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
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I think you got a great deal there. I have a Borla system on my Testarossa that uses the same mufflers and orientation. But the tips on my system are slant cut and very close to the factory style. Can you elaborate on what you found about the internals of the mufflers? Is the chamber divided length-wise or? I've always thought my system is too quiet and I wouldn't mind it a bit louder. How will you repack the mufflers?

I think that when new these Borla systems were about $2,800 or so.

 

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

 

Hi Dave,
Thanks for sharing the info and good job!
Both of my BBi's have Borla systems on them right now. Borla must have made them in different sound levels. One of my cars is very quiet and the other is much more aggresive sounding.

 

Too loud? How is that possible?

 

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

 

Well, I would have invested in a nice set of noise cancelling head phones for her, and kept the sound the way it was meant to be.

 

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

 

There's nothing wrong with the exhaust in that case... it's your wife that needs fixing...

remind her, good wives are much easier to find than good Boxers...

that ought to do it....

#this helpful bit of consultancy comes with no warranty#

 

You must be single or will be soon, lol.

 

Or very very wealthy.

 

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

 

ha ha... it's my wedding anniversary today...(4 years married but together since 91')

she bought me "Mr perfect" underpants....

 

yes... I own a boxer... isn't it a pre-requisite?

 

never post anything that could result in being alone, less weathy, and the ex is driving a Boxer.

 

I got the boxer before the wife. But then she who was then the fiance said if I wanted a ferrari the boxer was the one to get, so I bought the car and married her.