Discussion and questions related to the course Boost Control
Just wondering how everyone else sets up their base duty tables for their respective ECU's. I run a haltech elite 2500 and just started running closed loop due to daily usage of the vehicle in changing climates.
I mapped out my base duty table as (rpm x tps%) but it does see quite a bit of fluctuation. Then again i have not activated the P I D controls as im still getting the base duty closer to my target boost of 160kpa.
What would everyone consider most common?
I would think the boost control would be boost aim (or boost limit) vs. RPM. Now your boost aim table might be TPS vs. RPM, or the input from a driver knob vs. RPM.
Hi David. Yes Sorry that is correct. I had a brain fart while typing. base duty cycle is (target pressure vs RPM). Have you guys ever used the spool assist feature on an Elite series ecu? it makes it a tough transition from the 100% duty it command then lets off to allow the closed loop control to come in and do its thing. at lower boost target levels i seem to always overshoot the target.
What type mapping methods are popular in regards to commanding duty cycles for rpm vs target boost?
I have it as such at the moment where lower rpms command more duty until it reaches just under target and then flatten the rest of the table out as rpms rise, then I would activate the PID controls to let it bring up the rest to the target. Again I know its more dependent of flow characteristics and turbo charger size. I'm running a gen 2 GTX3576R
Why don't you select a target that you can actually hit at a given RPM. So you actually control the boost and don't just rush up to the limit and have to do a cut to avoid overboost.
Thanks for providing some help. the way i ended up doing it was keeping the base duty table vs rpm vs TargetPres and zero'd the PID and tuned it in basically open loop with no pid correction until it got close to the target. i then set up another table that references this one as a 2d target vs rpm and set the targets flat across the table starting at spring pressure and dialing in,duty cycles to meet boost target, AFR's, timing, temp corrections. Then repeating that process and building up the duty map for up to whatever boost i plan to use. Once im close i slowly started ramping in the proportional gain and Integral. haltech has a different spin on Closed loop pid control vs other standalone ecus and they recommend the use of P and I and hopefully never D. never hit my Overboost cut so im doing well. A little oscillation here and there as rpms rise but i may need to tighten up the grouping near my target boost.