What Makes a Demon Blow Through Carburetor Special?
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- Опубликовано: 7 мар 2017
- Some have questioned my choice of going with a carburetor for my #FairmontProject engine, #DarkMatterPikachu.
In this video I talk about what makes my Demon carburetor special. I also show how to service the jets, adjust float level, adjust the idle, adjust the accelerator pumps, adjusting the opening of the secondary throttle plates, and what tools you'd need to do all of that with.
Is fuel injection better? I think that's a subjective question. I'll admit that you have better fuel control with fuel injection. I'll also admit that fuel injection would likely be more efficient. However, I feel this carburetor will work perfectly for my application. If not, I have a kick butt carburetor I can use on another engine.
No matter what, I think the engine will make plenty of power with this Demon carburetor and that's the main take away here.
My Demon Carburetor: www.jegs.com/i/Demon-Carbureti...
Gasket kit for Demon: www.holley.com/products/gaske...
Holley Jet Kit: www.holley.com/products/fuel_...
Holley Jet tool: www.holley.com/products/fuel_...
The #FairmontProject playlist: • ETCG Gets a New Car! -...
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Camera: Brian Kast
Eric Cook
Thanks for watching!
Discussion about this video: www.ericthecarguy.com/kunena/...
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Eric hopefully I'm early enough for you to see this. I love your channel, been with you since the start. You've taught me so much and I hope you know how influential you are to many young people in the industry.
Thanks very much for your comment. I never get tired of hearing how my work helps people. Thanks again.
@@ericthecarguy hello mr Eric, I also have a 650 demon bt carb. I boost tested it with a air compressor and I'm getting alot of air escaping through the side of the carb from the black rod that rotates the primary throttle plates. Is this normal? Thanks
When I watch this, I get a nostalgic feeling of an era gone by. In retrospect it is easy to see, we were on an accelerating escalator of technology. But at the time it was hot rods, cool stuff, and the timeless promise of youth. Even now it's interesting from an engineering and design perspective. Thanks for the walk through!
Thanks for all the vids. I watch them at the end of the night, not so much to learn, this vid is an exception, amongst others, but to chill out. I love the technical stuff but somehow watching you walk thru mediocre maintenance is just as enjoyable haha. I hope you understand my obsession
I've waited 3 years for the dyno session and the 'how-to' on the running on the carb to get it going right. Thanks!!!
Ah hah! THANK YOU! I've always seen carbs adjusted in different car shows, but never once saw them explained. I've worked on them in lawnmowers and motorcycles, but always found them to appear far too different to make heads or tails of on a car. This demystified it for me!
Now that's a quality carburetor, i like the access to all adjustments and jets.
I can see why you chose it, it's a beast :-D
Indeed it is.
The idle-ease is a nice feature when bigger cams get poor vacuum at idle. It takes the "oops" out of drilling butterflies to get the extra air needed to serve idle. Cranking the idle screw has limitations: go too far and the signal that the idle port is supposed to see gets sapped by the transfer slot and mixture control gets lost as pressures across the two ports equalizes. I have a [pre-Holley buyout] 650 serving a small block, and love it - after I did the QC work needed on the metering blocks. That took about 45 minutes each, using a set of pin gauges and jewelers glasses to inspect every hole and verify sizes. [tech tip: chinese pin gauge sets are cheap, so break out your micrometer - my set had 4 sizes duplicated or ground incorrectly]. They apparently drilled the idle screw cross feed first, then the idle well and... all 4 idle cross feeds had 40 to 50% blockage from metal that wiped [dull bit?] across the opening and I also had an air bleed with partial blockage. All good now, and since I did the work, I have a fully blueprinted baseline at my disposal should I ever find a need to fool with air bleeds & emulsions.
The thing I like about a [well tuned] carby is that it is not waiting on an o2 sensor to confirm what it's doing - it runs in the 'now': mash the accelerator and fuel is delivered before a computer can make adjustments. But for the basic fuel map being spot on, an EFI is always one cycle behind in finding perfection so the carb vs. efi debate may never end - no such thing as perfect.
That carb is awesome! Dialing the float height takes 5 minutes instead of 5 hours! Keep up the good work bud, not sure why people are knocking this build series, but I think it's fantastic
Watching the video when you try to set up this carburetor will be hilarious. All of the fun that we saw on the dynamometer, playing with different jet sizes, was just the beginning.
That thing is absolutely beautiful. A work of art.
I really miss ETCG! i hope you find a new shop and come back to RUclips! Hope you're doing well and had a good Christmas and new year!
Eric, that carb is so sexy! takes me back to my first ever job, 16, sweeping floors, sandblasting parts and building holley carbs. I'm starting to think that I'll love the fairmont more than you will! haha
Thanks for the detailed view of your carb Eric! Though I don't miss em on a daily driver, I'd go carb on a project like this, myself.
Great video Eric. That is a cool looking carb, and judging by the results from the dyno vid, looks like you made the right choice to go with the carb vs. EFI. Saved yourself a headache in electronic work. Now that the engine is mechanically dialed in, pretty sure Oliver is going to be scary fast.
That car will be a beast with those numbers Eric,congrats
I will say this, I had a speed demon on my 68 charger when I got it running the first time. It had a built 383 that was putting out 476 hp to the crank. Once I got the cab dialed in, it made the car rip!! Here I am adding a few thing to the car, and one major mod, is a PRO Charger D1SC super charger, with an intercooler. Doing a lot of research on what is out there for Blow through carbs, I decided to go with the Demon 750, like in this vid. Since I know what it took to get my speed demon dialed in, getting this one to all right should not be an issue..
I had so much fun with Holley four barrels in my younger days. I even got some advice over the phone from Holley tech line on how to modify a vacuum secondary so it works like a double pumper if you want to. It actually worked too well on the street as it smoked the tires in first gear ALL the time. Fast forward many years to old age and now I rather have fuel injection because my hot rod days are over. Pulling a travel trailer through different altitudes sort of requires it. Even my boat has direct port injection on the outboard. Starts first time every time! You just wait till you get to my age!
I just got this Carb for my 1970 Buick Riviera 455-4. I cant wait!
Thanks for sharing your knowledge, I have the same carb on my 355 SBC
I am using the exact same carb. The nice thing is though that Holley just had them on sale on their site for $256...list of over $800 :) Scored!! I should have bought more and re-sold them.
thanks for all the details on the newest demon
Nice run down on the demon.. if you start too lean out once in the teens with your boost, and tried bigger jets etc, go twin fuel lines from reg to carb..worked for me👍
Nice pretty Carb. Thanks for showin us around Erick & Brian... Angelo
I'm building my '78 360 LA for ~500hp (naturally aspirated), and went on to Holley's website and damn! Brawlers, Screamin' Demons, Street HP, Track Warriors, so many choices in the 500 to 600 range with.... what seems to be the same tune-ability! Idle and high speed air bleeds, idle feed restrictors, 4 door PV's and PV channel restrictors, emulsion bleeds, etc etc etc. It's so hard to make a choice like that! Care to shed some light? Hahaha Thank you for the video, brother!
I think your choice in carborators is top notch in fact I have the Street Demon 650 on my Chevy 350 sitting in my 1970 Jag
The most important thing you forgived to mention what makes this carburettor really special. But amazing carburetor, go on I like this build! /sorry for my bad english :) /
Who ever gave you shit for YOUR carb choice needs a front wedgie! The Demon carbs are incredible by design and quality. I've been fortunate to have owned 3 second hand well aged Demons. All have been reconditioned to new quality and given good homes. I used all 3, and I won a lot of money with those carbs. Good video!👍
well them carbinators where do you plug in the laptop to get the graph of how much rice oil to add?
Worth mentioning the floats are made of material that won’t crush or rupture. The extra machine work in the main body and throttle plate make the carb and excellent choice for blow through application.
Very good break down. Thank you.
Great video Eric! Way more advanced than my autolite 2100 on my 66 stang lol
that is one fine machine eric - thx 4 the walk through
sweet carb I'm old school I remember all this stuff points before msd nice choice
Sounds like you've had good results with your demon carb. and I do recognize the Demon carbs are a different animal especially your blow through design - but I cant help remembering how troublesome Holley carbs once were back in my day. Seems like every time 'ya turned around they were blowing out power valves, leaking like a sieve, mysterious tuning problems that couldn't be resolved etc etc., and some of this may well be due to improper set up as many have great success with Holleys, but in the end I remember I could bolt on a Carter or even a properly set up Quadradjet and once adjusted hardly ever having to touch it. I like the idea of how Holleys are made to be tunable for each application, but I eventually got the impression that unless you were born with the elusive Holley tuning gene they never worked right-lol But in your case the dyno results speak for themselves and I hope your success continues, cant wait to see the tire smoke-!
well explained Eric.love your carby mate good choice
Great video Eric
Great review!
also the floats are Nitrophyl instead of brass as a brass float would implode and sink ive done blowthrough conversion on a holley carb for my buick
I was waiting for Eric to mention solid floats to prevent collapse under boost pressure, but didn't see it
Thanks for sharing this
Nice presentation, and I'm happy for you that you're pleased with your decision to go with a carburetor. I do wonder with all of the Demon® carburetor's complexity if it would have been a better option to go with contemporary fuel injection. You've presented jet kits and mentioned dialing in the amount of accelerator pump "squirt". With all of that - not to mention adjusting for four separate fuel circuits after installation - wouldn't it be an all-around better choice for fuel injection?
Still, I respect your decision and value the information you are putting forth here on your channel. I am really coming from a position of embracing technology, and view anything based on classic, old-school methods as antiquated. That's just me and my bias; I'm not making a value judgement.
very neat video, thank you! I've heard the name Demon plenty of times but never gave them a second look. I've done a lot of research and learning on draw through turbo setups (specifically in the desperate want to build a boosted Ford big six for an off-road application) and figured it would be the way to go along with a methanol injection, but obviously an intercooled blow through would be ideal. will you be doing any videos in the future (going to check in a minute here if you beat me to it) on tuning a blow through setup? that'd be something I'd love to see laid out in a video. thanks!
All you need to tune a Carb is a wide band 02 and simple parts. A lot hate on carbs but when you are on a budget and you take your time to learn them they run really well. Are they as efficient as F.I. ... NO but they make very close to the same HP. I asked Sloppy to make a Carb turbo video but he said he had no interest Thank you for the video!
Very excellent good explanation video big fan of holley and demon carbs big fan of ur channel
I hope Holley type carbs have improved in the thirty years since I gave up on them. They would work great for about a week then they'd turn to crap and you couldn't tune them. It turned out that the channels in the metering blocks would get closed in by the gaskets. A quick track side fix was to take a razor blade to the hump and trim it down so the engine would run without coughing out. If they haven't improved the design or the gaskets you'll be Changing them weekly. I looked at Webber, SUs Rotchester and a bunch of other types until EFI started coming to the rescue.
Thanks Eric.
THANK YOU!! That was the ONLY good look anyone has ever given me, of a Demon.
I've done a LOT of Holleys back in the day... I think I'm more impressed with the fact that the Bowl Gaskets didn't WELD on the Carb!!!
That to me, was the worst thing about tuning a Holley. Well, that and the World's most fragile Power Valves!!! 😖
I just got two new edlebrock carbs for a duel quad set up on a big block ford. What modifications do you have to make to my carbs to make them work as "blow through" carbs?
I learned a lot thank you
wow KEWL 😊 thanks for sharing
I still think a carburetor was a poor choice for this application. But hay when you are pushing 500hp does it really matter.The cars shaping up very nice. Keep up the good work!
Eric, do G forces under acceleration affect the level of fuel in the float bowls?
Thinking I'll need one of those... eventually. Got a Pontiac 1966 Pontiac Sprint OHC Straight 6 that's begging for a turbo. (that's going to be an expensive journey / project)
that s what i wanted to know, thanks
nice job, good video
I think the overwhelming resistance to your choice to use a carb on this build is purely due to the fact that many younger people don't realize that there were turbocharged carburetor engines long before EFI was invented. I believe the first turbo chargers were used on airplane engines some time in the 1930's.... I think a lot of people are under the false assumption that turbos are never supposed to be used with carbs.
I agree, that's one of the reasons I decided to make this video. If nothing else, to give an introduction to what is possible.
Simon Coles it's also because EFI systems are superior in every way.
Except in cost, field serviceability, user tunability, space, lack of wiring, etc etc etc...
Cost for EFI kits, $1000US, not much more than a 750 Demon.
Field serviceability?? Lol, I tuned it for 14.7:1 at idle and oh look it's running exactly that AFR. Ooh no spark knock!!!! Ooh look the ECU adjusted.
If you can't tune EFI, you have no business touching a carb. Eric has the know how to do both. Like, really? Tuning lol. Just wow.
User tuning: in the comfort of your car away from spilling gas on a hot engine.
Jet kits cost less than tuners, so yeah.
I don’t see those throttle shaft ports on any of the Demon carbs I keep finding. Was that a specific model only thing?
Make sure your secondary butterflies are opening fully vertical at WOT. It looked like they weren't opening all the way, adjust with the rod.
beautiful
Eric how did you like this carb? Did you wish you would've gone another way? I'm building a turbo 4.6 4v and I'm stuck with what carb now. Because I'm not having EFI lol
great info
Question. My Deamon 850 is leaking fuel from the secondary linkage. In what direction do I take to fix this problem?? Thx
So to go from efi to carb would that be and undertaking or is it not to bad of a process
Rewatched this and i'm thinking, will we get a video of you tuning the carb when it all gets put together inside Oliver ?
Eric you should think about fitting a Miss Schillings Orifice in case you ever find yourself in a nose down position pulling prolonged negative G's, while racing a Messerschmitt between traffic lights, on a Sunday morning on the way to buy cigarettes, for instance.
Do you build them I have a holley carb double pumper I'd like to get build for a turbo set
My 94 toyota pickup smokes when parked at idle but when running down the road doesn't. Any videos that could help? Could A new carburator be the solution? The current one seems altered. The butterflies are tied open.
Can you do a review over a Japanese carburetor like the one I have. possibly find one in your area and look into it plz.
Hey Eric I'm not sure if you know the history of the Demon carbs but I'm good friends with the man that invented them. Hit me up and we might can arrange something with him. Let me know.
The Barry Grant Gold Claw Is really Gold When he built them
this is a dumb question but is it possible to use a vacuum advance distributor for a boosted application? I'm not sure if it would work under boost
that carb has a vacuum advance port in it so i guessing you can but mechanical or electronic would probably be safer
Looks like a maintenance nightmare with all those adjustments, must have a lot of time on your hands, good luck Eric enjoy!
Once you set it up you really don't have to mess with it much after that.
can i have ones of these, that only has a single barrel for my corolla?
i got same carb works really good i ask the Demon tech's they said is rated up to 1400 hp.
What size is your dual feed line??
An interesting note about carb vs efi performance is that in many large displacement applications (500ci and up) where non-streetable maximum power is desired carburetors often mix the fuel and air better than efi. I've seen a few multiport efi vs single port efi vs carb dyno tests and the single port efi and carburetors make the most power with a carburetor ofte coming out on top.
Care to back that up at all? Where the setups exactly the same? By that I mean the same... everything but the intake side.
If it were, then it could be some fluke that happens occasionally on carbs and intakes. Look to Eric's own issues with his carb setup, and the top hat he changed... Look into why he changed it. Barring any issues like that popping up, all else being equal the efi setup will almost always be either the same or better. If it is not... then it's not properly tuned.
I saw some tests like that many years ago (Popular hotroding or Super Chevy I think) where they had a dyne mule on the dyno and only swapped the intake for each test. Same person tuned each setup and they did a few dyno pulls with each. In that application, going for max power they were pretty damn close to each other. Mind you this was many years ago so I'm sure things have improved.
Yeah sure buddy.... Thats why 900+hp factory made cars, that drive really easy around town and also meet stringent emission standards use carburetors, wait, they dont! Carburetors belong in museums, so do single port fuel injection systems. Just like everyone said, one random dyno test in not representative, on the other hand an entire automobile manufacturing industry ditching carburetors, I think that depicts the situation pretty wheel.
This is hardly an example of "one random dyno test" many engines have been built with carbs that get the job done very well. When all you care about is max HP, its the simplest tool for the job, if you care about emissions, fuel economy, long term longevity then FI is the way to go. Not sure id want to run a carb with a turbo, but its not like it doesn't work.
Odds are, the pair of carbs that live on top of my supercharger aren't going anywhere anytime soon, because they work very well.
I was referring Steven Cash's comment. No doubt, carburetors still work, its just more time consuming to get the same driveability from them as efi, and they dont self adjust to temperature and pressure variation, fuel quality, etc.
How do you convert regular carburettor for boost?
I just repaired some of the threads on a Demon carb. Someone used an impact to tighten the fuel bowl mounting lugs, with predictable results.
Yikes.
All carbs should have sight glasses. What is C. A. R.B. for if not to regulate these things?
First thing I do with a new Holley is put the sight glasses on the bowels.
Eric I have been looking for a anular carburetor in the 600cfm range with anular boosters for my 9:1 357 with 54 degrees of overlap that is in my wood truck because I'm convinced that I will have more low rpm power and better economy. The thing is I would like it to have changeable air bleeds and power valve restrictions for better tuning ability. Would you know of a carb out there that fits this criteria?
I just realized how old this post was lol
Can this carb be used without a turbo untill a turbo kit can be saved for and bought? Thanks
Wrencher 65 yes any more as a performance upgrade I don't know why anyone would
I fucking love carbs
You'll get fat if you eat too much of it tho.
ha! without carbs i'm exhausted
I had a holley 4 barrel on a ford bronco II with a 302 v8. And that thing would squat when WOT.
I wasn't sure how to contact you exactly. A friend of mine has a 2003 Saturn Ion he replaced his steering intermediate shaft. From what I was told everything went pretty easy. but now his car wants to pull to the right hard. As soon as he disconnected the motor for the power assist motor. The steering is just fine. What may be his problem? Do you have any ideas of what may be causing the issue? The dealer in his area won't even look at it for some weird reason.
Why didn't my notif go on? Lucky i was browsing thru my subscription section.
once the car is running you should do a how to video on dialing in the carb!
he did that on the dyno but i guess just talking about it would work too
I plan to.
happy birthday
Eric.. that fuel log you got. is it a -6 or a -8 AN?.
Also. Demon comes with Brass floats or plastic floats?
-8. Neoprene floats.
Hey Eric, Stop scratching up that sexy new carb and braided fittings on that metal bench, put a rag/rubber mat down. Things can perform well AND look nice too 😉
Make sure the relationship of the butterflies to the transfer port is correct first. Should be about .040 of the transfer port exposed with the butterflies closed (should look like a square not a rectangle), set by the idle stop screw. Idle is adjusted up or down by the Idle-Eze screw. If the transfer ports are exposed too much you will be rich at idle and the idle air screws will not respond. Once set, if you move the timing or the idle-eze screw you must re adjust the idle air screws for highest vacuum.
Cool carb, Eric. What do u use to clean your bench top? I cannot get mine that clean.
Lately, Tub-o-Towels. www.tubotowels.com
Shouldn't it be called "DarkMatter+Sneak+achoo" since it's meant to be a sleeper car? hahaha I don't think it's much of a sleeper now though. Can't wait to hear it run, I love the sound of muscle cars engines idling
Cool with some oldschool carb!
Eric did you just buy the demon Blow Thru carb or did you modify it I pretty much fabricate all of my stuff but I really don't want to modify the carburetor I worked with Barry Grant Corporation was quite successful but this is the first time I'm using Turbos really don't want to mess with it so which one did you buy what carburetor number
Bob
that carb is designed for blow threw applications from the factory.
I've built a few mikuni CV carbs and man, these american carbs are SOOO much more complex!
can it run e85?
Can't decide if I want a carb in my camaro z28 I've been in the industry fur a decade but very little experience with carbs. Strictly eFI
Carburetors are like good old mechanical watches... obsolete but with soul
I don't really think they're obsolete, but I like your phrasing. Thanks for the comment.
kamiljp obsolete how? when tuned properly they can be just as fuel efficient as efi. the reason for switching to efi is most people didn't know how or wouldn't do up keep on carburetor
Annnnd that's why they are obsolete. His analogy is pretty bang on, in terms of the mass market they are obsolete, they can still perform well, and they can still be made to operate at a high quality, but products have emerged for the mass market that are better in every measurable way, much like a mechanical watch.
No, they cannot be just as efficient, they mix fuel inherently worse than a EFI system which can be tuned to change fuel input down to the millisecond! There is no smoother engine than one with a properly tuned EFI!
The Esseboy I don't know about all that now. The 366 LS2 my cousin stuffed in his mustang gets about 22 mpg and it's carbureted
when do we get to see the car go? im itchin to see what it'll do
I've been working my butt off for the past 3 weeks to make progress. I'm hoping to have it on the road by May. There are a ton of videos to work through though. If you want to stay up to date on the build check out my monthly newsletters. www.ericthecarguy.com/blog
why didnt talk about the boost reference power valve
How much fuel pressure will you need with that setup?
Just running it will be around 7psi, with boost, 14psi.
More of a question to whomever. What about csu or c&s from my understanding the build the carbs per your application. Anyone have experience with this? If so does it take the guess work out