Jenner

I've read about this "mod" and got one of their free caps.

My question is this. I read the following about the two stage resonance intake system on the 911.


INTAKE:
A two-stage resonance induction system located in the air-filter cover uses the vibration of the air in the intake duct to improve cylinder filling. An adjustable butterfly valve in the intake system closes at 2,500 rpm and opens again at 5,600 rpm, resulting in a corresponding increase in the amount of inducted air. The benefits are greater torque at low revs, a flatter torque curve, and the trademark 911 induction roar.

I assume Porsche installed that elbow on the intake for a reason other than sound dampening. Could the reason for it be to make the vibration of the air in the intake that they speak of below?

If anyone can shed some in depth engineering/physics type knowledge on the intake system and the pros/cons of the cap (other than sound which is why I want to do it) please post something. Many thanks!

Here is the install that I am referring to:
http://www.smiley.net/orangecap.htm

jetskied

You should have no problems. The fabspeed intake system removes this pipe and replace it with a stright one. The only difference you're gonna see is more sound at WOT.

jetskied

The two stage butterfly refers to the intake manifold. Porsche has two loops for the intake manifold. A shorter one which helps fill the cyclinder faster at high RPM to help with HP. A longer one is used at lower RPM which helps torque. It has nothing to do with the air filter box. It all happens after the Mass air flow sensor which is at the end of the rubber tube connecting to air box.

Jenner

I understand the concept of the valve in the manifold, but what about the part that talks about things happening BEFORE the throttle body ie:

"the air-filter cover uses the vibration of the air in the intake duct to improve cylinder filling"

Sounds to me like something is going on in the air filter cover which is exactly where the muffler box is located.

Poursha

A few months ago, after reading lots of discussion about the orange cap, I put one in my Carrera. It made a slight change in intake sound, but I have PSE so it wasn't very noticeable, and I ended up taking it out after a week or so because I found that it eliminated the nice gurgle sound when you're decelerating (which I like). Now the gurgle is back! If you have PSE or an aftermarket exhaust, I wouldn't bother with it.

TT Gasman

I would avoid a piece of plastic that is not rated for automotive use on your Porsche engine, it may not stand up to the heat etc... An intake is one thing, but adapting something that is clearly not intended for automotive use is quite another. Just leave the stock airbox alone, it already flows more air than the engine can use, there is zero power to be had unless you can cool the intake temp. and none of the kits I have seen do that. That's my free opinion, I may be wrong .

Jenner

DJ not looking for or expecting any power increase. Just heard this was a free way to change the sound.

Poursha I have the GHL exhaust loud version. I guess I'll give it a try and see if the sound changed much and if I lose the gurgle.

Jetskied one more thing. You said "The fabspeed intake system removes this pipe and replace it with a stright one"

The fabspeed intake is crap. I bought one and returned it as soon as I realized what a joke it is. $225 for a piece of red silicone hose and a plastic plug that is painted to look like carbon fiber. The total value of those two items isn't $25 nevermind $225. Based on that, I would be SERIOUSLY SHOCKED if fabspeed actually did some air flow testing on their intake, or could tell me the reason why Porsche put that elbow on their inake. Fabpseeds kit has you remove the air flow straightener(which I am sure is there for a reason that a well paid Porsche engineer thought of) and replace it with a faux carbon fiber ring claiming that the air flow straightener blocks the flow of air. I am sure that is exactly why Porsche put it in there....

As you can see I am very skeptical of the Fabspeed kit. The Niagara kit cost me nothing to try out, but I am skeptical about this too....

fahren affair

i did the orange cap mod. there's definitely an audible "roar" at wot that sounds cool. it's purely for vanity, and i'm probably risking ingestion --but i'm not exactly sure how it's possible. btw, i have the ghl mufflers and combined w/ the 'cap' it now sounds like 911s of yore.

gerry100

I used to sell Niagara Plastics raw materials. Their basic product line is cap plugs for various industrial applications. mainly to protect fitings and connectors during handling/shipping.

As I recall, all of their parts are molded of Polyethylene or Polypropylene. The PE will feel and look "waxy'. Either polymer softens or worse as it exceeds 180 deg F. I wouldn't have it near my engine if temps are in this neighborhood. Definitely not in the intake.

Could be the most expensive free sample ever.

jetskied

Jenner the point is that I mention the fabspeed intake is that pluging the whole would effectively do the same as puting that straight pipe from fabspeed. You will not experience and wave technology in the air system that will affect your intake of air. Since your worried about it then forget it you have exhaust and I agree that you probably won't hear anything by changing things in the air box.