DragBikeMike
Serious Thumper
Offline
SuzukiSavage.com Rocks!
Posts: 4398
Honolulu
|
Regarding Dave's comment: wonder how vacuum noise relates to engine intake noise. I'm not sure I understand the question but I will try to provide an explanation. My comments regarding noise were based on the noise level I heard with the engine running, not the vacuum cleaner. I would install the mod and run the engine. It was strictly my opinion based on what I heard with my ears. I wish I had some sort of sound measuring instrument. If it was hands down louder I defined the result as "loud", if it was obnoxious I defined it as "too loud", if it was a close call I would do several iterations with and without the mod until I felt comfortable with my final opinion of the sound level.
Regarding Dave's comment about the seat foam: I could actually watch the column drop in the manometer as I lifted the seat off with the test in progress. The foam blocks form a channel that guides the air in from the rear of the seat down to the snorkel. I'm pretty sure they are for noise mitigation. Taking those two out didn't seem to affect noise much. The rear foam blocks are a bit larger, but I didn't mess with them because I was able to achieve a reduction equal to total seat removal by just taking out the forward foam blocks.
Regarding comments on the ShopVac cfm: I used a 5.5 Hp vacuum rated at 140 cfm so I knew it would be a torture test. To amp it up a bit more, I removed the vacuum cleaner's filter so it was probably capable of moving more that 140 cfm.
Regarding justin O guy 2 comment about airbox volume: I don't believe I changed the airbox volume appreciably.
Regarding comments about resonance, reversion, etc. Fast650 has it exactly right, I was simply doing a comparison. I deem these modifications successful. The stock airbox restriction to flow has been significantly reduced without any noticeable increase in noise. This modified airbox will support higher airflows required by other mods like increased displacement, better exhaust systems, better flowing carburetors, head mods, etc. Will it fully support any and all mods? Don't know, but it will definitely do better than the stock box.
The testing I performed provides some concrete data. I know it's not very sophisticated but it's good solid data. To me, it's better than making a change and going for a ride to see if it works. Of course, the proof is always in the pudding. It's a beautiful sunny day here on Oahu. Perfect conditions for a little test-n-tune. I will let you all know how it works.
|