boost question

[xTSIx]

About a month ago i got my car back fromt he garage and it didnt feel as fast as it used to and the boost gauge says im boosting like 6psi at the most soooo. the car sat for maybe 5 months and im wondering if its a possibility that my actuator is maybe seized or something. im not sure if when u rev the car up and let it off when it hits BOV if the actuator arm is suppose to move or not, so thats the first question. and second would be my gauge is reading 20-25 vacuum and to me that doesnt seem right it sems it should be around 16 or so. if anyone can help id appreciate it. thanks

 

[diablos991]

I would do a boost leak test and see if that fixes it first.

 

[fourreGsixty3]

A good healthy engine at sea level should have a vaccum of about 22psi, aftermarket cams will make this # go down. I would boost leak test it like Shawn stated.

Dustin

 

[SBstar]

Sounds like a major boost leak, but also check the blades on the turbo although I doubt that would be your problem since you've owned the car for a while...My car would only boost to 5 psi when I first got it and I did have boost leaks but found all the fins were missing on my turbo, kind of hard to build boost that way. Also check that the wastegate is easily opened (don't do this with the car hot obviously). Best bet would be a boost leak though.

 

[xTSIx]

ok ill try that but do i put the leak tester on my lower IC pipe that come off the j-pipe? or where do i do that

 

[fourreGsixty3]

Take the intake pipe off the turbo, and attach it there.http://www.vfaq.com/mods/ICtester.html

Dustin

 

[duck95]

I would definetly do a boost leak check. I'd start at the TB and work my way back. Make sure you put something on the accel pedal so you have a free path into the TB. I found that on my T25 that if you put it on the turbo inlet, it blows by the seals and into the oilpan. Thus, not pressuring up the intake system.

 

[oldman]

A good healthy engine at sea level should have a vaccum of about 22psi, aftermarket cams will make this # go down. I would boost leak test it like Shawn stated.

You mean -18 to -20 inHG (-9 to -10psi).

 

[xTSIx]

i did a boost leak test and didnt find anything and i also replaced the vaccum lines and it didnt fix it. is it possible while it sat that the turbo assembly somewhere started siezing. also my autometer boost gauge seems off a little bit. when the car is off its at like -5 vaccum. my friend dropped it like 2 times before i put it in the car would that hurt it and make it incorrect? thanks

 

[SBstar]

Well your boost gauge is probably not reading correctly then, it could be just reading everything about 5 psi under what it should but it is also possible it is not getting correct readings at all. But you said the car doesn't feel quite right when driving either correct? Did you check the wastegate arm to see if it could be leaking at all? (meaning when its closed is there a possibility air is still getting out). You can try wiring your wastegate shut and seeing if it will build more boost but I would consider that a last resort (could cause yourself some major damage if it built too much boost). I would suggest trying a different boost gauge if you can to see if it is building boost properly then go from there. Just how different did it feel while driving? Just a little slower or was it like crap slow? When I was only building 5 psi (broken blades remember) the car felt just like any old 4 cyl. Was it like that?

 

[oldman]

when the car is off its at like -5 vaccum. my friend dropped it like 2 times before i put it in the car would that hurt it and make it incorrect? thanks

So what's the mystery here? The gauge is off, should have included that piece of information in the original post.

 

[SBstar]

Like I posted about I want to know how great a difference did you "feel" in power when you drove it then as compared to before. Its obvious the gauge isn't reading correctly so that could trick you into thinking the car feels slower.