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Shawnb7168

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Reply with quote  #1 
Hi Patric, that New dominator #51321 is fantastic it really gave the car more power first and second gear out of the box it was near perfect the Only thing I adjusted was the idle mixture screws on the Metering block there about a 1 1/2 turns out . At idle I’m about 13.1 and at wot at 14.7 is this acceptable or is it a little too lean. Plugs don’t look so bad to me a least… a little tan in color . If I am off a bit let me know what I can do to get it straightened out. thanks Shawn
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Reply with quote  #2 
Jet for best mph and thats where the air to fuel ratio wants to be.  If it has good color and its almost 15:1 you probably have an air leak into your headers OR its too close to the open air end of the header.
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Reply with quote  #3 
Hey Patric ,I wouldn’t say good color but some.... .go up 2 sizes in both primary and secondary when I do jet changes
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Reply with quote  #4 
To also add the car has the most power it’s ever had runs real strong .just worried about the 14.3 -14.7 wot aft don’t believe I have any air leaks in headers there new custom 304 ss. Plugs are not tan they have an off white color with a little tan in it . And the electrode strap is gold color . Would like to leave the Jets just the way they are just don’t want to do damage . Can’t tune by mph let closest track is 4 Hours Away . Thanks for any help
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Reply with quote  #5 
I would trust the plugs not the meter for now as you should've said it was popping lean or misfiring at high rpms or laying over on the track.  SO lets trust your plug reading.   But do Jet up 2 front and rear and see if it makes even more power... 



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Patrick James-President
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Reply with quote  #6 
Went up 2 jets sizes all around a/f is around 12.8 now . Issue that I have now is that the carb is a little fat off the the line a/f 10.2 ...and not as crisp off the hit . adjusted Idle mixture screws but can’t get it to hesitate per your directions but will lean out to 15.5 a/f at idle so don’t know if it’s necessary to start drilling bleeds . Back them back out and adjusted the idle mixture screws until the air fuel ratio is about 13.2 a/f . Do you believer the Idle mixture screws are set correctly now ? And how can I get that a/f a little leaner off the hit .thanks for any help Patrick
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Reply with quote  #7 
Before we go drilling on the carb to look for a target air to fuel ratio at the line... we already have supporting data that will tell its what the engine wants.

Is it lazy off the line because the idle is rich (tune with your ear not the meter...does it sound rich at idle?  If so lean it out at idle as that fuel will load up the intake and make it rich off the line as it cleans the fuel off the walls of the intake and its runners.  

Is it a foot brake car or Transbrake?

When you went UP 2 main jet sizes all around... if it picked up off the line and down the track, the curve is good.  BUT if it slowed down off the line and then picked up down the track... then we need to change the curve.  BUT only after we jet it for best mph.

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Shawnb7168

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Reply with quote  #8 
Believe I have curve correct at wot now . Pretty solid 12.7 - 13.2 a/f both n/a and on nitrous .just trying to get cruise mixture correct now at little or part throttle it’s a bit rich at 10.5 a/f .would like to solve this without interfering with wot . I changed from a 6.5 Power valve to 4.5 will this help ? BBC Cam is a solid roller 731/714 260 /266 duration at 50 to give u an idea of vac.thanks for any help.
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Reply with quote  #9 
If the power valve wasn't closing and a 4.5 is low enough to make it close at cruise, that is the answer for sure.  Drive it and see if you are barking up the right tree.
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Shawnb7168

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Reply with quote  #10 
Started using the trans Break same issue of being real rich when standing on trans break . As I go two wide open throttle it goes to 12.8 . Is there anyway to Get rid of that richness when I’m on the break . Maybe turn in Idle mixture screws a bit or is there a simple way to eliminatr this
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Reply with quote  #11 
When you are on the trans brake you want it to be in that 12.8:1 air to fuel ratio range.  Thats not rich, thats a proper ratio for its intended use and application.
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Shawnb7168

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Reply with quote  #12 
Sorry, did not explain clearly enough.... at 10.2 when On trans break and then two -three seconds into run leans out to 12.8 .
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Reply with quote  #13 
If you are up on the limiter on the trans brake that can change your air to fuel ratio as the meter reads the unburned fuel when the limiter shuts off the cylinders.  Is the engine creating excessive smoke off the starting line?  What happens when you pull the chip out and go on the limiter with no ignition interruption?


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