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Forum nameTurbo/Nitrous Tech
Topic subjectLots of Vacum but no Boost
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i8&topic_id=105455
105455, Lots of Vacum but no Boost
Posted by Trambone, Sep-19-08 01:58 PM
Hey guys,
Hope you the summer is/was going good for you all.
I have a quick question and hopfully this is a common problem, but Its killing me...
My car is building plenty of vacum (20lbs) but no boost, also it dosnt have much power to the wheels.
The turbo is fine, and there is no boost leak anywhere I can find.

Anyone have any idea?
105456, RE: Lots of Vacum but no Boost
Posted by Agas, Sep-19-08 04:05 PM
Boost leak, exhaust leak, either one try a boost leak tester (easy to build)
105457, RE: Lots of Vacum but no Boost
Posted by Trambone, Sep-19-08 04:58 PM
I "think", not sure till tomorrow when I can see better, but my timing belt may be off by one tooth.
Would this cause it to do this?
105458, RE: Lots of Vacum but no Boost
Posted by 96TurboGS, Sep-19-08 06:49 PM
You really need to look over this site before you detonate. Your posts are confusing the hell out of me; you need to at least come to a resolution before starting new threads. Did you ever figure out what regulator you had? Did you fix that problem when you said you were lean? If you’re idling at 20hg’s (perfect vac) and not building boost when you drive then you have something hooked up wrong. I hope you’re not trying to build boost at a stand still without driving it as stated in your other post. I highly doubt being a tooth off has anything to do with you building boost. Give us more INFO on everything your car is doing along with your set up, or better yet make a video of what your car is doing.
105459, RE: Lots of Vacum but no Boost
Posted by justins71, Sep-20-08 04:49 AM
if your timing was off a tooth, you wouldn't be at "perfect vacuum" (which by the way is 30Hg, ~20 is ideal vacuum for a healthy engine). It'd kinda lope on direction, and sound like it was under load if it's the other direction. At least with my cam gears that's what I came up with! lol Check and make sure your wastegate isn't stuck open, and i'm assuming since you did a boost leak test that your connections and BOV aren't leaking horribly.
From readin your other posts, can you put up a list of your mods? Sounds like you kinda have a grab-bag goin on, just wanna make sure you're set up correctly. And is it no boost in the entire RPM range or what? The more specific the better
105460, RE: Lots of Vacum but no Boost
Posted by 96TurboGS, Sep-20-08 05:28 AM
Originally posted by justins71
"perfect vacuum" (which by the way is 30Hg, ~20 is ideal vacuum for a healthy engine).

Perfect vac meaning in what he "should" see for his 420a at idle, 17-22hg’s is what he "should" be seeing not 30 – Chilton’s manual pg.105
105461, RE: Lots of Vacum but no Boost
Posted by justins71, Sep-20-08 06:30 AM
Originally posted by 96TurboGS
Originally posted by justins71 "perfect vacuum" (which by the way is 30Hg, ~20 is ideal vacuum for a healthy engine).
Perfect vac meaning in what he "should" see for his 420a at idle, 17-22hg’s is what he "should" be seeing not 30 – Chilton’s manual pg.105


lol I know what you meant, but just to keep facts straight. There's alot of science in these things and don't wanna confuse anyone that knows lesser.
105462, RE: Lots of Vacum but no Boost
Posted by nyBoosted420a, Sep-20-08 04:50 AM
check your intercooler pipes