massive reconfiguration time again.

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j par said:
View attachment 1715473378 View attachment 1715473379 View attachment 1715473381
This isn't giving my plugs a fair shake as they are the ones that I've been running for a little while. And of course yesterday they were really rich and today they were I believe a bit leaner. That's like the number eight number two and number three I believe. I don't know I figured I'd post them up anyways...
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That top plug is getting very close. You have enough ignition you can get the tune to where the upper part of the porcelain is a dull white. That would be about dead nuts.

Still looking at the top plug in these pictures, it looks like the heat range is about as good as it gets. Dry on the shell around the flat, 2 or so threads showing heat...that's about spot on.

Can't see WOT with the shells on and you'll need to make a hard pull to get a clean fuel ring down there.

Also, I don't know what you have for timing, but from the picture it looks like you could use a bit more initial, or bring the curve in quicker. Or maybe both.
 
j par said:
That first picture was number one on the front and this is number 8 on the back..
View attachment 1715475181
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I forget...what fuel is this? Just straight pump gas or a mix? This plug has the total timing looking good, but I'm having trouble getting a read on the initial.

It looks a bit rich at idle still and probably cruse too. If that door isn't opening, I'm not sure what that does to the fuel curve. No air, no fuel flow. But it has to be screwing with cylinder to cylinder distribution.
 
yellow rose said:
That top plug is getting very close. You have enough ignition you can get the tune to where the upper part of the porcelain is a dull white. That would be about dead nuts.

Still looking at the top plug in these pictures, it looks like the heat range is about as good as it gets. Dry on the shell around the flat, 2 or so threads showing heat...that's about spot on.

Can't see WOT with the shells on and you'll need to make a hard pull to get a clean fuel ring down there.

Also, I don't know what you have for timing, but from the picture it looks like you could use a bit more initial, or bring the curve in quicker. Or maybe both.
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I know I have the timing set a little low at 33 all in and 19 at idle. I could bring it up a couple. I was kind of seeing that on the plugs as well. I had tuned it back a couple degrees when I was trying to go from av to a small mixture the race gas added to 92..
 
yellow rose said:
I forget...what fuel is this? Just straight pump gas or a mix? This plug has the total timing looking good, but I'm having trouble getting a read on the initial.

It looks a bit rich at idle still and probably cruse too. If that door isn't opening, I'm not sure what that does to the fuel curve. No air, no fuel flow. But it has to be screwing with cylinder to cylinder distribution.
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It seems to have decent low throttle response but when I get into it it definitely has a bad hesitation. I tried letting the door open a little faster and that didn't help and then I tightened it a little bit and that seemed to help but I haven't given it enough test tries to see if I need to do it more. What really gets me is when I do get the RPMs way up and then I throttle back it really seems to run like crap on the throttle back down to cruise...???
 
j par said:
#1 after second drive..
View attachment 1715475320
And # 8...
View attachment 1715475321
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This makes sense to me. Number one is getting fed off the front of the front carb.

Number eight is getting fed from the rear of the rear carb and if the secondaries don't open at WOT that plug will read a bit leaner than number one. IMO, number eight is what you should be shooting for. That plug is close. You get all eight looking that way, you'll be popping in the tall cotton.

Still a little unsure of intial timing. Looks like it might like more to me.
 
j par said:
I run 3 gal of 92 non-ethanol with one gallon of 110 Sunoco...
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Ok. That's some of what I'm seeing on the plug. You got 19 intial at idle, but how quick is the mechanical coming in? You may be able to speed the curve up a bit and leave the intial where it is. The total looks nice to me. Just the curve may be a bit slow right off idle.
 
yellow rose said:
This makes sense to me. Number one is getting fed off the front of the front carb.

Number eight is getting fed from the rear of the rear carb and if the secondaries don't open at WOT that plug will read a bit leaner than number one. IMO, number eight is what you should be shooting for. That plug is close. You get all eight looking that way, you'll be popping in the tall cotton.

Still a little unsure of intial timing. Looks like it might like more to me.
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It would seem like there would be plenty of mixed time as they not only drop into 2 inch risers but also another four in opened punim before they start cutting into their own individual ports of the lower plenum of the tunnel ram and there is a crossover as well.
 
yellow rose said:
Ok. That's some of what I'm seeing on the plug. You got 19 intial at idle, but how quick is the mechanical coming in? You may be able to speed the curve up a bit and leave the intial where it is. The total looks nice to me. Just the curve may be a bit slow right off idle.
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I swear I got it set on the softest Springs and it comes in pretty quick I'll check my records here..
 
Like I said I got one silver one blue Spring. For anything faster would be to silver Springs I believe or two blues I can't remember...
IMG_20200222_183353.jpg
IMG_20200222_183353.jpg
that would be the middle right hand side. I could crop that picture a little bigger as well if need be?.
Here's the thing though all this timing and everything was all perfect and still is set exactly how I had it with the old carburetors and running spectacular..
That's why I'm feeling a lot to do with these carburetors needing adjustment..
I do have a set of primary and secondary jets that are leaner The next step. And I've already went 2-Step softer on the step up Springs which made it a bit leaner as I believe it allowed the metering rods to drop down in the primary Jets at idle..
 
Some of me wants to just put the old carbs back on the way they were set up and check this O2 sensor.. I bought some off cheap brand to go on my wideband and it's all over the place. But when it does seem to be reading correctly it is reading a point or two richer than what I'm used to seeing.. and I wonder about the set or the dark color on the plug outer ring that's just being rich?.
 
Also to add to this both my old carburetors were set one step cleaner on primary and secondary. And I said it earlier if you didn't catch it but the step up Springs I used were the ones out of my old carburetors as well. I'm crossing over Edelbrock Springs into this Street Demon. But from all indications they're the same ones as per our phone conversation on price LOL..
 
Just my 2 cents…. put tape over the O2 sensor and start working the carbs towards tip in and WOT. Sounds like the idle is satisfactory. The bog would be "lack of fuel".
 
j par said:
Like I said I got one silver one blue Spring. For anything faster would be to silver Springs I believe or two blues I can't remember...
View attachment 1715475424 View attachment 1715475427 that would be the middle right hand side. I could crop that picture a little bigger as well if need be?.
Here's the thing though all this timing and everything was all perfect and still is set exactly how I had it with the old carburetors and running spectacular..
That's why I'm feeling a lot to do with these carburetors needing adjustment..
I do have a set of primary and secondary jets that are leaner The next step. And I've already went 2-Step softer on the step up Springs which made it a bit leaner as I believe it allowed the metering rods to drop down in the primary Jets at idle..
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You may be right about the carb tuning (actually you are) but the plug says it wants more initial, or atleast some more timing at idle and cruise. You may need to dig up a sping with a loop on the end to get the curve to move quicker.
 
318willrun said:
Just my 2 cents…. put tape over the O2 sensor and start working the carbs towards tip in and WOT. Sounds like the idle is satisfactory. The bog would be "lack of fuel".
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Yeah I'm not paying much attention to the O2 sensor as far as worrying about the tune.. more so how it's actually running and operating. I just don't think the spark plugs need to look that dark that new with only 12 or 15 miles on them? Also that really crappy running as I roll off of a heavy throttle softly just kind of wants to stumble its way down? And definitely a large hiccup if I jam it to the floor out of nowhere in a high gear.. I'm feeling I can tighten the secondary doors even more.. again my old carburetors grin best one step cleaner primary and secondary. That is 1250 CFM..
 
yellow rose said:
You may be right about the carb tuning (actually you are) but the plug says it wants more initial, or atleast some more timing at idle and cruise. You may need to dig up a sping with a loop on the end to get the curve to move quicker.
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Like you're saying the tune is very very close. As again this is the same tune that work perfect with the old carburetors. They're sitting right there on the bench I could put them back on. I'm just trying to get these running the same way.. it starts and idles just great but under part load or slamming down it's not doing what I want it to..
 
The hesitation I'm sure I can get to go away but the crappy when it runs when I slowly roll off of a hard throttle has my concern...
 
j par said:
Yeah I'm not paying much attention to the O2 sensor as far as worrying about the tune.. more so how it's actually running and operating. I just don't think the spark plugs need to look that dark that new with only 12 or 15 miles on them? Also that really crappy running as I roll off of a heavy throttle softly just kind of wants to stumble its way down? And definitely a large hiccup if I jam it to the floor out of nowhere in a high gear.. I'm feeling I can tighten the secondary doors even more.. again my old carburetors grin best one step cleaner primary and secondary. That is 1250 CFM..
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I think (without being there, of course) you are fighting different issues at the same time and trying to solve it with one course of tuning. Get your primaries in sync and working flawlessly first. I'd disconnect the back secondary linkage on both carbs and focus on primaries only. Get it to work on both primaries at idle, part throttle, and sudden mash to the floor. Then introduce the rears by hooking up the secondaries. I've done this before (not on dual quads) to sort out one issue at a time.
 
318willrun said:
I think (without being there, of course) you are fighting different issues at the same time and trying to solve it with one course of tuning. Get your primaries in sync and working flawlessly first. I'd disconnect the back secondary linkage on both carbs and focus on primaries only. Get it to work on both primaries at idle, part throttle, and sudden mash to the floor. Then introduce the rears by hooking up the secondaries. I've done this before (not on dual quads) to sort out one issue at a time.
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interesting idea I'll take a look at the carbs here real quick and see if that's even possible..
 
j par said:
interesting idea I'll take a look at the carbs here real quick and see if that's even possible..
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I'm guessing you'll have mechanical secondaries, like a TQ or eddy, with a vacuum air door.
 
318willrun said:
yep. That's where I'd start, solve the primaries, then work on the secondaries. A guru may instruct differently, but that would be my approach
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I've never messed with a Demon carb. Make sure the back barrels are pressured shut so nothing stupid happens. I've never seen a carb that didn't, but I've never worked on a Demon.
 
318willrun said:
yep. That's where I'd start, solve the primaries, then work on the secondaries. A guru may instruct differently, but that would be my approach
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well the kid on the techline said pretty much starting from the ground up and from the primary circuit on back.. it's all making sense that's for sure.. I have a lot of different direction to go of course with even another change and step up Springs but I wouldn't be surprised if it wasn't just tightening that secondary door even more. That's one thing the Edelbrock didn't have... well I guess they did some kind of weighted door...
 
318willrun said:
I've never messed with a Demon carb. Make sure the back barrels are pressured shut so nothing stupid happens. I've never seen a carb that didn't, but I've never worked on a Demon.
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it's nothing like a traditional Demon carburetor its 90% more like an Edelbrock..
 
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