my boost leak tester >$9
 

saw this on an evo forum and made my own.
sized for a t3/t4 turbo w/ a 3 inch inlet.

1 rubber pvc connector i got from home depot 3" to 3" with hose clamps on it.

1 3 inch threaded pvc plug

1 valve stem i got from discount tire for free, i just told him that i needed an old one for a boost leak tester and he got one for me.

final product!!
http://i49.tinypic.com/2ag3y13.jpg

un assembled, kinda
http://i48.tinypic.com/246vo7k.jpg

obviously get the right size parts for your turbo inlet,
and follow the rules to testing,

dont go too far over your max boost.

just hook up your bike pump to the end and get pumping!

a+

do you get any leak past the TB and then through open valves etc? or with the plate closed does it seal well enough?

The boost slowly leaks past the throttle body. I used a pvc cap for mine, i believe its a 2.75inch pvc cap with a tire valve in the middle =-)

throttle body position doesnt matter since half the valves are closed at all times. either the pressure will stop before entering the cylinder or in the cylinder.

unless the engine stops on valve overlap. remember some of us are running NA cam timing/cams :p

I like it... so easy

hell if i know, ive never heard of valve overlap lol, im guessing you wont be able to hear the air leaking into the exhaust there though.

Valve overlap is prominent in NA engines and not so much turbo (factory specs on both). This is where both the intake and exhaust valves are open at the same time, this lets fresh air in and clear the combustion chamber at a high velocity as both ports are open. On turbo cars there still may be some overlap but it is much less as the air is being forced through at a much higher rate.

On NA cars that have been turbocharged excessive overlap can cause problems, nothing bad just efficient use of potential power (volumetric efficiency is lower). The cheap way to get by this, on a DOHC engine, is buy adjustable cam gears and clock them each away from eachother slightly to tune out the overlap. The best way is just new cams. On single cam engines and some DOHC it isnt possible to tune out the overlap with cam gears. The last option is to have the cams reground to a different profile, mixed results on this (either they last or they dont)

Valve overlap is prominent in NA engines and not so much turbo (factory specs on both). This is where both the intake and exhaust valves are open at the same time, this lets fresh air in and clear the combustion chamber at a high velocity as both ports are open. On turbo cars there still may be some overlap but it is much less as the air is being forced through at a much higher rate.

On NA cars that have been turbocharged excessive overlap can cause problems, nothing bad just efficient use of potential power (volumetric efficiency is lower). The cheap way to get by this, on a DOHC engine, is buy adjustable cam gears and clock them each away from eachother slightly to tune out the overlap. The best way is just new cams. On single cam engines and some DOHC it isnt possible to tune out the overlap with cam gears. The last option is to have the cams reground to a different profile, mixed results on this (either they last or they dont)