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  1. #51
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    3 out of 3 members liked this post. Yes Reputation No
    Could not help but to comment here. I have been pro-tuning Subaru and Mitsubishi for a few years now, both of these platforms offer opensource and free tuning software to go with the Cobb AP. Our shop will tune a customers car however they would like. We have customers that just want the Cobb off the shelf tunes. A Cobb unit sells for around 600-800 a custom tune from us is around 200. Cobb still sells 100s of units a month to that crowd. So the statements about Cobb or BMS being out in the case of opensource or free tuning is nonsense and it has been proven wrong already. Even Cobb knows this or they wouldn't hand out free tuning software...

    In terms of this thread...I have tuned a lot of different ECUs and they all seem to approach things differently. Mitsubishi EVO is all load based tuning, unless things are hacked up boost targets are based on a calculated load only. Subaru bases many tables on load as well however with boost maps they do acknowlege actuall manifold presure and will follow set targets based on pressure not load. Just using this as an example to say that even the engineers building the tunes at the factory seem to dispute load targeting vs boost targeting.

    Personally I prefer boost based targets when tuning, but only for the fact that the average customers seem to care WAY more about target boost then load. From a personal perspective I prefer load based since while tuning thats what we are really looking for is good sustainable load numbers.

    Keep in mind boost in not a constant on a motor like a calculated load factor can be. 15 PSI on a stock turbo has less input/output then 15 PSI on a modified or larger turbo. Load which is in some cases based on per rev airflow numbers (Subaru anyway) makes more sense and better represents output based on input. Its also a hell of a lot easier to understand what loads break things vs what PSI breaks things.

  2. #52
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    In my humble opinion and based on my experience you can call the tune targeting whatever you want but the ECU works on a torque relationship regardless what the boost is. You can tune the car for boost but have to adjust the torque targets so you can avoid engine check lights. There are certain points in the torque range that there are further fail safes put into place. The first one is at approximately 1.19bar where the car measures 600nm of torque, thereafter there are a few more. It is no coincidence that most commercially available flashes have been pegged at 17psi.
    A while ago the engine fault trigger maps where leaked with various faults that could be deleted completely and this in my opinion has opened a pandoras box.

  3. #53
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    2 out of 2 members liked this post. Yes Reputation No
    I am hitting 18-18.5 psi with cobb stage 2. So I guess the over came those limits.

  4. #54
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    Click here to enlarge Originally Posted by 2nr1 Click here to enlarge
    I am hitting 18-18.5 psi with cobb stage 2. So I guess the over came those limits.
    Or the fault code reference has been erased although I do not think a outfit like cobb would do that. It will be interesting if someone like Dzenno could log the torque outputs on a BT tool and see what numbers the ECU is seeing.

  5. #55
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    Click here to enlarge Originally Posted by George Smooth Click here to enlarge
    Or the fault code reference has been erased although I do not think a outfit like cobb would do that. It will be interesting if someone like Dzenno could log the torque outputs on a BT tool and see what numbers the ECU is seeing.
    FWIW there is a problem with their logging reporting maybe 30% lower boost values at higher RPM based on the TMAP input so I think it's easy to guess how they have modified the mapping for more top end boost. It's a very piggyback like approach. Fudge the sensor values. Click here to enlarge

  6. #56
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    Click here to enlarge Originally Posted by 2nr1 Click here to enlarge
    I am hitting 18-18.5 psi with cobb stage 2. So I guess the over came those limits.
    Then why isn't it available to the public?

  7. #57
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    Click here to enlarge Originally Posted by Terry@BMS Click here to enlarge
    FWIW there is a problem with their logging reporting maybe 30% lower boost values at higher RPM
    Why? 30% is kind of a large margin of error, way too large.

  8. #58
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Then why isn't it available to the public?
    Because it is in beta. There are some logging issues still to be resolved. Overall my stage 2 drives like a dream.

  9. #59
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    Click here to enlarge Originally Posted by Sticky Click here to enlarge
    Why? 30% is kind of a large margin of error, way too large.
    The approach is probably what all the other flasher tuners do for more top end boost. But that they forgot to fix the logging offers some speculative insight in to what they are doing on the back end.

  10. #60
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    Click here to enlarge Originally Posted by Laloosh Click here to enlarge
    Because it is in beta. There are some logging issues still to be resolved. Overall my stage 2 drives like a dream.
    Just feels like a long time already.

  11. #61
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    I think the procede has been in beta for over a year, its pretty much an excuse they use when $#@! doesnt go right. These stage 2 maps are released to a couple of people, its not open to the community, so it will take longer to finalize.

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    Click here to enlarge Originally Posted by Laloosh Click here to enlarge
    Because it is in beta. There are some logging issues still to be resolved. Overall my stage 2 drives like a dream.
    same!

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    1 out of 1 members liked this post. Yes Reputation No
    Click here to enlarge Originally Posted by Bash Click here to enlarge
    laloosh please direct me to those places selling for 750 im in the market for one, cant get better than 895$
    Contact Sal at Autocouture motoring (http://autocouturemotoring.com/?page_id=26) and let him know that "Kamal" sent you in search of the best price. He supplies many of the vendors that claim they have the best price.
    Click here to enlarge

  14. #64
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    Click here to enlarge Originally Posted by Kamal Click here to enlarge
    Contact Sal at Autocouture motoring (http://autocouturemotoring.com/?page_id=26) and let him know that "Kamal" sent you in search of the best price. He supplies many of the vendors that claim they have the best price.
    I see this Sal fellow browsing from time to time.

  15. #65
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    Sorry to bump an old thread, but I did a search and couldn't find the exact answer I was looking for and I thought this thread was the closest. Can someone explain load versus boost targeting with the N54? Boost targeting seems pretty clear (it targets a set psi through the rev band?), but what exactly is load targeting? With two years from when this was last posted, has Cobb officially changed what they target?

    And one final question - how might load vs boost targeting vary at altitude (say 6500ft ASL)?

    Thanks,
    Rich

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    A while back Cobb described the load target as more of a "load limit" and that may make a lot of the older discussion in this thread obsolete. The boost target can be set independent of the load target/limit and as long as you don't go too far over either one everything works nicely. The trick is getting the wastegates to act the way you want by default so that everything stays a little under the limits without the boost control system having to react too much.

    I'm also at relatively high elevation and we do have some unique issues that make our ideal maps a little different than everyone else's.

    But to address your original question, load is usually defined as the air mass entering the motor per revolution. So it correlates to torque all the time and boost most of the time, as opposed to horsepower which correlates to air mass entering the motor per unit of time.

  17. #67
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    Load Targeting is used to try to keep the car running in a manner that feels the same to the driver in any condition. If the target load is the equivalent to 300HP the DME will adjust boost according to the environmental conditions to overcome temperature and altitude changes that would normally affect power output. Tuning issues appear when the Load Target is upped and the turbo's are reaching the limit and maxing out the duty cycle that the DME will allow. It's a lot easier to tune for a specific PSI than to keep tweaking things for the Load Targets, but in the end in the hands of a proper tuner the results should be about the same.
    2008 135i - Cobb AP, JB4 G5 w/2Step&FSB, MS DP's, Berk street exhaust, AMS IC, VTT Inlets, UR Intake, ER CP w/Tial BOV, Spec 3+ & Steel FW, CDV delete, Quaife LSD, DSS Axles, M3 control arms, M3 rear SF bushings, M3 Trans bushings, SS brake lines. Pics

  18. #68
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    Thanks guys - very helpful. So does load targeting use additional levers besides boost (e.g. timing) to target the specified load?

    -Rich

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    1 out of 1 members liked this post. Yes Reputation No
    Click here to enlarge Originally Posted by richpike Click here to enlarge
    Thanks guys - very helpful. So does load targeting use additional levers besides boost (e.g. timing) to target the specified load?

    -Rich
    No, load is mass airflow per revolution. That's all. How much torque you make with that air mass can vary with things like timing.

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