SimonSTI Posted July 3, 2021 Report Share Posted July 3, 2021 I'm currently rewiring the EWG like suggested in the help file with a T fitting, full boost on the bottom port and using a solenoid to control boost on the top port. Turbo is connected on port 1, top port on port 2 and port 3 as an air filter on it. It's a grimmspeed 3 port (mac) and it's setup to 33hz. Just running open loop for now to get the data in before tuning in closed loop. I'm using a 10.15 psi springs setup, which net me around 27 psi MAP (13 psi boost). 0, 5, 10 and 15% duty cycle net me same boost level. At 20% I get up to 30-31 psi (15-16 psi boost) and at 25% it's boost creeping and hitting the map protection at 40 psi (25 psi boost). Car is tune in flex fuel, running around 15 psi on pump and will probably (not tune yet) run 20-22 psi on 70% ethanol. So would like to have the maximum resolution possible between 15 and 22 psi. Looks like it's way too sensible for now. Is that typical with these value? I'm a bit short on time and tuning this in the street is a bit time consuming, so looking for some pointer on what to try next. Reduce spring rate? Could my solenoid be broken (it's probably 10 years old)? I have another solenoid (Pierburg) I can swap to do some test as well. tx in advance Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 4, 2021 Report Share Posted July 4, 2021 I think it will be difficult to control if only 5% DC makes the difference between spring boost to over boost. I havent experienced this before, but if it were me I would try creating a small "leak" in the line that goes from port 2 to the WG dome. Something like a small piece of hard tube with a small hole drilled in the side of it or a tee with a mig welding tip in it. Quote Link to comment Share on other sites More sharing options...
SimonSTI Posted July 8, 2021 Author Report Share Posted July 8, 2021 In case someone is looking, switching to the HOA / Pierburg at 30Hz helped a lot, my Grimmspeed was probably getting old. I also added a little restrictor in that area in red (picture bellow), which helped give me way more resolution as well. I ended up with something like this: 5% 28psi 10%, 29psi 15%, 29.6psi 20%, 30psi 25%, 31psi 30%, 33psi 35%, 35psi I also tested the simpler setup that only push air on the lower port, worked pretty good also, but the recommended setup should get more flexibility to hold boost at high RPM. Good ref article: https://www.perrin.com/blog/post/boost-control-systems-explained-part-3 Quote Link to comment Share on other sites More sharing options...
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