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Christien's Avatar
 
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Difference between 175 and 185 air correction screws?

600 ft. elevation, for a Weber carb setup on a 3.0L.

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Old 08-19-2011, 04:26 PM
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The 175 will provide a richer upper RPM fuel delivery (above 4500 RPM) than the 185. If engine stutters or resists reaching high RPM you can install the smaller air correction jet and give it a try. Keep notes. Be methodical. Use a tail pipe exhaust analyzer to be sure.
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Old 08-19-2011, 06:00 PM
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Sorry, should've been more clear. I know it'll mean a leaner mixture at high rpms, the question is how much. WOuld it be noticeable in a regular street car that sees a couple track days per year? Can it be compensated for with a slightly overall richer mixture?
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Old 08-20-2011, 03:52 AM
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In case this is any help ... I've heard a rule of thumb is that a change of roughly three air corrector jet sizes = one main jet size, in terms of the magnitude of the enrichment you can expect.

Scott
Old 08-20-2011, 06:17 AM
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I'm pretty new to carb setup (tried it once for an entire day and half a tank of gas, end up taking it into the shop), so I'm not even familiar with what changing the main jet size would do.
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Old 08-20-2011, 10:55 AM
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The difference is exactly 10.
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Old 08-20-2011, 02:47 PM
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Hey, we have a comedian in the house! Damn Canadians...

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Old 08-20-2011, 04:28 PM
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Christien,

Is there a particular issue you're trying to address by changing the air corrector jets? Normally you'd change air correctors to adjust the enrichment at high RPM under load.

Scott
Old 08-20-2011, 06:01 PM
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Good question - don't know why I didn't explain earlier. I've currently got Webers on a 2.0L, and I've got a 3.0L coming next week. I need to rejet the Webers, and I've got someone who's got most of the stuff, but 185 air corrrections, whereas the recommended is 175. I'm trying to determine if they'll work, and why or why not. It's partly practical (would be easier to have one less shipping cost into Canada) and partly academic (still trying to learn the details of how carbs work).
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Old 08-21-2011, 04:15 AM
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185 air correctors will cause slightly leaner running in the upper RPM range than 175 (air correctors work the "opposite" of main and idle jets). If you're pretty sure about the 175, sounds like it would be better to have them. Plus, jets are cheap. Another way to look at it is than 185 to 175 is not a very big jump for air corrector jets, so you could try making the other jetting changes and see how it runs.

Scott

Old 08-21-2011, 08:35 AM
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