CS noise vs. Scud noise...

[hazy]

Dynamically the Scud is better, it's a newer car, sound wise nothing comes close to the howl of a CS bar a CGT IMO, totally totally addictive and epic

[Russell996]

hazy said:

Dynamically the Scud is better, it's a newer car, sound wise nothing comes close to the howl of a CS bar a CGT IMO, totally totally addictive and epic

Great sounding CS, but an even better sounding Scud. IMHO.

http://youtu.be/7F2AYBS4Lis

http://scontent-a.cdninstagram.com/hphotos-xaf1/t5...

http://scontent-b.cdninstagram.com/hphotos-xap1/ou...

Edited by Russell996 on Sunday 31st August 01:30

[roygarth]

hazy said:

Dynamically the Scud is better, it's a newer car, sound wise nothing comes close to the howl of a CS bar a CGT IMO, totally totally addictive and epic

Well summed up.

Saw and heard two CGT and two CS at a Spa track day some years ago. I was totally and utterly blown away by the sound of both cars. IMHO nothing comes close to these two cars.

I drove my CS from Battersea Park to the North norfolk coast yesterday afternoon. Epic drive at silly speeds. Lost count of the thumbs up I got for from cars I overtook at full chat/volume...although it was equalled by the number of flashes and fingers from those scared stless by the sound!

[Chris_VRS]

Both make a good noise but the Scud sounds synthetic in my opinion.

Full chat in a Strad in Race

[voicey]

Russell996 said:

The Scud actually has a rather convoluted valve system as you can see from the pictures. It is the reason the aftermarket exhausts that replace or remove this bit of pipe work achieve quite a different sound. The airflow even valves open looks to have a far from clean route.

Thanks for the pics. The pipes aren't only slightly more convoluted in design than the stock F430 tips. The exit position makes them look a lot different but the operating principle is the same:

a) Valve Open - gas runs straight out the tail pipe
b) Valve Closed - gas up the small pipe, into the silencer and out the other little pipe.

When the valve is open the pressure in the silencer is enough to divert virtually all the gas straight out of the tail pipe.


WRT Air injection: Since the Scud doesn't have a pre-cat in the header, air is pumped into the exhaust to burn off the excess fuel when running rich at start up (like having the choke on). This enables the car to pass the cold start emissions tests.

[Russell996]

voicey said:

Thanks for the pics. The pipes aren't only slightly more convoluted in design than the stock F430 tips. The exit position makes them look a lot different but the operating principle is the same:

a) Valve Open - gas runs straight out the tail pipe
b) Valve Closed - gas up the small pipe, into the silencer and out the other little pipe.

When the valve is open the pressure in the silencer is enough to divert virtually all the gas straight out of the tail pipe.


WRT Air injection: Since the Scud doesn't have a pre-cat in the header, air is pumped into the exhaust to burn off the excess fuel when running rich at start up (like having the choke on). This enables the car to pass the cold start emissions tests.

I've always wondered about the valves open operation, the design of the valves with so many bends, junctions and pipe sizes looks a recipe for an unusual gas flow, especially if you look at how simple the Capristo valve system is in comparison - totally straight with same diameter pipe all the way. I'm no expert on exhaust function (so expect to get shot down here) but to me the fast flowing gases when valves fully open would cause a low pressure in the muffler box as they pass the opening they usually go down with valves closed, this combined with the final bend in the pipe before exiting the valves on the left of the photo coinciding with the exit pipe from the muffler actually causes some of the gases to flow in the reverse direction around the muffler (following the low pressure route). So valves shut the gases flow one way round the muffler and valves open the opposite. Thoughts?

[red_duke]

I was underwhelmed by the noise of the standard 430 Scuderia exhaust when I test drove one a couple of years ago. I've always run my F430 with the exhaust valves permanently open (by disconnecting the vacuum lines) and that sounded significantly better than the Scud at both slow speeds and full chat to my ear.

Interestingly, the F430 muffler still leaked insulating powder even with the exhaust valves permanently open suggesting that exhaust gasses are still passing through it aggressively in that configuration. Until I had the entry/exit pipes welded up that is

Sadly I've never been near a Challenge Stradale so can't offer an opinion on that.

Right, off for a blast now as the car hasn't turned a wheel for 5 weeks. It's been a crappy August for weather hasn't it!

Edited by red_duke on Sunday 31st August 11:18

[Slickhillsy]

Russell996 said:

hazy said:

Dynamically the Scud is better, it's a newer car, sound wise nothing comes close to the howl of a CS bar a CGT IMO, totally totally addictive and epic

Great sounding CS, but an even better sounding Scud. IMHO.

http://youtu.be/7F2AYBS4Lis

http://scontent-a.cdninstagram.com/hphotos-xaf1/t5...

http://scontent-b.cdninstagram.com/hphotos-xap1/ou...

Edited by Russell996 on Sunday 31st August 01:30

Great vids... CS sounds epic but omg best I've heard the scud sound! Very different from stock... In line with other comments here that seemingly the stock system has much to give up with an aftermarket unit.

On that note is the general consensus that for the Scud a Capristo is the way to go?

[Russell996]

Slickhillsy said:

Great vids... CS sounds epic but omg best I've heard the scud sound! Very different from stock... In line with other comments here that seemingly the stock system has much to give up with an aftermarket unit.

On that note is the general consensus that for the Scud a Capristo is the way to go?

Scud in the video is using an S-line motorsports x-pipe. Non valved replacement for muffler/valves.



Capristo system is a complete replacement including manifolds/cats/muffler with remote valve control.

Scuderia Systems did have a lightly used complete Capristo for sale for £5500 earlier this month with full warranty.

http://www.ferrarichat.com/forum/360-430/456841-43...

[Slickhillsy]

Russell996 said:

Slickhillsy said:

Great vids... CS sounds epic but omg best I've heard the scud sound! Very different from stock... In line with other comments here that seemingly the stock system has much to give up with an aftermarket unit.

On that note is the general consensus that for the Scud a Capristo is the way to go?

Scud in the video is using an S-line motorsports x-pipe. Non valved replacement for muffler/valves.



Capristo system is a complete replacement including manifolds/cats/muffler with remote valve control.

Scuderia Systems did have a lightly used complete Capristo for sale for £5500 earlier this month with full warranty.

http://www.ferrarichat.com/forum/360-430/456841-43...

Ooooooo look at that! What an exhaust pipe should look like! :-)

[Slickhillsy]

Some more vids on their site - sounds very good...

http://www.s-linemotorsports.com/XXXpipe/

[voicey]

red_duke said:

Interestingly, the F430 muffler still leaked insulating powder even with the exhaust valves permanently open suggesting that exhaust gasses are still passing through it aggressively in that configuration. Until I had the entry/exit pipes welded up that is

I'm going to address this point first as it'll be quick.

The white dust escaping has nothing to do with gas in the silencer - ie: it isn't being blown out by the exhaust gas. When the solid insulation breaks down into a powder and the outer shield opens up when heated the dust falls out into the engine bay. The air circulating in the engine bay (coming in from the NACA ducts on the undertray) spread it around.

[voicey]

Russell996 said:

I've always wondered about the valves open operation, the design of the valves with so many bends, junctions and pipe sizes looks a recipe for an unusual gas flow, especially if you look at how simple the Capristo valve system is in comparison - totally straight with same diameter pipe all the way. I'm no expert on exhaust function (so expect to get shot down here) but to me the fast flowing gases when valves fully open would cause a low pressure in the muffler box as they pass the opening they usually go down with valves closed, this combined with the final bend in the pipe before exiting the valves on the left of the photo coinciding with the exit pipe from the muffler actually causes some of the gases to flow in the reverse direction around the muffler (following the low pressure route). So valves shut the gases flow one way round the muffler and valves open the opposite. Thoughts?

The exhaust gas is pumped by the engine and down the exhaust system. When the gas gets to the Y piece it has a choice - go past the valve or into the silencer. When the valve is shut there's no option but to go through the silencer.

In the silencer are interconnected chambers. When the engine is first started these chambers are at ambient air pressure. The engine then pumps the pressure up in the first chamber until there is enough pressure to force gas into the next chamber and so on until the gases escape out the tail pipe. (There's a few pics of a stock 360 silencer cut open here - the principle will be the same for all Ferrari silencers).

When the valve is open the vast majority of the gas will go past the valve and straight out the tail pipe. There will be some gas pumped into the silencer but not much as the pressure need to overcome the restrictions wont be enough.

I would also guess that the second Y join at the tailpipe actually draws a small amount of gas from the silencer which would help "pull" gas into it at the other end. However, this is just a guess - it'd need some CFD work or some empirical research to prove.