Spiral insert volume
Thread Starter
Instructor
Joined: Jan 2018
Posts: 229
Likes: 31
From: Finger Lakes area NY
Spiral insert volume
I have order a set of the spiral baffle side pipe inserts. I am concerned about the sound still being too loud
has anyone with these tried putting cone inserts into collectors to further reduce sound level?
https://www.summitracing.com/parts/s...SABEgLXCfD_BwE
has anyone with these tried putting cone inserts into collectors to further reduce sound level?
https://www.summitracing.com/parts/s...SABEgLXCfD_BwE
Melting Slicks
Joined: Jul 2010
Posts: 3,176
Likes: 633
From: perth western australia
Yes I have them .
I put the 3 and 1/2 inch ones in .
What I have is the 2 and 1/2 inch sweet thunder inserts in the hooker side pipe.At the beginning and end of the sweet thunder insert the tube cones out to 4 inch to fit snug in the pipe. On the inlet cone I drilled 3 holes and welded 3 nuts on the out side of the cone . Using spacers between the perforated cone and the S.T inserts. ( I was worried about back pressure ) They sit just clear of a sealed fit.
They do make a noticeable difference.
I put the 3 and 1/2 inch ones in .
What I have is the 2 and 1/2 inch sweet thunder inserts in the hooker side pipe.At the beginning and end of the sweet thunder insert the tube cones out to 4 inch to fit snug in the pipe. On the inlet cone I drilled 3 holes and welded 3 nuts on the out side of the cone . Using spacers between the perforated cone and the S.T inserts. ( I was worried about back pressure ) They sit just clear of a sealed fit.
They do make a noticeable difference.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
I have Spiral Baffles, and I even drilled a 5/8" hole through the center caps. With the holes and the stock baffles, I can talk to the person next to me while driving with the top down. Sounds real nice, but I wouldn't want to be the lady in the convertible Mercedes next to me at a stop light trying to talk on her cell phone... 
Lars
Lars
Last edited by lars; May 24, 2019 at 10:00 PM.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
I have a 1” hole in place of the stock caps. Running 10.6:1 compression ( more compression makes the sound sharper and louder) and still find the volume suitable for cruising. At least until I tromp on it then yes it’s loud.
if you leave or put Caps on ( I’ve read they no longer come with caps) then it reduces the volume considerably. Anything that reduces the volume reduces the flow and thereby the HP potential to WOT high RPM. So it’s a trade off.
if you leave or put Caps on ( I’ve read they no longer come with caps) then it reduces the volume considerably. Anything that reduces the volume reduces the flow and thereby the HP potential to WOT high RPM. So it’s a trade off.
