DW450 Larger injectors on 86 - dial in Ecutek values

Hello guys, somebody installed DW450 PI on 86? I have hard time to calibrate them. Manufacturer values are far far from true. I was able to calibrate it somehow, but it goes randomly +- 10% ltft (mostly rich) and it makes strange spikes on accelerator movements (transition enrichment?).

now i have 378cc/min

minimum open time 0.610ms

opening time compensations 8-9-12-14-16 V

2.7490000725 2.3285000324 1.2935000658 0.8192500472 0.5390000343

thx

Hi Jan, unfortunately with many factory ECUs their injector characterisation is quite basic and this is how Subaru deal with it. While you could rightly expect the DW flow data to be the number you'd use for the injector scaling number in the 86 ECU but this isn't the case. Generally with a Subaru ECU the final number will be around 10% lower than the actual stated injector flow so your 378 cc/min is in the ball park. Have you followed through the injector scaling module in the Practical Reflashing course? As the technique discussed is exactly how you want to go about this. Essentially you need to dial in the injector scaling under moderate rpm/load until your fuel trims are very close to 0%. Once you have that dialled in you can then check what happens at idle and very low rpm as this is where the latency values have more effect over the trims. If you're seeing the closed loop trims doing work at idle then you can address this by adjusting the latency settings. It's an iterative process but not that difficult.

Hi Andre, thank you for reaction. I went through Practical reflash/Injector calibration carefully. Well explained - but it is still kind of very iterative work moreover if one doesn't access to dyno :-) I found that in moderate load/rpm trims are something like -7.2 ltft +2 stft. So I would try to add another 5% to the injector flow scaling and try to run in same conditions. After that I try to correct latency settings in idle.

(1) Next question is what about transient conditions? Calibration values were lowered with bigger injectors (almost a half) but it still makes a lot of trims/AFR spikes everytime throttle is moved. Perhaps with combination of improper latency settings it is just a double problem.

(2) Last question - you mentioned about running car 100% PI - to be able to finetune injector calibration. Is it safe for car, if no fuel is flowing thru DIs? Otherwise is it safe to run car 100% DI in light load just to confirm, that MAF scaling is not out of ideal?

Adding two pics - one with closedloop fueltrims, one with transient conditions spikes.

Thank you

Hi Jan,

You may be over thinking the transient conditions as it is quite normal to see some spikes in AFR or trims during these conditions. What you should be more worried about is smooth operation with no hesitation or jerking during sharp throttle applications.

You can run the engine 100% PI (I've done it many times in our own car), but there is a theory that doing so for an extended period of time can over heat and damage the DI injectors. I haven't personally seen this occur but I can't say it's not possible. I generally only run the engine for short periods on pure PI and only at light load where there is less combustion heat. You can however run 100% Di with no ill effect and this will let you know if your MAF scaling is a problem.

Hi Andre,

I got really hard times to dial it in, but I handled it somehow. It is far from ideal but I was able to manage keep FTs within +-5%. I still go quite rich in highboost/rpm areas open throttle open loop. I'll decrease MAF scaling in this area little bit.

Since I know more, how it works in general I will do another iteration from the start again. I will put standard port injectors in again, recalibrate precisely MAF, change injectors and finish the fine-tuning. And I am considering to buy some dyno time, believe it will be much easier to tune. Believe it will be well spent money and great experience.

Thank you for your work and your super-unique content you created!

Hi Jan, good to hear you're making progress. It's definitely easier to start with the stock port injectors so that you can get on top of any required changes to the MAF scaling first and foremost. Good luck with everything.