As an engineer and mechanic, I love teaching my son who is now 5 what I enjoy! So thank you Jeremiah, and the rest of donut for making it fun for him! We enjoy it together!!
@@tunerimpala5658 I’ll be completely honest. I felt the exact same way when he first joined the team. I almost found it annoying. But he has definitely grown on me and I love watching him now👍🏻 keep it up Jeremiah
One thing I personally love about carbs is their simplicity of tuning especially for small engines. There's something to be said for the fact that a carbureted engine can be run with nothing but a magneto powering the spark plug and no other electrical system.
Thats also their main problem. A carb never run correctly especialy if you live in a place where the conditions change a lot. You dont want to spend 15 minutes every morning under your hood to save a bit of fuel so you let them run rich😂
Jeremiah should be Donut's face for motorcycle contents. I'm a motorcycle enthusiast and it fills me with joy whenever motorcycles are mentioned in Donut.
I’m not that old and we used to call filling the tank with “Ethel”. Ethanol has a long history in America. Over 100 years ago, Henry Ford designed the first Model T to run on ethanol or gasoline - the original flex-fuel vehicle. He did this because gasoline was not commonly available everywhere in 1908, and farmers could produce ethanol very cheaply and use it to fuel their vehicles - essentially, you could run your Model T on moonshine. Ethanol also made a comeback as fuel during WWII when gasoline was strictly rationed.
The Ethel you remember is the poisonous leaded gasoline of the past, the one that increased everyones blood lead content and increased world aggression
My 12 old carbureted snowmachine got me and my buddy home safe from deep in the woods when my fancy brand new EFI sled had an ECM failure. Just can't beat their reliability and "simplicity"!
Worth a mention would be the short lived Hitachi electronic metered feedback carburetor mostly used by Isuzu, Nissan, & Suzuki. It used a MAP, O2, and Coolant Temp sensor to regulate mixture, and also control choke operation. Some even had an in-line resistance heater coil to warm the mixture at sub freezing temps.
Yes, an interesting side note as fuel injection is still best, for cars. Carburetors are best for things like my chainsaw, because it's really annoying when it breaks while I am chopping up annoying solicitors....
@@eriktruchinskas3747 "Piston rings? I thought those were like the plastic rings around beer cans, you're supposed to take them off after you buy the piston then stick them on a nearby seagull..."
Fortnine also has a great video on specifically why they can sometimes be better for motorcycles still too (mostly due to the fact that ECUs are tougher to tune for motorcycles, and not all motorcycles even have one). Not quite as in-depth as Smarter Every Day can be with the mechanics of it, but even more info for the motorcycle side of things!
4:53 That is what the accelerator pump on the carburettor is for. If you have to wait for more fuel with your carburettor, then maybe the accelerator pump needs adjustment or repair. Sometimes the accelerator pump diaphragm needs replacing.
There is still a huge delay compared to efi! I think your comparing street use to applications Jeremiah was leaning against. Take a drag app for ex, your doing the 60 in 0.6, thats with reaction time. That would be impossible from a carb system.
@@aaronjones9866 I'm not a drag racer, so if you get better results with efi, I believe you, but there is no "huge" delay with a properly setup carburettor system. The video claimed "the carburettor... needed to wait for the pressure differential to build, before more fuel was added". That is what the accelerator pump does, it provides more fuel without waiting. Carbs were responsive enough for WRC drivers up until the early 1980s, with Walter Röhrl beating the Audi Quattros in the drivers championship with his Opel with 2WD and Weber carburettors in 1982. So no. I wasn't talking about street use. The main reason WRC cars went to fuel injection, is that everyone was also switching to turbochargers, except Lancia who used a supercharger in the 037.
3:44 wait, you can just add servos to the adjustment screw and with a simple microcontroller, some programming and some sensors you can adjust things on the fly.
My automotive knowledge has only increased in my 3 years at a Donut lover. Wouldn’t change a single thing about it, thank you all for your hard work! Here’s to 3 more years
Big Donut fan here too. But, also I stumbled onto the channel Driving 4 Answers. I learned soooo much from that guy. He's a great teacher and I've been learning a ton.
Glad you guys are dipping into the motorcycle scene, conveniently for me it seems to be happening as my interests in bikes are peaking. Would love to see Jeremiah do a motorcycle specific show
I’m 35 now but when I was a child like 8 I think? My dad taught me how to tune a carburetor, said it was a skill I should know if I wanted to get into racing. One of the few things I’m really happy that we did together
I drive old carbureted cars all the time and the one big thing I like better about them is the throttle response. Is is immediate! All the newer cars I have driven especially ones that do not have a throttle cable have such a lag in acceleration I find them actually somewhat less manuverable trying to merge in heavy traffic. I'll keep my 40-50 year old cars.
The drive-by-wire vehicles definitely do have input lag. There is an aftermarket gadget that is supposed to bypass it to make your throttle response immediate, but I have yet to try one.
Totaly agree. I have a skoda and actualy enough power to accelerate good in traffic but the input lag is soo bad. If my turbos arent spinning fadt enough already i loose like 1-2sec. I bougth a pedal box that made my car like 10x better the pedal response was almost instant but after 2 months driving my egr and dpf died 😂😂 2k on repairs 🤣 now i just accept it 🤷♂️
The input lag is intentional, I always figured it was anti granny stomps the pedal down... Also a good e throttle stops you snapping the throttle open making the engine stumble
@@zzzires5045 yeah..i also removed the little delay in my clutch line so i can have full controll how fast i let it go. All these granny stuff in newers cars makes me sick. I want to be able to use my skills and drive my car dammn 😂😂 my pedal box actualy really helped me but the garage couldnt tell me wheter the problem came because of that or because age 🤷♂️ so im scared to put it back in even when i spent 400$ on it 🤦♂️😂😂 but i really miss the nice trottle response and all the mods that it gave me (sport, track, city, eco) 😭😂
I find the exact opposite. I'm curious what car you have, as the handful of carb cars ive driven, especially after calibrating/cleaning the carb + intake all still have response lag. EFI.... instant for me, especially if I give a decent throttle request.
As an automation engineer and programmer, I can say that the carb is still a stout unit being a harmonious blend of physics and fluid dynamics. The carb is still king in my book all day long. Uncle luke here may or may not of designed and programmed a universal adaptive control that trims carb afr in real time - more on that later. Thunderhead289
You did amazing work on that 302 maverick. I live in Fort dodge. I was was wondering if you would do an instructable or something on your iac controller. Keep up the amazing work.
The German Engineers Certainly DEMONSTRATED in REAL DIRE situations, that the Carb just could NOT Hold up in the British Spitfires with the HUGE/Efficient/POWERFUL MERLIN Engines that just DIED OFF Completely in many "High G's/Speed-Roll" Maneuvers and were TOTALLY OUTMANEUVERED and OUT RUNNED in the Air by the Messerschmitt Bf 109 with the the 1,455HP Daimler-Benz DB 605 Fuel Injected even MORE HUGE/Efficient/POWERFUL engine 😅🙃 and had no Speed/G/Maneuverability Limitations MOST of the Racing Tech Advances of Today were Effectively and FACTUALLY Made in WARTIME in WW1 and WW2 for piston Engines, just Research it and you WILL SEE that Most new things are CPUs-electronics 😁✌ Besides, TOYOTA already Solved the Problem with it's Dynamic EFI System, injecting DIRECTLY and in the Manifold when needed and Modifided the SHAPE-Size of the Piston and Combustion chamber/Timming, _Effectively Solving_ the Mix/Vaporization issue GreeTs guys and G0D✝Bless you ALL
To add to the part about carbs not liking ethanol, I would like to point out that small engines like on mowers and snowblowers are carburated. If you are using the 10% ethanol gas, I would suggest a switch to the more expensive one with no ethanol. It will keep that mower going stronger for longer. Same for your 2 strokes, mix with plain gas or buy premix.
That does not mean one should use the canned fuel. Chic-a-holic says it (brand with pink tint) is good for engine storage but does not run well. Some engines do not reach peak RPM others do not start. Swap out the fuel and it works.
This is because the ethanol binds with moisture from the air and combines in solution to make a yellowish sludge that literally clogs fuel lines and carb pinholes. I HATE ETHANOL AAAHHHH
The production level of you shows is fantastic. I can see the hours spent on set design, lighting, camera work, etc. Plus the post work is fabulous! After Effects and Premiere, etc. It certainly shows.
I'm not really a car guy but that carb visual helped me understand why my first car would shut off all the time, thanks! It was an '84 chevy celebrity and i knew "something something choke stuck at full open" and it was constantly blowing too much air so I always needed to give it a little gas to keep the engine running, but actually seeing that makes it make much more sense to me
I actually like carbs. When I was looking for a motorcycle, I really wanted one with a carburetor. Now I own an '01 Honda Shadow and it is the most beautiful thing I have ever owned
Early fuel injection on motorcycles was very abrupt. Especially at little throttle. Much better now. It's a shame that not one new motorcycle in Europe uses carbs now.
Daniel, you must have bumped your head when you were young:) carburetors drove me nuts on cars, didn't mind them on motorcycles. I had a set of mercury gauges to keep them setup.
@@JoeBlack1108 I have a 1968 Fiat 600 with still the 28mm original carb on it. Not a single problem! Gonna swap it for a 32MM motorcycle carburettor for a lil performance gain :))
@@Toxic2T that sounds cool, I have a 1969 Pontiac Beaumont I am rebuilding. I am putting in my 3.4 dohc chev that I turbocharged with a Simple Digital System efi that I had in my 85 Fiero, even got a T-5 worldclass going behind it.
Just in case it was a legitimate question, here is my take on vaporization, atomization, and emulsification: all of them tie in to the dispersion the (liquid) fuel into the air for an even mixture. Vaporization and atomization are closer to each other, atomization is done by pressure and velocity while vaporization seems to focus more on heating a substance. So a spray nozzle would atomize fuel, while applying heat would be vaporizing. You technically can disperse a large amount of liquid solely with one, but the most efficient way involves both processes. Emulsification, on the side, describes how well a mixture has been blended. Since pump fuel is a mixture of components, you want to make sure those additives are being evenly dispersed and not coming out of the mixture being made. The term could be used for the blended fuel, but it can also apply for non-engineered substances, such as water (moisture). I hope that explanation helps in one’s imagination. They do sound similar, but that’s because they depend on each other greatly to make a thorough mixture
Compress the fuel shortly before the very tight nozzle and watch friction heat it up. The heat also comes from the air. In bad weather you get ice. So better place the carb straight in front of the intake.
Atomization is a spray like from a garden hose, its still liquid in varying size droplets. Vaporization is like fog, its no longer in the liquid state, its a vapor. Emulsification is adding air into the circuit to start the atomization sooner. Boiling points decide when a liquid turns to vapor. Everything has a boiling point, even rock and steel. Some are higher than others, some lower in temp. Lower the pressure on the liquid, you lower the boiling point temp. Raise the pressure and you raise the boiling point temp. You can boil water in a styrofoam cup at room temp, if you lower the air pressure around it. The higher in altitude you go, the lower the boiling points are. Evaporation of water starts to happen across the temperature range as long as its above freezing. Water is kinda cool since it doesn't always act like other liquids. Gasoline is made up of various chemical compounds with boiling points between 80F and 450F. Its hard to get it to vaporize as a result. It takes time to vaporize it and needing 450F to do it means it will not get the chance until the combustion event, and then it is too late. Why does it matter to an engine? Well its about surface area, more surface area will burn faster, more completely, and therefore cleaner. If you can vaporize the fuel you will use less fuel to make the same power, because more of it goes to actually pushing the piston rather than going to waste heat. Gasoline in a normal vehicle is around 18% to 20% efficient, in a lab under controlled conditions they can improve that somewhat, but real world consider it well below 20%. That means 80% of the energy goes to waste heat and doesn't power the vehicle. Large droplets have less surface area in a given space than a vapor has. If you pour gasoline into a glass jar and light it on fight, you will see the flame is above the liquid, because it is burning the vapor coming off the liquid. The liquid doesn't burn, the vapor coming off it does. Dump it on the floor and you increase the surface area by a lot so the flame gets larger. Vaporize it so it is a fog and you have no large droplets, its in a different state which vastly increases surface area. Gasoline is relatively slow burning, especially race gas because it doesn't vaporize well. Even when you introduce it to the relative vacuum of the plenum/intake port, it doesn't want to vaporize well. On cold days it does it less effectively than on hot days, but with gasoline you have other things to consider.. like its propensity to ignite when it wants to due to heat and compression rather than when the spark is introduced. Dieseling, detonation, and spark knock.. its breaks stuff and its why diesel engines are built so heavy, because the combustion event happens when it wants to rather than when we tell it to. They also need high compression to get diesel to ignite, that also requires heavier construction. Lots of people are trying to build hot vapor engines that run on gasoline right now. The problem is they have to heat the fuel to over 450F for it to fully vaporize, and the lighter stuff is going to boil into gas long before that. So you get bubbles... and 450F is well out of the range of these engines, except in the exhaust system. Do you want to run your fuel through the exhaust manifold first? That is a not a great idea, very high pressure fuel, more than 100psi to keep the lighter components from boiling running through a exhaust manifold to get enough heat. Can't run it back to the tank either, and your injectors have to be able to withstand that temp. It just got VERY expensive and complicated. On the other side you have ethanol, which has a superior latent heat of vaporization, meaning it cools the intake charge as it vaporizes. The boiling point of ethanol at sea level is 173F, so you can get it to fully vaporize in the intake manifold as it hits the relative vacuum with only 200F fuel temp and 60psi to keep it from boiling. Well within the operating temp of our engines. You can run the engine hot, like 230F coolant temp, heat the fuel to 200F, and even heat the air coming in past the throttle blades, and ethanol will still cool the intake charge making it more dense for the combustion event.. and you will get better mileage than gasoline doing that as well. Throw 20:1 compression in on top of the heating/vaporization and you increase mileage and power well above that of gasoline engines, and possibly above diesel engines as well... but in a lighter, easier to cool engine that makes plenty of power. I am doing that with Pontiac engines with anywhere from 11.5:1 to 13:1 static compression with iron heads and cam timing that builds as much cylinder pressure as I can get. I've surpassed mileage and power over pump gas engines of the same size, and the cool thing is I can go from 7:1 all the way to 13:1 on a Pontiac 455 with just a head swap. So I can do it with the same car, engine, trans, rear, etc. Only the heads and fuel change. 20mpg and 550hp near 600ftlbs from a 7.5L engine running ethanol through an old Qjet carb in a 1970 GTO that weighs 4100lbs and doesn't have all the nice friction reducing things like modern sealed wheel bearings, low aspect ratio tires, lightweight drivetrain components, and reduced rotational mass. It ran mid 11s with a 2.93 gear behind it. I am working on a couple vehicles with less weight and far better aero than my GTOs. Click my name on here if you want to see them and follow my fuel project..
@@SweatyFatGuy partial pressure. Air is only 21% oxygen molecules, which only have two atoms, which can bind two hydrogens from fuel. Even methane has 4 hydrogens and the carbon catches two oxygens. Equilibrium partial vapor pressure is high enough for most components. I don't know why after destillation high boiling point components still end up in the fuel. Each drop is cooled by evaporation of the lighter fractions and survive until the flame front arrives. The temperature then bakes it into soot (captures only the hydrogen while the fuel forms polymere). Graphite does not evaporate anymore. You may want to look up how fog does scatter light and why that is wavelength dependent and car RADAR can pass it better than breaking lights than blue light.
If I recall correctly there are also some cars sold for really cold climates (yes I am looking at you Russians with their Ladas) That also have manual carb adjustments
Just for those curious, bikes like the dr400 and xr650l are completely unchanged from their original 1984 designs due to the grandfather law and how much they would have to change to meet modern emissions
Aircraft piston engines use carburetors with a feature called "economizer", which allows heeps of fuel into the cylinders to aid with cooling the interior cylinders and higher altitude flying. Btw, varnish is welcome vs cleaning leftover lead from an aircraft engine lol. Great video, keep it up!
I'll always love tinkering with carbs. They are what got me going fixing and modifying stuff, I think the first thing I really ever built was a 1987 Suzuki RM125 back when I was in middle school, came in a bunch of boxes all taken apart for $150. Once I got it together I loved playing with the carb on it changing out jets or adjustments when changing pipes or sprockets. Those older flat or round slide Mikunis I can still pretty much take apart with my eyes closed. In college I bought a brand new Suzuki DRZ400SM and hell they were and I'm pretty sure (10 years later) still are running Mikuni carbs. Sure I'd rather have fuel injection in a daily driver car but nothing beats the satisfaction of throwing a jet kit in a one lunger and having instant gratification when you get it all back together and running. Makes me happy to see such geezerly tech still getting attention.
I've also bought a kawasaki W175 which also runs on mikuni, I'm looking forward to buy a larger jet kit cause its quite difficult to start even when i live in a tropical country and its very sunny outside
I know how to adjust and tune a carburetor, but I personally don't want to go back to that hell. To me I think what the manufacturer should do is stick with fuel injection, but do what a few of them used to do. If you had a 6 cylinder you would have six injectors, one per cylinder, but some manufacturers also included a 7th injector in the intake. I would want modern manufacturers to do exactly that. Just tune that 7th injector to give only enough fuel to idle the engine. Yes you could do it with a carburetor, but if you do it fuel injection you can shut off that idle injector when moving and just rely on the other six injectors. That's seventh injector would allow the gasoline to clean the back of the valves. Even more so I would actually like to injectors for cylinder. One direct injector and one multi-port injector. The reason I would want 2 it's because then you could use smaller injectors which would help atomize the fuel even better. You could also have a idle and main circuit for each cylinder. Have the multiport injector run more when idling and then phase into both injectors when you need power.
I saw two small inaccuracies : carbon build on valves is currently remedied by both using catch cans for pcv air and applying dual direct and port injection from the manufacturers. And as someone says somewhere else carbs can have their mixture richness modulated, it's a basic operation by turning a knob on almost pre 1980 's piston engined aircrafts (but it would really too dangerous on a vehicle for the mass market since you can starve or damage the engine if you get it wrong or don' t know what you're doing)
Can be remedied is key. Not all OEM cars have catch cans and plenty of at least first gen direct injection did suffer from dirty valves due to not having port injection as well. Leading to problems. Not every one mods there cars.
@@charlesgatine7045 I agree. Lol. I'm sure in a clean room with idea fuel direct injection would be ok. But in modern engines especially with forced induction, catch cans and port injection should be a standard.
I love my carburetors for their simplicity and serviceability. Once I learned how to properly tune them and maintain them, I just fell in love with them. Hell, even took my 87 E-250 and converted it's 351W from TBI to carb.
I love my injectors because they've done 180000 miles and never needed servicing. Sure they'll be expensive as hell to replace if they ever fail but when they do it's just plug and play
German warplanes in WW2 were also fuel injected, which gave them a great advantage in air combat vs the carburated spitfire. The german BF109s engine didn't cut out when flying a loop.
That's a problem with a carburetor that relies on gravity to regulate the fuel going into the bowl (those which use a float). A carburetor using pressure regulators will not flood out the bowl in negative-g flight regimes. The Spitfire cut power in negative-g because British WWII fighters were barely a step above being put together in a whimsically mad inventor's country barn, not because the engine wasn't fuel-injected.
@@BogeyTheBear And the issue can be mostly circumvented by something as simple as an additional flow restriction plate in the fuel reservoir, which is what they actually did as an interim upgrade.
@@retiredbore378 There was no disparagement in that remark at all. It was quite literally a credit to her for acknowledging that sometimes the problem is as simple as it looks. Go put that nationalist insecurity back on the shelf.
Carbs can provide variable fuel mix ratios tho, just look at light aircraft engines - red lever is for fuel mix( you get injection on modern light aircraft but it took way longer to become commonplace- aircraft engines need a lot more resilience and redundancy so I assume this goes as far as dual ECUs running on separate electrical systems, or some kind of failure redundant controller to keep the fuel injection running even if you lose all electrical power.) Carbs dont need any electricity and will run flawlessly even in the middle of a thundercloud. Well, icing, but thats another issue... Thus why classic continental 4 liter H block aircraft engine has... Carbs with variable mix and heating Pushrods Two sparks per cylinder each fed by one of two separate Magnetos And Alternator for non engine electrics So you can suffer loss of a cylinder, loss of one complete ignition system, loss of electrical power, loss of a pushrod and it will still run and provide some propulsion. Carbs can also react quicker to deliver pulses of fuel air mix in very high RPM use cases. I don't think there is a fuel injector yet that can keep up at 20k plus RPM.
Mechanical fuel injection was a thing in WW2 where the Germans were using mechanical unit injectors (I recall them being unit but I could be wrong) on airborne diesels or on their gasoline engines. It has advantages at high g loading (no sloshing in the bowls) and offers similar benifits as dual carbs (redundancy) while being more fuel efficient.
@@greglirot8288 yes, but also with the attendant issues that mechanical fuel injection is on no way able to respond to environmental factors as well as EFI, and aircraft carbs were able to be modified to defeat negative g fuel starvation as well as automating fuel mixture adjustment with air pressure. Moreover, allies got all that juicy high octane pure race gas from the US vs the Axis who had to put up with dogshit gas produced from coal via the fischer tropsch process, thus the need for methanol or nitrous for very high altitude. Meanwhile, the USAAF and RAF are putting 110 or higher pure gas in their turbosupercharged giant radials or multi stage supercharger inline engines. For anyone interested in that stuff... Go on youtube and look up every interview with Eric Winkle Brown.
EFI can also work with high rpms (just look at older F1s or newer super sport bikes, all are EFI). The issue is direct injection; that can't work reliably over 6,5k. EFI can also react as quick, because ECUs are fast enough to calculate proper fuel delivery. Fact of the matter is that carbs are just not very percise. Elevation, humidity or temparature changes all affect them. So unless you set them up again, they'll never work great under all conditions. Just good enough for you to get moving.
@@greglirot8288 Their gasoline injection systems were very much like the notorious 'P-pump' beloved by Cummins diesel tuners, basically built like a mini inline engine with a plunger pump for each cylinder. The pump was mounted below the engine, sort of between the cylinder banks (the Germans, in a moment of insanity, chose to make all their high output inline aircraft engines inverted V-12s) in as much as that was possible with the intake manifold and the barrel of an autocannon also occupying that space. Fuel from the pump went to the direct injectors via hardlines, once again very similar to diesel practice. The mixture was controlled mechanically by an system of levers and cams connected to the throttle, pressure diaphragms and other sensors in the intake. If you ever want to make your head spin, look up a diagram of the 'kommandogerat' device used for this function in the Fw-190, it's possibly the world's first ECU, implemented entirely mechanically... which is about as complicated as it sounds, I can't imagine how anyone knew how to fix the thing if it went wrong.
The varnish issue is no joke. I have a 1952 Ford 8n tractor I use for mowing and I always shut the fuel off and let it run so it burns all the fuel in the carb and the fuel lines. If I don't it will get coated in varnish and then run like ass.
I took the throttle body off an 89 Nissan Pathfinder vg30, put on a small 4 barrel from a Furd 302 and welded the bottom half of the distributor to the top half of a 2.8l hei from an S10. That was in 1994. I still have it, it still runs like a Swiss watch and I gained 32 hrsprss and 4mpg average over stock. Plus now an emp won't shut me down. Long live the carb!!
for an enjoyable evening, look up videos of people starting 2-stroke V8 outboards out of the water where the exhaust is just blasting straight out of the prop into open air... brutal sound.
Sure was, a 2 barrel throttle body injection unit called CFI. Stood for Central fuel injection. Ford's alternative to GMs TBI. I had one on my 1985 thunderbird!
Donut needs to creating a marketing company. Yalls commercials are better then 99% of companies commercials. I honestly dont know how any of those people still have jobs.
also...alot harder to "Rebuild" an injector... where as a carb...well...shit we once got a truck 48 miles back to town using 2 jerry cans after the fuel pump died, just moved fuel to the cans and used gravity feed to the carb, no way we would have gotten back in an injected rig without parts... also why my friends crawling rigs are all "old tech".. even if modern versions i have seen and tested examples of are far more modern and the electronics can allow for alot better results BUT from the 2 we tested, you could hand tune them to run without the electronics engaged for emergency fallback. when i was in highschool a friends father bought a kit to rebuild a holly carb that he got free but that was over 500usd when new, he sucked at rebuilding carbs and had been putting it off... i was board waiting for the computer we were fixing to install windows, the carb and parts were sitting there... i rebuilt it... mostly as i talked to his dad.. when i was done, he asked me who taught me to do that... "taught me???" its mechanical... its honestly not that hard to rebuild most carbs... and in this case, the unit was gummed up after the fellows ex dumped some sort of varnish into his gas tank... he got the fuel system cleaned and just swapped the carb for the stock one the car came with till he could have the place install a better one... gave my buddies father the dirty one... later i went to his shelf of solvents and put the parts that were varnished up into a glass jar and put in a mix of solvents i knew was safe and would 100% break down the varnish given a bit of time..put the jar on his stereo speaker....ghetto ultrasonic cleaner.. LOL.. it worked great honestly... the parts ended up getting used years later to re-re-build it after his brother put corn race fuel into the car that he was told it was never to be used in... (they use the stuff for specific cars when racing, the carbs jets were...visibly varnished... a place i use to work has been working with other 3m companies to come up with a coating to prevent such issues for years, they have some promising projects going on im told... including a ceramic coating they have been testing with fuel injection, that apparently is the most promising because it could be made into a fuel additive that helps clean any varnish of and prevent more from sticking... they im told anyway, are in the phase of long term testing with a stack of engines and engine types to including 2 of my buddies RX7's hes not worried about having to rebuild even if that becomes needed, he doubts it will be... apparently from the testing they been doing it seems to reduce apex seal wear as well... (im told they are also testing a 2stroke oil additive thats what hes actually using with his fuel oiler setup...his rx7's are all modified to not pull oil from the oil pan... as that oils designed not to burn and leaves a mess inside the engine over time... hoping it turns out to be a good all around series of projects they are working on...
They should use a regular old fashioned lean tuned carburetor, with a 12v low pressure fuel injector (port injection) to compensate, and to use on a cold engine. Efi can be direct fuel injection, which can increase compression ratio vs a carb.
as a chemist, no one cleans there bench with benzene anymore, unless you want to get cancer. 🙂 I did it as a undergraduted but the practice was stopped by the time I got to grad school. great solvent for IR solutions between salt plates.
This! Very important to remember when building a car or a MC... With slightly less sarcasm: That's just one problem with inverting a running engine. There's also lubrication and possibly cooling problems if it's water cooled. The carburetor conking out when inverted was actually a problem with early Supermarine Spitfire and Hurricane. A lot of research was done and Rolls-Royce, the manufacturer of the Merlin engine, constructed a new carburetor to solve this, unfortunately it failed in testing. In the end it was solved by Beatrice Shilling, also known as Tilly, who made a flow restrictor that allowed for just enough pass through to support maximum power. She refined it to a flat washer that could be installed in the existing carburetors without any other modification necessary. Two versions were available to match the flowrates of the standard and supercharged version of the Merlin. In addition to making sure the carb can work inverted you also have to make sure the fuel tank can deliver the dino juice when inverted...
2:40 Does anyone else think the low pressure and high pressure zone are labeled wrong? Shouldn't they be the oposite... being the low pressure zone where the fluid speeds up and the higher pressure zone at the reservoir
@@dylanjones678 Things flow from high pressure to low pressure. By your idea, the air would be getting inside the fuel chamber. When the air speeds up through that tunnel, it creates a low pressure zone. And there isn't much pressure change on the bottom side, it just becomes high pressure comparatively to the top side which is now low pressure.
Yep, thought it was labelled wrong too. en.wikipedia.org/wiki/Venturi_effect . They explain this correctly in another video here though, ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-1ohL6KgasjA.html
@@dylanjones678 Sorry, buddy, but you're still wrong. You actually know how it works but I think you mixed up low pressure and high pressure. Let me explain it to you with airplane wing, you're right about the air moving over the wing, but when a fluid moves really fast, a low pressure zone is created according to the Bernoulli's principle(which the venturi tunnel is based on). And stuff moves from high pressure zone to low pressure zone. The airplane wing is an airfoil, which is the reason why the air moves over the wing and creates a low pressure zone, which then causes the air from high pressure zone to push on the underside of the wing trying to get to the low pressure zone, causing lift. Source: I'm an Engineer, and have worked on many carburettors. If that's not enough for you, maybe try google next time, you'll be surprised to know that it can give you answers pretty quickly.
@@naseeb46 actually yes their graph is off It should be high pressure on the left side low pressure on the right side. I just now realized that the float bowl is exposed to the high and the low side. Their graph was not descriptive enough, that explains what you're saying perfectly. And now it all makes sense.
The video says a carb can't change the fuel mixture. That is not true if you ask any general aviation pilot. Most piston aircraft are not fuel injected and have a mixture control knob that allows the pilot to adjust the mixture for changes in elevation and power. There is no reason that couldn't be on a car also.
Just did an overhaul on 2002 Suzuki gsx. figured the carbs were due for cleaning even though it ran fine. disassembled the carbs and found no effects of ethanol, the diaphragms were still in good shape. did change out the mixture screws with extended screws so they could be adjusted on the fly. I've had this bike at sea level (Florida) no problems and a mile high in Arizona mountains no problems. The only problems with carbs is lack of experience. Living in Florida by the ocean, I've noticed corrosion on wire harness from salt air and completely wiped out the wire harness on a previous bike. and for that reason makes me stick with carbs.
Not too long ago I watched an engineering explained video about direct injection and port injection. The way direct makes up for the short amount of time for atomization is the high pressure in which they are injected. The fuel is actually better atomized than from port injection because of the fine mist and high pressure. It still does have the other drawbacks you mentioned though!
In a carburetor, emulsification happens when the air mixes with the fuel inside the main jet throught the tiny holes on it. The air is coming from the tiny hole in front of the carburetor. Atomization on the other hand happens when the mist of air and fuel that is sprayed from the main jet by lifting the needle is hit by the air that is being sucked through the carburetor.
At my job we have a bunch of small engines and we use the standard 10% ethanol fuel in California for everything. If our operators don't run the small engines at least once or twice a month the carbs get gummed up and we have to either disassemble and clean, or completely replace the carb. We started buying ethanol-free fuel for our boats and stand-by generators and we haven't had a problem with gummed up carbs ever since.
@jakefinlay5312 Throttle body injection is electronic fuel injection. Anyone who works on or thinks about cars knows about it lol. Edit: the last part was for the original message
@@jakefinlay5312tbi is a form of efi, as is mpi, gdi, etc. however Bosch and Hilbourn made a mechanical fuel injection (there were versions of mechanical fuel injection used at least as early as WWII aircraft)
Even though the top flight of NASCAR; the Cup Series, moved on to Fuel Injection during the Car of Tomorrow era, carburetion is still the fuel delivery method of choice in some of the lower tiers, including the Whelen Euro Series, not to mention other niche championships across the world such as the National Hot Rods championships in the UK (no relation to the USA's NHRA).
I know mechanics in the Australian military that service the military dirt bikes, which often sit around and dont get used between the 6 months service checks. Very often, the fuel injected late model bikes they have now, have failed fuel injectors, just from sitting around.
The issue is, so many people did not tune carbs on a regular basis, you'd see cars driving around with a carb that had not been tuned in a decade or 2, but would still "run".
In all honesty I never "tuned" the Carter two barrel on my 78 E-150. I do lubricate the accelerator pump with Tri-flo. And have about 520k miles on the van, but the shop that rebuilt the 351W set the carb as they should have after a rebuild and warmer cam... One mistake that most mechanics often make is messing with the cab when the problem is with the Bloody Automatic Transmission. But my E-150 has a 4 speed manual trans as all my cars have been manual transmission cars and trucks. Why??? Because as a former Wrench, I hate cars as they make you bleed. I also hate annoying customers as well... @@mikem9536
The Carburetor is an Amazing device that will win to any fuel injected car. As long as there is an EMP strike right before the race and the injected car does not use mechanical fuel injection.
@@monte-zh9ue itb's (individual throttle bodies) are basically 1 small carb per cylinder, allowing you to tune them individually for all cylinders. mostly used for racing applications to maximise air/fuel ratios (or if you want that sweet succ sound). they typically have a small 'trumpet' on each carb meaning the air is jetted directly into the cylinder rather than through an intake manifold which benefits afr's by allowing the air to take a more direct path. they also sound fukken sikk :)
i'm no expert and as far as i could understand he did not said can't tune carb. he just explain that efi are more complex and more efficient and easily tuned. 😅
In a typical automotive application, you have 1 carb serving the entire engine. This prevents per-cylinder tuning. ITBs have only been common on motorcycles.
What I really have on my mind, can't figure it out and really REALLY would like to see from you guys is a video about BLOWN CARBURETORS ! I find the principle of turbocharged NON fuel injected systems rather fascinating. Thank you.
@@hojnikb Supercharged systems can use a 'draw through' design where the carb is upstream of the blower, in which case no boost reference is needed. Not necessarily the best setup for all applications however.
I fought with the stock efi on my truck for weeks, tossed on a carb, worked first crank, no adjustments needed. I'll deal with the possible adjustments in the winter, I just need my truck and not a lawn ornament
Your graphic at 2:42 is actually wrong, Bernoulli's principle means that the faster a fluid is flowing, the lower the pressure is. This means that in the carb's Venturi tunnel, the higher speed air is really lower pressure, this needs to happen for fuel to be sucked through the jets. The standing air in the bowl is higher pressure. Love the channel, because of you guys I got my first project car two days ago (95 Accord coupe 🙂 ), just figured I'd call this one out to help you guys keep on making great content that gets people into the world of cars.
Valves! Is there a video on the ICE valves, everything from normal to exotic materials used in them? Whatever happened to the company that had round valves that didn’t require springs(late 90s -2000)? Great content and the presentation is always amazing!
The carburetor has another problem, in High G movements off throttle the float can drop or lift causing proper fueling problems. In a carb'd race car I own, lifting in turns can stall the motor.
I actually think the idea of the Carb coming back is really cool, I’d love to see a Dodge Demon or Charger Hellcat with a carb and still push nutty amounts of horsepower.
The graphic at 8:20 says “benzine” but it should be “benzene” 🤓. Benzine is an old timey word for gasoline or similar blends of light aromatic hydrocarbons including benzene (c6h6). In Italy, “benzina” is the word for gasoline, which is a cool holdover from that time.
It is actually the fast moving, low-pressure air passing before the discharge nozzle which pulls the fuel from the nozzle. The air is pulled in by the vacuum created by the piston moving in the cylinder.
Jerbear needs more shows or, he needs to start teaching an automotive theory course. His videos are my go-to for teaching the lube monkeys the basics, I can always tell which ones are gonna make it into the shop and which ones need to start looking for another job, based on the way they intake the info from Jeremiah's videos. Keep up the good work!! 👍👍
I always skipped the whole carburator thing. And when we were driving around on the highest motor-able mountain passes, some guys with older Yamaha and BMW bikes had to mess around with the carburator because it would run bad. Thankfully I never had to deal with adjusting carbs. Or adjusting an EFI for that matter, because it would just work. Still great insight though. I guess any industry is going to continue do to the same if they can sell it, so that is the main reason why we have regulations.
Mustang got fuel injection in '85... Albeit throttle body injection placed on top of a 2 barrel carburetor manifold! I had an '85 Mustang lx convertible with 5.0 and factory fuel injection.
Got a 2020 suzuki dr 650. Love carb. I treat fuel for storage and its all good. Gotta keep in mind to empty the carb if you dont drive for a long time.
Here at S&S Performance Carburetors, many of our carburetor customers in drag racing, street rodders, air boats , etc...made the switch to efi systems. Most have experienced several very obvious issues. 1. Reliability in the after market efi systems. Failure to start when called up for the next round at a drag race, or out of town car show , hunting and fishing guides with air boats miles from help on the water, etc... can be very frustrating, especially at an out of town event. Very few individuals have the ability to diagnose a complex efi system and even with the ability will they have the sensors or governed parameters readily available for the repair. 2. EFI in most naturally aspirated applications do not make as much horsepower. Even bracket racers do not like slowing down due to the fuel system and the consistency isn't as advertised. 3. High performance street racers and air boat operators with an efi properly mapped out have learned to accept the fuel mileage actually isn't much better . As an end result, our 40+ year old carburetor business is stronger than ever. I know eventually that with improvement in technology and the brilliant minds continuously developing better systems that eventually EFI will displace carburetors for performance. But for now and the foreseeable future carburetors will provide a service for either performance use and or reliable power for our antique customers needs.
I chose to use a DR650 to ride around the world because it's been the same bike since 1996. It broke down once in a while but it always let me know it was going to break down. The Carb never just quit. It kinda slowed down.
I got a Smartcarb for my RM85 2 stroke. It is thr best carburetor I have ever seen. It has an internal shutoff for if the bike tilts over, so it just has 1 hose coming out the bottom for a bowl drain. It has a 'fuel screw' to adjust fueling and a choke. That's literally it. It's awesome
My buddy was resurrecting his pickup around the same time I was resurrecting a 74 Corvette. Non-original motors in both cases. He spent several thousand dollars on an EFI system. I literally went to a swap meet, plunked down 20 bucks on a Qjet, and probably 30 bucks more for an overhaul kit. I have a stash of jets and metering rods lying around. I have been riding around in the vette for years, he is still fighting with a chronic lean condition that he (and others) can't figure out. When peak efficiency and emissions are not your top priority, the carb is going to win the race every time
Seems like the only advantage is that it's cheaper which I don't really think qualifies for saying it's coming back. More accurately, It just hasn't been phased out yet in certain markets. The only advantage was the atomization mentioned because fuel is delivered further up the intake. That's not entirely a fair statement since you can always go with throttle body injection which would basically be in the same place as the carb but with injectors that can in compensate for air fuel ratios automatically instead of requiring a manual adjustment under the hood.
Carbs that are open to the atmosphere, like most found in cars/trucks, work great with ethanol. If left to sit for days +, the fuel will all evaporate and leave clear ports behind. My carburated 1971 daily works great with 10% ethanol fuel.