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Unraveling the 961

Discussion in 'Norton Motorcycles (Modern)' started by iwilson, Mar 11, 2019.

  1. iwilson

    iwilson VIP MEMBER

    Joined:
    Nov 6, 2015
    I'm going to try and avoid writing a novel here. ;)

    As some may know my bike has a programmable SCS-Delta 400 ECU installed in place of the factory SC unit (it's made by the same company, requires no modification to the loom, it simply plugs straight in). The bike was returned to me a few weeks ago after being mapped on a dyno. The tuner wasn't happy with the idle - but tuner time is expensive time, so I figured how hard can it be....

    Anyway after much digging, replacing of bits, multi-metering and trying to decipher the techno babble language that's the instructions for the ECU - I have made some progress I think worth sharing.

    First a picture...

    [​IMG]

    This is my bike currently!

    The big discovery I've made goes like this. Most of us who have checked our plugs will find one is darker than the other. Most of us also know that our bikes can at times behave like Prma Donna's when asked to idle nicely.

    Why is this? I believe I have the answer. With the ability to see what's going on inside the ECU and investing in a LM-2 dual channel wideband o2 controller with twin bosch 4.9 WB o2 sensors I can monitor the AFR of each cylinder simultaneously.

    Norton have mentioned at idle one cylinder will steal fuel from the other via the shared IAC pipe that connects both throttle bodies together. My investigations show cylinder 2 is not just stealing - IT IS COMMITTING DAYLIGHT ROBBERY! Norton said cylinder 1 robs No. 2, but my testing showed it's the other way round - but hey maybe they take turns!

    I know this because I can see the simultaneous AFR for each cylinder and if I add fuel to the lean cylinder's fuel injector it's the other cylinder that gets richer (and no I didn't get my cylinders confused)! The factory is required to sell its bikes with o2 sensors and this creates a problem. The o2 sensor looking after the lean cylinder keeps asking the ECU for more fuel, which of course goes to the other cylinder. The rich cylinder asks for less fuel which the ECU tries to trim until it runs out of adjustment. I know this because I 'switched on' cylinder 1's o2 sensor and watched on my laptop as the ECU added fuel until it ran out of adjustment.

    This can lead to one plug getting fouled (right hand cylinder) or at least darker than the other. If your bike spends a small amount of time at idle relative to normal running it won't be so apparent. Remember this is just an idle issue, once the throttle is opened up the IAC is out of the picture.

    This knowledge validates Richard-7's approach of blocking off the IAC pipe and instead setting the idle using the DO NOT TOUCH throttle position screw to crack open the throttle butterfly's just enough to achieve a stable idle. It's not perfect as you will get some fluctuation depending on engine temperature but you could argue it's better than doing nothing at all. There are other approaches I'm looking at but unless you have a programmable ECU they probably won't be helpful.

    I haven't finished fiddling around by any means, the fuel injectors are currently away being cleaned, flow rate and pattern tested (I expect there is nothing wrong but I want to make sure the bike is operating from a known reference point). To this end, it's got new plugs and the generic coil pack has been replaced with a bosch. For ease of fiddling the airbox has been removed and the throttle bodies have individual cone filters. This could make a difference so I'll be re-testing when the injectors are back in and the airbox refitted.

    My tuner has agreed to another mapping session once I've finished - I can't explore individual cylinder fuel trims under load without a dyno. In terms of where the engine ended up. The following graph shows the factory megaphone map compared with the current map.

    [​IMG]

    btw, these ECU's are incredibly complex with literally hundreds of settings! All to simply get a spark to ignite the right amount of fuel at the right time!
     
    Clive, pingu-nz, TonyA and 5 others like this.
  2. ntst8

    ntst8 VIP MEMBER

    Joined:
    Feb 14, 2004
    Impressive piece of work, looking forward to the updates.
    Presumably the cylinder which is 90 degree's ahead is the thief?
     
  3. richard-7

    richard-7

    Joined:
    Feb 24, 2014
    Great stuff.
     
  4. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Very impressive. I had not heard about one cylinder robbing the other, but it makes sense. I've played with the IAC settings in the ECU a bit, and had no improvement. The IAC doesn't seem to be performing the way it is advertised to, and I haven't been able to sort it out. I think I might just remove it.

    Ken
     
  5. comet

    comet VIP MEMBER

    Joined:
    Aug 23, 2016
    Excellent information.

    Are the changes you are making only achievable with the fully programmable ECU or could it be done by unlocking the factory ECU?
     
  6. kommando

    kommando

    Joined:
    May 7, 2005
  7. ntst8

    ntst8 VIP MEMBER

    Joined:
    Feb 14, 2004
    The obvious question now is what do the other manufacturers of 270 degree twins do so that they don't have this issue?
     
  8. kommando

    kommando

    Joined:
    May 7, 2005
    I would put an adjustable valve in the IAC pipe controlled by the ECU and vary the opening with revs and throttle position values.
     
  9. iwilson

    iwilson VIP MEMBER

    Joined:
    Nov 6, 2015
    These days they use electronic throttle control - Triumph calls it ride by wire. No need for an IAC valve. No throttle cable, the ECU instead decides how to adjust the throttle based on its programming and rider input. I’m not a fan as often ‘computer says no’, just when I need it to say yes!

    But I’d say it would be something that could be designed out. But please bear in mind I haven’t finished fiddling and despite my results something could still be amiss with either my testing or bike. However I see evidence from other owners that would seem to support my observations so far. I plan on making a video showing the testing process once the bike is back together.

    I can get a good idle by switching off the o2 sensors and tuning cylinder 2, but I don’t know if my map would work as well in someone else’s bike. In any case most bikes have OMEX ECU’s now.
     
  10. kommando

    kommando

    Joined:
    May 7, 2005
    Boeing are finding out about the issues with duff sensors and fly by wire currently.
     
    Britfan60 likes this.
  11. worntorn

    worntorn

    Joined:
    Dec 22, 2006
    The ride by wire on the Triumph 1200 works great ( so far) . I can't fault it, uniform startup and idle every time. Throttle response is perfect , as far as my crude human sensors can tell.
    The only time the power is cut back noticeably is when there is wheelspin , which saves the rider from going down( TC)
     
  12. TonyA

    TonyA VIP MEMBER

    Joined:
    Jan 16, 2015
    Hello Iwilson , Those are some GOOD gains ! Maybe running the clamp on air filters will help even more . A + 5HP gain and + 6 ft lbs , with a good spread of torque . Very very nice work Sir.
     
    Last edited: Mar 12, 2019
  13. iwilson

    iwilson VIP MEMBER

    Joined:
    Nov 6, 2015
    Problem is Glen that the ECU is not programmed with just your needs in mind. It's also programmed to obey the law with regard to emissions and whatever else they decide to do - the VW scandal is a classic example. I see it in my wife's diesel Merc. I don't dare try and nip across an intersection, since putting your foot down does not have the anticipated effect of actually moving! Instead the ECU tries to minimise any unburnt diesel escaping resulting in close to a seconds delay in much happening! Yes there are some positives and it will get better over time. But reading the news about the two recent Boeing 737 crashes possibly caused by a fly by wire system gone wrong is disconcerting.

    My own experiments with the o2 sensors show rather crudely what can go wrong when the ECU gets information it can't deal with.
     
    Britfan60 likes this.
  14. iwilson

    iwilson VIP MEMBER

    Joined:
    Nov 6, 2015
    Pretty happy with where we're at. I don't think the air filter has much to add. The gains in changing to a 'less restrictive' design are generally overstated by K&N's etc marketing department. I've found they're more of a sound upgrade than a power one. Designing a better air box however is a different story, but you'll need a passion for fluid dynamics.

    For e.g. https://www.researchgate.net/public...ent_for_Modenas_model_by_geometrical_analysis

    With the 961, I suspect the design was dictated by the available space and looks rather than the laws of physics - which is fine it's not supposed to be bleeding edge high performance engine and I'll take the good looks everyday!
     
  15. jan nelder

    jan nelder

    Joined:
    Feb 18, 2018
    or in their case, NOT fly by wire. I suspect there is a very significant problem there, which Boeing is making very little public comment on so far, which I take as a bad sign.
     
  16. swooshdave

    swooshdave

    Joined:
    Apr 15, 2009
    They can't comment until they know something or can say something.
     
  17. worntorn

    worntorn

    Joined:
    Dec 22, 2006

    This Triumph ECU is not working properly then. I keep getting speed warnings and tickets, the damn bike just won't obey the law!
    :)
     
    iwilson and Eljahara like this.
  18. Britfan60

    Britfan60 VIP MEMBER

    Joined:
    Jan 5, 2014
    No too many diesels I would try to nip across an intersection in. The response is just to slow. And Kommando beat me to the Boeing comment.
     
  19. ntst8

    ntst8 VIP MEMBER

    Joined:
    Feb 14, 2004
    Petrol VW's are similar, and the auto engine cut off often decides to do its thing just as you are about to floor it, which adds another 1/2 second or so to the get go timing.
     
  20. iwilson

    iwilson VIP MEMBER

    Joined:
    Nov 6, 2015
    If you switch the ECU into sport mode there's no hesitation at all. But it switches back to ECO mode by default when you turn the engine off.
     

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