[bioskyline]

the wastegate is what controlls boost levels. it opens and let exaust gas bypass the turbo and out, keeping it from spinning the turbo faster making more boost.

most internal wastegates using pressure from the compressor side to move the rod that activated the dump of exaust. inside the other end is a spring set to you stock boost level (useually 5-6 pounds) by putting the tee fitting in the line, it vents pressure, so it now takes 10-12 psi to move a 5 lb spring. the spring is what closes the wastegate when boost drops for shifting. pretty simple. shimming the wastegate with washers behind the spring to make the spring stiffer also works

problem is that stock our cars have the airflow meter on the intake of the turbo. meaning all the air is metered from the turbo to intake. hence why it has the recirc system so the pressure drops but air volume stays the same. with it vented to air like the hks ssq the eninge will stall as the air/fuel mix changes since all that metered air is now gone, and you run super rich. if you get the map or maft you can vent fine since air is measused after its compressed, not before.

as for exaust i had no problems running 10-11 psi on the stock exaust. it worked better with the 3 inch but you can leave the elbow in. the elbow outlet is 2 and a 1/4 and i use the megan racing dp that goes from 2.25 to 3 inch. i dont have the rest of the exasut so all i run is the dp. and it is LOUD!!!. all the ricer hondas with the bee-in-a-tin-can mufflers got nothing on me. i sound like i got a jet engine under the hood as all you hear is fan blades spinning.

as for hp gains. id think it would be around the 300 range, maybe higher. i raced a 427hp skyline and only lost by a fender length, so hard to say what i was running, but i also ran a hubless clutch.

and i want to see pics of you cars!!