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Help with A/F Ratio Numbers #1062760 08/25/11 11:05 AM 08/25/11 11:05 AM
Joined: Aug 2006 Posts: 38 Mass. charger_dart OP member
charger_dart OP member Joined: Aug 2006 Posts: 38 Mass.	I hooked up a NGK Air Fuel ratio guage to my 500 wedge motor with a Holley 80531 850 carb (vacuum secondary) The numbers I got were: Idle - 13.5 Cruise - 12.5 Light throttle - 13.5 Decelerate - 11.5 WOT - 13.5 dropping to 12.5 as the secondaries open Do these look like good numbers? This carb replaced an Eddy 800 and seems to run pretty good right out of the box. Thanks for all comments 68 Charger R/T 68 Dart G/T Convert 11 Challenger SRT

Re: Help with A/F Ratio Numbers [Re: charger_dart] #1062761 08/25/11 12:01 PM 08/25/11 12:01 PM
Joined: Jan 2003 Posts: 1,938 Sonora CA Mopar_Rich top fuel
Mopar_Rich top fuel Joined: Jan 2003 Posts: 1,938 Sonora CA	Quote: Idle - 13.5 Cruise - 12.5 Light throttle - 13.5 Decelerate - 11.5 WOT - 13.5 dropping to 12.5 as the secondaries open The cruise is too rich. That will hurt mileage. Idle should be about 14 to 14.5 (depends on what the motor wants) and your cruise should be about the same as idle, maybe a tad richer. The WOT is fine. The decel is showing rich only because there's excess fuel being burned off. On a long decel, given time to burn off the fuel, the AF ratio should go as lean as idle.

Re: Help with A/F Ratio Numbers [Re: charger_dart] #1062762 08/25/11 12:27 PM 08/25/11 12:27 PM
Joined: Jan 2003 Posts: 5,444 Indiana Y YO7_A66 master
YO7_A66 master Y Joined: Jan 2003 Posts: 5,444 Indiana	I started out with my in D idle around 14.2-14.4 but my rpms would jump around too much so now I keep it around the 13.6-13.8 range. My N idle is usually a tad leaner 13.8-14.0 or so. My cruising range is 14.2 to 15.5. Anything close to 16 and I get worried and retune. My light throttle feels more responsive in the 13.6-13.8 range. I have tried as lean as 14.4 but it just felt a little soft. My decel gets down to 13.5 or so. Once you lean out your cruise then the decel should lean out too. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Help with A/F Ratio Numbers [Re: YO7_A66] #1062763 08/25/11 01:05 PM 08/25/11 01:05 PM
Joined: Aug 2006 Posts: 38 Mass. charger_dart OP member
charger_dart OP member Joined: Aug 2006 Posts: 38 Mass.	Thanks for the comments. That's kind of what I thought - So maybe a jet change on the primary side will get me into a better condition? Currently I have 78's on the primary side and 82's on the secondary side. What jet size should i try to go to? 68 Charger R/T 68 Dart G/T Convert 11 Challenger SRT

Re: Help with A/F Ratio Numbers [Re: charger_dart] #1062764 08/25/11 01:17 PM 08/25/11 01:17 PM
Joined: Jan 2003 Posts: 5,444 Indiana Y YO7_A66 master
YO7_A66 master Y Joined: Jan 2003 Posts: 5,444 Indiana	You should see an immediate change on the A/F meter if you go at least 2 jet sizes and if you test with the same outside temps. But if the meter stays with the same reading, then the transition circuit would need to be tuned instead of the primary jetting. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Help with A/F Ratio Numbers [Re: YO7_A66] #1062765 08/25/11 04:12 PM 08/25/11 04:12 PM
Joined: Aug 2006 Posts: 38 Mass. charger_dart OP member
charger_dart OP member Joined: Aug 2006 Posts: 38 Mass.	Quote: You should see an immediate change on the A/F meter if you go at least 2 jet sizes and if you test with the same outside temps. But if the meter stays with the same reading, then the transition circuit would need to be tuned instead of the primary jetting. Ok, I will put 76's on the primary side and see what readings I get. Thanks!! 68 Charger R/T 68 Dart G/T Convert 11 Challenger SRT

Re: Help with A/F Ratio Numbers [Re: charger_dart] #1062766 08/25/11 04:38 PM 08/25/11 04:38 PM
Joined: Jan 2003 Posts: 5,444 Indiana Y YO7_A66 master
YO7_A66 master Y Joined: Jan 2003 Posts: 5,444 Indiana	Keep lowering your primary jetting until you get the cruising A/F that you want. Then you will have to go back and recheck your secondary jetting for your WOT A/F since you are removing jet out of the primary side of the carb. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Help with A/F Ratio Numbers [Re: YO7_A66] #1062767 08/26/11 08:18 AM 08/26/11 08:18 AM
Joined: Aug 2006 Posts: 38 Mass. charger_dart OP member
charger_dart OP member Joined: Aug 2006 Posts: 38 Mass.	I don't believe this! I pulled my NEW carb apart for the first time to change the jets and found the primary float has been crushed. It had barely 1/8" of movement!! Where is the quality control at Holley??? 68 Charger R/T 68 Dart G/T Convert 11 Challenger SRT

Re: Help with A/F Ratio Numbers [Re: charger_dart] #1062768 08/26/11 01:25 PM 08/26/11 01:25 PM
Joined: Aug 2003 Posts: 43,213 Bend,OR USA C Cab_Burge I Win
Cab_Burge I Win C Joined: Aug 2003 Posts: 43,213 Bend,OR USA	I have a Innovate dual wide ban on my car, I like to see 14.5 or leaner at idle and close to that at part throttle, 12.8 to 13.3 at WOT makes my car run the fastest at the track It is a pump gas car that runs in the low tens at 133. MPH so far As far as the float have you had the car real hot since putting that carb. on also did you buy it(the carb.) new? I have seen several floats ike that in used carbs. I don't think Holley has used brass floats in there new carbs. in a lot of years due to the fuel mixes that are used today, IE alholol Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

Re: Help with A/F Ratio Numbers [Re: Cab_Burge] #1062769 08/29/11 04:26 PM 08/29/11 04:26 PM
Joined: Aug 2006 Posts: 38 Mass. charger_dart OP member
charger_dart OP member Joined: Aug 2006 Posts: 38 Mass.	Quote: I have a Innovate dual wide ban on my car, I like to see 14.5 or leaner at idle and close to that at part throttle, 12.8 to 13.3 at WOT makes my car run the fastest at the track It is a pump gas car that runs in the low tens at 133. MPH so far As far as the float have you had the car real hot since putting that carb. on also did you buy it(the carb.) new? I have seen several floats ike that in used carbs. I don't think Holley has used brass floats in there new carbs. in a lot of years due to the fuel mixes that are used today, IE alholol Thanks for posting what numbers work well for you. I also run pump gas in my car. The carb was purchased new from amazon.com and I can't think of what would of caused it to crush like that. Its as if it was sent to the bottom of the ocean or something. The replacement float came air freight and was brass also - in perfect condition! Now I just have to see what effect the jet change and float fix has had. Will post pack later. 68 Charger R/T 68 Dart G/T Convert 11 Challenger SRT

Re: Help with A/F Ratio Numbers [Re: charger_dart] #1062770 08/29/11 08:04 PM 08/29/11 08:04 PM
Joined: Nov 2004 Posts: 173 Milano, Italia FK5 member
FK5 member Joined: Nov 2004 Posts: 173 Milano, Italia	Sorry if this is a bit of a hijack, but I'm interested in messing around with a wideband. I would hope to be taking it car to car, but cars I want to start out with already have narrow band sensors. Will I still be able to get a usable signal to computer? How's it work?

Re: Help with A/F Ratio Numbers [Re: FK5] #1062771 08/29/11 08:19 PM 08/29/11 08:19 PM
Joined: Jan 2003 Posts: 16,376 D dogdays I Live Here
dogdays I Live Here D Joined: Jan 2003 Posts: 16,376	You're at close to sea level. I bet you don't need to change jets at all. Just change the float and go for a drive. Those new Holleys are pretty close out of the box. My Holley was running way rich. I found the secondary float stuck open, I was getting fuel injection (well, kind of) out of the secondary side. I cleaned the needle and seat, reset the float and the condition went away. R.

Re: Help with A/F Ratio Numbers [Re: charger_dart] #1062772 08/31/11 04:13 AM 08/31/11 04:13 AM
Joined: May 2008 Posts: 5,399 Aurora, Colorado 451Mopar master
451Mopar master Joined: May 2008 Posts: 5,399 Aurora, Colorado	Does holley have a quality control department? My Truck Avenger did not run right either. When I pulled it apart there were two brass slugs in the jet wells behind the jets

Re: Help with A/F Ratio Numbers [Re: charger_dart] #1062773 08/31/11 08:28 PM 08/31/11 08:28 PM
Joined: Jan 2003 Posts: 31,045 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 31,045 Oregon	The problem you'll have is doing anything about those numbers. To lean out the cruise you'll most likely need to reduce main jets by a size or two, but when you do that the WOT will be too lean. To fix the WOT you'll need to open up the PVCR restriction. On the Ultra carbs you can change jets in the metering block but I don't think a 80531 will have jets in the PVCR. You'll probably have to do a little drill work to get that carb dialed in just right. Of course, you might get lucky. Start by leaning out the idle and see if that fixes the cruise also. If it does then you might be fine at WOT. Last edited by AndyF; 08/31/11 08:29 PM.

Re: Help with A/F Ratio Numbers [Re: AndyF] #1062774 08/31/11 08:52 PM 08/31/11 08:52 PM
Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central RobX4406 I Live Here
RobX4406 I Live Here Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central	You likely won't get it refined by changing main jets, especially if your cruise rpm is in the 2500 or less range. A side note: The HP series holleys are horribly rich pigs on cruise and main jet change don't clean them up.

Re: Help with A/F Ratio Numbers [Re: RobX4406] #1062775 08/31/11 10:30 PM 08/31/11 10:30 PM
Joined: Jan 2003 Posts: 5,444 Indiana Y YO7_A66 master
YO7_A66 master Y Joined: Jan 2003 Posts: 5,444 Indiana	If leaning out the main jets does not lean the A/F number, then the IFR's need to be smaller. The IFR's control the transition circuit which is activated after the idle circuit and before the main circuit. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Help with A/F Ratio Numbers [Re: RobX4406] #1062776 08/31/11 10:41 PM 08/31/11 10:41 PM
Joined: Jan 2003 Posts: 31,045 Oregon A AndyF I Win
AndyF I Win A Joined: Jan 2003 Posts: 31,045 Oregon	It is quite possible that the main jets aren't doing much at 2500 rpm. Every combo is different but even a 500 inch motor might not be pulling much fuel thru the mains at cruise. If that is the case then the idle circuit is the one to pay attention to. Once again, those cast metering blocks are going to be a hurdle. The Ultra Holley carbs have idle jets in the metering blocks which can be quickly changed. The other Holley carbs have pressed in restrictors which are not that easy to modify.

Re: Help with A/F Ratio Numbers [Re: YO7_A66] #1062777 08/31/11 11:09 PM 08/31/11 11:09 PM
Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central RobX4406 I Live Here
RobX4406 I Live Here Joined: Apr 2005 Posts: 12,271 Overpriced Housing Central	Quote: If leaning out the main jets does not lean the A/F number, then the IFR's need to be smaller. The IFR's control the transition circuit which is activated after the idle circuit and before the main circuit. Yep, and the blocks aren't that tough to alter to make them adjustable. Need the tools and brass and you're off and running.

Re: Help with A/F Ratio Numbers [Re: RobX4406] #1062778 09/01/11 11:06 AM 09/01/11 11:06 AM
Joined: Feb 2007 Posts: 1,025 Las Vegas, NV dodgeboy11 super stock
dodgeboy11 super stock Joined: Feb 2007 Posts: 1,025 Las Vegas, NV	For WOT tuning I like to have a dyno. The A/F ratio numbers are nice to have, but the dyno tells the story. Tuning for max power may want more fuel or it may want less. But I like to tune for it and that way I know which way I can safely go (richer or leaner) to tune for fuel economy and not hurt the motor when I do have my foot in it. It's often a compromise with a carb.

Re: Help with A/F Ratio Numbers [Re: charger_dart] #1062779 09/01/11 06:26 PM 09/01/11 06:26 PM
Joined: Oct 2006 Posts: 387 Montreal PQ, Canada 74_360_Cuda enthusiast
74_360_Cuda enthusiast Joined: Oct 2006 Posts: 387 Montreal PQ, Canada	Guys, I have been playing for years with my QF-750 and my LM2 and was wondering how can I make the part throtle richer while making the idle leaner? I Have changed my IFR down to 31's, my idle screws are still only about 3/4 of a turn to have 14 at idle but my part throtle is too lean... Also, my primary accelerator pump does not perform as well as the seconday... If I tap on the plunger with my finger I have an immediate spray on the secondary pump but not on the primary. I have changed all the parts for new parts with no improvement (diaphragm, valve, needle valve etc...) and there is no gap between the plunger and the arm...

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