Boxer:Custom Tuned Exhaust Under $800

Update: see photos
I picked up a Borla exhaust system for my 512BBI a few months ago for a very reasonable price, thinking I could use the system as an alternate to the original Euro four piece system when not doing shows. The original is a nice system but too quiet to my liking.

After mounting the Borla I found the system was way to loud. The Borla uses (4) 4" diameter X 21" long stainless steel glasspacks each serving (3) cylinders.

I drilled a 1/8" pilot hole in an end cap & found each muffler contains a solid bulkhead dividing each silencer's packing chamber. This is great news which means each silencer can be half packed. I also found that all four of the silencers were completely depleted of packing material which explains why they were so loud.

I will 1/2 pack (about 10" long) 4 of the 8 silencing chambers with medium grade, Type 434 stainless steel wool available from McMaster-Carr. Their stock#7364T45 $60/roll http://www.mcmaster.com/

Each silencing chamber will receive a 1/2" diameter access port in each end cap with a 1/2"-13 ss hex nut welded over the hole. A 1/2-13 x 1/2" ss hex bolt fitted with a copper washer will plug the nut & access hole. I'll use some nickel hi temp anti-seize on the threads. The ports can be accessed while the system is mounted to the car allowing wool to be added or subtracted from each chamber using mechanical fingers. This will allow custom tuning the exhaust loudness to my liking.

I'm not real big on the Borla tips. I'll be changing them to traditional slant tip design.

Dave
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

A doughnut shaped bulkhead divider is located at the halfway point of each muffler. The bulkhead divides only the silencing chamber across case diameter, not the perforated core. The core is completely free flow with no obstructions. You can see where the bulkhead divider is externally by (4) small spot welds on the outside of each case. I think they did this to allow half packing each silencer if desired. The bulkhead will stop packing from shifting to the un-packed half.

I half packed the silencer in the photo of my original post in 15 minutes after drilling the access hole. Using "mechanical fingers" to insert the ss wool. The flexible shaft of the fingers allows shifting the wool in the chamber for even distribution around the core.

When I complete this project, each silencer will receive 10" of packing over their 21" length.

I like the the Borla system. It provides flexibility because of it's modular design.


Dave

 

When your wife gives you the look I received when I had the un-silenced system hooked up on the BBI. My Tubi fitted 308 QV is just about right. Any louder, I know I'd be in trouble.

Dave

 

Nice thought, but I'll keep the peace at home by toning it down just a tad.
Have a good holiday,
Dave

 

I don't see the added value of your comment relating to this thread, although for your sake hopefully Britney Speers attorney isn't perusing your post or in contact with your better half looking for fresh business! lol

Dave