Re: Holley jet size question
[Re: mickm]
#2287696
04/14/17 03:01 PM
04/14/17 03:01 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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iirc someone priorly posted that 12.5 is a good number for WOT? but wait for guys who know more on that
live every 24 hour block of time like it's your last day on earth
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Re: Holley jet size question
[Re: mickm]
#2287714
04/14/17 03:32 PM
04/14/17 03:32 PM
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Joined: Jan 2003
Posts: 9,436 Blair County,PA
62maxwgn
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master
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Blair County,PA
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New to Holleys. I've just put a six pack on the engine, and A/F at WOT is in the mid-low 12's, cruise at low 13's. Seems ripe for a jet change. I have 66's in there now, and a set of 62's, is that too far to go to try and move that WOT up to about 13.0:1? With all the comments in your initial post,unless I missed it you never stated what cam,as far as 62's I think you will be lean with a 540 cu in motor at WOT.As far as what Cab posted,the replacement carbs are exceptionally lean and I think you stated you never did anything with the outboards.
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Re: Holley jet size question
[Re: 62maxwgn]
#2287826
04/14/17 07:11 PM
04/14/17 07:11 PM
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Joined: Jul 2006
Posts: 4,179 California
mickm
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New to Holleys. I've just put a six pack on the engine, and A/F at WOT is in the mid-low 12's, cruise at low 13's. Seems ripe for a jet change. I have 66's in there now, and a set of 62's, is that too far to go to try and move that WOT up to about 13.0:1? With all the comments in your initial post,unless I missed it you never stated what cam,as far as 62's I think you will be lean with a 540 cu in motor at WOT.As far as what Cab posted,the replacement carbs are exceptionally lean and I think you stated you never did anything with the outboards. I expected to be very lean as well, but the A/F meter is showing otherwise. I put 66's in as a recommendation from someone who know's six packs, although I really should have left it alone with the 62's and just started with that as a base. The cam is a solid roller, 248/255 .604/.582, 112 LSA, installed at 110 Centerline. For this engine I want to be 12.8-13.2 at WOT, so whatever it takes to get there. I will check again, but last time I had the idle doing well. Smooth idle, outboard carbs adjusted correctly, i.e. cover up the transfer slot and no change in RPM.
Last edited by mickm; 04/14/17 07:12 PM.
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Re: Holley jet size question
[Re: mickm]
#2287901
04/14/17 10:28 PM
04/14/17 10:28 PM
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Joined: Jan 2003
Posts: 9,436 Blair County,PA
62maxwgn
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Blair County,PA
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New to Holleys. I've just put a six pack on the engine, and A/F at WOT is in the mid-low 12's, cruise at low 13's. Seems ripe for a jet change. I have 66's in there now, and a set of 62's, is that too far to go to try and move that WOT up to about 13.0:1? With all the comments in your initial post,unless I missed it you never stated what cam,as far as 62's I think you will be lean with a 540 cu in motor at WOT.As far as what Cab posted,the replacement carbs are exceptionally lean and I think you stated you never did anything with the outboards. I expected to be very lean as well, but the A/F meter is showing otherwise. I put 66's in as a recommendation from someone who know's six packs, although I really should have left it alone with the 62's and just started with that as a base. The cam is a solid roller, 248/255 .604/.582, 112 LSA, installed at 110 Centerline. For this engine I want to be 12.8-13.2 at WOT, so whatever it takes to get there. I will check again, but last time I had the idle doing well. Smooth idle, outboard carbs adjusted correctly, i.e. cover up the transfer slot and no change in RPM. When you say outboard carbs adjusted correctly,what did you actually do ?
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Re: Holley jet size question
[Re: 62maxwgn]
#2287903
04/14/17 10:34 PM
04/14/17 10:34 PM
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Joined: Jul 2006
Posts: 4,179 California
mickm
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When you say outboard carbs adjusted correctly,what did you actually do ?
Per Dayclona's advice, I plugged the outer air bleed on each side with my finger. If the rpm rose or fell, which it did, I adjusted the idle mixture screw until there was no change when I plugged the hole.
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Re: Holley jet size question
[Re: mickm]
#2287912
04/14/17 10:42 PM
04/14/17 10:42 PM
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Joined: Feb 2005
Posts: 4,318 Prospect, PA
BSB67
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For this engine I want to be 12.8-13.2 at WOT, so whatever it takes to get there.
Why? Wouldn't you want to jet for max power at WOT?
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Re: Holley jet size question
[Re: mickm]
#2287920
04/14/17 10:53 PM
04/14/17 10:53 PM
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Joined: Aug 2003
Posts: 43,237 Bend,OR USA
Cab_Burge
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Bend,OR USA
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Last edited by Cab_Burge; 04/14/17 10:54 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Holley jet size question
[Re: BSB67]
#2288031
04/15/17 02:03 AM
04/15/17 02:03 AM
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Joined: Jul 2006
Posts: 4,179 California
mickm
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For this engine I want to be 12.8-13.2 at WOT, so whatever it takes to get there.
Why? Wouldn't you want to jet for max power at WOT? This is basically one of Tim Banning's engines. He runs his stuff there, so that's what I'm working with. Where do you run yours for max power?
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Re: Holley jet size question
[Re: mickm]
#2288091
04/15/17 09:28 AM
04/15/17 09:28 AM
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Joined: Feb 2010
Posts: 1,645 Phila. Pa.
Mattax
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Phila. Pa.
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Your reasoning is rational. It just came across as if you are tuning to AFR instead of tuning to torque and power. Differences in load, fuel distribution, and fuel itself are some of the things that can alter AFR that your engine appears to run best at.
One reason your engine may need to be richer is to provide enough fuel to take care of the leanest cylinder. If you know which cylinders are richer or leaner, then you can try to improve the distribution.
Another is that AFR will also vary with fuel composition and density. Race gas is held very close to whatever the manufacturer publishes. Pump fuel will vary from year to year, region to region and winter to summer.
(The AFR gage is an interpretation of a WBO2 which itself is an interpreted measurement of oxygen. There are conditions that will result in misreadings. Another reason to check the spark plugs.)
Last edited by Mattax; 04/15/17 10:58 AM.
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Re: Holley jet size question
[Re: mickm]
#2288142
04/15/17 11:55 AM
04/15/17 11:55 AM
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Joined: Jan 2003
Posts: 9,436 Blair County,PA
62maxwgn
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Blair County,PA
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When you say outboard carbs adjusted correctly,what did you actually do ?
Per Dayclona's advice, I plugged the outer air bleed on each side with my finger. If the rpm rose or fell, which it did, I adjusted the idle mixture screw until there was no change when I plugged the hole. If you are running the current Holley replacement carbs,the # 35 metering plate with your cam and the 540 cu in,I think you will still be lean at WOT.Buy a set of Ouick Fuel cast plates,$25 ea,take your time and eventually you'll get there.
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