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Exhaust Valve Bypass Mod

 
  #31  
Old 11-03-2018, 05:04 AM
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No worries disconnecting the vac tubes at the exhaust, no negative impact on cats warmup, ECU, CELs, etc, etc.

The valves stay closed under vacuum (which is idle to mid range RPM where much to some vacuum is present) then open at WOT or high RPM. They open to offer a little bit more exhaust flow in PE.

Exhaust sounds a little louder at idle through the entire RPM range disconnected. Performance will be slightly better. Exhaust sound is a personal preference. What one person thinks is loud or droney another person thinks is too quiet. Strictly personal.

On C6 Corvettes, where I first experienced these, they were a Factory option (called NPP exhaust). It was sold as a modest performance upgrade. Some cars (same engine) had a single functional exhaust tip each side, others had a dual exhaust each side, one of which opened under the absence of vacuum which was mid to high RPM or WOT. The NPP cars were specced at 436hp; the non-NPP cars at 430HP. So a 6 HP gain from the small extra exhaust gain at peak performance.

Disconnect and block the vacuum tubes at the rear exhaust valves, as shown here, and enjoy. Mine are disconnected, and on the Vette too.
 
  #32  
Old 11-03-2018, 07:18 AM
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Originally Posted by John Fiammetta View Post
That valve looks identical to the ones on Ferrari 360 ,s .
You just pull the pipe off and put a self tapper in it .
No detrimental effects , no ECU, s having fits ,no spurious CEL ,s .

Not sure which is worse B or F cars for hissy fits regarding throwing CEL.s - fuel or seated fuel caps , or just a strange way you looked at it

It only the OEM system and very few aftermarket that use the vac valve .
Same as B , sport mode and over a certain rpm , I think 4500 it opens .
Sort of neighbourliness thing really to pass a notional noise test .
How ever @ cold start as said above you get tick over at 12-1500 rpm for say 30 secs to 1-1/2 minutes , with what sounds like itís open .So I conclude thatís all it takes to warm the cats less than 2 mins - on a Ferrari .

Thought about it my self ( had a race exhaust on the 360 ) .TBO like the sound with stock esp as designed circa 2000 rpm on the motorways , the serenity, lux barge experience.

I might do it ,with a view to reverse it if it drones on the motorway.
Thing is makes a mockery of the recent thread on Naim ice upgrades .

hmm , Ferrari,s the other way the stereo is ornamental ,as is sensible conversation


I would say get your sound fix / kick from something else - Duc or Fezza / Lambo , pork GT3 etc
Yes my Panigale is insane wth the Acrapovic system.
 
  #33  
Old 11-05-2018, 02:48 PM
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I knew the wrench police would come out on that one.

I read that the exhaust flaps , additionally, aided catalytic warm up. Wasn't sure if true. Thought I put it out there and see the response. Kind of makes sense, perhaps only to satisfy EPA?

The deterrent is, if there's droning inside the cockpit.

We only live once. Whatever feels right.

Thanks.
 

Last edited by 1eapplebaum; 11-05-2018 at 03:22 PM.
  #34  
Old 11-11-2018, 08:44 AM
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I've been looking at what would be needed to create a button for the driver to override the exhaust valves. It looks fairly easy, a three port valve and a radio controlled relay on 433mhz . The valve would be installed to make the vacuum line look at either the valves or a dead end. The valves would look at either the vacuum line or fresh air. The 3port valve would be controlled by a 12dc radio relay. The keyfob for this would be learned to one of the three garage buttons on the roof.
 
  #35  
Old 11-11-2018, 08:55 AM
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Originally Posted by AngryBaldMan View Post
I've been looking at what would be needed to create a button for the driver to override the exhaust valves. It looks fairly easy, a three port valve and a radio controlled relay on 433mhz . The valve would be installed to make the vacuum line look at either the valves or a dead end. The valves would look at either the vacuum line or fresh air. The 3port valve would be controlled by a 12dc radio relay. The keyfob for this would be learned to one of the three garage buttons on the roof.
Already done.

Try these guys. Contact them, no reason why this wouldn't work for a Continental as the system operates the same way as the Corvette does:

https://www.southerncarparts.com/cor...tch-p-231.html

 
  #36  
Old 11-11-2018, 09:20 AM
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Originally Posted by BWings View Post
Already done.

Try these guys. Contact them, no reason why this wouldn't work for a Continental as the system operates the same way as the Corvette does:

https://www.southerncarparts.com/cor...tch-p-231.html
Not sure they'll ship to the UK and I think this installs where the "brain" for the valves is .has anyone found this brain yet?
 
  #37  
Old 11-11-2018, 12:25 PM
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Originally Posted by AngryBaldMan View Post
Not sure they'll ship to the UK and I think this installs where the "brain" for the valves is .has anyone found this brain yet?
I believe you're overthinking it, and looking for something that doesn't exist. These exhaust systems are pretty common and simple. The reason the valves are operated by vacuum (and vacuum lines run all the way to the rear bumper) is because vacuum is a natural byproduct of a running internal combustion engine. The intake manifold is high vacuum at idle and progressively lower vacuum as RPM increase.
What they all try to create is a progressive airflow (lower back pressure) as rpms increase in range to redline. The louder exhaust sound is secondary to performance (but feeds the male ego too, so a good thing).

On Corvettes, it is as simple as a vacuum port at the back of the the intake manifold with a vacuum line run all the way back to the valves....THAT'S ALL. No reason this system is any more complex than that, with the addition of a one-way check valve in the vacuum lines because of the turbos and pressure at the intake after one atmosphere.

The switch WS I sent you is an aftermarket device because guys didn't want to wait for 4500 RPM or more to hear the noise, so the switch is a way to intervene and interrupt the vacuum at low RPM and idle to play with the sounds at will.
 

Last edited by BWings; 11-11-2018 at 12:27 PM.
  #38  
Old 11-11-2018, 12:49 PM
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The device you sent the link to doesn't appear to have any pneumatic connections at all, so I imagine it's doing something else.
 
  #39  
Old 11-12-2018, 06:58 AM
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I know there is an electronic component to the system, and I shouldn't have described it so simply as to be just a vacuum line back to the manifold. I think it's simple though. like an electronic check valve. But as far as I can see, and that is looking at all the modules in the car using VCDS, I don't see any reference to a module for this.

In the Corvette application instructions, the device intervenes at a specific fuse. Some, in the Corvette world simply pull the fuse to allow full time open exhaust. They do not report a CEL, so the fuse doesn't power a complete Can-Bus module (or brain as you put it). Even if there was an external device processed through a can-bus module, let's say a body control module, the module would report a fault pulling the fuse to a device it controls.

Back to your idea. If the electronic device is simple, and if it works like the Corvette system, then that is all the device is doing - it is intervening at the fuse for the electronic valve by making/breaking the +v. Then they're using a simple rf circuit for remote controlling the on/off switch. I've looked at the fuse panels in the gen 1 GT and there are two fuses one for each dual mode exhaust bank located in the engine compartment fuse box. But unfortunately (and unlike the Corvette), the same two fuses (7+8) power several other components as well. So, maybe not as simple as intervening at a fuse(s), but maybe tracing the circuit and intervening at the +v feed to the dual mode devices.

 

Last edited by BWings; 11-12-2018 at 07:28 AM.
  #40  
Old 11-12-2018, 09:05 AM
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All that sounds much more complicated than my idea of the small three port valve controlled with a 12v relay.
 
  #41  
Old 11-12-2018, 10:36 AM
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Well, all the best to you on the pursuit.
 
  #42  
Old 11-12-2018, 01:18 PM
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Originally Posted by BWings View Post
Well, all the best to you on the pursuit.
I just think it'll be easier than taking the car apart.
 
  #43  
Old 05-09-2019, 09:26 AM
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Is there a significant difference?
 
  #44  
Old 05-11-2019, 04:48 AM
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I was asked in a private message how to bypass the quiet exhaust flaps. Thought it might help others so I am also posting my reply in the thread. This is a pretty old thread so might have been answered earlier too and I did not review the entire thread over again. Sorry if it is a duplicate:


Both flaps stay open until the engine starts. These flaps operate on system vacuum. At idle and midrange, vacuum exists closing the flaps. At higher RPM and redline, vacuum is low or gone, then flaps open.

If your flaps are open all the time with engine running idling, then yours are already disconnected.

I disconnected mine same as Corvettes as they use the very same system -

Take the rear plastic belly pan off. This exposes exhaust pipes/mufflers.
At the rear, by the exhaust tips you will see vacuum dashpots, one on each side.
Just remove the rubber hoses from the dashpots, plug them securely with a screw in the tube
Then tie them off with tiewraps so they are safely out of the way.
Replace the belly pan.
You are done.
 
  #45  
Old 05-11-2019, 11:55 AM
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I just replaced one of these. The car made a high-pitched whine every time I hit the gas, this was helpfully pointed out by a fellow poster here as an exhaust valve flapper valve.

On the ODB, I got that code, so it made sense. But that's why I'm writing this, there is some sort of Can Bus connection with these guys, because I got the error. I don't really care about the exhaust sound, the car already rumbles plenty for me, but the interior is so quiet, I absolutely had to get rid of that high tone every time I hit the gas. It was quiet enough I couldn't get a recording of, but loud enough to drive me batty.

Here was my error code:

-------------------------------------------------------------------------------

Address 11: Engine II Labels: 07C-906-018-BEB2.clb

Part No: 07C 906 018 AR

Component: BY-6.0L-TT G ™6521

Revision: 34ˇTT Serial number: 000-00005.11.

Coding: 0000173

Shop #: WSC 00000 000 00000

VCID: 75B7E0EC09D3073FBDB-5161

1 Fault Found:

19473 - Valve for Exhaust Flap 1 (N321)

P3017 - 001 - Short to Plus
 
 
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