F355 sound

A) you get the 5 valve heads
A.1) Independent Throttle bodies on each intake, this gives the crisp takeoff gurgle
B) a real velocity stack inside the intake helmholtz resonator; which is plastic
B.1) the intake is making a significant portion of the overall sound
C) the RPM band is 6000-8500 (F355) instead of 5000-7500 (348)
C.1) headers are tuned for this power band
C.2) intake is tuned for this power band
D) headers are a bit undersized (ID) which leads to a supersonic wavefront in the header primary pipes. This give the airy nasal quality to the sound. As you open up the system (lager ID) you lose this airy nasal quality.
E) 4-2-1 header style lowers the onset of airy noise down into the 3000 RPM band.
F) the exhaust bypass (and valve.)
F.1) exhaust bypass bypasses 2/3rds of the muffler
G) air intakes just behind your ears in the side vents

 

Watch the 355 video link on the last line of my signature .......

 

No, no, no! Wave speed in a fluid can never exceed the speed of sound. Speed of sound is what defines wave speed. This is why you can not hear an object moving towards you at supersonic velocity and why shock wave develop.

 

Exhaust gas itself travels at a fraction of the 'speed of sound' .... especially in the exhaust system ... as sound waves accelerate with exhaust gas temperature rise.
Exhaust size, shape and design obviously affects the sound ... but primarily because of how exhaust design propagates or attenuates sound amplitude and frequencies .... not because the 'speed of sound' itself creates the 'sound'.

 

Yes, speed of sound is related to square of absolute temperature. Sound itself will depend on the magnitude of the pressure pulses, reflections of the waves within the exhaust system, and frequency of the pulses. Different frequencies will excite and amplify or attenuate different resonances. Very complex. I modeled this stuff some 45 years ago when doing graduate work.

 

It sounds a bit better in person ...... in addition to the great sound, this exhaust upgrade gained nearly 30HP to the hubs ...... over the next few weeks, this 355 will be getting some new manifolds as well ......

 

Thanks. She's amazing. Love those tunes.

 

No video can really capture the true sound of a 355. The silver spider video is pretty good but he has a Tubi exhaust which is the wrong one

The dtrockstar video with the yellow spider and Capristo is pretty good and has the same set up as mine. Thing is, once the bypass opens it sounds like another world has opened up and then once you get over 5k the engine noise starts to change and when you get to around 7k you get that F1 scream.

The 355 is arguably one of the best looking cars ever made but I would definitely say top 5 as far as sound goes. The only Ferrari I think sounds better is the F50:

https://www.youtube.com/watch?v=H0M73wYuD6k

 

Here's another edition from a weekend cruise. Headphones on!
Tubi
New fabspeed headers

https://instagram.com/p/BLt4bA8jANX/


Sent from my iPad using Tapatalk

 

sweet

 

The F355 has a distinct second harmonic in its exhaust note. The muffler design is a significant contributor, although there are other factors such as valve quantity and exhaust header diameter.

The muffler can be tuned to generate the second harmonic by allowing a certain length of merge between the two exhaust banks. The technical details on tuning exhaust sound are probably in the competition-sensitive IP domain.

This harmonic has been successfully generated in aftermarket exhausts for the 348 and even the 458, but somehow the F355 still has the cleanest and most memorable 2nd harmonic noise.

The second harmonic is notably absent on the F355 Challenge exhaust. When tuning for peak power, the exhaust noise was sacrificed.

 

The number of valves per cylinder has no direct effect on an engines redline capability. Combustion efficiency, yes.

Nobody has mentioned this one yet.....the engine displacement. A big contributor to the F430/458 not sounding as good (high-pitched) as the F355 is that the engine displacement has increased dramatically without adding any cylinders. Even though these cars have a higher redline than the F355 they have a much deeper tone.

 

Right, Chan. The exhaust on my F355 Challenge is just loud...





[ame]http://www.youtube.com/watch?v=7ymWiTGmzIQ[/ame]

 

I agree with Chan, the Challenge doesn't sound as good as a Capristo for example. Yes the Challenge still sounds good but it's missing quite a bit of that F1 wail.

 

Breathing more efficiently I'm certain helps redline efficiency, no?

 

It won't physically aid in increasing the maximum safe engine rpm. That is solely dependent on the weight/strength of the moving components.

Now if we were talking a race engine with a stratospheric redline 3 smaller intake valves would allow a higher rpm over 2 (individually heavier) larger intake valves before valve float became an issue but I think on our engines that's not the case. IIRC the F355 can go to about 10,500 with stock cam profiles before valve float issues.

At any rate it is a glorious sounding power plant.

 

I love all the videos, so thanks I even watch them on rainy days.
But the BEST sound comes from the driver's seat, top down going through a long tunnel
.....at about 8000 RPMs.
Last time I did this with a friend all he could do was laugh out of control for 2-3 minutes straight.
"That's insane" is all he could say.

 

Hi everyone.
So why doesn’t the stock 360 Modena sound like the stock F355?
Ciao ciao,
Nic

 

Humm. Let me ponder that for a moment. Could it have something to do with the 360 having a different engine and exhaust?

 

I think it's mostly the exhaust setup on the 355. The 360 has a pretty different exhaust setup, especially from the header collector on, at least partially due to different packaging constraints with the gearbox flipped from transverse to longitudinal. ITB's vs. a throttle body per bank, the cam profile differences etc. probably also make a difference, but mostly the exhaust.

 

No Y-pipe

 

2 things:: intake and exhaust.

Intake:: F355 has plastic velocity stacks and Helmholtz resonators direct from its Helmholtz resonator. F355 also has individual throttle bodies.
360 has 2 different length velocity stack with a throttle plate in the middle between 2 Helmholtz resonators and valves which couple the resonators together (or not) and a throttle body per bank.

Exhaust:: F355 has an exhaust pipe directly to the muffler per bank and a Y pipe which uncorks the flow to the muffler above 3000 RPM.
360 has a more conventional pure dual exhaust with no mixing except what happens in the muffler itself; and 2 valves to allow
more exhaust flow at higher RPMs.