Boost Drop

[Mike Marnik]

Ok so ive been hunting down boost leaks for the past week now and im almost posative i have them all taken care of. Now when i boost it will go up to 18psi then begin to drop off to 14-15 psi and hold around there. Now when i was doing boost leak tests the line coming off of the valvecover on the pass side was blowing air out. this has happend on several occasions at differnt places. I bought a new pcv valve today because i was doing the throtlebody shaft seals and it made access easy. Well about a month and a half ago i had already replaced the pcv valve and when i took it off today and blew into it it sealed it self off like its supposed to. Also about 6 weeks ago i did a compression test and they all came back 145+ i believe might have been 155+ i cant quite remember. So i dont think blowby would casue this. Also one time after doing boost leak tests the exhuast smoked blue (oil) for a minute after start up but hasnt since. What do you guys think is going on here. I can do another boost leak test tomorrow.

 

[UCspyderGS-T]

Ok so ive been hunting down boost leaks for the past week now and im almost posative i have them all taken care of. Now when i boost it will go up to 18psi then begin to drop off to 14-15 psi and hold around there. Now when i was doing boost leak tests the line coming off of the valvecover on the pass side was blowing air out. this has happend on several occasions at differnt places. I bought a new pcv valve today because i was doing the throtlebody shaft seals and it made access easy. Well about a month and a half ago i had already replaced the pcv valve and when i took it off today and blew into it it sealed it self off like its supposed to. Also about 6 weeks ago i did a compression test and they all came back 145+ i believe might have been 155+ i cant quite remember. So i dont think blowby would casue this. Also one time after doing boost leak tests the exhuast smoked blue (oil) for a minute after start up but hasnt since. What do you guys think is going on here. I can do another boost leak test tomorrow.

How long has the boost drop off been occuring?

 

[Mike Marnik]

not quite sure for a while i wasnt getting on it much (untuned) and the boost was only set at like 12-14psi before. Werid thing is i used to have mad boost creep.

 

[UCspyderGS-T]

not quite sure for a while i wasnt getting on it much (untuned) and the boost was only set at like 12-14psi before. Werid thing is i used to have mad boost creep.

Stock turbos will not run high boost, it is not efficient at that level. That is why you are seeing the boost drop off. It is time for a larger turbo to push more boost.

 

[Mike Marnik]

so my 14 b will not beable to hold 18psi??? ive herd of people running in the 20psi range on a 14b

 

[Mike Marnik]

Well i did another boost leak test today. I check the pcv valve and it does not leak under pressure. I am still getting alot of air coming out of the valve cover vent on the pass side. Also after thetest when i started it it smoked a little bit. I wont beable to do a compression test untill friday afternoon. What do you guys think this could be Head Gaket, Rings, valve seals?? about a moth and a half ago the compression was 145+ across the board. all the otherboost leaks are now gone though except for a little air at the turbo itselfbut itsvery small. I am losing all the air from the valve cover.

 

[EclipseTrbo420A]

When you say by the turbo you mean out the exhaust end ? Could be valves there should be no pressure comming out of the VC or the Turbine housing.......or the turbo at all for that matter.

 

[Mike Marnik]

really i cant tell on the turbo but its very minute and not the big problem at hand here the blowby is.