NPP exhaust flap part 2- what mufflers to buy? - ZR-1 Net Registry Forums

mike100 · 06-21-2015

I had to swap my headers to pass the emissions test here so I'm running a stock exhaust system. At this point I'm not going to put the headers back on so I decided I need to have a little fun with the oem 2.7" pipe set. Recall I had made an automated vacuum circuit to open and close muffler valves based on engine speed and engine load here:
http://zr1.net/forum/showthread.php?t=21474
and here:
http://www.corvetteforum.com/forums/...ust-quiet.html

or in HoTB issue #35: http://www.zr1netregistry.com/LinkCl...alid=0&mid=725

I finally found the 2nd actuator yesterday on Craigslist. These are 2.25" Boysen actuators from BMW 335's. They are actually a little nicer than the GM ones and I'm inclined to think they are going to be less prone to rattling. I bought the BMW muffler for $40 (there's only one actuator per car) and the other one was a gift from my friendly neighborhood muffler guru.

I'm thinking some kind of turbo muffler with dual outlets or maybe even a flowmaster. The goal of the project is to be less restrictive than stock mufflers and still be quiet. It doesn't have to be maximum flow and the straight through type of muffler will probably not be considered. Also it has to be a center inlet to fit the C4 right. Has anybody ever made a quiet flowmaster system (lol).

Boysen exhaust flaps

06-21-2015	#1
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,801	NPP exhaust flap part 2- what mufflers to buy? I had to swap my headers to pass the emissions test here so I'm running a stock exhaust system. At this point I'm not going to put the headers back on so I decided I need to have a little fun with the oem 2.7" pipe set. Recall I had made an automated vacuum circuit to open and close muffler valves based on engine speed and engine load here: http://zr1.net/forum/showthread.php?t=21474 and here: http://www.corvetteforum.com/forums/...ust-quiet.html or in HoTB issue #35: http://www.zr1netregistry.com/LinkCl...alid=0&mid=725 I finally found the 2nd actuator yesterday on Craigslist. These are 2.25" Boysen actuators from BMW 335's. They are actually a little nicer than the GM ones and I'm inclined to think they are going to be less prone to rattling. I bought the BMW muffler for $40 (there's only one actuator per car) and the other one was a gift from my friendly neighborhood muffler guru. I'm thinking some kind of turbo muffler with dual outlets or maybe even a flowmaster. The goal of the project is to be less restrictive than stock mufflers and still be quiet. It doesn't have to be maximum flow and the straight through type of muffler will probably not be considered. Also it has to be a center inlet to fit the C4 right. Has anybody ever made a quiet flowmaster system (lol). Boysen exhaust flaps