Does size matter? - Wrist Twisters
 
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post #1 of 11 Old 08-02-2011, 09:35 AM Thread Starter
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Does size matter?

Currently looking into aftermarket exhausts. Mod goal is to replace the stock exhaust with a significantly lighter unit but want to retain low dB level and low/mid rpm torque.

I am under the impression that the smaller (shorter) the can is, the louder it becomes... and the more low-end and/or mid rpm torque is lost. is this somewhat correct?


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post #2 of 11 Old 08-02-2011, 09:44 AM
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Quote:
Originally Posted by applespeed View Post
Currently looking into aftermarket exhausts. Mod goal is to replace the stock exhaust with a significantly lighter unit but want to retain low dB level and low/mid rpm torque.

I am under the impression that the smaller (shorter) the can is, the louder it becomes... and the more low-end and/or mid rpm torque is lost. is this somewhat correct?

too general of.............a question

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post #3 of 11 Old 08-02-2011, 09:49 AM Thread Starter
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Hmmm take 2. Does the length of the can have a significant effect in the powerband? Also, between two internally similar exhaust cans, if one is 2" shorter than the other, would I detect a noise level difference?

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post #4 of 11 Old 08-02-2011, 09:59 AM
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Quote:
Originally Posted by applespeed View Post
Currently looking into aftermarket exhausts. Mod goal is to replace the stock exhaust with a significantly lighter unit but want to retain low dB level and low/mid rpm torque.

I am under the impression that the smaller (shorter) the can is, the louder it becomes... and the more low-end and/or mid rpm torque is lost. is this somewhat correct?

Short large bore cans will be outrageously loud, period. (when on the boil)
Longer smaller bore cans will be quieter, but there is a wide range of result, depending upon the level of silencer design sophistication.
Noise does not equate to power, be it Torque or BHP.
Generally speaking, the cans are not part of the interference wave tuning inherent with any kind of "timed" exhaust system.
The cans can bottle things up, in other words become a flow restriction. Proper dyno work will uncover this and allow mapping to compensate for.
More resistant gas flow cans will reduce the total gas flow from inlet to exhaust, thus triggering the need for less fuel for any given map co-oridinate.
The cans can bump the peak Torque and peak HP position on the RPM curve, as well as their values. Good cans will not move the RPMs at which peak T and HP occur by much if any, and instead should result in some T and HP gain.

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post #5 of 11 Old 08-02-2011, 09:59 AM
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My set up is probably the lightest one on the board and possibly the lightest ever on a 919 that still has a silencer. Over all weight loss of 18-19 pounds. Fabrication was needed since neither the mid pipe or silencer was made for the 919.

As for volume, not too loud til i get up in rpms. Ask Jumbodent since he rode behind me for about 50 miles.

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post #6 of 11 Old 08-02-2011, 10:11 AM
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My outrageously loud scorpion...it's inside the garage so it's a little louder than it would be outside due to echo. I would say I lost a tiny bit on the low end. No PCIII.

‪900RR Exhaust with Scorpion Can‬‏ - YouTube

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post #7 of 11 Old 08-02-2011, 10:33 AM
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My exhaust thread with sound clip

https://www.wristtwisters.com/forums/...ust-26961.html

I've changed the hanger under the motor to a sweet rubber mount set up. Will post pics if you want.

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post #8 of 11 Old 08-02-2011, 10:34 AM
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Titanium Sato Cans that need to be repacked.

Idling...

‪919 Idle‬‏ - YouTube

Short run to about 50 in 1st

‪Honda 919 With Sato Cans‬‏ - YouTube

Press Any Key To Continue.
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post #9 of 11 Old 08-02-2011, 02:53 PM
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Terrible audio. I need to do another video with a quality mic.

‪Honda 919 900RR header conversion Part 4: Scorpion Can sound check‬‏ - YouTube


Ferris, I'd really be interested to know how close mine is in weight savings to yours. I only have the mid pipe (which is very light) and that carbon fiber can, which I think would weigh the same or even less than your setup, only because I have lifted the thing and could not believe how light it was.

Either way, we both are cool. That's all that matters

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post #10 of 11 Old 08-02-2011, 02:55 PM
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@Cmurphy. *sigh* Sometimes I REALLY miss my CF Sato's. I don't think I appreciated the sound of them while I had them. Yours sound like music!

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post #11 of 11 Old 08-02-2011, 03:49 PM
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Modified Ixil hyperlow - 2.5lbs

Leo vince link pipe - 2lbs

Shortened 919 header - ???

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