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Side intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

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YOUR RESEARCHSide intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

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Test fan side

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Suggestion · Original poster

To properly test you’d have to test the fan side.

Side intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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Leading evidence: 'Test fan side' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Test fan side' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.

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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

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Suggestion

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Side intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Suggestion

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Side intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Suggestion

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Side intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners
Frequently discussed actions (2)

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Test fan side

No successful repair reported for this finding.

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Read evidence and context
Discussions that contain suggestions
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

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Suggestion · Original poster

To properly test you’d have to test the fan side.

Side intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Use tapatalk

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion

Sent from my SM-G970U using Tapatalk

Side intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Suggestion

Sent from my SM-G970U using Tapatalk

Side intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Suggestion

Sent from my SM-G970U using Tapatalk

Side intake acting as venturi? - 986 Forum - The Community for Porsche Boxster & Cayman Owners
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19 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

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POST 1 / ORIGINAL POSTEROriginal post

Maybe I'm looking at this incorrectly but wouldn't the side intake on the Boxster create a venturi effect and create a vacuum in the airbox?

POST 2Original post

Quotes source post: 593689

No. Attach a digital manometer and take the car for a run, it is a slight positive pressure.

POST 3 / ORIGINAL POSTEROriginal post

Quotes source post: 593695

For sure it has to be, otherwise the engine wouldn’t be getting air at all. The question is, is the engine vacuum having to overcome a vacuum in the other direction?

POST 4Original post

No, JFP just told you that there is a slight positive pressure. It's very unlikely that any manufacturer in modern times would release an air intake design that hurts performance.

POST 5Original post

Quotes source post: 593711

um, I think what tgh was saying was that if the car was running and moving, the engine drawing air would create that pressure so not a true test. you could do it on the other side when the fan wasn't running to get a truer test. if you look at velocity maps of cars you'll see that the air is at a lower velocity in that area relative to other areas of the car. perhaps due to turbulence induced by the front wheel? anyways, if the air moves slower relatively then there will be more of it in that area so higher pressure relative to the rest of the car.

POST 6Original post

A set of these ram air ducts would be nice, but Kokeln went out of business and I have not been able to find them anywhere.

POST 7Original post

Quotes source post: 593716

I had to read that twice..... and then think about it really hard, in order to wrap my mind around that. That's counter- intuitive.... but I think it's right..... right? Sent from my SM-G970U using Tapatalk

POST 8Original post

I'm not sure what TRK was trying to say, either! Ideally, an air intake is positioned at a high-pressure area, like the base of a windshield. The location of the engine in our cars rules that out, so Porsche has an intake on the side of the car, which isn't a high-pressure spot, Apparently, there is enough flow over the side intake that it isn't a problem.

POST 9Original post

bernoulli effect - pressure is related to velocity. think a wing; the air traveling over the longer curved upper surface has to travel faster than the air following the shorter straight bottom surface if all air is to get to the back of the wing at the same time. the faster air gets 'spread out' (same unit of air has to cover larger area) and if volume increases then pressure has to decrease (pv=nrt). lower pressure on upper surface of wing means wing rises. so, higher speed = lower pressure. conversely, lower speed = higher pressure. relatively (again, pv=nrt and if volume is proportional to velocity then a decrease in v means an increase in p). wind tunnel images show slower air in the area in front of the rear wheel.

POST 10 / ORIGINAL POSTEROriginal post

Quotes source post: 593716

Exactly, if the engine is running it would be overcoming the vacuum. To properly test you’d have to test the fan side.

POST 11Original post

[QUOTE=KRAM36;593723]A set of these ram air ducts would be nice, but Kokeln went out of business and I have not been able to find them anywhere. demonspeed has the driver side intake for about $100.

POST 12Original post

On my 2002 base. The shape of the air intake is different than the one on the passenger side(evacuation). Look carefully at how the neck protrude at the fender surface. You will see that one goes out more than the other. In my opinion, this tuned by Porsche engineer ?

POST 13Original post

Quotes source post: 596903

And? What's your point? Is your suggestion that it shouldn't be messed with because it was designed by a Porsche engineer? Let me ask then: do you think it was the same engineer who designed the IMS? or the 5-chain arrangement? Or the AOS system? Or the problematic and failure- prone oil-delivery? Or the window regulators? Or the cooling fan resistors? Or..... shall I go on? Sent from my SM-G970U using Tapatalk

POST 14Original post

My point is the air intake or the heat exhaust vent have different shape exactly to prevent this venturi effect that the OP is talking about. In my opinion, the AOS or the fan resistors and even the IMS are perfectly designed and all of those systems work for thousand and thousand miles like they are suppose to. The fact that they fail on many cars, and I agree with you on this, is probably the consequence of suppliers who put crap in the material used to build the parts. But again, this is just my non engineer opinion.

POST 15Original post

Quotes source post: 596903

On my 03 Boxster S, the passenger side (USA) vent pulls air into the engine compartment.

POST 16Original post

Quotes source post: 593689

Visually, looking down the side of the car, you can see that the intake vent presents a certain amount of its cross section (although at an angle) into the airstream flowing around the car. It looks like it catches air so it is not likely that a negative pressure or suction could be created a the air box entry.

POST 17Original post

Quotes source post: 596923

Agreed! Sent from my SM-G970U using Tapatalk

POST 18Original post

Quotes source post: 596924

Exactly right. I don’t understand how the fallacy persists that the right side vent intake is an exhaust but I see it a lot. If you want to prove it for yourself, when stopped place a strip of tissue paper over the vent when the engine compartment fan is running. Just be sure not to let it be sucked in. It is true that heat radiates from the vent when stopped if the fan is not running but that is true for the entire mid/rear section of the car including the wheel wells.

POST 19Original post

Quotes source post: 597078

I don't know why people keep saying this either? If people want proof, I'll hook up my Durametric and have it turn on the fan for that vent and video record a piece of paper being sucked to the vent.

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