2nd throttle??

[truepinoy]

theres 4 butterfly valves that is in the intake right before going into the head. im just wondering if i could take this out ,would it increase air flow and horse power??? all 4 valves are connected to a rod that is controlled by this thing(inside red circle)lol

[wa-chiss]

those are the sencondaries. They're closed at low RPM to keep the velocity of air for better fuel atomization. But at a higher rpm when the pressure dropes in the manifold, that little control valve you circled opens them up for better high RPM flow. I took mine out and niticed a more smooth acceleration. You won't gain any hp up high but you might loose a little down low. If you go turbo you will gain from removing them. There are two ways to do so. 1) just unscrew the valves from the shaft, or 2) remove the shaft and plug up the holes somehow. Hope this helps.

[dkdeleon68]

its called the swirl control valve, and yes it helps a little to remove it and the secondaries. unless you live in a cold climate.

[SR20drftSX]

Uber clean SOHC by the way..i dig

[jeremy242]

I have heard that you might have a rough idle with it removed. If you are going to the effort of removing that are still going to keep the other emmissions stuff on there. I am building a sohc and there is going to be nothing emissions related on there.