So, what's the final verdict re exhaust valve?

I connect, disconnect, re-connect all the time... depending on what my mood is

I agree with all your comments.

When disconnected, off-the-line performance does feel more sluggish. Also, from a standing start... unless you pull-away aggressively, the noise when you start off is not all that good. Sounds like a truck with a bad muffler. If you take off more aggressively, all is well again.

My car is a coupe, so I can escape the noise if needed by rolling up the windows, but sometimes the resonance can be annoying.

I actually keep the car with the valves connected most of the time. I like it stock... go figure.

 

I haven't tried it disconnected. I guess I like it just the way it is as well.

 

+1

 

Get a valved Capristo or Kreissieg with remote controlled solenoid for the valves for the best of both worlds. Or just buy the Capristo solenoid with remote control for your OEM exhaust. Then you can change sound and not get your hands dirty.

Taz
Terry Phillips

 

- back pressure is no good. period!
- it is louder at low rpm, but it is unhealthy sound.
- lose low rpm power.
- makes your car shiver.

I can not think of a single advantage, you will probably leave it alone too if you understand the physics behind.

exhaust system are designed to make gas flow out in steady rhythm, smooth waves of pulses. you will hear beautiful rhythm of pulses if you play them back in slow motion. speed of air flow is important, each pulse of gas coming out carrying enough momentum to suck out the next wave . The thickness, the length, the bend, the valves, everything are tuned to optimize the speed of the air flow. if the pipes are too wide, speed will be too slow, the wave can not from.
the shivering and the bad sound is the result of erratic turbulent air inside the system. but of course some people like that kind of sound. but as a musician I prefer rhythm and solid pulses.

 

I drive my F430 always with unplugged valves and wouldn't plug them again. The results are all the opposite as written before:

Much better sound, just incomparable
Much better engine and throttle response
Better torque at low revs, yes, really makes a difference
Right before the valves open, there is a lost of power due to the inertia of the vacuum line.
There is indeed a resonance between 3500-4000 rpm but I like it
Less pressure on the exhaust brackets which is real weakness on the F430 and can brake the headers due to the strain on the entire exhaust line
The engine has already enough to deal with backpressure with the precats and cats
The exhaust valves are there only for one reason: noice regulations

So, I see only advantages in keeping it open all time ;-)

 

http://www.capristoexhaust.us/Remote-control-to-open-or-close-exhaust-valves-p/rm.htm


the adove is a link to a remote that at a press of a bottom you can drive with the valves open or closed .This is for any Ferrari with a valved exhaust system .
Some info on the topic can be read .

 

He is right, I have the capristo twin sound and it is amazing. It's super loud and when you press the button, it really quiets it down. Most times I keep the valves open as my intention was to have the loudest 430 possible. The exhaust system with test pipes also reduced the weight of the car about 54 pounds after weighing everything that was taken off. That's always a plus. Talk to Andrea, he'll give you the run down.

 

Slightly less torque but I do mean slightly.
It does sound a little rough at idle but yes, noise level is quite a bid louder.
I have my valves wired back to the cabin with a wee switch beside the petrol cap so I can open and close at will. I leave them open half the time and closed the other half!

Vive la difference!

 

i'm sure this has been done, why not put the loss of torque question to rest and someone dyno with it unplugged and plugged?

 

Yeah. Someone should but who's gonna bother? From my experience, there will be slight loss of low end torque but for a car that has over 400nm of torque, it's not like you're going to feel a masive difference. Unless you're driving a 200-300nm car, then a loss of low end torque would be a real killer. I guess were splitting hairs here. The tiny loss will be over compensated by the gains in improved throttle response, mid to higg end gains in torque and most importantly aural enjoyment.

Andrea from Capristo can help.

 

I do own a remotes for my capristo and I don't use it. Think about it, the factory setup is just perfect! You have a euc that opens and close those valves for you. When the car most need the valves ia at start and low rpms. The car starts better and you have the low end torque and when you need free flow exhaust to achive full flow at high rpms the euc just open up the system!
I bet that if the stock systems comes with remotes a lot of tuners will make a automatized system to control the valves! Lol ;-)

 

Is there a write up or pictures that show how to disconnect
valves? I would like to try it for myself. I hit the search button
But could not find any info.

 

What I did is to screw a small screw (see picture, allen type) directly into the vacuum line, deep enough, and plugged the vacuum line back on the exhaust valve. With the right screw size, it's easy to reverse and unscrew it out without damaging the vacuum line. Did this for a long time and works perfectly well
Image Unavailable, Please Login

 

Thanks for the info. I just got home and looked. Mine are
already disconnected and the two hoses have a screw in the end
with a clam on it and they are neatly zip tied to the rear facia.
I've only had the car for two weeks and like the sound. Maybe
I'll return back to stock to see the difference.

 

Stef- Please explain to me what you mean by inertia of the vacuum line. The vacuum comes from a vacuum accumulator also used to power the servo for the brake system.

Taz
Terry Phillips

 

I'm not sure about that Taz.
The brake systems feeds directly from the back of the intake manifold. The drepresor tank feeds from the front of the intake manifold ant it serves the exhaust valves, the intake manifold upper and under vacuum actuators. The socondary air system which serves the fuel vapor system also feeds directly from the intake manifold.
Correct me if I'm wrong.