New Exhaust Valves From Dotworx.Uk

[Gazcw]

In what way do GT boxes not fit? Is it the exit pipe length or the pipes before the box not longenough/wrong shape?
Could you just swap the boxes and weld?
Eb

The ones I bought, the pipes 'in' were at the wrong angle and the box would not go high enough up behind the bumper and onto the hangers. The tailpipes will always need lengthening.

If you want valves on qp boxes you could fix the internal one open and then put the valve into the large tailpipe. This would stop it exiting and redirect through the smaller tailpipe. I think that's how the gs boxes work.

 

[CatmanV2]

That's not a GT box unless I am very much mistaken. More like GS

C

 

[Gazcw]

That's not a GT box unless I am very much mistaken. More like GS

C

Correct that's what I am saying. Fit valves to the qp box like a gs

 

[Gazcw]

That's not a GT box unless I am very much mistaken. More like GS

C

Back in.

 

[CatmanV2]

Correct that's what I am saying. Fit valves to the qp box like a gs

Oh right! Gotcha!

C

 

[CatmanV2]

Back in.
View attachment 83378

You know cats love boxes

C

 

[BDM]

Is it an mot requirement to have them working?
I've never understood why you would want a valved system, just something to go wrong, and a lot of people I know, with them on other Marques, just wire them open. To me a decent sounding aftermarket unvalved exhaust would make far more sense.

I defo like a valved system with the 4.7 oval system and x-pipe installed. Wouldnt change it. Sometimes you just want a quiet drive to the shops lol

 

[Gazcw]

I defo like a valved system with the 4.7 oval system and x-pipe installed. Wouldnt change it. Sometimes you just want a quiet drive to the shops lol

With double glazing I have to have it loud to hear it!

 

[PaulCambio]

With double glazing I have to have it loud to hear it!

With triple glazing you’d hear mine loud!! Great x-pipe from SportsItalia and knackered valves. Next stop will be 200 cell cats when @conaero has them ready.

 

[Gazcw]

With triple glazing you’d hear mine loud!! Great x-pipe from SportsItalia and knackered valves. Next stop will be 200 cell cats when @conaero has them ready.

I have empty boxes, Mario x pipe and larini cats going on at Matts on the 6th.

 

[Ebenezer]

The ones I bought, the pipes 'in' were at the wrong angle and the box would not go high enough up behind the bumper and onto the hangers. The tailpipes will always need lengthening.

If you want valves on qp boxes you could fix the internal one open and then put the valve into the large tailpipe. This would stop it exiting and redirect through the smaller tailpipe. I think that's how the gs boxes work.
View attachment 83375

So closing one pipe would reduce the sound? But opening the internal valve would have increased the sound.
Must be dome jiggery pokery in teh GS back box bwtween the two pipes...One must be more or less straight through and the other muffled. Perhaps that's an option...
Eb

 

[Gazcw]

So closing one pipe would reduce the sound? But opening the internal valve would have increased the sound.
Must be dome jiggery pokery in teh GS back box bwtween the two pipes...One must be more or less straight through and the other muffled. Perhaps that's an option...
Eb

Closing the large pipe would force the exhaust through the sound deadening. There is a thread somewhere that has an image which explains how it works better. Opening the valve and larger bore makes it pretty much unsilenced although there is a space between the in and out so not fully straight through.

 

[Gazcw]

So closing one pipe would reduce the sound? But opening the internal valve would have increased the sound.
Must be dome jiggery pokery in teh GS back box bwtween the two pipes...One must be more or less straight through and the other muffled. Perhaps that's an option...
Eb

Closing the large pipe would force the exhaust through the sound deadening. Opening the valve and larger bore makes it pretty much unsilenced although there is a space between the in and out so not fully straight through.
Picture may help. It has had the wadding removed. Enters top right, pushes valve open a little and enters box. Leaves by small tailpipe. More exhaust and it pushes valve open further which in turn opens up the larger tailpipe and diverts away from wadding and any restriction.

 

[Ebenezer]

Is that the inside of a 4.2 QP box? If so then if there's room to fit a valve on the tip then you could remove the valve in the box...
Are all 4.2 boxes the same. Mines an auto...
Eb

 

[Gazcw]

Is that the inside of a 4.2 QP box? If so then if there's room to fit a valve on the tip then you could remove the valve in the box...
Are all 4.2 boxes the same. Mines an auto...
Eb

Yes the 4.2 and 4.7 are the same. Mine is 4.7 and exactly the same.

 

[ChrissGT]

The valved and non valved boxes are different. The valved has an extra straight through pipe with a vacuum valve before entering the muffler.
So the non valved actually has a pressure regulated valve inside the muffler. Needed to make sure the engine can breathe properly when pushed hard. These boxes only came on the 4.2 engines and are only quad tip.

The vaccuum valved boxes (either quad tip on the cabrio or oval tip) have a vaccuum controlled valve which opens based on rpm and/or sport button.

Qp and gt share the same exhaust systems and mufflers. Except for some different lengths and angles.

I can tell you a 4.2 with sport cats and x-pipe you want a valved muffler that you can control from a remote or button. Massive drone and way too loud for cruising. For 4.7 engine the droning is a lot less, but its still going to be very loud.

Its not hard to install the 4.7 valved mufflers, lots have done it. You can always leave the vaccuum and they will always be 'open'.

 

[BDM]

Yeh tbh with these new valves *(which are better than original) i would stop at an x-pipe. I wouldn't want anything more. Dotworx do custom work to remove certain frequencies / drone noise which I may look at in the future for sport mode

 

[Leicesterminiracer]

I have a 4.2 but the rear box is different to the pic above. It’s been replaced by previous owner

I’ll try and get a closer picture of it. But underneath is as per my link

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[Ebenezer]

Hmm so adding a control valve to the large pipe and removing the internal pressure regulated valve the would actually not be so good in "quiet" mode as it would mean that there would be a restriction all the time unless the manual valve was opened, impeding the engine "breathing" at higher revs.

So does this mean that there's a pressure regulated valve inside the "valved" 4.7 too so that in normal mode the large pipe is still activated at higher revs? This would then be bypassed by the vaccuum controlled valve on the extra straight through pipe? Does anyone have a picture of the inside of a valved 4.7?
Eb

 

[Gazcw]

Hmm so adding a control valve to the large pipe and removing the internal pressure regulated valve the would actually not be so good in "quiet" mode as it would mean that there would be a restriction all the time unless the manual valve was opened, impeding the engine "breathing" at higher revs.

So does this mean that there's a pressure regulated valve inside the "valved" 4.7 too so that in normal mode the large pipe is still activated at higher revs? This would then be bypassed by the vaccuum controlled valve on the extra straight through pipe? Does anyone have a picture of the inside of a valved 4.7?
Eb

Use the FD valve controller. It opens them up at certain revs. Edit... no that won't work as it is the ecu that controls them in stock form. You may be stuck with having it quiet or remove internals and have it noisy.