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Thread: G8 LSA no PE enrichment in dynamic air

  1. #21
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    Quote Originally Posted by hjtrbo View Post
    Here is a screenshot of my old factory PE settings to demonstrate what I mentioned above. You can see I have blown well into boost by the time PE lands at 0.8 Lambda. This was with MAP set at 75kPa and PE TPS at 15. Cylinder air mass spikes up early with the shot of PD boost when the throttle blade snaps open.

    Attachment 107212

    I'm not a tuner but I am of the opinion it is important to snap the throttle open at low rpms locked in gear to see how PE and transient fuelling is going on PD blower cars
    Your experience is quite different than mine in the couple of ~525-550rwkw LSA cars I've done. Different strokes for different folks

  2. #22
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    Quote Originally Posted by 1 Slow GTO View Post
    Enlighten me on how you plan to do that in a pd blower vehicle, without boost enrichment, and without burning a tank or more of fuel and a bunch of hours datalogging?

    When you're done with that, explain how doing it that way makes any difference in how the vehicle drives compared to setting MAP enable to 95kPa (where I usually set stuff that gets part throttle boost), and what the customer will notice that makes doing it that way worth all the time you spent on it when you could have already been working on something else.

    I'm also curious what your MAP/RPM/TPS cutoff is for where n/a stuff "needs enrichment" when not at WOT, as well as what boosted vehicle you've dealt with that you felt needed enrichment under 95kPa, and/or was below 95kPa when you hit PE enable TPS.
    mine sees PE at about 35% tps (78kpa) and BE at 43% tps so works out well and it dosnt have to be full enrichment can ramp it in, adding some fuel adds torque so if u have it come in a little more in the mid load u can gain some torque, map is slower then a tps enable as tps is the first to move above all other settings which can be good for PD instant boost, think i brought in map once as i found i went into PE to early so i just lifted it up a little but i dont like the map alone as the main trigger, each to there own tho my way works for me u can keep doing it your way if it works for u, my initial comment was just trying to help people find more torque by setting it a little lower then 100kpa

  3. #23
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    PE enable settings are always setup dependent. You stick a PDS blower on a LS3 or L76 decent compression engine you want PE on under loads above 75-80kpa. Otherwise you'd just run stoich all the time when it was NA... not the case.

    The lower compression LSA and LS9 engines can tolerate stoich ratios at a higher load due to the lower compression. 120kpa on a 9:1 motor is still probably less cylinder pressure than a NA 11:1 LS3 at 98-100kpa. It's all heat control, enrichment is for pulling heat out of the chamber.

    I take it a step further based on what the customers driving style is and will enrich even sooner if they are hard on stuff. This is also where the AFR spark correction comes into play. You can keep the PE delayed to 100+kpa but the leaner mixture will not tolerate as much timing as it will enriched. So in those instances you can add the spark advance back into the AFR spark correction table so timing whether it be knock limited or at MBT can be achieved under all scenarios. The fuzzy part about delaying though is you get that torque surge when PE kicks in because not only is it enriching fuel at heavy load which will make more power generally it'll also be getting a 3-4+deg bump in timing.

    For smoothest operation enriching early dampens down that torque increase and will give a much more pleasant feel on the street.
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  4. #24
    Senior Tuner LSxpwrdZ's Avatar
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    To answer OP question you need to calibrate both MAF and VVE separately or together with it only in MAF mode. You can't calibrate two airflow models when they are blended. How do you know where the airflow source is coming from in a blended state?

    The VVE needs work as that is not what the table will look like once calibrated.
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  5. #25
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    Quote Originally Posted by hjtrbo View Post
    You'll find after you burn a tank of fuel and a few hours logging that MAP alone is no good for PD blower cars. I have found many times by my own testing of these PE settings that by the time the MAP setpoint (factory was 75kPa) is met and the PE ramps in and the fuel catches up that I am well past 120kPa.

    It takes a combination of TPS and MAP to keep fuel economy and make it always in PE above say 85 - 90kPa.

    Here are my settings for example. E67 470rwkw LSA

    Attachment 107211
    Pretty sure your screenshot is showing that you are using MAP only as those numbers in your TPS table are triggered long before 75 kpa.

  6. #26
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    Quote Originally Posted by hjtrbo View Post
    Here is a screenshot of my old factory PE settings to demonstrate what I mentioned above. You can see I have blown well into boost by the time PE lands at 0.8 Lambda. This was with MAP set at 75kPa and PE TPS at 15. Cylinder air mass spikes up early with the shot of PD boost when the throttle blade snaps open.

    Attachment 107212

    I'm not a tuner but I am of the opinion it is important to snap the throttle open at low rpms locked in gear to see how PE and transient fuelling is going on PD blower cars
    You also need to realize there is a delay from when you get into PE and when your WB actually reads the fuel

  7. #27
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    Quote Originally Posted by LSxpwrdZ View Post
    To answer OP question you need to calibrate both MAF and VVE separately or together with it only in MAF mode. You can't calibrate two airflow models when they are blended. How do you know where the airflow source is coming from in a blended state?

    The VVE needs work as that is not what the table will look like once calibrated.
    Because at steady state the airflow source is exclusively MAF. You really don't want this to be true do you

  8. #28
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    Quote Originally Posted by smokeshow View Post
    Because at steady state the airflow source is exclusively MAF. You really don't want this to be true do you
    In the real world where people don't have nice eddy brake dyno's like me or you steady state doesn't exist street tuning. Get the SD model completely out of the way so it doesn't contaminate the data you are gathering. Pretty simple and literally two small RPM values to change to make it happen.
    James Short - [email protected]
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  9. #29
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    Quote Originally Posted by LSxpwrdZ View Post
    In the real world where people don't have nice eddy brake dyno's like me or you steady state doesn't exist street tuning. Get the SD model completely out of the way so it doesn't contaminate the data you are gathering. Pretty simple and literally two small RPM values to change to make it happen.
    In the real world, the VE is the last thing that's going to cause issues with replicating steady state. After all, as you know, the air mass calculation is a filtered value. So it can't respond too quickly. It is the actual (real world) dynamics that cause the vast majority of the issues...transient fuel being the biggest violator here. Barring those actual complications, a set of decent filters in the scanner is plenty to filter out transient behavior. You're right, most people don't have dynos...and they also don't want to spend 6 months trying to dial in their fueling. This is simply a procedure for the layman to use to both speed up the calibration process and actually provide a safety net when one model has a lot of error.

  10. #30
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    Quote Originally Posted by smokeshow View Post
    In the real world, the VE is the last thing that's going to cause issues with replicating steady state. After all, as you know, the air mass calculation is a filtered value. So it can't respond too quickly. It is the actual (real world) dynamics that cause the vast majority of the issues...transient fuel being the biggest violator here. Barring those actual complications, a set of decent filters in the scanner is plenty to filter out transient behavior. You're right, most people don't have dynos...and they also don't want to spend 6 months trying to dial in their fueling. This is simply a procedure for the layman to use to both speed up the calibration process and actually provide a safety net when one model has a lot of error.
    Can you provide the filters you use to filter out transients?
    Thanks!