De Snorkeled! Does it negatively effect HP or torque?

[Pianohawk]

Just de snorkeled my 99 porsche boxster. The difference in sound is great! One question, does it negatively effect HP or torque at all? If you've de snorkeled your boxster feel free to take a minute and describe the effects...your experience will be useful to those who are researching this simple mod.

[sickbananas]

On my 2000 S it def. did nothing negative. Awesome sound and better response. Generally a better feel. Recommend this mod. to all.

[Lil bastard]

There has never been any quantitative data released on de-snorkeling. All the info. is, to-date, just anecdotal.

The snorkel's intended purpose is to meet noise abatement laws in some countries, especially Switzerland and it was included in models for all markets (since the legislative environment is always changing).

My personal opinion is that it neither positively or negatively affects performance, but greatly improves the intake sound of the motor. My car is de-snorkelled.

Plus, if you're careful and don't damage it on removal, it is totally reversable. So there really is no downside to trying it.

Cheers!

[chaudanova]

Bisimoto had a thread where he dyno'd before and after the desnorkeling. It gained power. Runs were on a dynapack...

Thread is here on 986forum...

[backman_z]

I was ambivalent about it, until I spoke with Jaay (whose posts are all over this forum). So I removed the snorkel. I agree with what he told me: “Just look at the snorkel.” There is a very significant narrowing at the end closest to the side air vent. I just got the snorkel and traced the inside of both ends as best I could, just to take a look. Without getting out my protractor and brushing up on my geometry, I would guess that there is about a 40-50% reduction in size from the large end compared to the small end.

Now, how many people spend all lots of cash to increase the diameter of the air intake system in order to improve airflow. You cannot convince me that the small end of the snorkel does not constrict airflow, even if only a little.

Did I notice a difference in performance? Not sure. I like to think I did, but it could all be in my head… in any case, I'm keeping it out.

[yimmy149]

Isn't there increased risk of cigarette ingestion after de-snorkeling?

[Pianohawk]

I don't smoke so I'm not worried. But I HIGHLY doubt it. Regarding the potential negative effects of de-snorkeling Pedro (http://www.pedrosgarage.com/Site/Technolab.html) told me:

"There are no cons on the '99.
It's a great mod.
Just pull out the snorkel.
No need to add mesh.
I de-snorkeled mine in 1998.
No issue with MPGs either.
Happy Boxstering,
Pedro"

[Boxtaboy]

Originally Posted by yimmy149

Isn't there increased risk of cigarette ingestion after de-snorkeling?

Nope, there is absolutely no increased risk of a cigarette or other large particle getting into the engine if you remove the snork, cause as you see below, there's a mesh screen in the intake right before the MAF.

[yimmy149]

I don't smoke either - but my radiator cavities seem to fill with butts quickly.

Getting a butt into the engine wasn't what I was worried about. If someone flicks a still-lit butt and it ends up ontop of a paper filter having massive amounts of oxygen pulled through it, it will catch the filter on fire.

I know the stock filter has foam on top of the paper, not sure if that would help or not.

-james

[Tranlm]

Thinking about this, the diameter of the snorkel from one end to the other should not really matter. In dealing with fluids, there are two things to distinguish between: flow speed and flow rate. Flow speed is just the instantaneous speed of a molecule of fluid (in this case, air). Flow rate is the amount of fluid passing a cross-sectional area given a unit of time. Flow rate is what we're interested in if we want more horsepower, torque, etc.

Though the snorkel does converge in, I don't think removing it would do anything to increase the flow rate of the air. You have to remember that the end where the snorkel connected is same diameter as that end of the snorkel. So, even if you do remove it, the size of the hole for the air to be sucked in is still the same.

Originally Posted by backman_z

I was ambivalent about it, until I spoke with Jaay (whose posts are all over this forum). So I removed the snorkel. I agree with what he told me: “Just look at the snorkel.” There is a very significant narrowing at the end closest to the side air vent. I just got the snorkel and traced the inside of both ends as best I could, just to take a look. Without getting out my protractor and brushing up on my geometry, I would guess that there is about a 40-50% reduction in size from the large end compared to the small end.

Now, how many people spend all lots of cash to increase the diameter of the air intake system in order to improve airflow. You cannot convince me that the small end of the snorkel does not constrict airflow, even if only a little.

Did I notice a difference in performance? Not sure. I like to think I did, but it could all be in my head… in any case, I'm keeping it out.

[Boxtaboy]

Originally Posted by yimmy149

I don't smoke either - but my radiator cavities seem to fill with butts quickly.

Getting a butt into the engine wasn't what I was worried about. If someone flicks a still-lit butt and it ends up ontop of a paper filter having massive amounts of oxygen pulled through it, it will catch the filter on fire.

I know the stock filter has foam on top of the paper, not sure if that would help or not.

-james

Thing is, the snorkel tube itself was not put in for the purpose of blocking out cig butts...the protruding lip on the painted air vent housing was put there to redirect objects over and behind the intake, so taking the snork tube out will not increase the risk of a cig butt going into the air filter housing. In fact, I have seen cig butts in the foam portion of the air filter even in cars WITH the snork still in place. If a cig butt is going to get in there, it will get in there regardless if the snork is in or not.

I've had my snork out for years without issues. I even took a dremel to the section left after pulling the snork out to smooth out and widen the hole since I didn't like the hard edges left in the opening after pulling the snork out. The sound is terrific, and my filter hasn't caught fire.

[mts]

I don't have any dyno evidence but something that was interesting to me none the less. I have a 2004 special edition which had slightly more power than the standard 2004 Boxster S from the factory. My understanding is the extra horsepower was basically achieved by an intake change and an ECU re-flash from the factory.

I compared my intake to one from a friends older Boxster S and indeed mine was pretty drastically different. However, one other thing that was interesting was my snorkle was massively larger than his was. I've not been able to compare a "standard" 2004 Boxster S to mine yet, but if it's the same situation it might lead one to believe a de-snorkle could have some slight added hp benefit.

Anyone got a picture of a snorkle off a standard 2004 Boxster S? I'll take a picture of mine and post it.

[backman_z]

Here is a picture if the inner dimensions of both ends of my snorkel. It was taken from a 2004. I have done my best to be as accurate as I can.

http://www.flickr.com/photos/backman_z/4670777862/

Doing the math indicates that the cross section area of the small end is about 44% smaller than the larger end (which goes directly into the air box). When you remove the snorkel, the air entry into the air box is now slightly larger than the large end of the snorkel. I still find it hard to believe that this does not cause some obstruction of airflow.

I am hoping to do some mods to my car this summer. I was thinking about doing a dyno it after each mod. If I can, I will try to get with and without snorkel dyno results.

[t2-bxtrs]

quite interesting.. a year ago i've put up this question if it was possible to do this on an 04S and i don't think anyone had done so, or just did not post a reply.
reason was, i attempted to do it on my 04S and no amount of wiggling the plastic grill after taking off the one screw, did not budge and i was afraid to break the part..
i hope you could shed light on this?
thanks for sharing.

[mts]

I did my 2004 S. I remember it being a bit scary to get it to come loose though.

[backman_z]

I was also very concerned about breaking the vent to get to the snorkel. I had to pull and wiggle over and over again, but eventulally, it came out.

The area inside was so small, that I could not get a good grip on the snorkel. So, I clamped some vice grips on, and it came right out.

[Pianohawk]

De-snorkling coupled with building a hi flow air intake = deep, amazing sound.

[jaykay]

Lets leave out intake tract acoustics and ECU response to airflow changes which affect performance. Assuming that these that these factors are not affected by de-snorking, we now basically left with flow considerations. A normal Boxster engine has to draw air in like a pump. Flow losses upstream of the engine will reduce the flow rate at a given rpm. Fluid energy is lossed by having to make through obstacles. Air flow is a tricky thing; one has to test what is an obstacle in combination with everything else.

Generally section changes, area reductions, sharp edges surface friction all give rise to losses in steady state pipe flow. The flow loss reduction or lack there of, with respect to a de-snork comes down to the flow losses associated with the snork (area restriction; the cup is a sharp edge vs. the sharp edge you are left with upon its removal. I would guess that the huge intake area increase would just beat out the losses associated with the air box sharp edge....but one has to test.

I did this mod for sound; it is fanastic and I want more of it. If you are after a significant power go for an under drive pulley instead. I do get worse fuel economy because I am hard on the throttle enjoying the sound!

One day when I get around to it I will fabricate and post my solution to the de-snork sharp edge

[Boxtaboy]

That's exactly what I did. I didn't like the sharp edge left after pulling out the snork, so I took a dremel to the sharp edge, and ground it to a smooth curvature. I then vacuumed out all the stuff I ground down. Here's a blurry pic I took after it was done...

Originally Posted by jaykay

Lets leave out intake tract acoustics and ECU response to airflow changes which affect performance. Assuming that these that these factors are not affected by de-snorking, we now basically left with flow considerations. A normal Boxster engine has to draw air in like a pump. Flow losses upstream of the engine will reduce the flow rate at a given rpm. Fluid energy is lossed by having to make through obstacles. Air flow is a tricky thing; one has to test what is an obstacle in combination with everything else.

Generally section changes, area reductions, sharp edges surface friction all give rise to losses in steady state pipe flow. The flow loss reduction or lack there of, with respect to a de-snork comes down to the flow losses associated with the snork (area restriction; the cup is a sharp edge vs. the sharp edge you are left with upon its removal. I would guess that the huge intake area increase would just beat out the losses associated with the air box sharp edge....but one has to test.

I did this mod for sound; it is fanastic and I want more of it. If you are after a significant power go for an under drive pulley instead. I do get worse fuel economy because I am hard on the throttle enjoying the sound!

One day when I get around to it I will fabricate and post my solution to the de-snork sharp edge

[jaykay]

Nice work! I didn't there was enough material there to shape a lip; I have 2000. Plus my plastic panelling is much tighter around the opening than yours. Huge losses can occur on sharp intake edges. Did you get a different sound out of it?

I was thinking about something a little more sneaky......I am betting someone here has probably done something similar already. I will post it up when I get it done.