Holley/Demon Carb stumble

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Cudafever said:
You are not helping me with my confidence to learn to tune this carb!:BangHead::D

NO it is still the original BG/DEMON metering blocks

So i called NGK and was amazed that the recording said i had 10 sec wait.........And that was all i waited.
After taking with him a bit he gave me three spark plugs that he recommended. A platinum and double laser platinum plug and a race plug.
I haven't priced them yet but the RACING plug is no resistor. What is your thoughts about no resistor plugs!?..?!

Going to scare myself on price now.
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I was paying $399 a piece for the auto light 3934 s and the NGK 4554 for $249 at Baxter's and most places.
Like I was just saying I called NGK also and decide to go one heat range lower and I had to make one store price match another to get them for $249. I like getting a set for under twenty bucks...
 
j par said:
I was paying $399 a piece for the auto light 3934 s and the NGK 4554 for $249 at Baxter's and most places.
Like I was just saying I called NGK also and decide to go one heat range lower and I had to make one store price match another to get them for $249. I like getting a set for under twenty bucks...
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399 dollars holley ****!!!:rofl:
 
You are not helping me with my confidence to learn to tune this carb!
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I’m not trying to be the voice of gloom and doom........ but I think it’s foolish to not at least be aware of how totally out to lunch that carb body/metering block combo could be.
 
So the 2668 is 10.99 and in stock. The 5068 is 13.99 and can't ship until the middle of next month. The "racing plug" 7173 is only 2.99 each. HOW EVER!!!!! They won't be available to ship until the end of next month.............................
 
So, NON REsistor plugs.........Pros and cons.............I have a am/fm radio........but it don't work so no radio noise.

Now i'm thinking back to my o2 meter problems. One of them problems was was the RPM signal was whacked. And i had to put an adjustable resistor in line and then turn it up until there was not rpm signal and then turn it back just enough to get the signal back. The spark plugs i have in there now(i didn't know this at the time) are non resistor plugs.

Sorry kind of answered my one question.:lol:
 
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cookietruck said:
about ten minutes on any forum is probably the sweet spot.

i don't like to type long messages so posting an image is easiest.

i pulled this from the tapatalk carb forum,
holes A and B would be the emulsion bleeds in your holley carbs.
Hole D would be the high speed bleed...i guess this is the way it works. people that know more than I do seem to agree with it...

View attachment 1715368142
Click to expand...

I said i would take a better look at this graph when i got time and i have. Even printed it out a little bit bigger but ..............

I mean i get it... as it solid fuel that you add air to (emulsion) before it is discharged into the eng.
more air makes it lighter(so to speak ) and allows it to come in faster or slower(into the carb)

But one hole 2 holes ..3 and are some of them in fuel. aka pulling fuel or are all them bleed in the metering side, air.
I have to go out and look at one of my carbs/ metering block to figure this out.

Man i wish i had another 3310 (750 vac secondary carb)
 
Cudafever said:
I said i would take a better look at this graph when i got time and i have. Even printed it out a little bit bigger but ..............

I mean i get it... as it solid fuel that you add air to (emulsion) before it is discharged into the eng.
more air makes it lighter(so to speak ) and allows it to come in faster or slower(into the carb)

But one hole 2 holes ..3 and are some of them in fuel. aka pulling fuel or are all them bleed in the metering side, air.
I have to go out and look at one of my carbs/ metering block to figure this out.

Man i wish i had another 3310 (750 vac secondary carb)
Click to expand...



Hang with it. What you learn will be priceless. You're going to find out that many of the carb gurus are not. That's why in 1987 I switched to mechanical fuel injection, which has its own set of issues that require more work than it's worth.

You are now finding out why I tell anyone who asks not to buy an off the shelf carb. I can name 5, maybe 6 guys right now who I'd trust to set up a carb. Maybe more if I typed them out. All have a proven track record of producing killer carbs.

Emulsion is tricky. It was all the rage in the 1980's and 1990's to use as much emulsion as you could. Now, that is not so much the case.

IMO booster design and placement in the Venturi is just as important, or maybe more important than emulsion on the whole. There is way more science to this stuff than is actually understood.
 
I find that a lot of playing with carbs in the vehicle is tactile.
If it doesn’t “feel” like the motor is responding favorably to the changes....... it probably isn’t.

It is much easier on the dyno looking at the power, air, and fuel flow and just chase the numbers til it’s doing what you want.

It’s also way quicker to figure out when it’s too far off to be able to just “tune” it and make it good....... and that it’s going to need some “parts”.
 
Agree but a eng or chassis dyno is 150 mile away from me. and i don't have the $$$$ for a day of carb tuning.
 
first verify that my artwork is right.
#8 is MAB......?
Help me to understand all the rest of them holes/numbers between my fuel and air red circle.
Numbers 22,23,24,25
upload_2019-7-24_18-23-22.png

THIS IS NOT MY CARB! IT'S FROM A BOOK OF THE 80'S
 
For 5 bucks I dropped the hammer and bought it!!!!!!!
Thanks
so how far off am i on my drawing???
 
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Cudafever said:
first verify that my artwork is right.
#8 is MAB......?
Help me to understand all the rest of them holes/numbers between my fuel and air red circle.
Numbers 22,23,24,25
View attachment 1715368717
THIS IS NOT MY CARB! IT'S FROM A BOOK OF THE 80'S
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The main air bleed is in the main body. It's the smaller of the two. The bigger bleed is the idle bleed.

23 looks like it's pointing out the emulsion channel.

The bottom and middle 22's are the emulsion holes. The upper 22 is the kill bleed.

That is a 2 emulsion block. Those are generally .026 holes. Evidently your Demon block has three of those and all three are bigger than .026 which as PRH pointed out is a lot of emulsion.

I think 8 connects to the MAB in the main body but to be sure I'd rather look a onto my blocks in the shop to say for sure.
 
Cudafever said:
k so is there air or fuel coming out of the lower holes number 22?
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Both. Fuel is coming up from the main jet and air from the main bleed is drawn in and then added to the fuel in the emulsion well. That's why size and placement of emulsion makes a difference.

I have a couple of cutaway metering blocks out in the shop. I'll see if I can dig them out in the morning and take some pictures. As long as the wild fire doesn't make me evacuate tonight.
 
If your ordering parts make sure to get a power valve plug for the rear, along with the notched float and jet extension kit. Also make sure you have those plastic vent baffles/whistles on both blocks. Another thing to verify is that the bowl vent tubes are not up tight against the air filter lid.
 
skrews said:
If your ordering parts make sure to get a power valve plug for the rear, along with the notched float and jet extension kit. Also make sure you have those plastic vent baffles/whistles on both blocks. Another thing to verify is that the bowl vent tubes are not up tight against the air filter lid.
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Sounds like we're getting ready to launch missals...
 
skrews said:
If your ordering parts make sure to get a power valve plug for the rear, along with the notched float and jet extension kit. Also make sure you have those plastic vent baffles/whistles on both blocks. Another thing to verify is that the bowl vent tubes are not up tight against the air filter lid.
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These are some good thoughts, will check on them tonight.
 
You are now finding out why I tell anyone who asks not to buy an off the shelf carb. I can name 5, maybe 6 guys right now who I'd trust to set up a carb.
Click to expand...

I’m actually in the other camp.
I try and use off the shelf carbs most of the time.
Especially nowadays........ there’s some pretty good stuff out there now, for reasonable money.

For hot street/strip builds we use the QFT street Q’s, and Holley race Brawlers pretty often, and they’ve been pretty good right ootb.
The key is buying the right one.
I feel like most people buy carbs that are too big for the application........if you’re trying to find the best balance between streetability and power.

It’s like the OP’s 850 Demon in its original form.
Ran decent, power was good....... couldn’t get it to leave well.
It’s too big for his combo.
Had it been a 750, you could have added some adjustable air bleeds to the main body, and with a little tuning it would have been fine at the line, and would have given up almost nothing on the top end in a combo like that.
 
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PRH said:
I’m actually in the other camp.
I try and use off the shelf carbs most of the time.
Especially nowadays........ there’s some pretty good stuff out there now, for reasonable money.

For hot street/strip builds we use the QFT street Q’s, and Holley race Brawlers pretty often, and they’ve been pretty good right ootb.
The key is buying the right one.
I feel like most people buy carbs that are too big for the application if you’re trying to find the best balance between streetability and power.

It’s like the OP’s 850 Demon in its original form.
Ran decent, power was good....... couldn’t get it to leave well.
It’s too big for his combo.
Had it been a 750, you could have added some adjustable air bleeds to the main body, and with a little tuning it would have been fine at the line, and would have given up almost nothing on the top end in a combo like that.
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I haven't had a chance to play with any of the QF stuff since Holley bought it out. Calling QF today gets you Holley. Holley tech is pretty much worthless IMO.

The QF stuff we used bofore the buy out was very good. Hopefully it's still the same.
 
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