Holley Carb Experts Please Step In... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TIMSPEED · 06-16-2003, 04:05 AM

I'm trying to figure out how to tune my Holley 600cfm 4160 Carb. (Vacuum Secondaries, Electric Choke). A good friend of mine, let me borrow his $500 Wideband O² Sensor, and I hooked it up to a custom made O² Sensor bung on my exhaust (The sensor is heated, the bung is right behind the header collector), and it showed my tune was WAAAY off! I finally got the idle set @ 750rpm, with an A/F Ratio of 14.2:1. Then, when I did a WOT test, it showed, @ WOT (from 3000-5000rpm) it was at 11.5:1. Isn't that running a little rich? Shouldn't the A/F Ratio @ WOT be around 12.8:1?? My question is, how do I lean out the carb @ WOT? Do I need to adjust the float levels in the secondaries? Thanks guys!

sbc350gearhead · 06-16-2003, 07:35 PM

Adjust the floats so that the fuel level just reaches the sight plug and leave it there for eternity. Change to smaller secondary jets to lean it out. I have tuned many a holley but never with a tool like you have. Sounds pretty trick.

Cole's 87 · 06-16-2003, 09:25 PM

Go here and you should find every thing you need to know hope this helps . http://holley.com/HiOctn/TechServ/TechInfo/FMCTech.html

*mike reeh* · 06-17-2003, 10:54 PM

did you check it under load at WOT? you dont have air injection or any exhaust leaks do you?

06-16-2003, 04:05 AM	#1
TIMSPEED Join Date: Jan 2003 Location: Modesto, CA Posts: 1,321	Holley Carb Experts Please Step In... I'm trying to figure out how to tune my Holley 600cfm 4160 Carb. (Vacuum Secondaries, Electric Choke). A good friend of mine, let me borrow his $500 Wideband O² Sensor, and I hooked it up to a custom made O² Sensor bung on my exhaust (The sensor is heated, the bung is right behind the header collector), and it showed my tune was WAAAY off! I finally got the idle set @ 750rpm, with an A/F Ratio of 14.2:1. Then, when I did a WOT test, it showed, @ WOT (from 3000-5000rpm) it was at 11.5:1. Isn't that running a little rich? Shouldn't the A/F Ratio @ WOT be around 12.8:1?? My question is, how do I lean out the carb @ WOT? Do I need to adjust the float levels in the secondaries? Thanks guys! __________________ I have a few cars... See Them Here

06-16-2003, 07:35 PM	#2
sbc350gearhead Registered User Join Date: Mar 2003 Location: Columbus Ohio Posts: 1,413	Adjust the floats so that the fuel level just reaches the sight plug and leave it there for eternity. Change to smaller secondary jets to lean it out. I have tuned many a holley but never with a tool like you have. Sounds pretty trick.

06-16-2003, 09:25 PM	#3
Cole's 87 Registered User Join Date: Nov 2002 Posts: 272	Go here and you should find every thing you need to know hope this helps . http://holley.com/HiOctn/TechServ/TechInfo/FMCTech.html

06-17-2003, 10:54 PM	#4
mike reeh 5 day ban, learn to behave. Join Date: Nov 2002 Location: san diego, ca Posts: 684	did you check it under load at WOT? you dont have air injection or any exhaust leaks do you?



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