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OK, I ran another test over the weekend to help give a better picture of the three valves I'm comparing. One of the biggest unanswered questions I had was, "What about flow?" If you look at the bypass chamber for the piston valve, it appears to have a much more open, unrestricted design than either the Bosch or the DVR. I read another guy's test where he ran a controlled amount of water (20 oz) thru the Bosch & the 007P valves in a controlled amount of time (8 sec). In his test, both valves flowed the same. But I had this third valve, the DVR. I was concerned that the less-open design of the high-performance DVR might restrict flow more than the other two valves.
I liked the idea of measuring flow with water, but 20 oz in 8 sec isn’t very much. (This corresponds to only 1 liter of volume every 13.5 seconds.) I wanted a LOT more flow than that! I decided to see what the garden hose would do. I brought out my 17 liter bucket & ran a “full flow” test of the hose by opening the spigot all the way & timing how long it took to overflow the bucket. This “bench-mark” test (patio-mark test?) yielded 17 liters in 42 sec, or the equivalent of a liter of volume every 2.5 seconds. This is still nowhere near what the valve will see in operation, but it’s the best I can do!
The procedure consisted of using a short length of bicycle inner tube as a sleeve to join the hose to the port of the valve (I tightly wrapped both ends of the inner tube to ensure there were no leaks), using my vacuum hand pump to open the valve to its full-open position (what the valve will do during high-rpm actuation between shifts), opening the water spigot all the way, & timing how long it took to fill the bucket to overflowing.
The results were simple but surprising:
ALL of the valves flowed the same as the unrestricted hose.
That’s right, NONE of the valves created ANY additional restriction!
Damn. I was really looking for an excuse to dislike the DVR! I mean, there HAS to be a reason why more people don’t use something this straightforward in design, right? Isn’t there SOME reason why nearly all of the aftermarket valves are piston type? Some OBVIOUS reason why people are willing to add another maintenance item to their list of car-care steps?
Well, I certainly can’t think of any after this. But if you can give me something to grab onto, let me hear it!
Hmmmm ... decisions, decisions ...
-Greg
posted by 216.160.177...
Diverter Valve Mini Comparison
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