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Active Exhaust Cold Start

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Old 10-15-2018, 12:07 PM
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Default Active Exhaust Cold Start

I've only just begun to get to know my 2016 R vert, but so far I really only have one complaint. It seems that with every cold start, the active exhaust is opened up for a nice throttle blip, then left open for ~10 seconds. This is cool in many circumstances, but not all. Especially not if I want to go run a late night errand without irritating my neighbors and getting a nastygram from my HOA. I love the sound, but one of the things that drew me to this car was the dual personality of it. Raw and mean when i want it to be, smooth and civilized when I don't.

Has anyone had any success keeping it quieter for cold starts?
 
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Old 10-15-2018, 12:40 PM
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Exhaust valves are closed by engine vacuum as far as I know, so it takes a few secs to close them when firing up the engine.
 
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Old 10-15-2018, 01:03 PM
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Another bit of interesting info: The VAP valves have a stiffer spring than the OEM valves and require more vacuum to close. As a result, they are never closed at idle.
 
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Old 10-15-2018, 01:43 PM
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Unless you would add an electrical vacuum pump, with short vacuum lines - otherwise it would take some time still -, there is no way to keep the valves shut at start up,
other then physically close them permanently.

There do exist little electrical boxes that keep power alive a set time after activation, so that could be a possible workaround until engine vacuum takes over...

Unhinged - did the early F's not have an electrical vacuum pump?
 
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Old 10-15-2018, 02:02 PM
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Originally Posted by KVO View Post
Unhinged - did the early F's not have an electrical vacuum pump?
Yes they did. Somewhere around MY16-17, they got rid of the vacuum pump and ran a vacuum line back from the engine. There's a TSB to remove the vacuum pump on earlier cars and run the line, if requested. I never did, which I sort of regret.

 
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Old 10-15-2018, 02:10 PM
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I wonder if a valve could be designed to be "normally closed" and still integrate with the car's active exhaust control. Seems like something VAP could pretty easily retrofit into their design... I'd be very interested in purchasing one of their systems if they did (hint, hint)
 
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Old 10-15-2018, 02:52 PM
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Originally Posted by Unhingd View Post
Another bit of interesting info: The VAP valves have a stiffer spring than the OEM valves and require more vacuum to close. As a result, they are never closed at idle.
I have the VAP system on my car. The valves are open on the cold start, but then close when the car idles down. I have a MY16 with no pump... could it be that the V8 pulls more vacuum? Or, maybe you need to adjust the rods on your canisters?

I liked the sound of the VAP exhaust when the valves are open so much that I ended up plugging the vacuum lines and now just run it with them open all the time.
 
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Old 10-15-2018, 03:23 PM
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Originally Posted by baldguy View Post
I wonder if a valve could be designed to be "normally closed" and still integrate with the car's active exhaust control. Seems like something VAP could pretty easily retrofit into their design... I'd be very interested in purchasing one of their systems if they did (hint, hint)
Or get rid of (disconnect) the vac system, and switch to electronic exhaust cutout valves...
 
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Old 10-15-2018, 03:27 PM
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Originally Posted by DJS View Post
Yes they did. Somewhere around MY16-17, they got rid of the vacuum pump and ran a vacuum line back from the engine. There's a TSB to remove the vacuum pump on earlier cars and run the line, if requested. I never did, which I sort of regret.
+1. My MY16 never had the vacuum pump.

Originally Posted by MI-FType View Post
I have the VAP system on my car. The valves are open on the cold start, but then close when the car idles down. I have a MY16 with no pump... could it be that the V8 pulls more vacuum? Or, maybe you need to adjust the rods on your canisters?
.
I adjusted the rods to ensure valves are wide open with zero vacuum. Thatís more important than adjusting them to fully close when under full vacuum. I would think that full vacuum for both engines would be similar, but not certain. All I know, is that it takes a lot more vacuum to close the VAP valves than the OEM valves.
 
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Old 10-15-2018, 03:38 PM
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Originally Posted by Unhingd View Post

Thatís more important than adjusting them to fully close when under full vacuum. I would think that full vacuum for both engines would be similar, but not certain. All I know, is that it takes a lot more vacuum to close the VAP valves than the OEM valves.
Agree with both of these statements... the springs are very tight and it does take quite a bit of force to close the valves if you try it by hand. Hard to believe the vacuum is even strong enough to do it.
 
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Old 10-15-2018, 04:00 PM
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Originally Posted by Unhingd View Post
I adjusted the rods to ensure valves are wide open with zero vacuum. Thatís more important than adjusting them to fully close when under full vacuum. I would think that full vacuum for both engines would be similar, but not certain. All I know, is that it takes a lot more vacuum to close the VAP valves than the OEM valves.
Either your logic is backwards, or the VAP valves work the opposite of the OEM valves. On the OEM exhaust, strong springs keep the valves open, until vacuum closes them. Hence, they're open (loud) before vacuum is present at start-up.


 
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Old 10-15-2018, 06:09 PM
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A return visit to this subject. I agree one of the annoying aspects of the F is the LOUD start-up, Maybe its not so bad if you park in a field, but in a home garage it really is annoying and unnecessary, unless are you trying to impress the family canine. I can recall quite a few tricks that were tried to keep the noise down and none of them worked. Now, the electric vacuum pump may provide an opportunity for those of us who own earlier vehicles (I am <10,000). This is way over my level of expertise, but if there was some way to get the pump on at start and then to operate normally it would be a blessing.

Mods, maybe this is a candidate for a sticky. A regular program of identifying topic that cause multiple threads would be an aid to research and keep our forum clean.
 
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Old 10-15-2018, 06:48 PM
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apologies for the revisit. I did search first, but perhaps my search terms were inadequate. That said, if this is indeed a popular topic then it seems like an opportunity for the aftermarket to develop a product that allows for choice in the matter. Here's hoping someone with that level of access/ability takes note.
 
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Old 10-15-2018, 06:51 PM
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If you want them to shut quicker just put the car in gear, it quietens down straight away then.
 
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Old 10-15-2018, 10:39 PM
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Originally Posted by DJS View Post
Either your logic is backwards, or the VAP valves work the opposite of the OEM valves. On the OEM exhaust, strong springs keep the valves open, until vacuum closes them. Hence, they're open (loud) before vacuum is present at start-up.
Didnít we both say the exact same thing in slightly different ways?
 
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Old 10-16-2018, 09:42 AM
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Would have sworn I read the opposite of that. Sorry - I should know better than to doubt The Unhingd.
 
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Old 10-16-2018, 09:50 AM
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Originally Posted by Timbo View Post
If you want them to shut quicker just put the car in gear, it quietens down straight away then.
I also have left the garage door down (closed), and after the loud initial bark, I open the door. Then as Timbo says, engage R and exit. Havenít tried engaging R, then P...
 
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Old 10-16-2018, 10:55 AM
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the personal example that prompted my post was a few nights ago when i went out to configure the remote app, which requires a start. It was late-ish, 11pm. My beautiful bride was already asleep. I did open the door before starting because I am more afraid of incurring her wrath than the HOA's .
 
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Old 10-16-2018, 11:40 AM
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Press Start.
Leave garage door closed.
Car rages angrily - wants out.
Put in gear, put back to park.
Open garage.
Warm up, leave.
 
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Old 10-17-2018, 10:11 PM
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I've never found the start-up volume to be a problem. Then again, I saw Hendrix live (so they tell me).
 

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