Any updates on cat deletes and tunes for the 790?

Discussion in 'Parallel World (790/890)' started by doctorblanco, Aug 20, 2019.

  1. Toddv

    Toddv Long timer

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    My guess on the Arrow pipes bulge is that it's a solution that more closely mimicks the converter to eliminate tuning issues. The limitation that piggyback tuners have is that they have defined blocks and values of adjustment, at least all the ones I've fooled with. So say the factory exhaust setup requires a lean spot or bump in timing at a defined spot in the map due to it's design, then you change the exhaust (or any other hypothetical mod) that changes the dynamics so that lean spot/ timing bump is no longer required, it now needs a smooth fuel curve in that spot. So with a cracked or directly tunable ECM you can do exactly what you need but with a piggyback tuner you can only adjust the area contained in that particular cell by a positive or nagative value, so your basically taking a predefined segment containing the lean Spike and moving the entire thing toward the rich side which fixes part of it but makes other parts richer than they should be. Now it's not some massive section of the map in each cell but it can create difficulties, flat spots/hesitations in some situations that can't be entirely fixed. And that's all considering your in closed loop running off the map directly. Hopefully that makes sense... Open loop using the ECM's "auto tune" is a little different.

    I contacted Bren tuning to see if the 790 was on their radar and they said it wasn't but that they may look into it. They did offer flash tunes for the 1290. They are a top notch tuner, I had their tune in my 1299 and it turned a very refined bike into near perfection.
    #41
  2. TrailTrauma

    TrailTrauma Nemophilist

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    Thanks for the explanation. This is why I keep going back to Rottweiler's mid pipe - we should know that before we chose a new mid pipe IF we are to fully appreciate the tunes/performance he achieved with decat'ing. IOW's if he used an Arrow mid pipe which I suspect he did, and we use a straight pipe, perhaps we shouldn't share the same confidence in how well our bike will run, or whether we'll avoid lean areas here and there. I'm not a tuner, so I don't know if mid pipe differences make a bikes performance apples and oranges or golden delicious and granny smith ;)
    #42
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  3. Salzig

    Salzig Long timer

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    My guess on the Arrow cat delete pipe is much simpler: I'm italian and so they are :D

    I mean, IMHO they made the pipe so that it looks like the cat is still there.
    A straight pipe would not pass our biannual inspection.
    #43
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  4. Toddv

    Toddv Long timer

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    Good thought! It might be enough to fool them?
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  5. Salzig

    Salzig Long timer

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    I guess so.
    They also do exhaust fume analisys, but it's far from accurate.
    Last year my dirt bike passed the inspection despite me forgetting the choke engaged :lol3
    #45
  6. brianbrannon

    brianbrannon They'll ride up with wear

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    All ECUs use cells to set fueling whether piggyback or stock. It's not a limitation it's standard
    #46
  7. amschnellsten

    amschnellsten Been here awhile

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    Toddy is referring to blocked cells and the inability of some piggybacks to segment.
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  8. Toddv

    Toddv Long timer

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    Sorta... Stacking cells on top of cells that are not the same size does not give you full control of the map. I've seen factory maps and have spend a fair amount of time fooling with piggyback maps, they are not the same. All the factory/original maps that I've seen in comparison to piggyback controllers are adjustable on a much more precise (higher cell count) scale. So with an aftermarket controller you are probably adjusting 4 or 5 cells (just a guess) of the factory map at a time up or down, so if there is a feature on there that you really need to change or smooth out you can't, you can only move it around along with the section of map around it. It's rarely a big deal unless you are trying to work out a flat spot under a specific condition. I'm not a pro ECM tuner and my observations may not tell the whole story, but that's my experience.

    I've had to tune out factory flat spots with piggyback controllers using fuel and ignition maps and it can be tricky and requires some compromise. Especially when they do funky stuff with the timing to keep NOx at bay during tip in... Again, they will normally get the job done ok, but it's just not the ideal way to go at it. Not to mention the other things you can adjust once the ECM is cracked.
    #48
  9. brianbrannon

    brianbrannon They'll ride up with wear

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    Dynojet software has cells every 250 rpm. Do you actually think you need more resolution? You aren't riding an F1 engine
    #49
  10. Toddv

    Toddv Long timer

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    Sometimes it takes more control than a open loop only piggyback controller can provide if you want a properly running and efficient bike.

    If you're okay with either disabling closed loop and loosing the a self tuning ability of the ECM and the fuel economy/efficiency/flexibility that goes with it, or are only concerned with correcting the fueling above 80% throttle where the bike defaults to open loop (or wherever this bike does) and aren't concerned with tweaking anything else on the bike, a piggyback controller is where you should go. I'm waiting to see what else comes along before I go that route.
    #50
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  11. brianbrannon

    brianbrannon They'll ride up with wear

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    I'm not putting either on mine it runs fine. Just pointing out your incorrect information and unfounded prejudice against piggyback ECUs
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  12. Toddv

    Toddv Long timer

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    lol ok. A bit combative over the limitationss of piggyback controllers for some reason? What exactly did I say that was false? I missed that part... I'm not going to argue with someone that just wants to be right because they said so but if you have something to add I'm all ears. If not I'm done and you're free to have the last word...
    #52
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  13. Orfeas

    Orfeas Been here awhile

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    Arrow Decat is here:

    70B464BC-CA53-4504-A704-2C8009CE8053.jpeg

    Attached Files:

    #53
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  14. kubcat

    kubcat Been here awhile Supporter

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    That's the first pic I've seen of the inside of one of those bulges on a decat pipe. I had previously assumed that it was all smooth walled, with a diameter increase at the bulge, but now I see that there is a baffle in there. Clearly this is actually a "muffler" - maybe more accurately a "tuner" - since I would guess the primary purpose is to tune the sound of the output, rather than muffle it. Come to think of it, these days all mufflers should really be called tuners, because the OEMs really pay attention to the sound of the exhaust during the build process.
    #54
  15. Toddv

    Toddv Long timer

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    It does definitely look like it could fool the emissions inspectors...
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  16. TrailTrauma

    TrailTrauma Nemophilist

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    Is there a sound clip circulating anywhere which has the stock can but the Arrow decat? I suspect the sound is not as robust as a straight decat pipe with the OEM muffler, but if it's a phatter sound it would still be nice.
    #56
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  17. Bamboo Baby

    Bamboo Baby Been here awhile

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    Any Dongles available for the O2 sensors like on the 1290?

    My Rade exhaust will be here tomorrow.
    #57
  18. ramirin

    ramirin Ready to push

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    I haven't seen any. 790 would need smarter dongles to somehow keep it on the open loop all the time - not sure if it's even possible.
    #58
  19. Bamboo Baby

    Bamboo Baby Been here awhile

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    Thought so, thanks!
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  20. BobcatSig

    BobcatSig They call me... Huckajawea

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    I've read through this thread and the related cat/tune thread and I'm not quite clear. If I opt to decat my 790 and add a different silencer (WINGS, Arrow, Akro, et al), will I need a Power Commander? Further, when implementing this tune, will the OEM cruise control now be non-functional?

    If it's of consequence, my thought process for removing the cat is mainly heat and weight. Though I've read that the OEM cat isn't all that heavy. Therefore, it's mainly about heat radiating off the cat. Is that the case with the OEM unit, it's nuclear reactor hot?

    On my 690, the cat was the silencer and it about melted the plastics so I swapped it for a WINGS with great success. On my Ducati Multistrada, the cat was partly responsible for absolutely destroying the rear brake fluid and rendering the rear brake near useless. A full Termignoni system remedied that.

    For that that made the swap(s), what say you?
    #60