Valve muffler fermer

[stephane]

Bonjour à vous, ma question! avez-vous déjà mesuré la perte de HP pour une GT350 2016+ avec les soupapes complètement fermées ? Au Circuit Mont-Tremblant au Canada je dois fermer complètement les vannes et j'ai un Fehling qui perd beaucoup de performance, qu'en pensez-vous ?

 

[Mad Hatter]

Hello to you, my question! have you ever measured the HP loss for a 2016+ GT350 with the valves fully closed? At Circuit Mont-Tremblant in Canada I have to close the floodgates completely and I have a Feeling that it loses a lot of performance, what do you think?

 

[Mad Hatter]

Now what do you mean by valves fully closed??? I have no idea....

 

[stephane]

Maintenant, qu'entendez-vous par vannes complètement fermées ??? Je n'ai aucune idée....

Soupape d'échappement

 

[Mad Hatter]

Ahh the exhaust cutouts... Yes am sure they will take a bit away. I would guess somewhere around 10rwhp??. Whats your track sound limit?

 

[stephane]

Ahh les découpes d'échappement ... Oui, je suis sûr qu'elles enlèveront un peu. Je suppose quelque part autour de 10rwhp ??. Quelle est la limite sonore de votre piste ?

92, j'aimerais savoir si quelqu'un a déjà fait le test sur un dynamomètre?

 

[stephane]

Ahh les découpes d'échappement ... Oui, je suis sûr qu'elles enlèveront un peu. Je suppose quelque part autour de 10rwhp ??. Quelle est la limite sonore de votre piste ?

92, j'aimerais savoir si quelqu'un a déjà fait le test sur un dynamomètre

 

[Bill Pemberton]

Dang , this has me believing Madhatter is not only a talented racer in South America he likely speaks English, Spanish and the lovely Romance language of French?! Damn, he is a crazy racer and also a Renaissance man ! Sacre Bleu !!

 

[JDee]

Le Circuit Tremblant is a wonderful track, I'd put it on par with the best in North America. It's fast with a very interesting mix of corners and a couple of straights that end in challenging corners. My best lap there was a 1.57 on 200TW treaded street tires.
The problem is it seems that the town hates the track these days. It was built right next to the town many years ago and now the town is growing around it. There is a noise meter on the track and if you exceed sound an alarm goes off in the local Surete station and a photo is automatically taken and you get a noise ticket and the track gets more local hate. It was 92 dBA when I was there and the sound meter was on the pit straight right when you are at full blast. The cops visited a couple of times that day and a couple of guys got tickets. No warnings, the cops just showed up, found the offender and wrote a ticket. We were warned about this by the organizers at the drivers meeting before anyone went on track. It was suggested to kind of "breathe it" when near the meter but I guess some didn't do so well at that.
I ran there with stock GT exhaust except for a resonator delete and I had no trouble making sound. I expect a GT350 would be louder than a GT though.
No problem, Mosport is just 15 minutes from my house and there are no sound meters there.....

 

[stephane]

ndeed it is a very beautiful circuit.

here is my question in English, have you ever measured with a dynamometer the loss of HP for a GT350 2016+ with the exhaust valves completely closed? At Circuit Mont-Tremblant in Canada I have to completely close the floodgates I feel like I'm losing a lot of performance,

 

[yotah1]

Valves closed and valves open don't really change a lot in terms of HP on the Shelbys. We did dyno runs on the Mach1s during the testing phase (5.0 480hp with SHelby GT350 intake manifold and GT500 axle back exhaust). Very little difference, about 6-7hp. The main difference is back pressure in the exhaust system, but really that didn't hurt the performance that much.
The valves are here 99% for sound regulations, where when open they also a straight flow through the muffler, while when closed the exhaust gases have to go through a more sound insulated chamber (still not a very restrictive airflow though).


Bref en français, les soupapes changent majoritairement le son du fait du passage des gaz dans une chambre beaucoup mieux isolée que la section de tube toute droite par laquelle les gaz d'échappements passent quand les valves sont ouvertes. Sur Mach1, on avait noté une différence de 6-7cv aux roues, rien de plus. La différence de son fait certainement plus d'effet que la différence de puissance.

 

[stephane]

tank you

 

[Mad Hatter]

Le Circuit Tremblant is a wonderful track, I'd put it on par with the best in North America. It's fast with a very interesting mix of corners and a couple of straights that end in challenging corners. My best lap there was a 1.57 on 200TW treaded street tires.
The problem is it seems that the town hates the track these days. It was built right next to the town many years ago and now the town is growing around it. There is a noise meter on the track and if you exceed sound an alarm goes off in the local Surete station and a photo is automatically taken and you get a noise ticket and the track gets more local hate. It was 92 dBA when I was there and the sound meter was on the pit straight right when you are at full blast. The cops visited a couple of times that day and a couple of guys got tickets. No warnings, the cops just showed up, found the offender and wrote a ticket. We were warned about this by the organizers at the drivers meeting before anyone went on track. It was suggested to kind of "breathe it" when near the meter but I guess some didn't do so well at that.
I ran there with stock GT exhaust except for a resonator delete and I had no trouble making sound. I expect a GT350 would be louder than a GT though.
No problem, Mosport is just 15 minutes from my house and there are no sound meters there.....

YE GADS!

 

[Mad Hatter]

Dang , this has me believing Madhatter is not only a talented racer in South America he likely speaks English, Spanish and the lovely Romance language of French?! Damn, he is a crazy racer and also a Renaissance man ! Sacre Bleu !!

Grew up in Canada eh. But the west side,...