DragBikeMike
Serious Thumper
   
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SuzukiSavage.com Rocks!
Posts: 4469
Honolulu
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This is a very long post with lots of pictures. Please hold your comments and questions until I have made the final entry, which will be obvious.
In preparation for future performance upgrades, I decided that I was going to need a better tool to measure improvements in air flow. I want to improve the cylinder head flow. I could always just hack away at the ports, valves & guides, but it seems more prudent to try and see if I can monitor the changes to verify that they are in-fact improving flow. It’s very hard to put the material back on once you grind it off.
Armen was gracious enough to send me a sectioned LS650 cylinder head to play around with. It had been subjected to one of those disconnected cam chains that we keep reading about on the forum. As such, it was toast, so Armen seized the opportunity and cut the thing in half, right smack down the center of the ports. It’s a thing of beauty. You can now really get your eyeballs around the problem areas.
Fast 650 held my hand through the basics of port flow and served as a mentor. He is a fabulous resource and provided a wealth of hard-earned knowledge on the ins & outs of cylinder head mods. He fixed me up with a great article from an outfit named “DTec” that provides all the details for fabrication of an inexpensive flow bench.
Up to this point, I was trying to measure my flow improvements by simply attaching a vacuum cleaner with a u-tube water manometer in-line. It worked OK and I could pretty much see big changes in pressure which indicate a change in flow, but I had no way to keep the test pressure constant, and the resolution on the manometer was poor. Also, changes in atmospheric conditions and variations in line voltage and frequency seemed to make repeatability difficult.
After reading the DTec article on the DIY flow bench three or four times, I felt that I could fabricate a very simple tool that would allow measurement of flow with good resolution so that very small changes (good or bad) would be easy to detect. The tool would also allow me to test each change at exactly the same pressure, so there would be no doubt about other things affecting the results (things like atmospheric pressure, humidity, temperature, electrical voltage & frequency, vacuum cleaner performance, etc.). If you always adjust to the same test pressure, the playing field will be level, and the results should be consistent and accurate.
I used the info in the DTec article to fabricate a smaller and cheaper version of their flow bench. I wanted something that would be very simple, compact for easy storage, provide good resolution to make interpretation fool proof, cheap (of course), and not necessarily accurate. I’m not worried about accuracy in terms of cubic feet per minute (CFM). All I want is a tool that shows me if I made the flow better, or if I made the flow worse. I want the tool to give consistent, repeatable results. The budget flow bench meets those requirements.
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