Any updates on cat deletes and tunes for the 790?

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

  1. doctorblanco

    doctorblanco Adventurer

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    On various 790 Duke forums, there is lore that KTM "designed this engine around having a cat, and removing it will decrease power", which of course strikes me as rubbish: the cat impedes exhaust flow and numerous tests have confirmed that exhaust restriction doesn't necessarily increase torque.

    I know that Coober has a tune for the 790 Duke. I have spoken to the Rotweiller guys and they are preparing a Power Commander tune for the 790 Adventure.

    I see that Arrow and others have made a cat-delete mid pipe.

    What I would like to know is if there is some consensus around the best route for cat removal and the required tune.
    #1
  2. chippertheripper

    chippertheripper motorcycle junkie Supporter

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    Coober and Rottweiler would be the two I’d wait to hear from, for sure.
    At least one person here’s ecm will have the rotty tune, so I’d wait to see how his masterpiece turns out.

    There’s no tunecu type solution yet for this like the lc8.
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  3. gearheadE30

    gearheadE30 @LC8Adventures Supporter

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    KTM did design the engine around having a cat, just like all other modern bikes. What it means is that removing it will exacerbate an already very lean calibration, however if the calibration can be updated as well then it should be safe to do. If nothing else, it's a reduction in weight and heat.
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  4. doctorblanco

    doctorblanco Adventurer

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    Gearhead, agreed on all fronts, the engine is certainly designed around Euro 5 emissions compliance. What I intended to convey was that other posters believe even with a midpipe and a tune to correct AF ratio, the engine will make less power than with the cat -- which I find very hard to believe.
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  5. sunnyside

    sunnyside Adventurer

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    I installed the cat delete pipe. The reason I wanted one was to get a better sound. When ridding i can't hear the motor over the wind. Plus i like the sound of a big bore roar. I can confirm the sound is awesome and the power has been dropped from the whole rev range. Power is no good at all. I cant even get it sideways around corners. The traction on these bikes are great, but when it's underpowered you cant even spin the rear with this pipe. So I got home and put the cat back on. I still wouldn't mind knowing how to get a nice note from the bike.
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  6. braaap!

    braaap! Long timer Supporter

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    Likewise @sunnyside ... even with the Akra, the engine note is tame and doesn't emit quite enough 'Bark'. I don't want onbnoxious Bark but would love to hear the motor above the wind noise.

    We're all awaiting further developments from the team at Rottweiler Performance... Believe that they're making inroads on the dyno with good results. Patience :)
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  7. TrailTrauma

    TrailTrauma Nemophilist

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    Can I clarify one detail?

    What Throttle Response setting were you in? Because based on what you're telling us, I would want to know how Rally Throttle Response performed. When it comes to breaking the rear loose Rally ThR rules. That and TC ~1.
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  8. Noyah

    Noyah poser

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    I been using de-cat for 8 000km and what you say does not compute.... at all.
    Yes you loose some punch (perhaps) at 4k rpm but at 6k and up its a spaceship and no power loss whatsoever, unless your lugging about in 50km/h in 5-6th gear obviously?
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  9. sunnyside

    sunnyside Adventurer

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    Rally and turned TC off. I tried all options.
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  10. sunnyside

    sunnyside Adventurer

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    I think the majority of the power loss is exactly where you can’t afford to loose it.
    Maybe it’s the pipe I was using that made it worse than yours. I’ve Sean different designs out there but I think you can’t afford to loose any low rpm power on these bikes, it takes away the fun factor.
    #10
  11. TrailTrauma

    TrailTrauma Nemophilist

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    I'm going this route. Thinking a shitty Coors Light might produce a nice light note, but a Belgium Blonde or Stout might give me that deep rumble I'm after! Sahweeeeeeet :rofl

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  12. sunnyside

    sunnyside Adventurer

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    It seems it might be the only possibility at the moment. Bourbon and coke for me. It’ll give that bouuur it needs.
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  13. ShaftEd

    ShaftEd Long timer

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    Here is a bit more data. My buddy who has a 790 R has the Coober kit with Wings exhaust, cut out airbox lid and the Coober addon ECU. Bike runs great compared to my bone stock R. He wanted to try decat and bought one of the cheapie Chinese mid-pipes, but was concerned about running too lean. He actually took the bike to a local shop and dyno'd before and after cat removal. Bike still had Wings, Coober ECU, and airbox lid. Just testing cat vs no cat. Unfortunately, he didn't get dyno printouts. The printer was down. Anyway, basic info was that the bike made slightly more HP from 4k to redline without the cat. Really only about 1 hp, but the torque in the middle was at some points 7 ft lbs better. However, at 4k rpms his AFR was 16 to 1. That is not safe. By 5k it was down to a safe 13.8 and stayed that way the rest of the way through the rev band. He put the cat back on. Seems the only safe way to decat is bypass the stock map and 02 sensors and run a completely new custom map. i.e. PCV or some other remapping device.
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  14. ramirin

    ramirin Ready to push

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    I think there's 3 reasons to decat:
    - Gain more power
    - Make it sound better
    - Remove signifigant heat source from the area where heat is absolutely not needed

    Extra weight down there should be a minor issue and what I've heard cat is not too heavy.

    For me it has enough power.

    I would surely like to hear the motor over wind but I can live with that.

    :kboom But the heat! I'm really concerned what happens with the bike in conditions like below - or when going from there to soft sand uphills where things get really hot and all those small pockets are filled with flammable peat.. Not to mention the nightmares I already have for burning down the woods with 790 leaving smouldering pieces behind..

    mopo.png
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  15. Nowwhat

    Nowwhat I'll Go Second... Super Supporter

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    Great info... poor Coober just getting slaughtered by facts.

    There are some graphs out there that show that lean spike right where your buddy had it... I think it is when the bike shifts from closed to open loop.

    Stock the bikes are too rich above 5k stock so his in spec A/F makes sense there too

    Would be interesting if he put the stock lid back on the airbox...

    I am expecting my graph to show significant hp gains across the board...the longer it stays at the shop the more hp they find hahaha.
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  16. ShaftEd

    ShaftEd Long timer

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    Nowwhat, I think you are right about the closed loop/open loop transition. Are you running complete new map with PCV and bypassing o2 sensors?
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  17. Tripped1

    Tripped1 Smoove, Smoove like velvet.

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    Assuming that its not an autotuning rig, you have to bypass the O2 sensors, or the ECU will run right over the mapping on the piggy back.
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  18. justinope

    justinope Long timer

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    I'm very close to pulling the trigger on the Sharon Exhaust over the other options on the market, especially now that it is in V2 format which looks much more refined / potentially quieter due to length, etc. I'd love to see at least 1 more glowing review though.

    I might just go for it then drop it off at Dynojet up the road here and see what happens :-)

    They're only a few minutes away from the office after all..
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  19. Nowwhat

    Nowwhat I'll Go Second... Super Supporter

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    PCV ... map and Auto tune...
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  20. Roadhawg011

    Roadhawg011 Been here awhile

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    So decatting these things (without doing anything else) is a bad idea?

    I haven’t bought one yet but but I would definitely like more noise if I do.

    I struggle to see how the ECU can’t compensate for the extra O2 though.
    I live at fairly high altitude around 5800ft. Many places adv bikes go are much higher than that. The ECU needs to cope there and at sea level. Just from me to the coast is a difference of about 15% oxygen (more at the coast obviously). Surely that’s a MUCH bigger change than just removing a CAT?
    #20
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