How to tune?
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How to tune?

This is a discussion on How to tune? within the General forums, part of the Caferacer.net Forums category; For me this is more of a academic question but anyway. Lets assume that you have access to dyno with datalogging for a/f ratio, throttle ...

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Thread: How to tune?

  1. #1
    Senior Member kerosene's Avatar
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    How to tune?

    For me this is more of a academic question but anyway.

    Lets assume that you have access to dyno with datalogging for a/f ratio, throttle position or manifold pressure, rpm, and exhaust temp.

    The things you could play with were :
    -basic carb tweak (needle, jets)
    -timing (base and advance)
    -cam advance
    maybe even things like trying a few different exhausts or airbox/filter designs

    How would you (or a pro) proceed? I am assuming that there are so many interconnections from one adjustment affecting another that you would need to proceed in sort of circles.

    For example after base values
    Tweak A until good -> tweak B until good -> tweak C until good -> repeat (as C might have thrown A off)

    ('until good' meaning you get most satisfactory result)

    How do the pros do it? basic fuel ratios 1st and then tweak timing and go back to fuel?

    It seems that there might be some kind of routine that would make the whole process less guess work. We all hear from the dyno sessions where huge improvements are done. Where could I learn from what exactly is being done. I am sure experience is king as always but any tips or links to good reading material would be much appreciated.



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  2. #2
    Senior Member crazypj's Avatar
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    Depends on what you intend bike to do?
    A street bike ridden mainly at half throttle or so for extended periods is going to be a lot different to a drag bike held full throttle for a few seconds or a road racer which needs to accelerate hard then be on the brakes.
    I dabble in rocket science, when I\'m not picking my nose
    The other night I gave my girlfriend an orgasm, but, she spat it back at me

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    Senior Member crazypj's Avatar
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    Depends on what you intend bike to do?
    A street bike ridden mainly at half throttle or so for extended periods is going to be a lot different to a drag bike held full throttle for a few seconds or a road racer which needs to accelerate hard then be on the brakes.
    I dabble in rocket science, when I\'m not picking my nose
    The other night I gave my girlfriend an orgasm, but, she spat it back at me

    'you can take my word for it or argue until you find out I'm right'

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  5. #4
    Senior Member KeninIowa's Avatar
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    K, my experience is with a few circle track engines and the big-block in my Chevelle.

    A good dyno operator/tuner is under appreciated.

    The dude that dynoed my 496 would look at the data in totality at first and make multiple changes. We then might tweak them individually, but took big swings at first.

    Couple things;

    The idea to stick to one thing at a time is nice, but you're paying by the hour. I spent a grand dynoing the Chevelle engine ten years ago on the supposed buddy deal.

    Things work together, for instance we always put fuel and timing in together esp initially.

  6. #5
    Senior Member KeninIowa's Avatar
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    K, my experience is with a few circle track engines and the big-block in my Chevelle.

    A good dyno operator/tuner is under appreciated.

    The dude that dynoed my 496 would look at the data in totality at first and make multiple changes. We then might tweak them individually, but took big swings at first.

    Couple things;

    The idea to stick to one thing at a time is nice, but you're paying by the hour. I spent a grand dynoing the Chevelle engine ten years ago on the supposed buddy deal.

    Things work together, for instance we always put fuel and timing in together esp initially.

  7. #6
    Senior Member kerosene's Avatar
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    Cool thanks. For any input. I ordered couple of books and am trying to roam different forums to get a better idea.

    these guys had some good info - under tech articles and under procedure. Targeted to customers but still ok stuff.
    http://www.bristoldyno.com/info/procedure.htm

    Ken if dyno time was drastically cheaper do you think you would be using it to tweak your bikes too?

    and PJ - I was more curious of the general approach but the scenario I am thinking would be road racing style application where throttle response and partial throttle performance are also important.
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  8. #7
    Senior Member kerosene's Avatar
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    Cool thanks. For any input. I ordered couple of books and am trying to roam different forums to get a better idea.

    these guys had some good info - under tech articles and under procedure. Targeted to customers but still ok stuff.
    http://www.bristoldyno.com/info/procedure.htm

    Ken if dyno time was drastically cheaper do you think you would be using it to tweak your bikes too?

    and PJ - I was more curious of the general approach but the scenario I am thinking would be road racing style application where throttle response and partial throttle performance are also important.
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  9. #8
    Senior Member KeninIowa's Avatar
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    quote:Originally posted by kerosene



    Ken if dyno time was drastically cheaper do you think you would be using it to tweak your bikes too?
    If you figure the initial cost of the equip, maint, building overhead and operator wages you'll never get it much under $100/hr, esp if dyno time is all you're selling.

    Think about sound attenuation, even bikes are loud.

    But yes, I was going to dyno my 05 this summer. The shop in Waterloo(40 miles north) I wanted to do it closed. There are three bike dynos in Cedar Rapids(40 miles SE) two at dealerships , one performance shop. I won't take my stuff to any of them.

  10. #9
    Senior Member KeninIowa's Avatar
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    quote:Originally posted by kerosene



    Ken if dyno time was drastically cheaper do you think you would be using it to tweak your bikes too?
    If you figure the initial cost of the equip, maint, building overhead and operator wages you'll never get it much under $100/hr, esp if dyno time is all you're selling.

    Think about sound attenuation, even bikes are loud.

    But yes, I was going to dyno my 05 this summer. The shop in Waterloo(40 miles north) I wanted to do it closed. There are three bike dynos in Cedar Rapids(40 miles SE) two at dealerships , one performance shop. I won't take my stuff to any of them.

  11. #10
    Senior Member kerosene's Avatar
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    just pure scifi speculation - if there was cheap (<1000$) dyno equipment - do you think there would be broad interest or do you think that the Sunday tuner would be too clueless to use the data provided by dyno.
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