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 Post Posted: Wed Mar 07, 2012 10:24 pm 
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Having gone through a number of Dominators in the last 3 weeks including a Quick Fuel QFX and a King Demon, I felt this would be a good topic to address. The variety of t-slot sizes and positions can change the calibrations needed to make the idle and transition work well. I recently had a Dominator that had the transition slot placed .100 high above the closed blades, after cutting it down it made the t-slot very long. It took a .052 t-slot jet, .042 IJ, and .060 IAB to make it work.

One thing I have found is when tuning it, I bring the engine RPM into the transfer slot, and see the effect of placing my finger over one or 2 idle air bleeds. When the tune is close I've found when it's cold it will pick up a little RPM, once it's warm it will not. Too lean and it picks up a bunch when cold, too rich and it kills a little when it's warm.


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 Post Posted: Thu Mar 08, 2012 3:23 am 
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I find the right tune on any carby is when you partly block the air bleed with your finger, enough to restrict it but not seal it and it doesnt change the engine when its warm. It means your in the zone of happiness. Gotta make 'em happy otherwise they bitch at ya, bit like lifes other experiences really. .


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 Post Posted: Sat Mar 10, 2012 11:54 am 
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Are you IAB test conducted under load?

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 Post Posted: Sat Mar 10, 2012 2:58 pm 
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Not on mine, a 5900 stall doesn't change the load too much at idle. And ideally yes, but hard to do by yourself.


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 Post Posted: Sun Mar 11, 2012 12:35 pm 
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Mark,

Do you know what the calibrations were in the King Demons? And what size the carb was? Just trying to get a good comparison for mine.........I had it pretty good last year except for the top end, but hopefully I've fixed that now..........

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 Post Posted: Sun Mar 11, 2012 2:26 pm 
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I didn't do a conversion on the King Demon, made very small changes to lean the idle/transition and intermediate circuits but overall left it alone. It came to me plugged up, the fuel filter on the car came apart and plugged everything. He was happy with the operation prior so I was reluctant to make any major changes, just a basic clean and rebuild.


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 Post Posted: Sun Mar 11, 2012 6:13 pm 
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Thanks!

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 Post Posted: Mon Mar 12, 2012 8:19 am 
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jmarkaudio wrote:
One thing I have found is when tuning it, I bring the engine RPM into the transfer slot, and see the effect of placing my finger over one or 2 idle air bleeds. When the tune is close I've found when it's cold it will pick up a little RPM, once it's warm it will not. Too lean and it picks up a bunch when cold, too rich and it kills a little when it's warm.

Thank you for this tip. This fits well with Tuner telling me "If it idles cold without feathring, you are way rich."


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 Post Posted: Mon Mar 12, 2012 1:38 pm 
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webermaniac wrote:
jmarkaudio wrote:
the transition slot placed .100 high above the closed blades, after cutting it down it made the t-slot very long.

Does extending the T-slot upwards make possible the use of late engaging (less sensitive) boosters?

Up to a point yes. There is only so much you can get from a T-slot. With whatever design low speed circuit you have be it slots or holes etc the more you try to make it extend further up the load range the more air it will bleed at idle closed position etc. The more above the blade at idle the more air it will leak but the more it will extend the range of operation too. The trick is in bringing the booster into play at the right time. Thats what booster sizing and main venturi relationship to the throttle bore is all about. Varying the aspect of the throttle bore to the venturi alters how much emulsion air you have to use to lift fuel to the booster with whatever booster design you have. You can make a booster start really early if you want by using lots of air but then your stuck with that air once the system gets going. Unless moving parts to correct these problems are used it will never go away. The solution most manufacturers use is some form of main jet flow control. Air flaps, Doors, Power valves, needles, etc.


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