Two Brothers P1 Tip Nerdy Scientific Test

[EffZeeOne]

Wow, it's been a long time. How is everybody? :cheers: Still loving the FZ1, and got a Two Brothers exhaust recently. Which brings me to my topic. The P1 sound suppression tip. This is an add-on that costs about $30 and installs between the pipe end and the outlet flange.

I tested the sound output of the TBR exhaust both with and without the P1 tip, with a good quality dB meter which has a peak reading. Here's some results:

WITH P1
Starting: 90.1 dB
Idle: 85.1 dB
Rev to 6k RPM: 103.4 dB
2nd gear 4k RPM "drive by": 81.8 dB

WITHOUT P1
Starting: 89.1 dB
Idle: 88.4 dB
Rev to 6k RPM: 106.6 dB
2nd gear 4k RPM "drive by": 80.3 dB


The data at Idle and Rev to 6k backs up TBR's claims, that the device lowers sound by 3-4dB. So I have no problem with the claim.

On the other hand, the data at "drive by" is... interesting. For all intrinsic purposes, they are the same. You may not even perceive a 1.5dB difference while outside, but the strange thing is that the lower value came from the test WITHOUT the P1 tip.

:eyebrow: Know what? all this nonsense doesn't mean anything without an empirical test. And empirically, I think the P1 device gives a higher-pitched, buzzier sound, and makes little difference off idle, riding in normal street conditions.

I realize that TBR also makes the P1X and a P4 suppression tips. That's another test, but I ain't buying 'em to find out.

I have some pictures of the test setup, and will post them when I find the camera.

 

[Hellgate]

Interesting. Maybe FZ1inNH can ship his P4s down during the off season for testing?

 

[EffZeeOne]

Interesting. Maybe FZ1inNH can ship his P4s down during the off season for testing?

I'd be glad to! I might eventually need new torx bolts. rolleyes:

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One thing I forgot to mention, as cars drove by, they did not even rigister 60dB (the lowest setting on the 60 to 130 dB setting I was on). But, lets say a car was 60dB. The FZ1 with TBR was 81dB. It takes about 10dB to perceive something being twice as loud. So, in case you were wondering, 81dB is still a bunch louder than typical cages.

 

[EffZeeOne]

Pics -----------------------

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http://www.998cc.org/forum/attachment.php?attachmentid=7935&stc=1&d=1321234360

 

[Dustin]

Wouldn't recording the sound levels in a garage skew the results a bit?

 

[EffZeeOne]

Wouldn't recording the sound levels in a garage skew the results a bit?

Louder, maybe. Skewed, no.

As long as both tests (with and without P1) were done in the exact same conditions, then we're still comparing apples to apples. The garage afforded a lower background noise. The door was open.

 

[FZ1inTX]

With the bike parked for the winter, I can ship the P4 Tip down to you for the same comparative testing. I still have a few more rides but next month, I'm sure it will be put to sleep for a long winter's nap.

 

[Jboat]

I have the P1X tip. It went from being too loud, to just barely tolerable and I wear earplugs! I made audio recordings before and after, but they sounded exactly the same so I didn't even bother to upload them...

I keep meaning to order the P4 tip. I'm hoping it's a bit quieter. Thanks for the reminder...

 

[FZ1IL]

I have a TBR slip on as well, first I put a P1 silencer and still it was too loud commuting in the city, out in the highways it was fine.
so I ended buying the P1X and the sound know is good to live with.
The acceleration of course isn't as good as without the silencers but it's fare enough to me. still that engine is a beast.

regarding the bolts, they sucks!!! and very expensive!!!

Enjoy your TBR!

 

[FZ1inTX]

The P4 tip is much closer to the stock exhaust sound. I like the looks and weight reduction of the Two Bros and don't care about loud pipes.

 

[EffZeeOne]

The P4 tip is much closer to the stock exhaust sound. I like the looks and weight reduction of the Two Bros and don't care about loud pipes.

I just tried the P1 because it was free with the eBay buyer I used. The P1 was delayed a few days so I ran with the normal pipe for a day. After putting in the P1, I was thinking TB's claims were patently false. Came to find out, it does make a difference, it just depends on "where" you measure the difference.

Regarding the wight difference, I swear I could feel the difference hoisting the bike off the side stand after first putting it on. You can lift the Two Brothers exhaust with clamp and midpipe with two fingers.