DIY Variable vane turbo controller using cheep programable petrol engine ECU. (1 Viewer)

[macca1590]

Hi guys, I have been dreaming of a VNT controller for a mechanical engine and have come across a few set ups that are available, if anyone has used any good ones id be interested to get some feed back.

However I have my own idea for anyone else playing at home with some idea on Petrol engine ecu theory and workings. Keep in mind this would possibly be only for a open loop vnt/boost control and only for a vacuum controlled VNT.

So I'm thinking you could use a cheep (microsquirt or speeduno) engine ecu running in alpha N mode, set up for single injector with the injector output to a vacuum solenoid that controls the turbo. This way your fuel table (RPM x TPS) gives you a injector open time or in our case an output for a vnt vacuum actuator.

So in theory i think would be better than mechanical dawes or needle valves since its fully adjustable in all rpm/tps zones. You can set your 0 %TPS zones (decel) to full open so the turbo has no chance of overspeed, able to set light load and cruiser somewhere in the middle for low EMP and good economy and full load to max boost as required and everywhere in-between.

I have a old Adaptronic 420d in a Corona with a 22re turbo, (currently set up on speed density) , but might play with some settings and see what I can and cant do in alpha n mode and weather it would actually work or not.

Thoughts?

 

[AirheadNut]

Very cool idea! Having put a few thousand miles on my VW TDI powered Prado I would suggest a couple of things. On the VW, the vanes are full open in a resting position (car off) but full closed (max boost) at idle or when coasting. Having the vanes closed on deceleration provides excellent engine braking; my little 1.9 boosts up to 10psi coasting down hills and slows the vehicle down better than the original 2.4 diesel.

However, when at idle the having the vanes closed fully means the turbo takes longer to cool off before shutdown, so a special shutdown setting that opens the vanes fully would be really nice.

I'm really curious to see what you come up with; this is something I have thought about in the past but I don't have anywhere near the know-how to execute it properly.

 

[macca1590]

Engine braking dose sound nice but I'm just a little worried about over speeding the turbo, however a lot of people run a set up like that and have no troubles so it could be just overthinking the situation or being scared after reading a few once off problems people have had. At coast there wouldn't be much heat/energy in the exhaust so it probably wouldn't drive the turbo that much I suppose.

Yeah its just wild idea for now but could work with a bit of tinkering, sure a custom set up arduino or something might be best but that's out of my league haha