That's correct. A smooth interior pipe will have less resistance thru it than a rough one . How much ? that will depend on the actual roughness .
Since the Porsche hose is smooth except for a few indentations, I assumed 20 % less .
But even if it were 100% less , it would still be insignificant .

I'm not sure if I would call a less than 0.1 hp gain " effective " . Lol

$250 is what Fabspeed charges for their " cold air " intake rubber elbow .

 

Ok I got it all and thanks for taking the time. All makes sense.

$250.00 is a lot of cash for a small pipe!

many thanks again.

BTW, do all 997's come with this air box resonator assembly?

 

Whats that mean? NJ is the $hiT
only the strong survive

Yes I believe they all come with a resonator

 

Just bought my hose its 4ply silicone 500 degree resistant (not that ill reach that, i hope) it cost me $30

 

[quote=rah79;1581287][quote=Gcalo;1397656]JCS,

For a guy from NJ you are all right.



WHAT???????????

 

very interesting.....let me start looking into it..

 

FYI,

http://www.hightempsilicone.com/ is apparently out of business...Their phone is disconnected and not responding to emails. My CC was charged on the 6th but no product delivered.

Elastofab is company listed on CC statement and is also bogus!

Live and learn.

 

Yikes...sorry about that. Back then I just posted a bunch of website I found that sell silicone hose. I just use the stock airbox myself.

 

Same story with me, I called Hitemp. and they were out of business but still got dinged the $38.

 

Call your CC provider and dispute the charge.

You have 60 days from the charge date to do so.

 

Crod,
Wonder how your mod is holding up? Are you still using it?

 

hmm this is new to me,.. may i ask what this mod does?.. seems like it alters the intake and presumably more sound is obtained.. ?

 

The 997 air filter box has a resonator built into it .

It's purpose is to alter the sound coming from the engine .

The outlet of the resonator connects to the main air intake hose to the engine ( see red arrow in picture )
As the outside air ,on it's way from the filter to the engine inlet , is drawn past the resonator , it creates a sound frequency which cancels out some of the engine noise ( since similar frequencies tend to cancel each other)

If you want to know how it works, blow over the top of a bottle .
Depending on the volume of the bottle and the velocity over the outlet , the frequency changes (the Helmholtz principle )

The resonator outlet has a vacuum activated butterfly valve in it which closes at high rpm's , thereby disabling the resonator effect , and is open at lower rpm's.

If you want your engine to sound a bit more aggressive at lower rpm's, all you need do is to disable the resonator .
It will not do anything for performance, but it sounds cool . A bit like a mild performance muffler .

Some do it by replacing the OEM air intake hose with a rubber elbow from a plumbing supply place, or as I have done, just put a plug into the resonator hose ( see previous threads )

If you go the hose replacement route , be sure to put a cap over the resonator outlet to prevent dirt from accumulating inside

Or, you can buy the Fabspeed "cold air kit " for a little over $200 .
You will receive a pretty red rubber elbow and , according to Fabspeed , get at least a 10 hp gain to boot . Lol

 

One option I've not seen discussed, but which should work would be to unplug the vacuum tube that connects the Helmholz resonator to the vacuum solenoid, and plug the vacuum solenoid with a $.02 vacuum cap. I wasn't sure what size I needed so bought a multi-pack from Auto-zone for $.99.

Capping the vacuum solenoid is a necessary step when removing the OEM airbox and installing an EVOMS box, so I don't see why it wouldn't work to just stop the suction from activating the resonator if using the stock box.

Am I the winner of the cheapest solution contest?

 

Used parts found at OSH