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Overboost Problem...searched To No Avail, just installed hard upper pipe w/1g bov |
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Jul 7 2008, 12:21 AM
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Senior
  
Group: Members
Posts: 326
Joined: 14-February 08
Member No.: 52,619
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Location: North Dakota
Drives: 1998 GSX, 2006 G6, 1990 Escort

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Hey all.. i just installed a hard upper pipe with a 1g bov.. cleaned outside and inside the intercooler... and reinstalled everything. All of the clamps on everything were loose, i tightened all of those... runnin a big 16g turbo...
before i did anything i know i had some major boost leakage... before when i would adjust the boost controller(obx manual) nothing... i mean nothing would happen.. it all stayed the same... 14lbs... it would only go to about 9lbs and then slowly climb to 14 at about 5500 revs... it was like the turbo was screamin just to hit it...
now, i can't keep it under 15 lbs.. i have made the plug so loose on the manual boost controller i can and did pull it out, it made a difference, but still was hitten 16lbs at about 80-90% throttle at 5000+ revs.. (i have stock fuel system.. ) so i immediatly let off.. I don't know why even with the boost controller ALL the way down with the plug pulled, it is still boostin like crazy!!
ANY HELP, INPUT, SUGGESTIONS ARE ALL APPRECIATED..THANKS IN ADVANCE
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Jul 7 2008, 01:07 AM
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Senior
  
Group: Members
Posts: 326
Joined: 14-February 08
Member No.: 52,619
Status: 
Location: North Dakota
Drives: 1998 GSX, 2006 G6, 1990 Escort

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QUOTE(Rob @ Jul 7 2008, 12:25 AM) Do you even have a boost guage? [right][snapback]180042[/snapback][/right]
Yes... lol.. Please guys, i know that you deal with some newbies on here but c'mon how would i be telling you what the psi's are goin to??? I believe it is all hooked up right... When i bought the car it had a greddy profec ebc on there, and i just put this one right in its place... Now, i am new to turbo diagnostics coming from a supercharded world, so please feel free to give me a verbal diagram to follow that i can check first thing in the morning.. Thanks guys :thumbsup:
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Jul 7 2008, 02:50 PM
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Expert
   
Group: Members
Posts: 1,048
Joined: 21-May 08
Member No.: 58,134
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Location: Chiang Mai , Chiang Mai ,TH
Drives: 1997 Mitsubishi Diamante VR-S SUPER INVECS II , 1990 Mitsubishi Galant VR4 , 2006 Mitsubishi Triton PLUS 3.5 DOCH

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On my system , i have intake vacuum line , a vacuum check valve and then the vacuum line goes Tee's to a vacuum solenoid and Vent solenoid and goes to the wastegate, im not sure if yur system is setup like this one but , possibly check the BOV operation and possibly operation of the wastegate, that its fully retracting and extending , depending the size of of the charge air piping , if will keep a higher charge side pressure if the inlet nozzle is factory size.
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Jul 8 2008, 03:34 AM
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Senior
  
Group: Members
Posts: 326
Joined: 14-February 08
Member No.: 52,619
Status: 
Location: North Dakota
Drives: 1998 GSX, 2006 G6, 1990 Escort

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QUOTE(pwee05 @ Jul 7 2008, 03:17 PM) stock fuel system causing boost creep. did you enlarge your wastegate vent and flapper? [right][snapback]180330[/snapback][/right]
No. What the heck ... i have never heard of this.. please explain...why.. how..
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Jul 8 2008, 10:07 AM
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Bleeds black and gold

Group: Admin
Posts: 6,458
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Location: Lancaster, PA
Drives: 1996 Talon AWD. Built, but no longer drives: 1997 mitsubishi eclipse RS; 1990 Talon AWD; 1995 Talon AWD, 1997 Talon AWD. Seems like a pattern

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this is a very good write up http://www.dsmtuners.com/forums/articles-t...ep-porting.htmlbasically, the wastegate flapper and the arm that controls the flapper inside of your turbine housing don't swing open far enough. To make matters worse the hole that the flapper opens or closes isn't large enough to let the proper amount of exhaust gasses to escape. When exhaust cant escape it flows into the turbine wheel and creates more boost. In this case, when you go lean because you have a stock fuel system, the lean condition creates more heat. turbos love heat because it helps them spool and boost. More heat = more boost. More heat + more boost + wastegate that can't allow enough exhaust gas to escape = boost creep and possible engine damage Lean doesn't always mean a bad thing. someone that runs a 10:1 AFR will run richer than someone who runs a 11:1 AFR. both are safe, but the 11:1 AFR will burn hotter than the 10:1 and can cause the boost creep 16g's and actually all td05H turbos had this issue when trying to control low boost numbers at leaner than stock conditions. Thats why people always yell, WATCH OUT FOR BOOST CREEP when someone says they are turning up their boost on a stock car :thumbsup:
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