richardpalinkas Posted February 26, 2019 Share Posted February 26, 2019 Is there any benefit in running boost in open loop compared to closed loop? Vehicle is an FG running 20psi on E85. And reverting a tune from open loop to closed loop, is it best to run the standard settings regarding boost control as in the pid values? Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted February 26, 2019 Share Posted February 26, 2019 Running closed loop is much more time consuming to tune, as if you don't make the desires boost table match exactly what the open loop duty cycle table shows on the dyno you will end up with a horrible oscillating boost curve when you turn closed loop back on. For this reason most tuners just tune the car in open loop. If you want full closed loop boost control at 20psi the method is as follows. Tune the car in open loop and log the boost against rpm and temp. Set your desired boost table to match what is logged at that temperature and guestimate the other temperatures. Ultimately you want to do a dyno run for all conditions but this isn't possible without a temperature controlled dyno cell. Now reenable closed loop. If you have changed the turbo wastegate actuator or turbo you may need to fine tune the PID gains. This requires knowledge of tuning control systems. There are some good guides online. Even Wikipedia is quite good. Simple guide is if you are getting oscillation (and your desired matches what you see in open loop) decrease the proportional gain and also decrease integral. If you see that the boost never reaches target (undershot) increase the integral gain. The benefit of closed loop is you will get the same boost pressure on 5c and 40c weather. Same with low and high gears. Without it you will see less boost in the lower gears and if you hold it at peak torque in a tall gear you may overboost. This is especially true with the stock gt3582 turbo and actuator which is almost uncontrollable at peak torque and >18 psi. 1 Quote Link to comment Share on other sites More sharing options...
richardpalinkas Posted February 27, 2019 Author Share Posted February 27, 2019 Thanks for that explanation. My car is tuned to open loop, and I'm logging exactly what my desired boost table is, so it might be a good idea if I re enable closed loop boost control Quote Link to comment Share on other sites More sharing options...
sadennis1086 Posted July 10, 2020 Share Posted July 10, 2020 Hi, just starting to get my head around this software, only looking through the demo at the moment and trying to make sense of it all but could someone point me in the right direction to be able to change to open loop WG only? cheers Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted July 11, 2020 Share Posted July 11, 2020 20 hours ago, sadennis1086 said: Hi, just starting to get my head around this software, only looking through the demo at the moment and trying to make sense of it all but could someone point me in the right direction to be able to change to open loop WG only? cheers Have a read of these two guides. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.