I need to pass a sound check at a couple tracks that are strict and it's blowing 100db right now, the exhaust is quiet until under load and over 4k rpm then it gets really loud

Currently the car has a 4:1 long tube into a new JCW rear muffler setup. I've been told by a few that adding a resonator close to the header will help.

anyone done this? How much does it cut down on the noise? I hate to hack up my exhaust only to find out it's still too loud and have to put back on the stock header.

 

If you have a boost gauge, you could add a silencer to the tips. The boost gauge would reflect an increased boost as the silencer would impede a small amount of exhaust. Can make a silencer by taking a smaller OD pipe, cut holes in it, put some rock/mineral wool insulation in it. Use a wire mesh to cap both ends. Would need to fabricate a full length "tee" that also has some holes in it. This would be like a spark arrestor in a cycle exhaust.

You could remove it easily when at another track. Would think you could go to a track without the db limit, make a run on a certain section without and then install the unit and test it out.

 

I'm looking for a permanent solution, it's too loud for me to want to drive it like this

if a resonator does not cut the sound enough I'll put the stock header back on, this noise is not worth 5 hp and lower EGT

 

vibrant 2.5" ultra quiet resonator did not do crap to quiet it, I ordered a high flow cat that should get things reasonable

 

Were you able to leave the heat shields in place or did you have to remove and wrap the header?

 

heat shield is in place, I had to modify it. Wrapping the header is a good idea for scavenging but it's a lot of work

 

I have had great success with an exhaust auger on my setup. Very noticeable decrease in volume and drone is gone on the highway. Speedway makes them in the 3" variety, I took a grinder to it until it fit in my tailpipe. I cut one "baffle" off so mine is only using 2 of the 3 and it still works really well. Butt dyno says there is no different in performance.

 

I just found this thread and I have a tangential question. Where along the exhaust did you install the Vibrant Ultra Quiet? Did it fit within the confines of the heat shield duct? I ask because I’m debating adding this resonator but unsure if it will even fit. Thanks in advance!