Valved Exhausts QPV

IanU

Member
Messages
336
Hi All,
Apologies if this is a daft question, but I may have got crossed wires with another thread. Regarding the operation of the silencer exhaust valves on my QP via the 'Sport' button, is there a minimum engine rpm/speed that they would normally open when the button is selected, or if the car is parked at idle speed would they still open?
Just trying to establish if mine are working, at idle no hint of anything changing and I'm certain the actuator doesn't move - although I'd expect to hear a difference anyway.
Is it time to get the WD/Plus Gas out and a wrench?

Cheers
Ian.
 

Ewan

Member
Messages
6,757
As far as I’m aware they should open when you press Sport, and stay open until you press it again (or turn off the engine).
 

IanU

Member
Messages
336
Thanks Ewan - I'll start with some basic troubleshooting first then starting with the WD40.
Cheers
Ian.
 

Wagons-Lits

Member
Messages
250
Hi Ian,

Yes I’m pretty sure they should be open at idle (when you press Sport - and from there @ any rev range) - I think only on the S does it require a certain level (3000 or thereabouts?) to open. I can tell mine are open at idle as there is a noticeable change when you jab the Sport button.
 

IanU

Member
Messages
336
Thanks Jon, as I suspected.
So I'm certain they haven't actually worked since I've had the car - I'm in for a treat then :)

Cheers
Ian.
 

Hurricane52

Member
Messages
1,211
I get the impression they open on startup anyway, then close, then Open again whenever you press the “big kid” button?
 

CatmanV2

Member
Messages
48,557
They will open when the engine is off. They are held closed by negative pressure in the manifold. That will leak out over time when the car is off, so when you come to start up, they are open.

C
 

IanU

Member
Messages
336
OK that's useful to know. So first step is to see if they move at all on start up and go from there with linkage and valve movement diagnostics. I love working upside down on my back in the cold!!

Marvellous
Ian.
 

CatmanV2

Member
Messages
48,557
You should be able to move them by hand anyway. That's where I'd start.

If they've been stuck, they might well need a drift, lots of spray lube. Worst case, the actuators and valves can in fact be cut out and replaced for rather less than the Maserati solution

C
 

IanU

Member
Messages
336
You should be able to move them by hand anyway. That's where I'd start.

If they've been stuck, they might well need a drift, lots of spray lube. Worst case, the actuators and valves can in fact be cut out and replaced for rather less than the Maserati solution

C

I think I know the answer already then tbh as I tried at the weekend when I swapped my wheels over, but I'll see if I can free them up first and go from there.
Thanks
Ian.
 

Mattp

Member
Messages
501
Where on the exhaust are the valves found? And they can be activated by the button with the key in the on position?
 

IanU

Member
Messages
336
The valves are tucked in front of the rear silencer just behind the rear wheels. From the sound of it it is a vacuum operated mechanism so needs the engine running - not just ignition on.
 

CatmanV2

Member
Messages
48,557
The valves are tucked in front of the rear silencer just behind the rear wheels. From the sound of it it is a vacuum operated mechanism so needs the engine running - not just ignition on.

Correct on both counts

C
 

Ebenezer

Member
Messages
4,445
As a matter of interest, why would you design this to use vacuum actuators rather than electric? Less moving parts in a harsh environment?
Also I thought that none of the QPV variants ever had valved exhausts? The Sports GT had an unsilenced X Pipe. Stand to be educated
Eb
 

Mattp

Member
Messages
501
Only the facelift (4.7) GTS version of the QP V has the valves exhausts.

Ahh! That's good to know, mines an 06 Sport GT, so no valves... saves scrabbling under the car and one less thing to go wrong!
 

Razz

Junior Member
Messages
123
Ahh! That's good to know, mines an 06 Sport GT, so no valves... saves scrabbling under the car and one less thing to go wrong!

On all QPs (except 4.7 GTS) the sports button is not connected with the exhaust in any way whatsoever. A slightly louder/raspier exhaust note is had on pressing the sports button on account of gear changes at higher revs. Pressing the sports button at idle will not produce a change in muffler sound.

Now on the 4.7GTS the mulffers have valves that connected to the sports button. At idle the sports button transforms the muffler into a delectable sound experience. And at speed.....
Best
Razz
 

namaste

Member
Messages
212
As a matter of interest, why would you design this to use vacuum actuators rather than electric? Less moving parts in a harsh environment?
Also I thought that none of the QPV variants ever had valved exhausts? The Sports GT had an unsilenced X Pipe. Stand to be educated
Eb

At a guess I'd say heat is the reason they use mechanical actuators.
 

Ebenezer

Member
Messages
4,445
So would 4.7 GTS face lift exhaust fit on a 2007 ZF auto? And could you get them at a reasonable cost - and do something equivalent to what Catman has done with his GT?

Eb