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Porting you own intake :O?

2K views 8 replies 4 participants last post by  Mile30 
#1 ·
My friend suggested to me, that i go to the junk yard and find a standard 2.o zetec intake many and mach it up to the gasket, mark the outline and grind away. Sounds like it would work, im not sure really how much youd get out of it? also he thought instead of looking and paying big bucks for the svt head pull a bone yard stock zetec one and rebuild it. also anoption i know would work but will it give me the same power of a svt?
Just trying to get some decent power outta my zx3 :p
 
#2 ·
You won't find much power doing that; even if you were to match it up with a 65mm or 70mm throttle body. UNLESS you were to also use a power adder that could take advantage of the ability to breath more.

In the meantime, you'll notice throttle response change drastically! If you trawl long enough, you'll see Turbo Tom going medieval saying he's tested that on a dyno and yielded no HP/TQ gains. I have a Zetec with an FC 65mm TB and an intake manifold that was dremelled to match up to the TB... that's how I know the differences!
 
#4 ·
Butt dyno and real dyno are two different things. What you are actually feeling is more throttle response due to the spring on the throttle body having a different tension than the one on the stock throttle body. Other than that, you won't feel any difference in power other than the placebo effect.
 
#7 ·
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!
 
#9 ·
When you find it, hit me up for the DSIM; I have an extra one cleaned up and ready!

The SVT head has better flow characteristics too. Keep searching; the more research you do now, the less will surprise you when it comes time to install... like a VCT delete (unless you want to get an SVT ECU to use the intake manifold runner controller). Some have used a vacuum actuator to do that job though.
 
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