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Performance Products shows a cold air upgrade for 997 and 997S in their recent catalog. They claim 11.8 HP and "significant" torque upgrade. All for only $225 and 20 min install. Could this be true?? Has anyone tried it?

For "only " $ 225 you get a ~ 3"dia. rubber elbow and a plug to close off the Helmholtz

resonator.

If you believe replacing the factory air intake with a new ~ 6" long elbow will get you an increase of 12 hp and "significant" torque, go for it .

What you WILL get is a louder sound by rendering the resonator inactive.

( And you can just plug the small bypass yourself if you want a louder engine )

Edited by Jean
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I am still amazed at the aftermarket people who claim anywhere from 10-20HP gains for a bolt on... they must think that owners are really dumb.

X51 Powerkit is... $20K+? And gives 26hp? So, if it was that simple to pull an extra 10HP out of the flat-6, why wouldn't Porsche have done it?

Save your motor, save your warranty. I would think that blocking the intake resonator would reduce torque, but I didn't design the motor, so I don't know.

Just MHO,

-ds

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I am still amazed at the aftermarket people who claim anywhere from 10-20HP gains for a bolt on... they must think that owners are really dumb.

X51 Powerkit is... $20K+? And gives 26hp? So, if it was that simple to pull an extra 10HP out of the flat-6, why wouldn't Porsche have done it?

Save your motor, save your warranty. I would think that blocking the intake resonator would reduce torque, but I didn't design the motor, so I don't know.

Just MHO,

-ds

The Helmholtz resonator is a closed box with a butterfly valve in the opening .

As the combustion air is drawn past the opening, it creates a resonance

(similar to to the sound produced when you blow over a bottle neck )

At low speed ( rpm ) the valve is open and at higher rpm it closes off the resonator

for a more agressive sound.

It has absolutely nothing to do with engine performance .

All it does ,as the name implies, is alter the sound emanating from the engine air intake ,

presumably to comply with the more strict European noise emission laws when cruising

in residential areas ( similar to the reason for the valves in the PSE exhaust system)

I closed mine (plug in the bypass hose ) and I really like the more " throaty "sound .

(Almost like a mild performance muffler) It's a cheap mod and if you don't like it

it's very easy to un-do .

Edited by Jean
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  • 3 weeks later...
  • 8 months later...
question: is there a helmholz resonator valve in the 3.6 liter 997 (non-s) motor/airbox? or does the "sound mod" only pertain to 3.8 liter motors? thanks

The resonator is specifically designed for the 3.8 liter 997 S engine air intake only.

It's purpose is to :

1. reduce cabin background noise in the higher frequency ranges

2. emphasize the sporty, load related air intake noise between 300 and 600 Hz.

( per Porsche "Technik" manual )

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question: is there a helmholz resonator valve in the 3.6 liter 997 (non-s) motor/airbox? or does the "sound mod" only pertain to 3.8 liter motors? thanks

The resonator is specifically designed for the 3.8 liter 997 S engine air intake only.

It's purpose is to :

1. reduce cabin background noise in the higher frequency ranges

2. emphasize the sporty, load related air intake noise between 300 and 600 Hz.

( per Porsche "Technik" manual )

Jean, thank you for your reply. Glad i didn't spend any unneccessary money.

Regards

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  • 5 months later...
Performance Products shows a cold air upgrade for 997 and 997S in their recent catalog. They claim 11.8 HP and "significant" torque upgrade. All for only $225 and 20 min install. Could this be true?? Has anyone tried it?

This has been discussed before and for $12 you can get the Home Depot rubber elbow, (if you can still find it) which works just as well. Not as elegant, but Cheaper and just as effective. Check other forums if not on here!!

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Jean,

What did you use to plug the bypass hose? How did you make sure that what ever it was did not get sucked into the intake?

I filled the hose from the resonator with silicone mold material .

It stays put , but can be removed anytime since it does not bond to the rubber .

You can also just buy a rubber plug in a Hardware store.

Just insert it deep enough to allow the hose end to fit over the resonator outlet .

The elbow in the hose will prevent it from going any further ,but also, since

the resonator is a closed box , it won't get sucked into the intake since there is

never any pressure on it .

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After 2000 km with the Schnell elbow, I could not stand anymore and took it off at the same time I got the PSE mod done to the mufflers. Above 5000rpm the resonator bypass just gets very loud and it drones. It does not have any sound characteristics so try the cheap way and see if you like it first.

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