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tunning

  1. #1
    Senior Member ohflat's Avatar
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    Default tunning

    correct procedures for tunning or the ten mistakes we make learning curve bbc natual asperation

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    Platinum Member BigSteve's Avatar
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    Quote Originally Posted by ohflat View Post
    correct procedures for tunning or the ten mistakes we make learning curve bbc natual asperation
    The best thing you can do is put it on a dyno

    The data on the dyno can spot trouble spots in power curve

    And establish base line performance levels

    Once tuned and jetted correctly,@ those Air temp,baro, relative humidity.

    There are jetting formulas to correct for air changes you will experience during the season or altitude you boat at.
    If you ain't the lead dog the view is always the same !

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    Senior Member TNYoungblood's Avatar
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    Can you elaborate on the formula Steve. Mine was alittle fat on the dyno(done in February) and is alittle lean out on the river in the summer time.
    Thanks



    WFLC Boat #321 M/E Kentucky Drag Boat Association

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    Platinum Member BigSteve's Avatar
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    Quote Originally Posted by TNYoungblood View Post
    Can you elaborate on the formula Steve. Mine was alittle fat on the dyno(done in February) and is alittle lean out on the river in the summer time.
    Thanks
    Sure I can
    I bought a autographed book, from forum member -Inquisitive Gearhead
    He wrote the book On the Dyno packed full of information,Tuning tips on weather conditions, i.e. baro pressure, wet and dry bulb temps, and putting it together to get a correct fuel factor going in to the motor with a given oxygen content of air
    He has done much of the hard work on Psychometric charts and conversions tables. This is the key to understanding correction factors CF on the Dyno

    I would give him a PM
    Its a excellent resource book
    Big Steve
    Last edited by BigSteve; 02-19-2012 at 07:46 PM.
    If you ain't the lead dog the view is always the same !

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    Senior Member Hass828's Avatar
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    Absolutely no reason that you couldnt use an O2 sensor setup with datalogging capabilities and just tune it on the lake in the exact enviroment that it will be operated in. They are very inexpensive today and can be setup with a warning light that will tell you if you are getting lean anywhere in the run. An LM2 with these capabilities is under $300 on E-Bay . It also can datalog 5 more channels if you choose to watch boost, oil pressure, intake pressure,rpms,fuel pressure, nozzle pressure, ect. But you have to purchase the transducers just like with any other datalogger.JMO.
    Racing is who gets there first, not who gets there on schedule.


    "if we keep doing it the same way we always do..we will always get the same results"
    H8-2-W8
    5.89@139.4

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    "Need For Speed" Gearhead's Avatar
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    Quote Originally Posted by TNYoungblood View Post
    Can you elaborate on the formula Steve. Mine was alittle fat on the dyno(done in February) and is alittle lean out on the river in the summer time.
    Thanks
    If your engine was lean at the river in the summertime..... it was not rich on the dyno in the winter....... unless you dynoed on top of a mountain and ran the engine in the boat in a low valley..... ..

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    Platinum Member BigSteve's Avatar
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    [QUOTE=Gearhead;1582203]If your engine was lean at the river in the summertime..... it was not rich on the dyno in the winter....... unless you dynoed on top of a mountain and ran the engine in the boat in a low valley..... ..[/QUOTE

    True enough!!!
    If you ain't the lead dog the view is always the same !

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    Senior Member TNYoungblood's Avatar
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    Plugs look alittle on the lean side After a pass Gear And of course my dyno session was junk

    Gonna start fresh come springtime and get her dialed in



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    "Need For Speed" Gearhead's Avatar
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    Quote Originally Posted by TNYoungblood View Post
    Plugs look alittle on the lean side After a pass Gear And of course my dyno session was junk

    Gonna start fresh come springtime and get her dialed in
    The constant load of a jet on the lake likes fuel Don't be timid about adding more while watching your tach, plugs, gps and time slips. It will show you what it wants

    Gear

  11. #10
    Senior Member Hass828's Avatar
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    Quote Originally Posted by Gearhead View Post
    The constant load of a jet on the lake likes fuel Don't be timid about adding more while watching your tach, plugs, gps and time slips. It will show you what it wants

    Gear
    Yeah, and if you dont pay attention, it'll show you what it dont want.
    Last edited by Hass828; 02-21-2012 at 05:57 AM.
    Racing is who gets there first, not who gets there on schedule.


    "if we keep doing it the same way we always do..we will always get the same results"
    H8-2-W8
    5.89@139.4

  12. #11
    Senior Member TNYoungblood's Avatar
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    Quote Originally Posted by Gearhead View Post
    The constant load of a jet on the lake likes fuel Don't be timid about adding more while watching your tach, plugs, gps and time slips. It will show you what it wants

    Gear


    No time slips but i can do everything else .. I had these carbs on a 468 and then put them on the 540 and took it to the dyno .. Dyno man said I was alittle on the fat side, witch I like, but we never pulled a plug to have a look .. I always liked to see alittle black on the back of the boat at the end of the day and noticed when I would go out it was clean so I pulled a few plugs after a pass and noticed they looked alittle lean .. I'm gonna go up a few jet sizes until i get the plugs looking better


    FWIW
    BBC 540 runnin on 93
    2 QF 750s
    Primary jets 72
    Secondary jets 84
    Power Valve 4.5

    Boat runs great at mid RPM range and at WOT.. I'd just like to get a little fatter tune on it
    Last edited by TNYoungblood; 02-21-2012 at 09:00 AM.



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    Senior Member Reservoir Dog's Avatar
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    Default what ignition system?

    I WAS running a pump gas 9.3 comp. n/a 540 w/2 850s and a msd ignition. i was told reading the plugs when running the msd, that you look at the threads of the plug not the electrode. The msd has such an efficiant fire that it will burn the carbon off the electrode. I was told that w/msd that around 3-4 threads from the end of the plug should have a little color change (slight carbon). My header pipes were a very light chocolate color at the end of the collectors, some days it would be white to light gray (like race fuel) depending on air temp and quality.

  14. #13
    Senior Member cyclone's Avatar
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    Quote Originally Posted by TNYoungblood View Post
    Can you elaborate on the formula Steve. Mine was alittle fat on the dyno(done in February) and is alittle lean out on the river in the summer time.
    Thanks
    how fat is fat on the dyno? what were the a/f numbers at WOT and do you have them for each cylinder or just from a collector?

    And how are you determining that its lean in the summertime?

    If it truly is lean, it could be due to the exhaust and/or fuel system in your boat, if you didn't tuen the engine with those exact parts on the dyno.

  15. #14
    Senior Member cyclone's Avatar
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    Quote Originally Posted by TNYoungblood View Post
    No time slips but i can do everything else .. I had these carbs on a 468 and then put them on the 540 and took it to the dyno .. Dyno man said I was alittle on the fat side, witch I like, but we never pulled a plug to have a look .. I always liked to see alittle black on the back of the boat at the end of the day and noticed when I would go out it was clean so I pulled a few plugs after a pass and noticed they looked alittle lean .. I'm gonna go up a few jet sizes until i get the plugs looking better


    FWIW
    BBC 540 runnin on 93
    2 QF 750s
    Primary jets 72
    Secondary jets 84
    Power Valve 4.5

    Boat runs great at mid RPM range and at WOT.. I'd just like to get a little fatter tune on it


    black on the tansom is not necessarily and indicator that the engine is running fat at WOT. that's likely from idling or part throttle operation. And unless you are making a pass with brand new plugs and shutting the engine off immediately after and pull the plugs to look at them, you are not getting a proper plug reading. lots of guys mistake a sooty looking plug as the engine running fat when it really isn't because they've been driving all over the lake before pulling the plug to check it.

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