the air box and noticed that the intake was teeny-tiny. So I removed the top of the air box. Surely, this engine would now breathe so freely that my arms would pop out of their sockets when I hit the gas. I started the bike, pulled away slowly then gave the throttle a good twist -- nada -- the power was gone. It was so stunningly dramatically devoid of power that I aborted the test. To this day I have no idea what physics lesson I was learning, but I've learned that modifying things put in by clever engineers means I've turned my precious vehicle into an experiment.

I wish we had a Porsche engineer to enlighten us on the purpose of the snorkle

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  • 3 weeks later...
You might want to order the 987 tech intro booklet.  The part number is PNA 488 521 05 and it is about $25.  When the mechanics go to training school for a new model this is given to them.

The 987 intake is a new design.  There are drawings of it in the booklet.

At the local 987 tech session last month I wanted to take the filter out to see how it changed but Peter said it was a pain to get out.  I went to the parts department but they did not have one in stock.  The drawing of the filter on the parts list shows it as a round filter.  The 986 is flat.  Loren has the drawings.  I do not know if the 987 filter has foam on it like the 986.

What is interesting is that the part number for the 987 filter is the same as the 986 special edition, unless there is a mistake on the 986 parts list.  One of these days a special edition and 987 will show up at our work on cars days so we can check it out.

Are these Technical Booklets still available? Please post the new ones as they become available. These Tech Booklets are the most informative publications Porsche produces. Thanks-Gary

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