Exhaust valves are a bit "binary"

[Bobajobbob]

When I bought my 2013 Vantage the valves were cable tied open, something I only realised after much messing around with Fuses and the switch from my previous Vantage. My local dealer freed up the valves by removing the offending cable ties and I can now permenantly open the valves using the Fuse 22 switch or leave the car in standard mode where they are open up to 2k RPM, then closed up to 4k rpm and then open again.

The issue I have is (when in normal mode) that the transition from open to closed and back again feels very sudden/binary now and when the valves are closed the car is almost totally silent. I can only compare to my previous 4.3 but in that car it felt like the transition between open and closed was more gradual and that even in closed mode there was some exhaust note.

Is this just a reality with the 4.7 or could it be a legacy of the cable ties
somehow stiffening the responses of the valves?

[nickv8]

Nope - very binary / night-and-day. Especially with the S back box and secondary de-cat. Quite a bit less-so with the non-S back box.

[Bobajobbob]

Thanks, so it is very much like a switch turning off the noise at 2k and then back on again at 4K in your car too?

I guess I expected 100% open at 4K and 25% open between 2k and 4K whereas it’s feels like 0 straight to 100%.

[bogie]

Same here on a 2012 4.7...the cold start cycle is more noisy then it settles down after a while then back at 4k. I have replaced the secondary cats so its a bit more noisy overall anyway.....have a remote switch for those early mornings when Im trying not to wake the whole village

[Bobajobbob]

I’ve removed secondary cats too. I’m sure it exaggerates the binary nature of the valves due to the thunder storm of noise when they do open. I’m just still surprised by exactly how quiet the exhaust is when valves are closed.

[bogie]

Yes the valves do a good job at keeping the noise down...a bit. I do get what you mean with it being like an on/off switch. To be honest I cant remember what my 4.3 was like in comparison, would have to do a back to back test. I dont remember reading about any changes to the valve mechanism or the cycle of when its open/closed. Assumed it was same on both 4.3 and 4.7.

[yellow_tang]

On all pre 2nd century cars, the exhaust valves are either open or closed. DB11, new DBS and new Vantage have more advanced valve control that allows partial opening.

[krisdelta]

Is there anyway to force a closed position for a cold start? I fear my recently acquired 4.3 is significantly louder than my last one and I don't want to upset my neighbors more than I already do.

[Bobajobbob]

Thanks for all the feedback. I wonder whether a small ‘stop’ could be welded in place to keep the valves open a fraction even when closed?

[yellow_tang]

krisdelta said:

Is there anyway to force a closed position for a cold start? I fear my recently acquired 4.3 is significantly louder than my last one and I don't want to upset my neighbors more than I already do.

There actually is, but not sure if it carries across all models. It is a car setting option in AMDS that closes the valves on startup instead of them being open.

[bogie]

yellow_tang said:

krisdelta said:

Is there anyway to force a closed position for a cold start? I fear my recently acquired 4.3 is significantly louder than my last one and I don't want to upset my neighbors more than I already do.

There actually is, but not sure if it carries across all models. It is a car setting option in AMDS that closes the valves on startup instead of them being open.

Thats good to know. I did also read that Bamford Rose offer similar on their remote switch i.e. closed at startup

[leerandle]

krisdelta said:

Is there anyway to force a closed position for a cold start? I fear my recently acquired 4.3 is significantly louder than my last one and I don't want to upset my neighbors more than I already do.

You want to own my 4.3 Vantage which has the upgraded manifolds, 200 cell cats, engine tune (Velocity AP), bespoke ITG air filters and Tubi 'loud' non by-pass valved exhaust.......I sometimes cringe on start up depending on where I am.