darrenjlobb's Adaptronic Managed Compound Blown Derv Bus Build

[darrenjlobb]

Another end of week update!

Got the car all strapped down on the dyno ready for initial testing / setup.








Again its a bit of a boring update with little photos, but have now got the fuel control fairly dialed, and also got the pilot injection sorted, although not fully mapped yet, but working / able to be.

The main thing I have been sorting is the boost control for the compound setup. First step was to create two ECU pages, to contain the PID loops for each turbo, so one for the WG turbo and one for the VNT, in basic terms, these pages basically take a target MAP (pressure) input, a feedback pressure (map pressure input) and output a correction duty cycle to open / close wastegate / move vanes in turbo to correct the pressure towards the target.  The WG turbo is just using an external WG with a 3 port MAC valve, so this is able to be controlled directly off the back of the PID loop into one of the AUX outputs, setup for PWM. The VNT however is being controlled with a Hella Electronic actuator, this has its own ecu page for the "actuator control", which essentially is a small PID loop of its own, using the duty cycle output from the turbos PID control page as an input, then a 0-5v feedback on an analog input channel for feedback of vane position (the direct control hella units have a 0-5v feedback output) and then output the final output to a pair of AUX outputs to drive the high side of the servo via a DBW card (bunch of mosfets to cope with higher current).
So essentially with the above, each turbo has control, and just needs to be fed a target. So for that I created another ECU page, for the "Boost Control" which essentially contains the tables / maps, and some logic. It basically looks at MAP1 and MAP2, and calculates the current pressure ratio, and then corrects the output to hold the VNT's P/R in the current request area, while also holding the overall map pressure at the requested map, by letting the WG turbo's output raise / fall as required. So essentially this entire thing is controlled with a 3d map (RPM vs TPS) for target MAP pressure across the engines range, and also a 2D map for the target VNT P/R across the engines range. 

This took quite alot of setting up / getting right on the dyno, had to add a base duty map for the WG turbo as was finding the PID controller was getting a bit wound up at higher boost levels and oscillating a bit. Not yet found the need for the VNT, I think mainly just due to the lightening fast responce with the electronic actuator...

Also swapped out the Zeitronix 5 bar map sensor for an AEM unit, the sensor has been being used on the dyno for logging for last coupe years, and think has taken a knock at some point as always reads 4-5 psi out, so not idea, and had to have a summer in the logic to "correct" it, so that is now reading correctly.

Next project was making a stock dash tacho work off the ecu, wanted to use a GTI6 dash as the DT dash only reads up to 6k, and has always annoyed me having the redline at 5k?!

So took apart a couple GTI6 dashs and made up a bit of a hybrid, and managed to adjust the milage to match my original set, not that it really matters on a car like this, but just wanted to keep it correct! Found the wire on the back of the dash for the tacho input, and setup and aux out on the ecu, connected it up, and then setup the output to be a PWM output, relative to the current RPM, simple multiplyer in the logic sorted this, and hey presto the tacho was working!










Other than that not much to report really, have been slowly working on the tune. Pretty much at the limits of my current injectors now for the power delivery I am after, so now starting to sort out a much bigger set to replace them with. Have been trying to tame the power curve to a nice linear petrol like output, rather than the typical huge surge of mid range resulting in lots of tyre smoke / snapped shafts and clutchs. Car is currently sat at around 205hp @5krpm, with durations pretty much at there limit without making the EOI problematically late.

Safe to say I am learning alot in this process, very quickly getting the hang of the ECU / software now, and really starting to make some good progress. Also great to finally be able to use the dyno for what I bought it for, tuning this car! And it really is prooving to be the most useful investment I have ever made with respect to this car!  The work I have been doing at the moment with the turbo control etc would be simply impossible on the road.

The latest video probably shows more than I can explain in here.

Thanks for reading

https://www.youtube.com/watch?v=6ZmGIbnWPl0