Open Loop or Closed Loop...?

Discussion in 'Engine, Fuel and Exhaust' started by VMGR252Nav, May 11, 2011.

  1. VMGR252Nav

    VMGR252Nav Member

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    Did a good bit of searching through the numerous threads on this topic and got a lot of bits and pieces of very helpful information but couldn't find anything that addressed my question exactly. Apologize if I missed something and thanks in advance for pointing me int the right direction.

    Riding a 2011 FLHX with the 103 Power Pak. Already installed V&H big shots and the HD heavy breather. Still running great but only have about 500 miles right now. Am debating which fuel management strategy to go with and am on the fence with the Dobeck TFI.

    What bothers me is the Dobeck approach of bypassing the O2 sensors. I may be a bit dense but I am not getting the logic behind doing so. I could understand the benefit of the manual tuner before the O2 sensors were there. Seems to me that bypassing them would be discarding data that should support automatically making the tuning adjustments based on actual conditions. I am certainly no expert but have been reading about closed loop vs open loop. Am I missing something?
     
  2. Hoople

    Hoople Account Removed

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    That is exactly what you want to do. You need a way to take away the ability of the ECM to make changes based on exhaust sampling.

    The TFI does not instruct the ECM on what mode to run (open or closed),, so if you were to leave the O2 sensors hooked up, both sensors would see the exhaust richer than stoich (~14.5) and the ECM would then shorten the pulse width of the injector which is the opposite of what the TFI is doing to start with.

    The net result would be "no change" in the way the bike performs after installing the TFI because the ECM would just take away any added fuel the TFI injected.

    BTW,, I don't know what a 103 "Power PacK" is, (maybe it's a download of some kind? I don't know) but I would not be waiting too long before I added some kind of fueler. My calculations say your in the Red zone right now.
     
  3. VMGR252Nav

    VMGR252Nav Member

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    Thanks Hoople.

    PowerPak is a factory option package including 103 engine, security and ABS.

    I do understand that the TFI would not be effective with the O2 sensors hooked up. Not suggesting to do that at all.

    Am looking to get thoughts on the pros/cons of open loop vs closed loop systems. Had the Terry Components Terminal Velocity closed loop system on my previous bike.
     
  4. BUBBIE

    BUBBIE Well-Known Member

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    What was the cost of that system?? and How does, did it install?

    Did you have it checked for Fuel ratio on a dyno using that system? and If So what were the numbers please.

    signed....BUBBIE
     
  5. VMGR252Nav

    VMGR252Nav Member

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    TV system was expensive at the time ~$400. Didn't have the quick connect plugs and I had lots of splicing into ECM bus and fuel injectors. Pipes already had the O2 port. Newer ones are still expensive but are much more plug-n-play.

    Never did a dyno because all was running well. Clean plugs, cool temp and no decel popping.
     
  6. Hoople

    Hoople Account Removed

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    Need to be more specific.
    The phase "closed loop" just means the ECM has some sort of feedback information to base it's future decisions on. The feedback can be in the form of narrow band (it's rich or it's lean switch control) or wide band (how much rich or how much lean control). So....

    Open loop vs narrow band closed loop
    or
    Open loop vs wide band closed loop

    If you mean wide band vs open loop, see Auto Tune - Harley Davidson Community
     
  7. BUBBIE

    BUBBIE Well-Known Member

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    I thought decel popping was controlled by HD's ability to shut off the fuel on OFF throttle on the newer bikes???

    Dobecks HAS a new system that will Blow the Socks off the HD community with a New Plug and Play device that uses the infra red into the 02 hole in the front pipe to Do its' magic... Stay TUNNED and you can read about it here ON HDT .com..

    signed....BUBBIE
     
  8. Hoople

    Hoople Account Removed

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    Bubbie, I thought the new unit Chopper was testing was just an "On Board" wide band air/fuel ratio meter. Something that allows you to see what you a/f ratio is under "street dyno" conditions. Is there more to this new product or are we not talking about the same item?

    Is it integrated into a fuel controller?
     
  9. VMGR252Nav

    VMGR252Nav Member

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    Look forward to hearing more about this. Any idea on timing?
     
  10. BUBBIE

    BUBBIE Well-Known Member

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    ****************
    Choppers Quote:

    Here's a short of what I've written on my face book page so far:
    Mark Dobeck CEO of Dobeck Performance called me about a month ago and asked if I would be interested in letting him install a new tuner he has been developing on one of my customer's bike for testing, this tuner is not on the market yet but I'm sure it will be in great demand once it is. It installs a wide band 02 sensor in the front pipe and replaces Harley's useless air temp gauge with something the rider can use, a AFR Gauge telling the rider what his air fuel ratio is in real time while he's riding. The tuner itself is totally programmable and upgradeable using a infrared sensor built into the AFR Gauge, uses Dobeck's load base technology and the AFR Gauge has control buttons that allows the rider to adjust the air fuel ratio alongside the road, once adjusted you shouldn't have to mess with it unless you change air cleaner, pipes or maybe just want to fine tune your fuel mileage a little. It was quite the honor to have the legendary Mark Dobeck at Chop's Garage installing something so cutting edge and then having one of my customers be one of the first to try it out. Unfortunately, being a one man show and slammed with work, I haven't really had proper time to play with the unit much yet, but I am certainly making time the first part of this week.
    There has been a couple of bugs in the beta unit and Mark is coming down Monday to upgradse the box with some new info, my customer has really loved the unit so far, big gain in perforamce for him. I will post more as I get a better understanding of the Beta unit for sure, I'll get more information from Mark when he comes down Monday. Mean while here's a few pix's of the install, more will follow.
    ********************
    This sounds GREAT and I for one can't wait to give it a Whirrrrrrl....

    signed....BUBBIE