Focus Fanatics - View Single Post - Porting you own intake :O?
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Old 09-13-2012, 06:06 PM   #6
Mile30
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Join Date: Apr 2010
Fan#: 74686
Location: Westminster, MD
What I Drive: '03 ZX3

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Quote:
Originally Posted by (:HippiefocuS:) View Post
So lets say just as a whim, i throw on a 65mm tb and do nothing else, there wont be any serious or maybe even noticeable power coming out? with out upgrading your intake and or your manifold?
I'm not versed with an unmodified intake manifold and an upsized TB... the spring tension sounds bunk to me (but again: I never had the aforementioned setup). I also never compared the springs on the two TBs either... spring-force doesn't seem like a change you'd feel in engine response; more of a tactile change as more tesion would translate to a stiffer pedal fell... semantics though!

A larger opening will allow mir air into the runners, but the valve timing won't allow more air in; you end up with a venturi effect inside with air slamming into the back of a closed valve and more air forcing into the same area...

A CAI won't allow anymore air ineither. It simply directs it in differently, and grabs a 'charge' of cooler air from outside, whereas the RamAir pulls in the heated air from the engine bay. An upgraded intake manifold delivers the air charge to the combustion chamber in a completely different fashion, though! The shape and length of the runners can be 'tuned' for effeciency or torque... the SVT's dual stage intake manifold has two sets: one for low end power, and then switching to longer runners at a higher RPM. That setup was engineered and optimized to do what it does. If you can get an aftermarket intake manifold, you'll probably want to get a tune so the car takes full advantage of the changes (the stock maps in the computer won't mesh with the input signals it would get with the new piece)... That's a fairly expensive proposition though!

Unless you're doing the racing manifold and a tune there will be no power gains though! If there is it would be negligible; you WILL feel like there is, but perception and reality differ here!
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