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Evo boost problem


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Hi guys got a customers car at work that we have just built the engine for. It’s a evo 4. Running a link g4 plugin ecu. Turbo is a gtx35. With tial external waste gate and 3 port boost controller. Engine is fully built etc. The car starts and runs fine. Some fine tuning needed but no real problems. The problems come when boosting! So I had it on the dyno setting  the fuelling sites and then as it got onto boost it’s like it his it’s map limit and just stuttered. Until I let off. So I tested the boost solenoid and it is clicking fine. So checked the boost control table again and had it set ok. But upped it a bit just incase. Same again. So put it back. Map limit set to 320kpa. Run it again and seemed ok 40% throttle fine. 42% throttle full uncontrollable boost! So played with the boost control but soon realised that no matter what I entered into the table it has no effect on the actual boost control!! 

The wastgate is plumbed in as follows. Turbo nipple to T-piece one side of t piece off to soloniod and the other off to the wastgate. And then the other side of the soloniod to the wastegate. Same as the photo attached  however our middle “com” port is vented to atmosphere.

Anyone have any ideas or can point me in any kind of direction ? It is so aggressive that we can’t even get a run on the dyno as it is literally ON or OFF 


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Your diagram is wrong if you are using a common mac valve such as 35A-AAA-DDBA-1BA, The pressure source should be connected to port 1 (normally closed), and the wastegate dome to port 2.  You show the opposite in your drawing which would mean the wastegate would see no pressure source at all - it would be dumped straight to atmosphere.

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