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Supra 2JZ Haltech with MAC 4 Port - Boost Control Problems

Boost Control

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Hi,

I am trying debug a 4 Port Mac boost Solenoid

Basic setup: Haltech Elite 2500 on a Supra Mk4 2JZ Non VVTi With a big turbo and a Dual Wastegate setup.

In Open Loop with 0% Boost Control Duty Cycle I get 42-43 kpa of boost all through the rev range i.e the combination of wastegate springs.

Aim Boost of 120Kpa @4000rpm is acheived with approx 23.6% of boost solenoid duty cyle. Any higher and I hit the 140Kpa 'Overboost Cut' that has been setup.

Boost is controlled by the DP03 on the Haltech as per their Haltech PNP Supra Non VVTi Kit (Digital pulsed output/Low side driver).

Any help would be much appreciated.

I have cross checked the Boost Solenoid Plumbing multiple times along with using multiple DPO Outputs on the ECU with same results.

Hi. This is the issue with 4-port solenoids - sometimes increasing duty cycle even a little bit may result in high spike or creep of boost. I came across such case in the past and changing back to 3 port solenoid helped the issue.

Hi, I understand your reply. I was hoping that the four port might be made work if enough time is spent on the dyno and if the changes are in 0.1% Duty cycle. But we are now spending a whole lot more on the fuel used during the dyno tuning in 0.1% changes than just buying a 3 Port and finishing the tune.

I have also spoken to Nick at Haltech Usa, who I must say has been super helpful.

Thank you for the help.

You need to run a 4 port in closed loop once you base duty is close.