A new take on snokels

I read numerous posts regarding the de snorkeling, so I did mine last weekend. The sonic characteristics are really much less pronounced if you already have a low restriction air filter in place. As I've had time to think about it, I've decided to replace the snorkel without the #1 end cap on it. My thinking is a more directed cooler stream of air (tip is closer to outside of the vehicle than just a pulled snorkel) would be as important as air volume. However, I also think cutting the snorkel halfway down might be beneficial as the oval would be about an inch larger in diameter, thinking about it like a straw, it would make sense that a larger opening in a shorter length would add air volume. Now, I'm torn between modding the snorkel of leaving it with the end cap off, cool air Vs air volume, I know the difference is minimal but I'd like to read some other thoughts...

PS cutting the snorkel would also remove the lip around the oval which I presume is to direct the air, replacing the tip by enlarging it and blending with glass is possible but it seems like a long way to go for nothing...

[CJ_Boxster]

I already did that mod, I dont have a dyno, but the sound is alittle better than with snorkel and not as loud with the snorkel but your low end acceleration is alittle better than without the snorkel and not as good as with the snorkel in.

Modding the Snorkel rather than removing it...
look below for images of how i made the cuts.

The snorkel reminds me of a velocity stack. I bet the lip works the same. I think a mod'd snork that didn't neck down so much with the bell lip would be optimal.


I like CJ's mod...


Hey Bismoto, don't you want to dyno this??

[Allen K. Littlefield]

This snork mod talk has me thinking, (always a bad sign) that what if a trumpet/funnel snork was fashioned and replaced the original. Would that not a certain amount of ram effect (poor mans supercharger) into the intake thus increasing performance, at least a little bit? I notice that the stock snork seems to get larger as it enters the intake manifold which is the opposite of what I am suggesting. Also if the new Boxster/Cayman animals have a larger air vents there must be a valid reason, more cooling air perhaps? Is there a larger or should I say, more open replacement for the vent cover on earlier models? You understand I mean less metal around the opening cover and more sreen area? Any of you engineer types have any thoughts on this, Jim etc.?

AKL

Originally Posted by Allen K. Littlefield

This snork mod talk has me thinking, (always a bad sign) that what if a trumpet/funnel snork was fashioned and replaced the original. Would that not a certain amount of ram effect (poor mans supercharger) into the intake thus increasing performance, at least a little bit? I notice that the stock snork seems to get larger as it enters the intake manifold which is the opposite of what I am suggesting. Also if the new Boxster/Cayman animals have a larger air vents there must be a valid reason, more cooling air perhaps? Is there a larger or should I say, more open replacement for the vent cover on earlier models? You understand I mean less metal around the opening cover and more sreen area? Any of you engineer types have any thoughts on this, Jim etc.?

AKL

I'm not sure the effect is going to be overwhelming, I'm just trying to tweak my intake to match my lower restriction exhaust. The so called "cold air intakes" breathe from under the hood, where's the cold air in that formula? I prefer to keep the outside air sealed from the engine compartment. I may mod the snorkel, if I do I may take a different path than the one posted..

[Allen K. Littlefield]

Originally Posted by DrRoentgen

I'm not sure the effect is going to be overwhelming, I'm just trying to tweak my intake to match my lower restriction exhaust. The so called "cold air intakes" breathe from under the hood, where's the cold air in that formula? I prefer to keep the outside air sealed from the engine compartment. I may mod the snorkel, if I do I may take a different path than the one posted..

Dr. R, the evo intake closes the chamber off so only outside air (cool air) enters the cone filter. I am not so sure if this is good or not because I don't know if the opening around the stock intake area allows for some air flow over the engine and cutting it off may contribute to high engine temps. Again, the more experienced here should chime in. Cooler intake air and a cool engine are both goals that are hard in a mid-engine car. I have also seen air scoops that would tend to ram more air into the intake. I think cooling air comes in the right side vent, over and down and out the bottom so the scoops would work on the right side too. Again, I am new to this and am learning so my info. may not be totally accurate but that gives others with more knowledge to post corrections. What ever the case, have fun with your car.

AKL

Originally Posted by Allen K. Littlefield

Dr. R, the evo intake closes the chamber off so only outside air (cool air) enters the cone filter. I am not so sure if this is good or not because I don't know if the opening around the stock intake area allows for some air flow over the engine and cutting it off may contribute to high engine temps. Again, the more experienced here should chime in. Cooler intake air and a cool engine are both goals that are hard in a mid-engine car. I have also seen air scoops that would tend to ram more air into the intake. I think cooling air comes in the right side vent, over and down and out the bottom so the scoops would work on the right side too. Again, I am new to this and am learning so my info. may not be totally accurate but that gives others with more knowledge to post corrections. What ever the case, have fun with your car.

AKL

AKL,

I'm always learning as well, the sealed evo intake makes much more sense. I had read some corroborating information regarding the engine temps and de snorkeling. I'm hoping someone will post and comment on the following:

Does the snorkel taper accelerate the airflow?

Would shortening the length provide an advantage over just leaving the snorkel out?

If you shorten the length should the outer lip be enlarged and blended into the new end?

I worked on the car as a hobby all winter long in my own shop. I have enjoyed the car since the first day I drove it and improved it each year with whatever it has needed. Fact is I was so effective in my approach to perfecting my Boxster that I was awarded with a ticket this past weekend...

RE: Ram air

Doesn't take effect until triple digit speeds. Although the intake tract length can be tuned for a certain harmonic.


RE: Snork length and taper


According to velocity stack wisdom, the longer length helps out low end while a shorter is better for hp up top. The reverse taper of the snork actually slows down air velocity within the snork since the air has to expand, but I've seen this design before soo?

[2000SoCalBoxsterS]

Yes. The right side air vent is for engine compartment cooling and the left side vent is for the engine intake. As to the snorkle, I believe that desnorkling would only serve to slow down air flow and give it a lack of direction. Air direction to the air filter and air velosity will be better with the snorkle. You've got to believe that the Porsche engineers knew what they were doing and put it there for a purpose. That being said, I do believe that that purpose can be enhanced with a FabSpeed or EVO Cone shaped Cold Air Intake system.

I was at the Porsche dealer a few days ago and I was looking at the new Boxster's, I was curious about the larger vent on the 987 so I knelt down and looked inside the driver side vent. I was surprised to see that it looked more restrictive than the 986 vents. The larger vent appears to be mostly for styling. When you look into the vent most of it is closed off by black plastic leaving only a small opening for air to pass through to the engine air filter.

[insite]

here's an engineering take on this:

1. because there is an air filter directly following the snorkel, any tuned effect due to the length of the tube is negated when the air flow is interrupted by the filter.

2. the tube is designed with a trumpeted end to act as a venturi. it will actually flow more air than a non-trumpeted design of slightly larger cross-sectional area.

3. the tube cross-section grows as it gets closer to the airbox. the primary purpose of this tube is to suck cold air at a reasonable velocity and expand the cross-sectional area of the charge to roughly match the cross sectional area of the air filter. the idea is this: rather than have a stream of air hit a small section in the center of the air filter, static friction from the filter can be reduced by using the entire filter. if the air flow is expanded to hit the entire filter at once, resistance to flow is minimized and filter efficiency is maximized.

4. the cup on the end of the tube was an afterthought designed to prevent rain water from entering the motor. reports of hydrolock caused this modification. removal mayl negate the purpose. it should be noted that the hydro-lock modification also included a drain in the airbox; it is my personal feeling that the cup on the end does nothing and the drain in the box does everything.

5. i believe that the snorkel was designed to work best without the cup on the end. i bet a dyno will show that the snorkel in place without the cup yields a more positive result than no snorkel at all. them engineers is smart.

[Bisimoto]

Originally Posted by boxsterz

The snorkel reminds me of a velocity stack. I bet the lip works the same. I think a mod'd snork that didn't neck down so much with the bell lip would be optimal.


I like CJ's mod...


Hey Bismoto, don't you want to dyno this??

Of course. Carlos does reside near me.. would be more than happy to.

Everyone should bare in mind that venturis can also act as a restriction at certain flowrate demands based on design and inside diameter. A pure example is the simple carburator: venturis are present to present a presssure differential to help improve velocity across the smallest cross section of the venturi due to pressure differentials. This allows excellent atomization of fuel and enhances the fuel "pull" from the carb well or "float bowl". At higher RPMs, this also poses as a restriction to flow and power...hence large displacement and/or high revving engines require much larger venturis to allow for high end power production.

I have a few algorithms which I developed with emphasis on rpm & displacement...what is sad id that for 2.7~3.2L engines, the boxster intake is extremely restricted, even with the snorkle off...let alone with it installed. It is painfully obvious that that is why we saw this:



Based on experience with other highend and performance vehicles, by removing/decreasing further restrictions, and keeping the inlet temps the same, or cooler....more power gains are to be had.

[insite]

Originally Posted by Bisimoto

...what is sad id that for 2.7~3.2L engines, the boxster intake is extremely restricted, even with the snorkle off...let alone with it installed.

i bet the air box, filter and snorkel are a compromise to work with the 2.5, 2.7 and 3.2L motors. my guess is that it works best with the 2.5L since that's what the original design was for.

[CJ_Boxster]

Originally Posted by Bisimoto

Of course. Carlos does reside near me.. would be more than happy to.

Ill take you up on that offer soon, maybe in acouple months, I have to find where i up that modded snorkel first, and locate and repair a vacum leak... probably the oil tube between the engine and the firewall.

[aussieboxy]

Hi Guys,

Iv'e read about the desnorkling and the benifits and am ready, but how do I do it. Is there a walkthrough somewhere?

Thanks

[blinkwatt]

Originally Posted by aussieboxy

Hi Guys,

Iv'e read about the desnorkling and the benifits and am ready, but how do I do it. Is there a walkthrough somewhere?

Thanks

http://www.realtime.net/~rentner/Porsche/SideVents/SideVents.html

Now when you get everything taken apart you will see a tube with a cup on the end. Try to remove the cup part and then yank the tube out.

Good Luck!

Aussie,


There is no reason to remove the cup while the snorkel in installed, the unit comes out just fine will all pieces attached. As far as the yank and twist, I found my snorkel to be held in place with a small nub designed to allign with a punchout, no big deal to remove, no need to be gorilla like in your approach, good luck..

[aussieboxy]

Thnaks guys. I'll have a play & see where I end up.

[aussieboxy]

Thanks guys,

It was pretty easy. A little fiddley getting the side scoop out, but once done was very straight forward. I had to use a little more force than I was comfortable with but in the end nothing broke.

Just took it for a test run and it sounds great, wasn't really sure if it had any more get up and go until I went through a sharp coner that I have been through lots of times, it's a second gear puch the exit at about 4K type of corner & for the 1st time it actually stepped out a little at the rear so maybe the desnorkleing gives that little bit more at higher revs.

I do have a question. Am I best off to do the mod described earlier in this thread and open up the snorklw with a 3" pipe and then put it back on the car or just leave it off. I'd appreciate your comments.

Thanks

Originally Posted by aussieboxy

Thanks guys,

It was pretty easy. A little fiddley getting the side scoop out, but once done was very straight forward. I had to use a little more force than I was comfortable with but in the end nothing broke.

Just took it for a test run and it sounds great, wasn't really sure if it had any more get up and go until I went through a sharp coner that I have been through lots of times, it's a second gear puch the exit at about 4K type of corner & for the 1st time it actually stepped out a little at the rear so maybe the desnorkleing gives that little bit more at higher revs.

I do have a question. Am I best off to do the mod described earlier in this thread and open up the snorklw with a 3" pipe and then put it back on the car or just leave it off. I'd appreciate your comments.

Thanks

Welcome to where I live...(same thoughts).

I want to add for anyone taking off their side vent. Look for two small catches that actually hold the backside of the vent to the outside scoup. If you gently pry them with a flatblade as you work them to an appropriate angle, you won't scratch your paint or wrestle with the vent, everything comes apart nicely with patience and a gentle hand.


As for the snorkel, for now I'm running it sans cup #1 part. I'm wondering the same as you Aussie but in the meantime I have made no non reversable mods and I've improved the flow and sound.

My gas mileage dropped about 1mpg after de-snorking. Co-inkydink? I normally get 24 and change. Therefore, I re-snorked today, and I definately noticed more torque off idle, though it seemed slightly slower to red-line.




Bisimoto,

does your data confirm this? Your graph starts at 1800rpm. I putter around on flat roads sometimes around 1500rpm, and milk it right around 2000rpm on moderate hills. Without lugging the motor I've gotten close to 25mpg driving this way combined with several redline trips and freeway onramp launches per tank.


I'll test this a few more weeks and see if I can baseline this.



Update: I de-snorked my car again, and my mpg went back up to 24-25. It must have been the oxegenated gas, or possibly the climate control kicking the AC on too much. I'm leaving the snork off.