F430 Air Intake Mod : Increased Sound : DIY

Subject: F430 Intake Resonance Modification

Reason: Increase intake sound

Background: The DOT has sound limitations on exhausts (we all know this) and on Intake noise. The more tuned an intake is the louder the intake noise, in general. To reduce the noise emitted at the intake opening on many vehicles the manufacturer adds a "Y" pipe to the intake where one pipe goes to the intake path, and one dead ends after X inches. The sound reducing tube is tuned to the intake harmonic with the most volume in theory. The tuned tube has no outlet and basically absorbs intake noise usually using destructive interference. Sometimes a box is added for the same reason. Both can be added to remove different frequencies. Remember sound comes out of the intake as air moves in (unrelated actions), and the sound exiting is no different than a musical instrument or speaker box and can be tuned using the same generally understood principals. The 2006 F430 Spider has both a capped tube and a resonance box. Also note they put the tube and box opening at the Bend in the intake where the sound waves must bounce on the walls of the intake to turn.

*There are many air intake configurations for the F430 / Scud / Challenge with different sounds. Please see RichardCH's posts for more information on that topic.

Theory: If I were to plug the intake Y pipe and resonance box with a high temperature adhesive metal foil, the intake noise should increase audibly because the sound can not enter the tube or box. This will have little affect on air moving into the engine, maybe removing a few vortices caused by high speed low pressure air moving past the openings to the tube and box.

Material: I used the AF 100 HVAC Metal Foil tape because of its high temperature capacity, moisture resistance and thickness. This stuff is like sheet-metal with an adhesive backing.

Safety: This mod is BEFORE the air filter. If I lose a piece of tape it will be stopped by the air filter. Its been >1 year and no issues, tape is like day 1 and I have driven >3K miles.

Credit: RichardCH gave my this idea with his quest for better intake sound. I did this about a year ago and wanted to post the results.

Simulation: I simulated the intake with and without the resonance tube. The results were as expected. On the simulation the brightness of the wave is directly proportionate to the signal level. I used the 2D wave ripple tank simulator [ http://www.falstad.com/mathphysics.html ]

Empirical Data: This was a bit harder. I purchased two boom microphones (directional) and a high quality audio recorder (Tascom DR-05). Also I made cones to shield the microphones from air noise while driving. I recorded before and after audio and analyzed the audio using audacity in the frequency domain. I also did the test with the microphones on the dash pointing at the air intakes, (line of sight). This worked a bit better than the cones.

Results: Sound seems to be a subjective area, but it is my opinion after driving the vehicle, listening to the playback of both the before and after sound tracks using Sennheiser's best 50 ohm headphones (HD-598) for accurate sound reproduction, and reviewing the frequency domain information, I believe the sound emitted form the intake is audibly louder and sounds more aggressive to my personal taste. The sound is more pronounced when the throttle bodies are wide open, and the engine is under heavy load because it is in this configuration the engine (at the intake) is making the most noise and the path out is least restricted.

Side Note: I did a similar mod on my 3.4L converted Boxster many years ago, and the results were even more pronounced.

*Disclaimer: Any damage that results from attempting this DIY is because you are an clumsy idiot, and not the responsibility of the author. Use at your own risk.
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Great post ... Thanks for sharing very impressive project.

 

That pretty slick, Trent. You even got the microphone cones to almost match your Rosso Scuderia!! I've got to hear it in person sometime.

 

I am to presume that this will work on the 360 as well?

 

I skipped 360 ownership (my fail, missed years of fun). So I am ignorant to the intake other than the Ricambi provided pictorial.

http://www.ricambiamerica.com/parts_catalogs.php?M=FE&P=&V=diag&I=674 (First Image)

It seems the sound diffuser is part #8 the "air conveyer". It is my somewhat ignorant conclusion that the #8 piece would need to be replaced with a different intake tube. More like RichardCH's mod.

Options:

The CS intake seems to have a less restricted end near the mouth. $600/side : http://www.ricambiamerica.com/parts_catalogs.php?M=FE&P=&V=diag&I=477

The Challenge intake looks like your best bet, its $800/side for the two parts and appears to be somewhat of a flex hose. http://www.ricambiamerica.com/parts_catalogs.php?M=FE&P=&V=diag&I=400 (second Image)
*Paying $263 / side for 2.5ft of flex tubing might be a bit high, so you might be able to just buy 2x of the #8 from the challenge for $550 each and then just get the flex hose from a local speed shop to save money. The money saved might not be worth the effort in sourcing the flex tube.
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Interesting mod Trent, thanks for the detailed writeup.

so ... this is a straight forward process? remove the side panels and tape the resonance air inlet? that's it?

 

Yes, its that simple, but that does not make for a good write-up.

 

Lol, that's true....wish I could do it but after $1k vs $15 not so much....

 

Hate to revive my own thread. But I just noticed that my F430 has sound absorbing flutes on the engine side of the factory air box. Just had never noticed before.

These flutes have nothing to do with air flow specifically, however they should induce some turbulence in the intake ruiner which is not optimal.

Their intents to reduce sound levels emitted from the intake system that is traveling counter to the air flow.

Intake sound is regulated as is exhaust sound. The intake sound originates from your valves (especially at overlap) and at the intake runner mouth where air speeds can be near supersonic. This is a spectacular sound and humanoids interpret it as a "roar". The sound levels can reach pain threshold depending on the intake to human distance.

The DIY up to this point closed the sound dampening flutes between the air box and the side intakes (air inlets). The new flutes (see image) are on the other side of the air box, but are there to reduce sound. These flutes are NOT on the Scud (at least per ricambi diagram)

Photocredit: Ricambi [esteemed and inexpensive FChat sponsor]

Orange: Previous flutes plugged with Metal Tape. Like thin aluminum plate with adhesive, designed for attic temps. Protected by air filter.

Red: Proposed flutes to cover, would cover with the same tape. A little more concerned with tape delimitation, being sucked in intake. I don't think there is a safety screen on the 430 intake, some cars have it. I am not sure the tape would do any real damage, its quite malleable, and would probably be a higher risk to the CAT. I don't have pre-cats.

QUESTION: Anyone think its worth it, or would be interested in me investigating this further?
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Interesting. You know its almost too bad you didn't use inflatable balloons in the resonators to block them off.. or at least distort the harmonic. Inflate to block, deflate to open them up and quiet it.

 

I wouldn't want to risk anything that could get sucked into the engine. I know its only aluminium tape but you never know what it will do.

I don't want to read a thread that says "Oh dear I have just turned my nice engine into an expensive coffee table"

Simon

 

This is an interesting experiment. You have definitely put quite a bit of thought in your analysis.

In terms of airflow the tape would work but I don't think that the tape would not do a good job at reflecting the sound. The tape is quite thin and in my estimation would be quite "acoustically transparent" (meaning that a lot of sound would transfer into the channels). I think that the best way would be to actually remove the resonating chambers and patch the holes or have a new part made without the resonating chambers.

 

I want to know what makes a Maserati sound so amazing

 

+1; Just drove the new Maserati Ghibli, spectacular sound, but different than 430. I think it is the long exhaust pipes because it is a front engine car. Its a different musical instrument all together. I might pick up a Ghibli soon, but thats another thread....

 

Pretty sure that the Maserati uses a cross plane crank V8 whereas Ferrari uses a Flat plane crank. Although, the Ghibli should be a totally different beast with the V6 TT!

 

Yep correct but still no other cross plane V8 sounds like a Maserati, what are the key factors ????

 

So based on the diagrams it looks like the 360 has one side-intake while the 430 has two? If that is the case then is it not the cost of the upgrade just 1X Challenge intake (either intake itself or entire assembly with hose)?

Does anybody have the before/after with this mod as it applies to the 360 only?

Thank you.

 

I agree. I testdrove a GT MC Convertible and I swear it sounded better than my Scud and 458. I might need to buy one soon...it's quite mesmerizing.

 

Yes correct the 360 incl CS only has an air intake on one side

 

Just reading through this lot and absolutely doing this to my 430 when I get home, excellent idea!

Just one question; did you ever get any further with plugging the flutes downstream of the air filters? And did it make any appreciable difference if you did? If not I will look into it and do some experimenting myself to try and find a safe option so as to minimise the risk!

 

Does anyone have a spare part #8 from a 360? I'd be happy to pay shipping on it and modify / redesign it and try it out in my own 360 to see the difference? =)

 

Were there any sound files to listen for ourselves?

 

For those who are interested, I've just completed the modification for my 360 spider. Got a spare air intake snorkel for the 360 Modena, and plugged up the baffle holes.

Air induction sound is fantastic!! Very obvious, even with the exhaust valves opened all the time. Car feels smoother during acceleration as well.

If anyone else is interested, I can upload more pictures, with relevant instructions on what to do.
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I am very interested. Please share more!

 

+1 show for 360. Also is this a diy mod?