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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 08-27-2007, 03:37 AM   #41
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http://cgi.ebay.com/ebaymotors/ADJUS...8716QQtcZphoto

well one of these just arrived today Should be putting it on tomorrow. Overall it seems like a pretty sturdy piece but the piston seems to be a bit sticky while moving up and down. I assume this is to the rough surface of the bore in which the piston moves up and down ... luckily I have a small hone that works well for stuff like this (and clutch slaves) Then a little dremel polishing action and teflon grease should have it moving really smooth. Also, it can be fully disassembled and rebuilt with orings in a year or two when the old ones have seen better days.
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Old 08-27-2007, 10:14 AM   #42
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I took mine apart before installing to check it out and it looked clean... do you have a cam? pics? Mine is still working great. I'm running around 15psi peak with the weakest spring and minimal tension. I believe it's quieter than the bosch too- and holds boost way better.
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Old 08-27-2007, 11:10 AM   #43
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I got mine in, with the weakest spring, and needed the adjustment unloaded to the weakest point to avoid compressor surge...but it's working like a champ now
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Old 08-27-2007, 11:13 AM   #44
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coo deal Benl--so you car doesn't snicker at you anymore?
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Old 08-27-2007, 11:36 AM   #45
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Quote:
Originally Posted by m2cupcar View Post
I took mine apart before installing to check it out and it looked clean... do you have a cam? pics? Mine is still working great. I'm running around 15psi peak with the weakest spring and minimal tension. I believe it's quieter than the bosch too- and holds boost way better.
well it probably is fine, but what im talking about is nothing that a camera could convey. Just that the bore of the thing was machined and there are ridges that can be felt with my fingernails which seem to make the orings of the upper piston stick just a little bit.
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Old 08-27-2007, 01:07 PM   #46
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Quote:
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coo deal Benl--so you car doesn't snicker at you anymore?
Nope...well, not as discernible.
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Old 08-27-2007, 01:35 PM   #47
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I just ordered one of these too. I pumped 10 psi into my system and heard the original FMII BOV leaking. Plus I'm losing boost like Savington, but intermittently so I think it's got to be the BOV sticking open some times.

Frank
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Old 08-27-2007, 01:46 PM   #48
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ryrye- thought maybe some disassembled pics for others IF it's apart
I sprayed the inside of mine with some silicone lubricant when I saw the Orings... And there are silicone Orings if the rubber rings stick.
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Old 08-28-2007, 01:43 AM   #49
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thanks rob (wait thats ur name right?), I had it apart earlier today and installed it on the car but I am getting nothing but compressor surge. When i had it apart, I honed the bore of the thing until it was really smooth and the piston now moves smoothly up and down (as it sees vac/boost) I also gave it a little vacuum to see how it reacted, and it moved the piston up ... not sure how much pressure was put on it though. Anyway, ill have to mess with it some more and figure out whats goin on ... maybe a new spring is needed (aka cut a coil off of this one?
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Old 08-28-2007, 10:11 AM   #50
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Are you using the weakest spring and adjusting (minimizing) the tension on the spring? That's what I had to do for 15psi. Compared to my bosch, it was WAY stiffer as delivered, so I immediately swapped in the weakest spring. That adjuster nut should get the tension to the point to where you can just compress it with your pinky - MAYBE 50% stiffer than a good bosch. - rob
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Old 08-28-2007, 10:14 AM   #51
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He probably got one like mine, where the adjuster nut is replaced by another piece; the vacuum port screws in and out to adjust initial compression on the spring. It came with two springs, and it seemed that the weaker was already in it.
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Old 08-28-2007, 10:56 AM   #52
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your's doesn't look exactly like mine?
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Old 08-28-2007, 11:10 AM   #53
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Not quite, I don't think. Instead of the chrome acorn adjustment nut shown in the picture, the vacuum port screws in there, and can be adjusted in and out.
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Old 08-28-2007, 11:48 AM   #54
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I finally got my turbo installed, and I'm using this BOV with it. I get a lot of compressor surge pretty much however I adjust it.... except after a 15-20 minute drive. By the time I am pretty much at my destination, I hear little squeaking sounds as I tip into the throttle from a stop, and I can rev the throttle and let the rpms fall again without surge. The only thing I can think of is that the BOV is just getting warm after a while, and actuating differently. I have mine adjusted so that it just barely seals at idle. If I loosen the screw any more, it'll leak.

I've got the straight VTA one, not the recirc bosch replacement.

-Mike
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Old 08-28-2007, 12:02 PM   #55
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hmm I guess the thing just likes to stick. Im thinking this is either one of two things; the spring on the upper diaphram (for vac port) is too stiff or the little piston which the release valve moves up and down on tends to stick. I bet its the latter or maybe even both. I think Ill chamfer the edge of the lower piston a litttle bit. Guess I should have gone with the other one ...
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Old 08-28-2007, 12:18 PM   #56
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welcome to the world of precision chinese engineering
Hopefully these are orings sticking. I had very minor compressor surge with the weak spring, but the adjuster got rid of it.
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Old 08-28-2007, 10:35 PM   #57
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Should the BOV be open and venting at idle? Certainly there's a lot of vacuum pulling from the manifold, and it seems like there should be positive pressure in the intercooler from the turbo. But I don't have experience with that. My STI has a recirc valve, so I've never noticed whether it's open at idle or not.

-Mike
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Old 08-28-2007, 10:37 PM   #58
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Quote:
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Should the BOV be open and venting at idle? Certainly there's a lot of vacuum pulling from the manifold, and it seems like there should be positive pressure in the intercooler from the turbo.
???
How would there be positive pressure at idle?
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Old 08-28-2007, 11:51 PM   #59
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Quote:
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???
How would there be positive pressure at idle?
Well, the turbo and compressor are still spinning somewhat, even at idle, right? It seems like air pressure between the compressor and the turbo should be near or a bit above atmospheric. But certainly the pressure there would be greater than in the intake manifold when the throttle is closed.

-Mike
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Old 08-29-2007, 12:00 AM   #60
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the compressor might be turning at idle, but it's not doing much. you could stop it easily if you wanted to.

there are losses in the charge pipes, especially with an intercooler. so at some moderate load, it's definately possible for the hot side to be above atmo pressure and the cold side to be below atmo pressure. but not at idle

Ben, does your new BOV make a nice continous 'woosh' when it opens? or does it oscillate like mine?
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