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Old 07-05-2010, 11:14 PM   #18
WBVenom
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Join Date: Jan 2009
Location: CA
Posts: 206
My Ride: Car 54
I just finished machining and welding up a custom non-M aluminum radiator.

I started with the OBX-R aluminum non-M radiator, which has the wrong necks welded on, but fits relatively well otherwise. They are standard barb fittings for rubber/silicone hoses. Not compatible with the BMW E46 quick-connect hoses (more complicated must mean better, right BMW?). So with the help of my boss, I cut them off, turned new necks out of 6061 2" OD, 1.25" ID aluminum tube on a lathe, and then welded them on. I very carefully measured the OE radiator's necks for dimensions, and machined the new necks to the correct specifications. Here it is:











As you can see above, fewer features are necessary in the necks than are molded into the OE plastic. The groove secures the quick-clip, the chamfer centers the fitting on the neck and stops its travel at the correct place, and the radius cut on the end spreads the o-ring for easy install/uninstall. The o-ring seats in about the middle of the smaller OD neck flat, just as with the OE neck. The recess machined into the back allows the new neck to slip onto the cut-off OBX stub for fixture-free welding. It is installed and running now, with no problems.

The OBX radiator is the ONLY alternative to the Zionsville at the moment. I'm the one who posted the review of Mishimoto's attempt (and failure) here: http://forum.e46fanatics.com/showpos...5&postcount=34

Mishimoto's only fits the M3, and the necks are welded on backwards anyway! Mishimoto told me their entire stock has the problem, and they have no solution. That's a lot of scrap aluminum. Almost every online vendor is misinformed about Mishimoto's radiator. Mishimoto told them all it will fit the non-M. It won't.

The custom build cost me approximately $200 for the OBX radiator + $35 for the aluminum tube stock. A steal if you have the tools. Get the necks made and welded if not. Or the Zionsville is a direct drop-in.

Last edited by WBVenom; 07-05-2010 at 11:49 PM.
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