i mentioned earlier that i thought i had a boost leak becuase after about 5000 rpm's my turbo gauge would show me that i was loosing pressure. well me and a friend ran a boost leak test today and we did not find any leaks. we used a compressor at about 10 psi and followed the instructions we found on this forum to make the tester. is there something im missing or could it just be the gauge.

 

How long did it hold pressure? This is a 2G correct? If so, you're only going up to the lowest stock pressure. I would at least go to 12psi and it should hold for at least 10 seconds. Get your soapy water and start spraying couplers, injectors, vacuum hoses, breather hose, bov, throttle body, meaning everywhere the air can go. Don't stop at the couplers/junctions on the intercooler piping. The smic may even be leaking. This is almost a free check and by far the easiest IMO, spray bro, just spray

 

well ill try and do that on my next day off. we pressurised to about 10 psi and did not hear any leaks. we also tryed it on my friends 2g and heard some leaks coming from some vacume hoses and throttle body gasket.

 

are you on a stock BOV, and at what psi are you running. Also how much does it drop back down

 

yeah i get to replace the throttle body gaskets and a vacuum tube. we'll turn the psi up next time. we held the pressure for a good while on there. oh well we'll try again.

 

im still running a stock bov at only 10 psi. and it will steadily drop usually to about 6 psi. but only at higher rpms.

 

That bov could be your culprit. Next time you test it, spray the bov and go up to 12psi. It won't hurt anything.[sm=smiley20.gif]

 

a half clogged cat, or really dirty air filter can also cause that when it runs out of airflow way before its done revving
my GSX would do that from 18 down to 15psi over 5500 untill i took the stock exhaust off.

 

guys... correct me if i'm wrong but am i the only one who has though of just straight boost taper? all turbo'd cars lose a lil bit of boost at higher RPM's... he says it's happening at 5k rpm's which seems just about right for when boost ususally starts dropping off. i realize it shouldn't drop that much with only being 10psi but i'm sure that's part of it. i bet ur leak is very minute.

 

10 down to 6 is pretty low. you know that boost taper goes away if theres no restrictions, unless your just beyond maxing out your turbo.
a boost leak i dont think will do it unless its a huge one, then it would run horribly rich and probly hit fuel cut by that point.