Quick Fuel Slayer Rich!!!! installed LC-1 wide band

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67/6barracuda

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I been tuning my car for sometime now. Its tough being new to an unfamiliar engine and components as we build these cars (novice). The deal is everything is somewhat new to me. New dist., cam, carb, exhaust, ect. It ran like a turd. I re-curved the dist. light springs and made a little more power with 19* initial, 16* in the dist. 35* total with V can plugged.

However, the quick fuel slayer 600cfm carb was running extremely rich. Had it adjusted 1 turn out from the seated position on the idle mixture screws. Was adjusting it to get the best vacuum reading of 17-19". Which I thought was pretty good with the very mild xe256 cam. I was still running way rich.

Well today I got my LC-1 WB installed. My AFR was in the 11's at idle...O-boy. Reset my idle mixture screws about 1/2 turn out from seated position and now my AFR is 13.9 (better). My guess is ill have to jet it down form the #68 mains to probably #66.

I still need to go for a ride tomorrow and see how the rest of the throttle relations are reading. I'm going to order those jets and a new 8.5 power valve. Does this sound about right to the experienced folks out there? Hopefully im headed in the right direction. Got my new fuel pump and regulator installed as well. It's set at about 6.25psi. I figured ill leave it there for now. Don't mind my wires bellow I will get that cleaned up.
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How were you "setting" the idle? Almost sounds as if you "didn't."

Adjust the screws with engine fully warmed at tweeking idle speed to keep it in range, screw them in slowly one at a time until tach or vacuum gauge drops, back them back out SLOWLY until the RPM/ vacuum "peaks" and then turn each of them back in "just a touch" until RPM or vacuum just barely drops "or doesn't."

What I'm saying is you want them "on the lean side" of the peak

You have to go back and forth with these a bit alternate.

If you have a huge / overlap cam you WILL NOT be able to get a decent idle at a fairly lean mixture. This is one reason "built" engines will never "meet" emissions
 
67dart273,
I did originally set it with a vacuum guage got my highest reading which did raise the idle. Thats when I set the idle down to 750rpm. Idle good but at a rich condition
I'm now at the point were I believe my mains are to big. Which using the AF guage in my opinion confirmed. Once I get the smaller jets, I will start from scratch again as you described.
 
AFR gauges aren't always accurate at idle. For idle purposes, go by vacuum reading (and plug color...if it's pig rich, you'll blacken the plugs).

Main jets won't affect your idle, but the Slayer has replaceable idle air bleeds and idle restrictors.

To check your idle circuit, drive the car at a steady 40-50 mph and take an AFR reading. To check your mains, drive a steady 70. Take a reading there. If it's rich at 40-50, you'll probably want a smaller idle restrictor or LARGER (edit) idle air bleeds. If it's rich on the mains, smaller main jets (or larger bleeds).
 
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yeah, dont buy jets yet. Idle mix is in the air bleeds. if you want to lean out your idle (outboard bleeds) then you INCREASE the size of the bleed jet or orifice. Does your carb have a air screw under the air cleaner stud? That can be turned to adjust idle speed while keeping the transition port square shaped. also you dont want to get out of the 1-2 turn idle screw adjustment zone. use the bleeds to alter that. The wideband is the ultimate carb tuning tool .
"...If you want to richen up the idle simply replace your idle air bleed with a smaller one (less air in the system = more fuel = richer idle), this will help you get your mixtures screws within the 1-2 turn range..." Carb Class: Air Bleed Basics - Holley Blog
 
Oops! Thanks for catching my air bleed brain moment!
Ok guys I appreciate the input. I do my research on the air bleeds. At the moment I believe those are the jet looking t
yeah, dont buy jets yet. Idle mix is in the air bleeds. if you want to lean out your idle (outboard bleeds) then you INCREASE the size of the bleed jet or orifice. Does your carb have a air screw under the air cleaner stud? That can be turned to adjust idle speed while keeping the transition port square shaped. also you dont want to get out of the 1-2 turn idle screw adjustment zone. use the bleeds to alter that. The wideband is the ultimate carb tuning tool .
"...If you want to richen up the idle simply replace your idle air bleed with a smaller one (less air in the system = more fuel = richer idle), this will help you get your mixtures screws within the 1-2 turn range..." Carb Class: Air Bleed Basics - Holley Blog

Appreciate that pista i read the Air bleed Basics. Aaron I will take a test drive as you described taking readings at prescribed MPH and see what I get. Thanks again.

The quick fuel does have the changeable idle and high speed air bleeds. Perhaps I can get back into that 1-2 turns out with just the air bleed adjustment. I will need to add air by going bigger on the air bleeds presumably, by what 2 sizes? I check back with yeahs when I get those readings.
 
You guys were dead on with the advice. At idle the AFR is in the 11's (rich) slowly leaning out with speed...(idle air bleeds). At 40-50 mph at steady cruise I get high 14's low 15's (Optimal Main jet). Beyond the 50 mph up to 70 mph it begins to fating up rich again. Running down the highway at steady cruise of 70 mph my AFR is high 11 low 12's AFR (High speed air bleeds).

Is it safe to say that I need to adjust both idle/high speed air bleeds? The main jets probably do not need to be touch at this point. Secondly, my carb came with a 6.5 PV should I change it to a 8/8.5 if making between 16-19" of vacuum? Thanks again
 
If the carb has adjustable emulsion in the metering block you can open the bottom hole up .002-.003 and see if it cleans up the top end a bit.

You can also open up the main air bleed but that will delay the mains coming on a bit.
 
Now the problem is this: if you open up the idle air bleeds to give you more control over your curb idle, your 40-50 mph cruise will be too lean, and you'll run into surging. It's almost like you'll have to try some combination of smaller IFRs and smaller air bleeds to try to make it work.

Your cruise on the mains is quite rich. More than likely, you'll have to step down several jet sizes if it's cruising at 12:1. I don't think just bleeds will clean that up. Then you have to worry about your power AFR, so you'll likely have to open up your power valve restrictions. As you can see, this is a long process (and sometimes expensive if you're buying jets and bleeds).
 
Now the problem is this: if you open up the idle air bleeds to give you more control over your curb idle, your 40-50 mph cruise will be too lean, and you'll run into surging. It's almost like you'll have to try some combination of smaller IFRs and smaller air bleeds to try to make it work.

Your cruise on the mains is quite rich. More than likely, you'll have to step down several jet sizes if it's cruising at 12:1. I don't think just bleeds will clean that up. Then you have to worry about your power AFR, so you'll likely have to open up your power valve restrictions. As you can see, this is a long process (and sometimes expensive if you're buying jets and bleeds).



All true but I doubt the idle air bleed is big enough to lean it out at a cruise by much.
He could use a smaller IFR but then he has to get the metering block off. He can also install a T slot restricter (spelling) to help get the fuel curve in shape.

Just depends on how close he wants it and how much work he wants to do.
 
Now the problem is this: if you open up the idle air bleeds to give you more control over your curb idle, your 40-50 mph cruise will be too lean, and you'll run into surging. It's almost like you'll have to try some combination of smaller IFRs and smaller air bleeds to try to make it work.

Your cruise on the mains is quite rich. More than likely, you'll have to step down several jet sizes if it's cruising at 12:1. I don't think just bleeds will clean that up. Then you have to worry about your power AFR, so you'll likely have to open up your power valve restrictions. As you can see, this is a long process (and sometimes expensive if you're buying jets and bleeds).

I appreciate the input guys. Sounds like im about to chase a rabbit down a hole. Originally I was going to jet down the mains from 68's to 66's. Thinking it would lean out my rich condition. But as it turns out its just at idle and highway cruising above 60+MPH's. 40/50 mph is about perfect. As determined by the AFR.

Do you recommend leaving the main jets alone? Do I start with the air bleeds or the emulsion restrictions on the metering block as yellow rose suggested? Air bleeds are easier there right on top of the carb. Those small restrictions on the metering block are adjustable but will require the song and dance of removing the fuel line, bowl, etc. Which i would need to anyway if I change my PV and main jets. I am learning through this process guys sorry for all the questions.

Remember as I was taking these readings. I was about 3/4 turns out on my idle mixing screws as well. If I was to set them at 1.5 as suggest in the instructions I bet i would be at 9:1 or worse its that bad you can smell the gas. I had it at 1/2 a turn got better readings 13.9:1 but it wouldn't stay running.
 
I appreciate the input guys. Sounds like im about to chase a rabbit down a hole. Originally I was going to jet down the mains from 68's to 66's. Thinking it would lean out my rich condition. But as it turns out its just at idle and highway cruising above 60+MPH's. 40/50 mph is about perfect. As determined by the AFR.

Do you recommend leaving the main jets alone? Do I start with the air bleeds or the emulsion restrictions on the metering block as yellow rose suggested? Air bleeds are easier there right on top of the carb. Those small restrictions on the metering block are adjustable but will require the song and dance of removing the fuel line, bowl, etc. Which i would need to anyway if I change my PV and main jets. I am learning through this process guys sorry for all the questions.

Remember as I was taking these readings. I was about 3/4 turns out on my idle mixing screws as well. If I was to set them at 1.5 as suggest in the instructions I bet i would be at 9:1 or worse its that bad you can smell the gas. I had it at 1/2 a turn got better readings 13.9:1 but it wouldn't stay running.


Mess with the air bleeds first. Just write down where you are and what you change so if you get off the rails you have a baseline to get to. It's easier to play with air bleeds than the others.

If you want to pick the fly poop out of the pepper you can play with emulsion and IFR's and Tslot restriction once you are close.
 
I'd square up the t-slot first, then turn your mixture screws out 1.5. Then start messing with the idle bleed. Some of the newer carbs have an extra idle air bleed under the air cleaner stud, takes the fun out of drilling your throttle plates with small holes. If you have a pipe cleaner tool with a bunch of wire gauges in it, you can hang those in the idle jets and take a reading, then mic the wire and bleed id and just do the math for what smaller bleed you need. Does Weber still make the "power plate"?
 
I'd square up the t-slot first, then turn your mixture screws out 1.5. Then start messing with the idle bleed. Some of the newer carbs have an extra idle air bleed under the air cleaner stud, takes the fun out of drilling your throttle plates with small holes. If you have a pipe cleaner tool with a bunch of wire gauges in it, you can hang those in the idle jets and take a reading, then mic the wire and bleed id and just do the math for what smaller bleed you need. Does Weber still make the "power plate"?

I tried verifying the proper adjustments for my carb. For every step forward I seem to run into something. As you guys may know tropical storm Cindy has been hammering the southeast. So instead of me going outside to verify my idle air bleeds size. I decided to pull the specs of my carb of quick fuels site and even though I look at several sources they all seemed to say the samething. Idle Air bleeds Primary .070 secondary .039. I placed my order for .073 IAB's along with .029 IFR's for the metering block. I read somewhere the the IFR's were 31's from the factory.

Well I pulled my carb today to verified the T-slots were in fact squared up on the primary side. Go to replace my IAB's and damn it .073 already in there from the factory. So I decided to dig into the Carb and replace the IFR's and they had unmarked drilled blanks from the factory. I had no idea what size the stock restrictions where. So I put the .029's in. Fired up the car seems to be running the exact same. This was my frustrating first lesson on Carb tuning but not for nothing I at least know exactly what's in my carb now.

I now have to reorder some new IAB's probably around .077 or .079's. My secondaries were suppose to have .039's for IAB's and they are in fact .033's so Ill probably go up on those as well.
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Peace of mind is a great starting point. Question: You got the old bleeds now, can you just drill them out? Some pin drills are cheap and the little finger turner is all that's needed to breeze through that brass bleed. Id give good money to have that O2 analyzer. I got an old narrow band still in the box, never bothered to take it out.
 
Plug that middle emulsion port. Move ifr to below fuel (easy tap job, google). 4 hole spacer, not just a gasket. Dont get all cray-cray on the bleeds, small changes. Make sure you change the right ones lol, that carb should have 70/39 and 31/31.
 
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Plug that middle emulsion port. Move ifr to below fuel (easy tap job, google). 4 hole spacer, not just a gasket. Dont get all cray-cray on the bleeds, small changes. Make sure you change the right ones lol, that carb should have 70/39 and 31/31.

Something is definitely up with this carb. Maybe blown PV or something. My transition slot is squared up on the primary and closed on the secondary. I just tested the car went from 73# to 76# then 79# on the IAB's made hardly any difference at all. Do you know what size IFR's come with these carbs. I installed a 29# didn't seem to make much of a difference either. Does the IFR regulate fuel or Air when installed at the top on the Emulsion with these quick fuels. I thought it was fuel but doesn't fuel enter from the bottom and air is introduce from the top where the restriction is currently installed?
 
Something is definitely up with this carb. Maybe blown PV or something. My transition slot is squared up on the primary and closed on the secondary. I just tested the car went from 73# to 76# then 79# on the IAB's made hardly any difference at all. Do you know what size IFR's come with these carbs. I installed a 29# didn't seem to make much of a difference either. Does the IFR regulate fuel or Air when installed at the top on the Emulsion with these quick fuels. I thought it was fuel but doesn't fuel enter from the bottom and air is introduce from the top where the restriction is currently installed?

I'm at a loss right now. Should I attempt to open the secondary throttle blades to get more air in the carb? everything I read says to keep secondary closed on VS carbs.
 
Something is definitely up with this carb. Maybe blown PV or something. My transition slot is squared up on the primary and closed on the secondary. I just tested the car went from 73# to 76# then 79# on the IAB's made hardly any difference at all. Do you know what size IFR's come with these carbs. I installed a 29# didn't seem to make much of a difference either.
From my understanding, small changes in IFRs make a lot bigger changes to AFRs than IABs. I'd have thought you still should've noticed a difference though. Maybe there's some thrash in the idle channel somewhere?

Does the IFR regulate fuel or Air when installed at the top on the Emulsion with these quick fuels. I thought it was fuel but doesn't fuel enter from the bottom and air is introduce from the top where the restriction is currently installed?
IFRs regulate fuel regardless of which position it's in. There are opinions on which is better, but on the carbs I've messed with, I tend to notice more steady AFR readings when the IFRs are in the bottom location.

I'm at a loss right now. Should I attempt to open the secondary throttle blades to get more air in the carb? everything I read says to keep secondary closed on VS carbs.
This is an interesting question. I'd be curious to see what other have to say. I would say since there is an idle circuit and transfer slot on both, the primary and secondary sides on a vacuum sec carb, and they more than likely run off the same idle mixture screws as the primaries, I'd think you would still want at least some of the secondary transfer slot showing at idle. Just thinking out loud on this one...
 
Just because I'm curious tomorrow I will drill my IAB to 3/32 or .094" the next size bit I have. If my AFR doesn't change I'll put my original .073 back in then order new IFRs go from .029 down to .025. I also want to try lowering my float level. It's right in the middle of sight glass. My fuel regulator is set at 6.25lbs I was thinking of dropping that as well for a test. The other thing is the power valve maybe malfunction.
 
You know I never did, my car is now in the garage for body work. I haven’t really messed with it. I did throw a edelbrock 600cfm just to see a difference and it appeared to still be rich with a lot of hydrocarbon smell. I want to verify that my balancer is still good at TDC with a piston stop, something is telling me it’s a timing issue. I hooked up the PVC system as well and still had issues.
 
Ok thanks, the reason I asked was because I've ordered exactly the same carb and as I only have tuned a couple of Edelbrocks before I'm trying to learn as much as I can about Holley/Quick Fuel tuning and what issues I can get into.
I agree, the ignition must be set correctly before start tuning AFR and with all the actions you have described it could be a timing issue.
 
Ok thanks, the reason I asked was because I've ordered exactly the same carb and as I only have tuned a couple of Edelbrocks before I'm trying to learn as much as I can about Holley/Quick Fuel tuning and what issues I can get into.
I agree, the ignition must be set correctly before start tuning AFR and with all the actions you have described it could be a timing issue.
You can go over to RFS and see what commonly has to be done to the specific carb to run well.
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There is a subforum under Holley called Stickies. Worth checking there first.
 
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