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Old 06-24-2015, 07:30 AM
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I figure 13-13.5:1 is good idle with car to go after no?
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Old 06-24-2015, 07:40 AM
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Idle AFR all depends on what makes it idle best and not load up.

It also greatly effects the transition into your primary metering, and the primary metering itself a tad.

Single plane intakes, big cams, tunnel rams, superchargers, exhaust system, etc,etc can all vary what it wants.
These are not your stock cam heated dual plane intake set-ups.

As I quote all the time, Darrin Morgan says "Your engine is telling you what it wants. Are you listening ?"
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Old 06-24-2015, 07:42 AM
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Originally Posted by Full Force
I figure 13-13.5:1 is good idle with car to go after no?
Try to go leaner than where you are now, and see how it shifts for you. Every engine is different. A mild cammed stocker might idle all day at leaner afr's. I'd shoot for the leanest idle you can get, without stalling when shifting around the dock, or sneezing trying to get on plane. The number there, is gonna be what its gonna be.
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Old 06-24-2015, 07:49 AM
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Originally Posted by Full Force
I figure 13-13.5:1 is good idle with car to go after no?
what carbs ? you may be able to change idle air bleeds or idle feed restrictions(if changeable) and lean it down and see what it likes, but I think mid 13's may be to lean
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Old 06-24-2015, 08:08 AM
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Originally Posted by MILD THUNDER
Try to go leaner than where you are now, and see how it shifts for you. Every engine is different. A mild cammed stocker might idle all day at leaner afr's. I'd shoot for the leanest idle you can get, without stalling when shifting around the dock, or sneezing trying to get on plane. The number there, is gonna be what its gonna be.
Cool that's kinda what I was gonna work on this weekend...
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Old 06-24-2015, 08:08 AM
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Originally Posted by ezstriper
what carbs ? you may be able to change idle air bleeds or idle feed restrictions(if changeable) and lean it down and see what it likes, but I think mid 13's may be to lean
1050 quickfuels
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Old 06-24-2015, 08:32 AM
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Originally Posted by mike tkach
12.2 at wot for your application would be golden.
and very safe,,no need for the lean is mean thinking w/ a boat.your still gonna get 1gpm at wot.
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Old 06-24-2015, 08:34 AM
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Originally Posted by MILD THUNDER
Try to go leaner than where you are now, and see how it shifts for you. Every engine is different. A mild cammed stocker might idle all day at leaner afr's. I'd shoot for the leanest idle you can get, without stalling when shifting around the dock, or sneezing trying to get on plane. The number there, is gonna be what its gonna be.
exactly,strap it to a dock,put a vacuum gauge on it w/ o2 sensors and have it it till it shifts nice.
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Old 06-24-2015, 09:17 AM
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Originally Posted by MILD THUNDER

What I've learned about locked timing, which is what I believe you run Tim, is that it sucks. There is no way around the fact, that with locked timing, there is some point in the engines powerband, where you either have too much, or not enough timing. As charge density increases, the need for advance decreases. As rpm increases, the need for advance increases. At 3000RPM cruise, your engine may want 36* of timing. AT 3000RPM wot acceleration, it may want 22 degrees of timing.

This is not new info to the pro's, but to a do it yourself guy like me, this data is priceless.

Locked timing is great for a lawn mower, for everything else it blows goats.

Playing with boosted 4 cylinder applications where you are pulling 500-750WHP out of 2.0 liters of displacement timing becomes VERY important. So 32 degrees of timing may work great for peak torque at, say, 4500RPM's, but as RPM picks up, piston speed increases but the speed of the flame in the combustion chamber stays relatively constant. Therefore to get the most efficient and powerful combustion starting the combustion activity earlier by advancing timing will improve power. My timing maps usually work out to be something similar to an inverse of the torque curve of the engine. By monitoring knock sensor activity as well as AFR I know what works well and what doesn't, as well as monitoring trap speed. My next theory is just a theory, and I don't know it to be true, but I believe by reducing your EGT with proper timing you are reducing exhaust valve temperature, valve spring temperature, and the end result is reduced oil temperature. There really is no downside here.
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Old 06-24-2015, 09:55 AM
  #20  
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As far as distributors locked I just run what has worked for years, of course there are more ways especially these days... I am gonna have a divorce if I do t stop wrenchin and use the boat, I can change all that over winter....

All my buddy's have locked timing we been doing it forever, for now that's what I gotta do at least for a bit I can't wrench daily all my other things in life been on hold.... Gotta focus
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