Wideband AFR tuning a carburetor

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500/600

Royal Smart Person
Nov 17, 2018
1,167
2,638
113
West Virginia
I’ve come really close over the past couple of months to buying a Holley Super Sniper EFI for the 519 Cadillac engine in my Malibu. The Quick Fuel 1050 annular booster carb with factory jetting does very well. Fires right up, good response, excellent road manners when cruising, very good plug color with no dampness. It really seems to be very close on my combo. It has a slight hesitation in 3rd gear when floor it which I believe either a rear powervalve change or 50cc rear accelerator pump would fix.

I’ve read loads of info, watched tons of videos, etc. I just can’t make myself spend in excess of two grand with so many neutral and negative reviews. I bought a Autometer Ultralight AFR gauge to match the rest of my stuff and will install this weekend. As much for enjoyment as anything.

Is anybody else out there tuning a carb with an AFR gauge? It has data collection capabilities so should come in handy once I choose a nitrous kit.
 
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1983calais

Master Mechanic
Feb 26, 2015
278
337
63
Tiffin, OH
I want to get one of those for my 67 k10. I’ve looked at a bunch of them and can’t pull the trigger. It would be nice to know where your at from idle to haul the mail. Let us know if you get one and how it works out.
 
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pontiacgp

blank
Mar 31, 2006
29,270
20,391
113
Kitchener, Ontario
I had the new version of the AEM A/F gauge and it takes all the guesswork away.
 
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Wageslave

Royal Smart Person
Jan 25, 2017
1,747
3,335
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I have an AFR gauge on my car, and it was just what I needed to finally get my Edelbrock to work correctly. They are definitely worth it.
 
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Supercharged111

Comic Book Super Hero
Oct 25, 2019
4,908
7,670
113
Colorado Springs, CO
I had the new version of the AEM A/F gauge and it takes all the guesswork away.

Yes, it's like a cheat code for tuning a carb. Set the main jetting, move onto needles (Edelbrock), do secondaries and done. It idled stoich all the time, cruised stoich, stepped up around 13.5-14:1 on primaries and secondaries took it down to 12.9:1. Every time, no matter the weather. Only reason I ditched it for EFI was it boiled fuel like mad and would leave me stranded. I tuned a friend's Holley and it didn't seem to have that big a range of AFRs, i.e. cruise with no stink then floor it and have all the fuel you need.
 
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Boglog

Apprentice
Mar 19, 2020
62
91
18
WA
I’d think one of the hurdles to overcome when adapting an afr to a carbureted vehicle is where to put the o2 sensor without a factory location? If it’s going to be permanent you’d probably need to weld on a bung. Does the gauge come with something like that?
 

500/600

Royal Smart Person
Nov 17, 2018
1,167
2,638
113
West Virginia
I’d think one of the hurdles to overcome when adapting an afr to a carbureted vehicle is where to put the o2 sensor without a factory location? If it’s going to be permanent you’d probably need to weld on a bung. Does the gauge come with something like that?

I added a bung when I built my headers months ago in preparation for EFI. The gauge also comes with a bung and instructions on where to put it.
 
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DSPbuilt

G-Body Guru
Jan 7, 2016
564
1,526
93
Cape Coral, FL
I have one on the Cutlass drove it yesterday for the first time. My problem right now is that i am open header and the sensor is too close to the tip so i get bad readings.
My carb is also very inconsistent. I rebuilt it many years ago drove a little and say for about 5 years. Im probably just gonna go to EFI honestly. the car was already LS swapped with a carb when I got it.
 
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500/600

Royal Smart Person
Nov 17, 2018
1,167
2,638
113
West Virginia
I have one on the Cutlass drove it yesterday for the first time. My problem right now is that i am open header and the sensor is too close to the tip so i get bad readings.
My carb is also very inconsistent. I rebuilt it many years ago drove a little and say for about 5 years. Im probably just gonna go to EFI honestly. the car was already LS swapped with a carb when I got it.

Cool. The 4150 EFI systems are just too hit or miss in the reviews. For a ‘bolt on and drive’ setup it sure seems like a lot of unexpected difficulties are out their with less than stellar tech help. My intake has cast-in injector bungs so if I go ahead with EFI it will likely be multport and me tuning it. That would be better anyway and not a lot more expensive.
 
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lilbowtie

Comic Book Super Hero
Jan 7, 2006
3,460
3,965
113
Canton Mi
IMG_4066.JPG
 
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