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The Radium King · 02-08-2012, 02:32 PM

all the parts in except for one. it looks like it will go together easy. finally understand why porsche uses a tb smaller than the maf housing; the maf is a thin-walled plastic and the inside diameter (3") is about the same as the outside diameter (3"). the throttle body, however, is cast; the inside diameter is 2.67" while the outside is 3". that way you can use a 3" pipe to join maf and tb but have a smaller tb as a result.

so, by going to a 3" tb to match the 3" maf, the throttle body has a 3.25" outside diameter. i've got a 90 degree reducing elbow (3.25" to 3") on order to join the two; once it arrives i'll assemble.

02-08-2012, 02:32 PM	#82
The Radium King Registered User Join Date: Apr 2010 Location: Canada Posts: 3,127	all the parts in except for one. it looks like it will go together easy. finally understand why porsche uses a tb smaller than the maf housing; the maf is a thin-walled plastic and the inside diameter (3") is about the same as the outside diameter (3"). the throttle body, however, is cast; the inside diameter is 2.67" while the outside is 3". that way you can use a 3" pipe to join maf and tb but have a smaller tb as a result. so, by going to a 3" tb to match the 3" maf, the throttle body has a 3.25" outside diameter. i've got a 90 degree reducing elbow (3.25" to 3") on order to join the two; once it arrives i'll assemble.