boost control

hi there,

I have an evo 8 with a link g4+ ecu installed and a mac valve for controlling boost. the engine is a 2litre block with a garret 3582r turbo .86 exhaust and tomei 270* poncams. With the wastegate in an vent to atmosphere state when the engine comes onto boost you can here what sounds like the wastegate to be pulsing and it is quite lazy to come on the boost.

Is there something that i can change like the frequency to stop the pulsing sound?

Would adjusting the duty cycle of the mac solinoid to 100% during the revs where boost builds help the turbo come on quicker ?

Hi Matt,

Does the boost level itself oscillate? or just the noise from the dump pipe?

https://www.hpacademy.com/previous-webinars/070-electronic-boost-control-link-g4-ecu/ This webinar covers a wored example of boost control on a G4+ but you should seriously consider taking the boost control course to understand what is happening and why

hi chris,

I am currently working through the boost control webinars at the moment and so far i am learning alot. from what i can see the boost is hitting the target without overshooting it just seems to be more the audible noise from the dump pipe. What led me to ask the question was, before i had the link g4+ installed and tuned I was using a BLITZ electronic unit to control the boost. With the BLITZ unit installed i noticed the higher i set the duty the more responsive things got. Also with the BLITZ unit i had no audible pulsing from the dump pipe. Also when there is no power to the MAC solinoid and i am running spring boost pressure there is no audible pulse. It only seems to be pulsing when I raise boost levels through the ECU

That's not uncommon with electronic boost control and a wastegate that's dumping to atmosphere. You're basically hearing wastegate responding to the pulsing of the solenoid. You can try increasing the frequency of the boost control solenoid a little and see how that affects the noise. I normally find that much over about 20-25 Hz starts to negatively impact on the boost control but see how it works for you.

thanks for that andre I will check the frequency and see how i go. keep up the good work :)