Stop Press: QPV Does Have Exhaust Valves!!

Gazcw

Gazcw

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Well I never. Searching for the source of my exhaust rattle on my S and Jason has found these! A progressive valve. Exhaust flows in from right pushing lever which opens spring loaded valve in centre pipe, which is the larger bore on the exit. I am having them cut off to stop the rattle. So QPV does have exhaust valves after all!57363
 
Wanderer

Wanderer

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Cool, are they actually working or is it Maserati using one exhaust fits all? And is it for all QP's I wonder inc. DS's?

Spent ages clicking on the play video button and who's iPad has 100% battery, honestly!!??
 
Gazcw

Gazcw

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Sorry video was too big to upload so I did a screen pic. They work. Sprung loaded shut. I will have to see if I can upload video somewhere to share.
 
Wanderer

Wanderer

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Gazcw said:
Sorry video was too big to upload so I did a screen pic. They work. Sprung loaded shut. I will have to see if I can upload video somewhere to share.
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I've no idea how the GT ones etc work but I though it was via vacuum. Interesting find!
 
W

Wagons-Lits

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I believe the valves on the QP S open only above 3000 rpm if the SPORT button is pressed. on a Sport GT S they are open throughout the rev range if the SPORT button is pressed.

From Maserati's brochure on the QP, relating to the Sport GT S:

"This version is fitted with the most powerful engine in the Maserati Quattroporte range. Capable of 440 Hp at 7,000 rpm and a maximum torque of 490 Nm at 4,750 rpm, it raises the car’s performance to unprecedented levels. These figures have been achieved not only by modifying the engine’s electronic control parameters, but also through in-depth development of the racing exhaust system installed on this version. The system is controlled by air valves that open in SPORT mode to reduce back-pressure in the exhaust; this increases the maximum power available, and creates a throaty roar at low engine speeds and full symphonic sound of a genuine sports car at higher rpm."

From the factory, a Sport GT S is noticeably louder than an S - presumably due to the racing exhaust system mentioned above (which as standard was not available on an S)
 
Gazcw

Gazcw

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Wagons-Lits said:
I believe the valves on the QP S open only above 3000 rpm if the SPORT button is pressed. on a Sport GT S they are open throughout the rev range if the SPORT button is pressed.

From Maserati's brochure on the QP, relating to the Sport GT S:

"This version is fitted with the most powerful engine in the Maserati Quattroporte range. Capable of 440 Hp at 7,000 rpm and a maximum torque of 490 Nm at 4,750 rpm, it raises the car’s performance to unprecedented levels. These figures have been achieved not only by modifying the engine’s electronic control parameters, but also through in-depth development of the racing exhaust system installed on this version. The system is controlled by air valves that open in SPORT mode to reduce back-pressure in the exhaust; this increases the maximum power available, and creates a throaty roar at low engine speeds and full symphonic sound of a genuine sports car at higher rpm."

From the factory, a Sport GT S is noticeably louder than an S - presumably due to the racing exhaust system mentioned above (which as standard was not available on an S)
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Nope. S does not have vacuum 'air' valves. Well certainly not on early ones anyway. Only the GTS had the ability to open valves the same as the later GT's. The valves inside my boxes are purely operated on exhaust gas pressure. The more gas in, the more they open.
 
W

Wagons-Lits

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Gazcw said:
Nope. S does not have vacuum 'air' valves. Well certainly not on early ones anyway. Only the GTS had the ability to open valves the same as the later GT's. The valves inside my boxes are purely operated on exhaust gas pressure. The more gas in, the more they open.
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Agreed that the QP S does not have the same set up (and therefore sound) as the QP Sport GT S; if my post was imprecisely worded, it was intended merely to clarify the differences relating to the two models
 
Gazcw

Gazcw

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Wagons-Lits said:
Agreed that the QP S does not have the same set up (and therefore sound) as the QP Sport GT S; if my post was imprecisely worded, it was intended merely to clarify the differences relating to the two models
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Righto. I just meant the S has no vacuum valve or any link to the sport button that's all. Noisier mode is operated by your right boot on mine. :thumb3: I guess that may be 3000rpm depending how much exhaust gas is being chucked out... who knows. Mine will be in noisy mode permanently soon.
 
W

Wagons-Lits

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Gazcw said:
Righto. I just meant the S has no vacuum valve or any link to the sport button that's all. Noisier mode is operated by your right boot on mine. :thumb3: I guess that may be 3000rpm depending how much exhaust gas is being chucked out... who knows. Mine will be in noisy mode permanently soon.
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that will be a good mode to have it in! The noise these cars make really is special
 
F

flat-12

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GAZCW...Thank You VERY much for your video! This topic has been discussed numerous times, and it was generally believed that only the Sport-GTS had exhaust vales (external type). Many QPV owners suspected that there were exhuast valves of some type, but this was only well-intended speculation, no facts. I have on occasion heard a strange rattle sound out the right side exhaust on my 2013 QP-S....now I know what it is!

So you have removed the valve and sound deadening material from your mufflers? I know this is subjective, but in your opinion, do the "internal valve" mufflers with the valve open sound the same as the "external valve" mufflers with the valve open?
 
Gazcw

Gazcw

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flat-12 said:
GAZCW...Thank You VERY much for your video! This topic has been discussed numerous times, and it was generally believed that only the Sport-GTS had exhaust vales (external type). Many QPV owners suspected that there were exhuast valves of some type, but this was only well-intended speculation, no facts. I have on occasion heard a strange rattle sound out the right side exhaust on my 2013 QP-S....now I know what it is!

So you have removed the valve and sound deadening material from your mufflers? I know this is subjective, but in your opinion, do the "internal valve" mufflers with the valve open sound the same as the "external valve" mufflers with the valve open?
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No problem F12. I had the same rattle and thought it was baffles or something hence opening them up. That turned out to be a delaminating handbrake shoe rattling and not the valve. You may want to check those out. Dead easy job.
Jason at Jarens made a bracket to hold them open rather than removing just in case it was too loud. It wasnt and I get no drone from this mod. If you want he will even take off the black paint and polish the boxes. I went with a new coating of black paint. Get them off and modded. No need for Mr Larini!
 
Gazcw

Gazcw

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7,757
Oh and yes pulled out all the fibre too! They are probably a little louder than the gts because of this, as I assume they would still have some wadding inside them. Never done a side by side with a gts though.
 
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Gazcw

Gazcw

Member
Messages
7,757
flat-12 said:
GAZCW...Thank You VERY much for your video! This topic has been discussed numerous times, and it was generally believed that only the Sport-GTS had exhaust vales (external type). Many QPV owners suspected that there were exhuast valves of some type, but this was only well-intended speculation, no facts. I have on occasion heard a strange rattle sound out the right side exhaust on my 2013 QP-S....now I know what it is!

So you have removed the valve and sound deadening material from your mufflers? I know this is subjective, but in your opinion, do the "internal valve" mufflers with the valve open sound the same as the "external valve" mufflers with the valve open?
Click to expand...
PM sent with the vids for you
 
Gazcw

Gazcw

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7,757
Wanderer said:
I'd imagine all the boxes to be the same just feature on/feature off?
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Well according to those on the other forum, they have opened up their qp boxes and found nowt. If you have a camera long enough to get passed the s of the intake pipe you will see the flap. Alternatively something flexible and you will be able to push on the flap..... awaiting thread drift!!
 
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