Forced Induction Custom FI Setup Questions

Boost spike?

Old Sep 13, 2004 | 06:30 PM
  #1  
Zeusfire69's Avatar
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Default Boost spike?

The turbo I'm using is listed below...the problem I'm having that I don't understand is. My internal gate is set to 9psi by shortening the rod, there is NO bosst controller at all, but I am still getting boost spike to 11 or 12 psi, then it will settle back to 9. Anybody know why? Can you create boost spike by ajusting the waistgate rod too?
Old Sep 13, 2004 | 07:45 PM
  #2  
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Default Re:Boost spike?

check to see if all your connections are tight and are you running the wastegate boost/vacuume hose from the compressor or intake manifold?
Old Sep 13, 2004 | 10:18 PM
  #3  
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Default Re:Boost spike?

I'm running it from the compressor to the wastegate (about 9 inches)...everything has screw on hose clamps on it...
Old Sep 13, 2004 | 11:04 PM
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Default Re:Boost spike?

your turbo will reach full boost by atleast 1000rpms quicker if you hook it up the wastegate to a vacuume/boost source off the intake manifold. T' off the charcoal canister emissions filter hose. it's one the other large hose that's not for the pcv valve. a 5/16" plastic T works good. that's how i did mine and it spools up way quicker. for the BOV i T'd it off the pcv valve hose. T these things off the closest to the manifold you can. the nipple on the compressor housing should come off, you can fill it with jb weld to plug it, or you can find a small bolt to plug it. don't put a vacuume rubber hood on it. i did that first and it was leaking bad.
Old Sep 13, 2004 | 11:13 PM
  #5  
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Default Re:Boost spike?

I'm not trying to spool up quicker! ----, I'm at FULL boost by 3800 rpm...I'm trying to figure out why it is spiking...
Old Sep 13, 2004 | 11:38 PM
  #6  
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Default Re:Boost spike?

lol. is your compressor nipple tight and do you have the hoses clamped? make sure you don't have another compressor nipple that is leaking boost. if you do, fill it up w jb weld then screw it back on after it dried. you should try connecting the wastegate to the intake manifold though, it opens the wastegate at the pressure in your engine and not at the compressor which is also a turbulant boost source(not silky smooth) the intake manifold has more stable boost.
Old Sep 14, 2004 | 12:34 AM
  #7  
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Default Re:Boost spike?

Full boost by 3800? Very good! I got full boost at 4800rpm and running 7-8psi only with internal wastegate.
Old Sep 14, 2004 | 09:38 AM
  #8  
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Default Re:Boost spike?

Can anyone else verify that you spool quicker with the wastegate off the manifold vacuum? I may look into this!
Old Sep 14, 2004 | 09:54 AM
  #9  
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Default Re:Boost spike?

you're spiking because the WG cant flow enough gases away quick enough. get a bigger WG dump tube.
Old Sep 14, 2004 | 06:51 PM
  #10  
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Default Re:Boost spike?

I don't have a dump tube, it got the internal gate with the housing that goes into the same as the down pipe...it's like the one in this picture... http://cgi.ebay.com/ebaymotors/ws/eB...&category=6755
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