dominator on a 540
07-10-2007, 01:01 PM
#11
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2 circuit is the way to go. You may need to change the air bleeds. Do you have bungs in your exhaust to run an AFR meter such as a FAST? If not.....you are pushing rope.
07-10-2007, 01:41 PM
#13
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I was a rope pusher for years...the Innovate Motor Sports LS-1 move the dyno based jetting from 93X95 to 87X87 with a new safe A/F ratio of 13.6 13.7 in the mid range and then 12.5 at WOT (above 5500 RPM w/PV open). With todays cost of fuel, it is a huge waste to be super rich in the mid range.
Jetting on the dyno likely lead you down the wrong path.
Jetting on the dyno likely lead you down the wrong path.
07-10-2007, 01:49 PM
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I would think you could hook up a vacuum gauge to the port under the carb, if not one there drill and tap one so you can get a vacuum reading for what the carb is seeing. Then you can tune your power valve according to when you need it to come in. Also power valve transfer slot holes, which are the small holes when you take out the power valve, can be enlarged to add more fuel thru the power valve. You could then adjust it to work on richening up your motor at pure WFO without fattening up the middle, by selection of your power valve size.
07-10-2007, 01:50 PM
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I was a rope pusher for years...the Innovate Motor Sports LS-1 move the dyno based jetting from 93X95 to 87X87 with a new safe A/F ratio of 13.6 13.7 in the mid range and then 12.5 at WOT (above 5500 RPM w/PV open). With todays cost of fuel, it is a huge waste to be super rich in the mid range.
Jetting on the dyno likely lead you down the wrong path.
Jetting on the dyno likely lead you down the wrong path.
I am still new at the tuning thing, i went out today after work and bought 5.5 and .6.5 pv's from the way it sounds i should maybe leave the jets where they are at 91 and put the valves in?
07-10-2007, 04:34 PM
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You're saying you have too big a cam. A 6.5 power valve may open when you shift gears (At 6.5 inches of vacuum) causing the engine to stall. That's why I use a 3.5. It waits until the vacuum drops lower before opening. Even a 3.5 will open long before you get to full throttle. It helps to have a vacuum gauge to tune it ocrrectly.
07-10-2007, 04:38 PM
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I drilled and taped a fitting in the carb just now, when i hook a vacuum gauge to it how will i know if i need a3.5 4.5 or 5.5 or 6.5...........
07-11-2007, 05:30 PM
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1050 80340 marine carb 2 circuit. Motor is 572ci 9.25 to 1 compression, 5 inch exhaust, dart 345 heads, roller cam 139651 632 lift, 96 square jetting, 6.5 power valve in the front primary and 6.5 power in the back valve in the secondary.
That is where I wound up with the carb. Also 71 air bleeds were in the idle circuit which went to 57 and finally ended up at 51s. Idles perfect in and out of gear perfect.
I had Barry grant 1090s which if anyone wants a deal on these carbs I have 2 with 10 hrs for $600 each paid a $1000.
That is where I wound up with the carb. Also 71 air bleeds were in the idle circuit which went to 57 and finally ended up at 51s. Idles perfect in and out of gear perfect.
I had Barry grant 1090s which if anyone wants a deal on these carbs I have 2 with 10 hrs for $600 each paid a $1000.
