Two Brothers Racing P-1 insert results

[SVonhof]

I decided to tone down the exhaust note a little on my new-to-me Titanium slip-on since my wife heard me start the bike up the one day I rode it to work since getting it. I found a black one from FlyNCycle on Ebay for $30 shipped (http://myworld.ebay.com/flyncycle) and I got it today.

It is said to reduce the DB output by 3-4db but barely changes the look, which is the real reason I got the exhaust (I am riding without the saddlebags 95% of the time).

I decided to check to see how much it would reduce the db, so I grabbed my Radio Shack SPL meter and tripod. I let the bike warm up a little and then took some readings at 2 feet from the end of the pipe and 3 feet.

Before numbers:
1300 rpm @ 24" - 82db
3000 rpm @ 24" - 95db
1300 rpm @ 36" - 82db
3400 rpm @ 36" - 90db
4500 rpm @ 36" - 96db

After the install (took less than 5 minutes):
1300 rpm @ 24" - 80db
3000 rpm @ 24" - 88db
1300 rpm @ 36" - 78db
3400 rpm @ 36" - 85db
4500 rpm @ 36" - 92db





None of the numbers are exact of course, but that's as good as I could get.

For what it's worth, it is a Radio Shack Analog SPL meter, set to A weighting, with slow response.

For me, the $30 investment is well worth it in the long run as my wife will appreciate it more than me since she doesn't have earplugs for riding and will be able to enjoy her music more. I wish I would have done the SPL readings the same way with the stock exhaust before removing it, but didn't think to do it that way.

[st2sam]

Thanks SVonhof.
I have 39,000mi. on my TB  Carbon Slipon and the P-1 insert was installed from day one.
 I never thought it was loud and now I know why, they work...

[W14]

I have the TB Titanium slip-on on my bike. At the time I purchased TB, I also purchased the P-1 insert because of the complaints on this forum about loudness of the TB. I have about a 1000 miles on the TB and have yet to install the insert. I like the sound produced by the muffler and it makes the C-14 sound like a motorcycle rather than a scooter, which it has been referred to on several occasions.  I have gotten a lot of compliments on the sound. And,  I have not had any complaints by neighbors or the wife.  I don't rev  the engine in the morning or when going through the neighborhood.

Regarding the various decible ratings, only on hard acceleration are the rpm's above 4500. At 80 mph, the rpm is below 4000 and I get more noise from the wind on my helmet (which I understand can have a decible rating over 100) than I get from the muffler. I do wear earplugs and keep the saddle bags on.

Just my opinion.

Ride On.

[Sea Level]

I have the TB Titanium slip-on on my bike. At the time I purchased TB, I also purchased the P-1 insert because of the complaints on this forum about loudness of the TB. I have about a 1000 miles on the TB and have yet to install the insert. I like the sound produced by the muffler and it makes the C-14 sound like a motorcycle rather than a scooter, which it has been referred to on several occasions.  I have gotten a lot of compliments on the sound. And,  I have not had any complaints by neighbors or the wife.  I don't rev  the engine in the morning or when going through the neighborhood.

Regarding the various decible ratings, only on hard acceleration are the rpm's above 4500. At 80 mph, the rpm is below 4000 and I get more noise from the wind on my helmet (which I understand can have a decible rating over 100) than I get from the muffler. I do wear earplugs and keep the saddle bags on.

Just my opinion.

Ride On.

+1. Although I have the TB V.A.L.E. Black series slip-on. Love the sound, get lots of compliments on sound and appearance.