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Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

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Old 11-04-2007, 12:16 PM   #21
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Die Grider with fine aluminum cutting bits (spade shape), and various sanding rolls. went from 30 grit down to 80/120
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Old 11-05-2007, 02:09 AM   #22
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Wow lol. Yeah... nice. I have a dremel... I shall work with that lol. I gotta pick up a carbide bit to cut with... and figure out exactly how to find the center of the port by reading those threads.
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Old 11-05-2007, 02:48 AM   #23
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why not mirror like, is that bad? or does it just not yeild you any results? (thuse being a waist)
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Old 11-05-2007, 10:15 AM   #24
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Mirror finish is bad. The air is static at the port walls. I was always told with a slightly rough finish, the air fills in the tiny gaps left by the finish and gives the air that actually moves a surface to slide over. Air won't stick to air, or something along those lines, but air will stick to metal.

Please correct my errors.
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Old 11-05-2007, 10:43 AM   #25
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Quote:
Originally Posted by MyLittleBlackBird
Mirror finish is bad. The air is static at the port walls. I was always told with a slightly rough finish, the air fills in the tiny gaps left by the finish and gives the air that actually moves a surface to slide over. Air won't stick to air, or something along those lines, but air will stick to metal.

Please correct my errors.
Actually, your right on with that
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Old 11-05-2007, 11:49 AM   #26
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This is why I leave the bottom of the L67 LIM rough. And don't fully polish the inlet of the SC to a mirror.

The SC outlet, however, I do polish to a mirror so that EGR/PCV grime doesn't have a rough surface to build up on. These deposits create tiny points of heat under boost.

Even my cylinder head porting wasn't a full-polish surface. I left a certain amount of roughness.

The rule I try to follow is a mirror finish ONLY in the areas where gunk buildup will be a potential problem. Semi-smooth finish elsewhere. The finest grit I use on LIM runners is 80.
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Old 11-05-2007, 01:55 PM   #27
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so what about themirror finnish I put on mt SC inlet? no one told me at the time it was bad.. I know the SC builds alot of crap in the inlet sao wouldnt the mirror be good for keeping awat the resrictive build up?
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Old 11-05-2007, 06:09 PM   #28
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the difference between mirror finish and a finish that i showed is 15-20 cfm at 28"
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Old 11-05-2007, 07:53 PM   #29
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(keep in mind my mirror polish on the SC outlets is only on the extreme edges)
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Old 11-12-2007, 12:18 AM   #30
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Golf balls are dimpled for the same reason. :P
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