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SD 2 bar tuning question

Practical Reflash Tuning

Discussion and questions related to the course Reflashing


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My question is a bit long so please bare with me ...So at 9:20 when we’re in the SD Eq error histogram we have to drive through as much as possible of the table up to 80 kpa to calculate the error between the numbers we copied from the VVE of the original file and the current measured afr to do the calibration and then do WOT ...

But what happens if I choose to have 2 bar SD and calculated my MAP for 200 KPA instead of the 100 KPA you set up during ( configuring base tune file ) step ... then the Numbers we’v got from that VVE won’t cover the whole table since now we’v extended it to boost so we end up with a relatively big empty area !

so will the ECU use the boost PE targets in those empty areas ? or we will have to run the engine through the transition area and through them ?!

What’s the proper way to go around this ?

Maybe Tune up to 80+ KPA and the ecu will use PE in 100 kpa transition area , and then the ecu will use boost PE values ? Or I have to creep on those empty areas of the table slowly ? or maybe extrapolate the last Column VE values before doing so ?

I’m pretty confused here :/

Also will the PE throttle/ pedal table affect when we go to PE mode here , therefore while doing the calibration I have to max it out so the ECU won’t go PE unless I’m Full throttle?

or PE won’t kick in if I go slow on the pedal?

Appreciate the help

what engine, what vehicle, what mods are done to it?

Hey Raymond . I’m not working on a particular car . I was just watching and studying the lesson but I’m mostly interested in GM vehicles that’s why I got curious because if someone would do the SD patch I assume the main reason would be to turbo charge the engine and add boost so ... my question was regarding the lesson example . so let’s assume it’s the same HSV but with a turbocharger

Ok. Are you assuming a GM vehicle that didn't come with factory forced induction and has something added on, or are you talking about something that came with factory forced induction? For example, the various 2 liter turbo engines (Camaro etc) already have a complicated algorithm to control boost, throttle, and spark, and to calculate airflow and enrichment. It's totally different from shoe horning in a turbo on an LS1.

If you're running a 2 bar SD tune then the best way to start is by extrapolating the shape of your VE table out into the higher boost areas of the table. You're unlikely to get these numbers right but we're just taking an educated guess so that the VE table is populated with data so we can begin using the histogram to fine tune the VE table. Also it's important to understand that in a boosted application the VE doesn't just climb indefinitely with more boost. The manifold pressure is taken into account inside the ideal gas law calculation and it's common to see the VE numbers plateau and even drop away as boost increases.

I set the ECU up to transition into PE around 100-120 kPa since I don't really want to be running a boosted engine at stoic. We can then basically complete the tuning using the histogram in three chunks. First the closed loop region up to 100 kPa. Secondly the transition area where we are in PE, and third our WOT ramp runs where we are also in PE. This should let you access and refine the majority of the VE table.

PE mode is affected by the pedal position but there are also other parameters that are based on MAP so you can use these to refine when PE is entered.

Thank you .