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 Post Posted: Wed Apr 25, 2012 10:00 am 
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Hi guys,

can you look over a dominator tune up I have here, just need some reassurances.

This was a Chuck Nuytten 1050, 3 circ build originally, I don't see a ton of dominators, but this stood out as something out of left field.

Idle feed restriction (IFR).031
Idle air bleed .024 (IAB)

At first I thought somebody mixed up the High speed air bleed with the idle, but the HS was at .030.

I have zero experience with IAB's that low, so I'd like to get this thing in the ballpark with a .040 IFR and .067 IAB?

It would be interesting to see what that combination of .031 IFR and .024 IAB would do, but this is not the time. My buddy had this carb and had alot of issues with the way it ran, and he wanted me to look at it as they are going to try it on the dyno this weekend. I won't be there so I need to get a good safe tune up in it.

Going to 2 circuit it,

92 main jets (no PV)
.028 HSAB
Two vertical emulsions at .028 (early met block locations), with one .028 at kill bleed
Trans slot restriction @ .060

IFR .040 (leaning to .041)
IAB .067

What are you guys doing to set the idle speed screws, I find 1.5 turns one each as a baseline?

Problem is I know very little about the engine, just that it is a Drag race SBC, 400 CID, 680 HP, C-12 fuel.

Pretty vauge engine specs... but just looking for a baseline.

cheers!


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 Post Posted: Wed Apr 25, 2012 12:17 pm 
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Most of that looks like "ball park" except for the MJ? Is this an annular or old style straight booster? Remember, you want to have it a little rich at WFO to start out. They can lean it down to see where it makes the best power.

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 Post Posted: Wed Apr 25, 2012 12:30 pm 
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It is a stock annular (eight .062 hole).

Yeah, I was thinking that a 94 might be a better start?


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 Post Posted: Wed Apr 25, 2012 4:05 pm 
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Having a little bit of an issue with the jetting on this..Now I have 94 jets square with some zip ties on 2 & 7??
So why is 92s may be lean on the dyno for a sbc??

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Last edited by Beretta on Wed Apr 25, 2012 4:27 pm, edited 1 time in total.

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 Post Posted: Wed Apr 25, 2012 4:23 pm 
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A way to see if the IFR/IAB/t-slot combo is close, crank it up cold and bring it up to about 2000 RPM (out of gear), put your finger over one or two idle bleeds and the RPM should come up. Once it's at operating temp do the same, the RPM should not change or drop slightly if you are close. This makes sure the transition fuel is close, you can tweak as needed from there. When it's right the mixture screws will usually end up between 3/4 and 1 1/2 turns for best idle. If it doesn't change when cold it's likely rich, if it gains RPM at operating temp it's lean.


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