I have fitted a Garrett hybrid turbo to a STi 8 with uprated fuel system, intercooler etc and re-mapped with Ecutek software. Cars making 380bhp and 350lb/ft running 100+RON fuel. . The boost curve is perfect in any gear from 2000rpm till 8000rpm , but I am having problems with boost control when feathering the throttle or changing up through the gears above 5000rpm . Boost bounces between 1.1 bar and 1.4 bar (target boost is 1.3 bar above 5000rpm). I have tried changing initial and maximum duty cycles , but no difference. Now I think it is a mechanical problem. Could it have something to do with the pre-load tension of the wastegate. Perhaps it is too strong and the solenoid struggles to control boost in high rpms or could it be that the standard brass restrictor is too small and the solenoid cannot react fast enough to catch the boost at high rpms. Which should I change first in order to see if it makes a difference?

rupert

 

either tbh. if your still running the two port or even three port it could be too much for it to control. to test the actuator, take a straight piece of pipe from compessor inlet pipe to the actuator pipe and take it for a hard run. put it in fourth and see what happens to the boost. goo all the way up to redline and let us know what the peak boost is.



ps: make sure the resistor isn't in the pipe that i've just told you to fit

 

I tried this and got a steady 1 bar boost steady from 5000 to 8000rpm

 

it should only be 0.5 bar. is the car set to run anything except standard boost?

 

So at 1 bar steady boost the actuator is set correctly at 1.2 bar cracking, dave he's got the same turbo as I have on the STi5 but with a weaker actuator, its a mapping issue, Rupert I'll send you some tips later this evening.

0.5 bar is only relevent to a std actuator from IHI.

bob

 

Thanks Bob

 

thanks bob

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