Boring out TB and IM
10-28-2009, 07:37 AM
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Boring out TB and IM
I just picked up a stock IM and TB on ebay for $50 total and I want to bore them out. Does anyone know how much I can go with them before its not good? I'm thinking about doing this myself.
10-28-2009, 10:11 AM
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The IM has plenty of room to handle any size you can bore a stock TB out to. The TB, unless you really know what you're doing I would leave to a pro. You'll need to keep it perfectly round, and you'll need a larger butterfly.
10-28-2009, 12:31 PM
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QUOTE (187sks @ Oct 28 2009, 12:11 PM)
The IM has plenty of room to handle any size you can bore a stock TB out to. The TB, unless you really know what you're doing I would leave to a pro. You'll need to keep it perfectly round, and you'll need a larger butterfly.
realize aswell. TOO big is also bad for porting out an IM..
keep it within reason.. dont go TOO nuts. and also remember IM insides arent supposed to be COMPLETELY PERFECTLY SMOOTH.. needs to have some grit/roughness to it. helps with fuel atomization. basically remove any large casting imperfections and casting marks.
and make sure to gasket match your IM to your head. a lot of cars from the factory have cast manifolds.. and have HORRIBLE gasket matching.
10-28-2009, 01:02 PM
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It's about not having features that interrupt airflow or cause unwanted turbulence. So, matching TB bore to IM bore and IM to head bore & shape, smoothing flow paths, reducing/removing intrusions and imperfections. If you gasket match the IM runners, make sure the gasket matches the intake ports on the head too. If the gasket has larger openings than either match to the head. If the head has larger openings than the gasket, shape gasket to match intake ports and then gasket match the IM runners.
