My coupe got a bypass!!!
#35
Registered User
iTrader: (3)
Don't ban him, he has done nothing wrong...
"Freedom of religion, of speech, of the press, to assemble, and to petition"
or if you're Canadian:
"Everyone has the following fundamental freedoms: ... freedom of thought, belief, opinion and expression, including freedom of the press and other media of communication."
"Freedom of religion, of speech, of the press, to assemble, and to petition"
or if you're Canadian:
"Everyone has the following fundamental freedoms: ... freedom of thought, belief, opinion and expression, including freedom of the press and other media of communication."
#37
Greg needs to chime in with some impressions...I'm impressed with his creativity!
I can't imagine that piping has valves. I imagine the exhaust sounds a bit louder under heavy load since some of the flow is going to route through the bypass.
I can't imagine that piping has valves. I imagine the exhaust sounds a bit louder under heavy load since some of the flow is going to route through the bypass.
#40
Registered User
Thread Starter
Join Date: Jan 2010
Location: SARASOTA, FLORIDA
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
My thoughts on the exhaust sound.
My impressions comparing just the 2 holes drilled in the pipes- this was good but the sound was too much in the low-mid register and the sound was affected by the surface of the pavement.
My next step was constructing special clamps to diffuse the exhaust coming from the holes. This had helped to achieve a quite exciting sound, good enough for me and some company is in the process of making the prototype for production. This setup was a very easy DIY ,offering a great alternative to the stock sound yet still too offensive to the ladies but not as loud as any aftermarket exhaust.
Finally my latest idea to do a partial bypass to give your exhaust more freedom: This is for those of you who want to have no cabin noise but want the people on the street notice you car as you pass by giving them that nice growl.
Keep experimenting, it creates the excitement and you learn by mistakes.
#41
1. What is the stock back pressure? What are the ideal back pressure levels for a G37? Did you obtain these values from a Nissan design engineer?
2. How can you revert to stock? You have 4 big holes in your exhaust. (Welding a plate over the holes still does not make you stock)
#42
Registered User
Thread Starter
Join Date: Jan 2010
Location: SARASOTA, FLORIDA
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
It would have Sam but we are using the bypass pipes of much smaller diameter therefore the bypass acts as a relief valve to direct the extra congested gas traffic thru. It is automatic in a sense without being mechanical. The main muffler still works the same way permitting just the amount of gas it was designed to permit at a certain pressure. It is only at higher pressures the gas flows by the way of a lesser resistance. Especially cause the joints are at almost 90 degrees therefore not picking up the gas as the Y pipe would have done. I think it would be quite easy to measure the flow at certain rpms with some wind speed meters. It would be necessary to put a valve in the bypass pipe to see the difference but it is too much work for me to devote to this project. My main concern was the sound and how to achieve a result of a quiet cabin with some extra VROOM outside the car.
#43
Registered User
Thread Starter
Join Date: Jan 2010
Location: SARASOTA, FLORIDA
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
Yes Raul, it is exactly the same in principle. Imagine the water flowing the opposite direction into your house coming in first thru the big pipe and getting into your sinks. If one of your sinks would have been partially filled with watter therefore creating a resistance not permitting any more watter to flow into it, the other pipe leading into the other sink would have taken over the watter flow. And this is basically the idea.
#44
Registered User
Thread Starter
Join Date: Jan 2010
Location: SARASOTA, FLORIDA
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
#45
Registered User
Thread Starter
Join Date: Jan 2010
Location: SARASOTA, FLORIDA
Posts: 431
Likes: 0
Received 0 Likes
on
0 Posts
1. What is the stock back pressure? What are the ideal back pressure levels for a G37? Did you obtain these values from a Nissan design engineer?
2. How can you revert to stock? You have 4 big holes in your exhaust. (Welding a plate over the holes still does not make you stock)
2. How can you revert to stock? You have 4 big holes in your exhaust. (Welding a plate over the holes still does not make you stock)
What are the back pressure readings with any brand aftermarket exhaust? Does anybody know?
Yes, welding 4 pieces of metal to your muffler would bring it to exactly stock option. If you want to be religious, buy the new muffler if your mechanic can't weld it up.