Now that I have good test results, I figured I would post some pictures of how I modifed Rod Bowers' ram air intake.
Rather than draw the alternate, filtered air through reed valves from the lower cowl plenum, I wanted to supply the air from the front baffle floor in the cooling air intake. This area has nearly the same ram pressure as the full ram intake, and only minor ducting losses, plus the loss through the conical K&N filter.
I made a replacement fiberglass canister that was the same dimensions as Rod's canister, then molded on the adaptor for the scat tube connection.
Rod's reed-valve canister is designed to prevent back-flow through the filter and out to the lower pressure area, loosing valuable ram-pressure. In my case, since the cooling intake area is essentially at ram pressure, there is virtually no back flow. What little back flow there is made up for by the over-size of the ram intake, able to supply much more air than the engine needs.
I get 0.5" hg lower MAP through the alternate filtered supply than the full ram air supply.
One thing that this suggests is whether the extra 0.5" hg pressure from the ram intake is worth the installation work? As I think Dan Checkoway showed, a well-designed filter mount on the baffle, followed by the standard curved intake duct, also gets within 0.5" hg of full ram pressure. This also preserves the completely clean lines on the cowl, which is nice, although I kinda like my air inlet too. But if I build another RV, I will have to decide if all this is worth it for a half inch of MAP?
here's some pic's
Rather than draw the alternate, filtered air through reed valves from the lower cowl plenum, I wanted to supply the air from the front baffle floor in the cooling air intake. This area has nearly the same ram pressure as the full ram intake, and only minor ducting losses, plus the loss through the conical K&N filter.
I made a replacement fiberglass canister that was the same dimensions as Rod's canister, then molded on the adaptor for the scat tube connection.
Rod's reed-valve canister is designed to prevent back-flow through the filter and out to the lower pressure area, loosing valuable ram-pressure. In my case, since the cooling intake area is essentially at ram pressure, there is virtually no back flow. What little back flow there is made up for by the over-size of the ram intake, able to supply much more air than the engine needs.
I get 0.5" hg lower MAP through the alternate filtered supply than the full ram air supply.
One thing that this suggests is whether the extra 0.5" hg pressure from the ram intake is worth the installation work? As I think Dan Checkoway showed, a well-designed filter mount on the baffle, followed by the standard curved intake duct, also gets within 0.5" hg of full ram pressure. This also preserves the completely clean lines on the cowl, which is nice, although I kinda like my air inlet too. But if I build another RV, I will have to decide if all this is worth it for a half inch of MAP?
here's some pic's
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