Does anyone else have older CMI headers that have NOT leaked?
#21
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Got a chance to look at the Hardin Hurricane 525 headers up close at the Miami show this week.. They look very well constructed. The outer tubes are bigger than the CMI's and the collector area is now coated with an anti-corrosion coating. Have no idea of they hold up better than the CMI's, but they looked pretty beefy.. Hopefully, it will be a long time before I need to think about this, but these are worth consideration.
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#23
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Like I said, I REALLY hope I'm not thinking about this for a long time having three engines but if/when it happens, I would seriously consider these. The Hardin headers really looked solid. The outer tubes are larger than CMI's to have more water around the inner tubes. The guy at the booth told me that they also started coating the inside of the collector and that looked pretty good too. Wish there were more guys that had direct experience with these but I don't think they've been in existence that long. Definitely worth a look..
#24
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Location: Clarence, NY
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2004 twin 525s with 370 freshwater only hrs., run 60 psi water pressure at WOT, no leaks. I have a theory that the higher operating pressure, same principle that a pressure cooker operates under (raising the pressure raises the boiling point), helps keep the water at the header flange from boiling which improves the heat transfer capability of the surrounding water. Airated/boiling water carries less heat away at the flange weld. Call me crazy...
#25
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2004 twin 525s with 370 freshwater only hrs., run 60 psi water pressure at WOT, no leaks. I have a theory that the higher operating pressure, same principle that a pressure cooker operates under (raising the pressure raises the boiling point), helps keep the water at the header flange from boiling which improves the heat transfer capability of the surrounding water. Airated/boiling water carries less heat away at the flange weld. Call me crazy...
#27
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Yeah, people rip on me for letting it go over 40. I had put in a relief valve but 25 psi is not enough. Brownie (yup, Brownie) told me to lose the relief valve because it could stick open at a bad time. Good to know that the various heat exchangers can handle 60 psi!