My audi did it to, but this is taking it to a whole new level!

 

Yes it is for show, not needed, definitely don't need to open valves on active exhaust for start up.

 

Really, in a quiet neighborhood at 5:30 in the morning a few feet from your wall? That's going to wake someone up.

 

It is there for show. As I posted in the other thread, if you start from cold you get the bark, if you then immediately shut off the engine and restart you don't. It's something that you should be able to turn off. I generally love it, but at 5:30am etc it has potential to disturb. You have to think of others.

 

Didn't get to discussing R values with them, but I asked my neighbors if they heard my start-up--they weren't bothered or never heard it. I figure most of my neighborhood is up and tending to their own business by that time, save Sunday morns (and I ain't startin' nothin' at 5:30 am on a Sunday).
Me thinks the sound may dissipate rather quickly on the outside, distance-wise, more than I perceive sitting on the inside. And start-up is just that--over with in a couple or three blinks. It's not like an incessant blat from some cheap glass pack.

 

Agree

 

My Neighbours have certainly noticed the bark and said so, they haven't complained yet as they are nice people who we get on well with but I am acutely aware that so far it hasn't been very often very early, but I do regulalry head for the airport at 5:30 or earlier during the week.

I also leave early on the ocassional Sunday to get to Cars and Coffee.

 

My neighbors and I all moved into our development at the same time (new construction at that time). Guess they broke us in (my family and I) as much as we did them, heh. In any event, the personality of every neighborhood is different, of course. It looks like you're doing what you can to minimize complaint.

 

My DB9 exhibits the same behavior - louder on cold startup than warm.

On the Aston the exhaust valves are operated via vacuum - vacuum is what keeps them closed until the computer tells the vacuum pump to open them. The valves can be left permanently open by disconnecting the vacuum lines.

I've always assumed the louder cold-start condition was simply vacuum bleeding off over night. I wonder if Jaguar's system is the same architecture?

 

No, it's not that on the F-Type. The base car has no exhaust valves, and it exhibits the same behavior--very loud on start-up, as well as pretty much all the time with a little throttle.

The ECU is programmed to rev the car on start-up.

 

Got it, thanks for the clarification.

 

Here's a look at the two V6 exhaust systems, with some help from my lousy photo editing app.

The first is a cutaway of the the active exhaust system, and the second is edited to show what the base exhaust looks like.

 

The systems with active exhaust do use vacuum to switch the valves.

 

My point was it isn't a question of opened valves per se (vacuum or electric) causing the loud start-up, but a function of ECU programming. I say that because cars without active exhaust also start with the high rpm bark.

 

Understood. Was just pointing out to Jeff that the active exhaust is a similar setup to his Aston with vacuum-controlled valves. I had originally assumed the solenoids directly open/close the valves, but the solenoids control the vacuum, which then controls the valves.