Silencieux Inox

[FlorentM]

Pas bête comme ça il va vite faire des progrès en Anglais !!

mouai... ça c'est pas gagné quand même

[Aston Dreamer]

Pas bête comme ça il va vite faire des progrès en Anglais !!

mouai... ça c'est pas gagné quand même

Non, je confirme, c'est pas gagné !



Et puis je suis loin de toi niveau documentation alors même pour être le petit documentaliste ça passe pas. Je préfère "Monsieur News"

[zorba06]

Bonsoir les amis,



Comme promis nous assistons tous ensemble à la naissance d'un petit bijoux pour nos V8V



Voici les deux premières photos d'un silencieux sport qui devrait faire économiser au mois une douzaine de kg, faire gagner quelques chevaux et faire un bruit

magique.



A bientôt pour la suite.

[zorba06]

Sous un autre angle.

[ASTON20100]

Une belle pièce d’orfèvre

[AstonDBS]

As-tu une idée de gain en puissance et du prix envisagé?

[Franck_Lyon]

Oui et à mon avis vu le petite taille du silencieux celui va faire du bruit ...

[zorba06]

Pour les détails c'est encore un peu tôt il n'a pas encore émis son premier son !!! Pour la puissance et d'une manière générale le gain d'un tandem silencieux / filtre à air fait gagner entre 10 à 15 cv et ceux sans aucune modification. On devrait donc se balader autour des 400 cv sur nos bébés.



See yu

[Jmarc]

C'est magnifique !

[astromega]

! Pour la puissance et d'une manière générale le gain d'un tandem silencieux / filtre à air fait gagner entre 10 à 15 cv et ceux sans aucune modification. On devrait donc se balader autour des 400 cv sur nos bébés.



See yu

That' s absolute rubbish!



Exhaust system:

Replacement of the standard silencer with upgrade to a sports system seems a very popular modification. One reason for this, additional to the search for extra performance, is the search for an exhaust note of personal preference, made necessary by the fact that the standard exhaust note is muted under certain conditions to comply with stringent noise drive-by regulations to allow the car to enter the market place. Simple solution.. Remove fuse 22 to prevent the bypass / silencing valve (located in the silencer) from closing and making the exhaust note quieter in these sensitive conditions. The valve is fully open in its default position, so electronic removal of control simply allows the valve to stay open at all times. The result, the exhaust note provided by the standard silencer is no longer muted at low engine speeds, there is no performance increase achieved via this mod, however, the drivers perception of performance will increase due to the simple fact the exhaust note is louder.



For those owners who have undertaken this mod already, but are still in search of a ‘different’ exhaust note, the next stage is the fitment of an aftermarket silencer system. Regarding sound quality, there is no right or wrong answer here, its personal preference and each brand does something different; from American muscle car V8 burble to a more European ‘refined’ racing note. As the exhaust note from aftermarket silencer will inevitably be louder than removal of fuse 22, the driver will yet again perceive greater engine performance, but, in reality the performance gain is something quite different. Reduced (louder) silencing is achieved by internal design changes which cause a reduction in exhaust system back pressure. The result of this increase in engine breathing is increased performance, however, the drivers perception of performance is greater than the actual flywheel / road wheel performance gain, and many aftermarket tuning companies prey on this fact by claiming more performance than is actually true. These days, it is pretty much industry standard concerning engines which produce close to 100BHP per litre to report that a silencer causes an exhaust back pressure rise of circa 10 Kilopascal (KPa), the same industry standard reports about a 0.7BHP increase per 1Kpa reduction of system backpressure. This means that even if you were to remove the silencer completely, with the intermediate pipes venting to atmosphere, the performance increase would be in the region of 7BHP. However, this is with no silencer box present, so with some form of silencing present, no matter how loud, there will be a small amount of additional back pressure increase. Given an average silencer backpressure rise of, say, 5 KPa, the true increase of performance would be (5x0.7) 3.5BHP. Anybody claiming more than this is preying on the fact the loud exhaust note is worth a perceived performance increase, should their systems come with ‘power test results’ claiming more, scrutiny of the test conditions must be made to verify claims.



Replacement of the Catalyst with upgrade to a sports system is the next step. The V8 Vantage has twin bricks fitted within the catalyst can. Using the same industry standard mentioned above, catalysts fitted to 100BHP per litre engines cause a typical increase in exhaust system backpressure of approx. 12.5KPa. There are two fitted, so, do the maths again, 2x12.5x0.7 = 17.5BHP rise if there were no catalysts whatsoever present in the system. There are plenty of motorsport catalysts on the market, all of which have some form of catalyst matrix present in the can. So, the reduction in system backpressure in reality would be, say, 15KPa (leaving approx.10). Meaning the true increase of performance would be 15x0.7=10.5BHP. Same as with the silencer, anybody claiming more than this is preying on the fact the loud exhaust note is worth a greater ‘perceived’ performance increase.



So, long story short, perceived performance increase from sports silencer and motorsport catalysts can often be…mega…. The reality is approx. 3.5BHP from silencer, 10.5BHP catalysts = 14BHP total. Because this performance increase stems from the reduction in the build-up of exhaust back pressure, the build-up of exhaust back pressure does not start until approx. 5500 rpm, and become significant until 6000 rpm to the redline. So, loud exhaust note and the potential of 14BHP aside, you will not realistically notice the difference in vehicle performance unless you drive consistently up to the redline speed.



The final step regarding the exhaust system would be the manifold / primary pipes. The standard exhaust system fitted to the V8 Vantage is a 4-2-1 configuration. The intelligent modification would be a 4-1 system that gives the same low speed torque figure, yet improved breathing at peak power speed to return the potential which comes from a 4-1 configuration (4-2-1 configurations give better low speed torque at the sacrifice of power, whilst 4-1 systems often sacrifice torque to give better breathing at peak power speeds). Combine a manifold of 4-1 construction (which does not loose any torque), which would increase power by approx. 15BHP, with motorsport catalysts (10.5BHP) and sports silencer (3.5BHP) and you have the potential of a fantastic exhaust note with real world performance increase above approx. 5500 rpm of circa 30BHP. And yes, this would be +30BHP for either 4.3L or 4.7L as the rule of performance increase from backpressure reduction is the same for both displacements.



Btw this not not a one man opinion statement but known since a long time therefor Mike of Bamford Rose is cited above.



All the rest is commercial blabla.



See you next year or not.