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Location:
Lismore, NSW
Registered:
February 2003
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Boost on a MA70 Supra with a 7MGTE
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Wed, 26 February 2003 09:02
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I used to beable to run 11psi in my car ok but now all I can get is 9psi and even then it goes to fuel cut can anyone explain why?
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Location:
North Sydney
Registered:
May 2002
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Re: Boost on a MA70 Supra with a 7MGTE
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Wed, 26 February 2003 11:26
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Did you install a larger exhaust or pod filter? Something that would change the flow of the engine?
Also what condition is your cat in?
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Location:
Sydney
Registered:
July 2002
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Re: Boost on a MA70 Supra with a 7MGTE
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Wed, 26 February 2003 15:29
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Or did you install a better intercooler ?
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Location:
Lismore, NSW
Registered:
February 2003
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Re: Boost on a MA70 Supra with a 7MGTE
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Thu, 27 February 2003 02:22
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I Have changed the exhaust to a 3" Mandrel bent, 1 cat, 1 resonator and straight through muffler, using a UNI air filter pod. After the changes the car was running ok for bout a month then the problem started happening. There are no air leaks. Please help... Also is the computer on these self learning?
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Location:
North Brisbane
Registered:
May 2002
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Re: Boost on a MA70 Supra with a 7MGTE
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Sat, 01 March 2003 07:28
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those mods mean the engine can breath better, so it will have lower psi but more flow, thus lowering boost cut, there is some backyard fixes for this, like changing air flow meters, but nothing truly reliable, just live with it until you can get a computer for it.....
c-ya,
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Location:
Gold Coast
Registered:
May 2002
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Re: Boost on a MA70 Supra with a 7MGTE
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Sun, 02 March 2003 11:18
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I think you'll find that this is *another* flaw with the MA7x Supra... the CT26 turbo suffers badly from cracking of the exhaust housing around the wastegate.
This will cause your boost to leak out - so the engine will meter the air coming in and THINK it is running more boost (effectively it is, but the engine is just not seeing it). This high amount of metered air is possibly the cause of the 'boost cut' (you may/may not be aware that it is not boost sensed but AFM sensed). You may be up for a reconditioning job or else a replacement, depending on how bad she is.
Could be something else, but having owned a number of 7MGTE's (I am actually using a friend's accound as I do not have Internet access) I think you'll find this is quite likely the cause.
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Location:
Lismore, NSW
Registered:
February 2003
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Re: Boost on a MA70 Supra with a 7MGTE
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Mon, 03 March 2003 04:25
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Should the crack be noticable easy? an when its still on the car? How can I test this? I also think the ABV (blow off valve) is leaking...
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Location:
Gold Coast
Registered:
May 2002
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Re: Boost on a MA70 Supra with a 7MGTE
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Mon, 03 March 2003 06:11
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You'll have to pull off the front section of your exhaust system (ie the turbo dump). Be aware that the bolts can be a pain and they are easy to strip out. Once you get it off it will be plain to see if there are any cracks... they crack in an outward pattern around the wastegate hole... either it'll look like a cat's ar$e or not 
Other thing is that those BOVs are prone to leaking, easily replaced with a few hose clamps, short bit of hose and a $40 Bosch plastic BOV from Autobarn. If it seems to shudder at all when you back off, then that generally means the BOV is toast.
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