PERFORMANCE Upgrade for the 4 Stroke TWIN Cylinder - *VALVE Lapping* - Supercharger Update

1. feb.. 2021
615 666 Ganger

While figuring out which supercharging method should I use, I always had the curiosity to know why this particular engine spits so much unburned fuel from the exhaust and the inlet as well. The siplest thought was valve leakage. There's no other way so much fuel can escape both from the inlet and outlet of the combustion chamber. I decided to use the lapping method which is used on full sized engines. In my case I used polishing compound (thicker one) instead of the actual paste that is used for this purpose as it's too thick and harsh for these tiny valves. The result speak for itself. I was never able to rev the engine past 11,000rpm, while now it revs happily almost to 16,000rpm. I still cannot believe that by simply polishing the valves we can have so dramatic changes in the performance of this little engine. Probaply after all the disassembly and assembly process, I accidentally fix the real problem.
About the supercharger. As you can see on the video, it's pretty much impossible to have any gains from an engine that barely works right. I'm surprised though that the blow through setup worked better. As I've said 2 years ago, a positive displacement supercharger would work perfectly fine.
Model engine companies like O.S have released in the past supercharged four stroke single cylinder engines with a roots type supercharger (O.S FS120 supercharged). This alone gives me hope that I will make it work.
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  • getting a whole lotta valve float at those high rpms

    thatonlyking 727thatonlyking 72720 timer siden
  • Cool video !

    BigdaddytruckerBigdaddytrucker12 dager siden
  • Johnny, excellent work! You up for other design mods to that twin cylinder unit?

    Mike NomathMike Nomath12 dager siden
  • But its a turbo 😕

    Hue ianHue ian12 dager siden
  • Okay so the tiny engine is cool and all but that electric screwdriver you used absoutlely blew my mind.

    Oven HeatingOven Heating12 dager siden
  • Why not connect the motor up to a air compressor with the regulator set to a constant PSI. See if you can tune the motor with boost to prove out whether it’s the supercharger or the engine which is your problem.

    mike spodemike spode14 dager siden
  • Taking material off of valves doesn't make them stronger my man. Try that with an ls lol

    EF-rythingEF-rything14 dager siden
  • maybe you find better results with a gauge with glycerine, just an idea

    ExupgenesisExupgenesis14 dager siden
  • Draw through setups become untunable when there is a boost leak. I would def start with looking for a boost leak. If you do not find any try a larger carb. I bet its super lean, which would also make it untunable.

    Logan JustLogan Just14 dager siden
  • What kind of oil does that thing use. And how many mililiters.

    Javier HernandezJavier Hernandez14 dager siden
  • Frist editing vcan yyou high volume vidio bro

    Ryan TapaRyan Tapa15 dager siden
  • He's building that motor like its a

    manny619ishmanny619ish15 dager siden
  • Bigger plenum on intake=less vacum spikes on intake stroke @ low rpm. You can smooth the issue, but u need more flow on compressor side

    Kilnuu KuKilnuu Ku16 dager siden
  • Are you now why it's clean? Nitro methane is only making clean burn in 2 stroke and 4 stroke or Kerosin too

    SOYLSOYL17 dager siden
  • We can probably do that to a cars engine right/??

    Prothom AnjumProthom Anjum17 dager siden
  • Awesome job. Nothing boring about what you're doing. A bypass valve may help the tuning of the engine. The increased booster is drawing more fuel into the engine making it turn up erratically.....just a thought

    Trent HarveyTrent Harvey17 dager siden
  • Make a bigger carburetor

    Giannis LamprakisGiannis Lamprakis17 dager siden
  • Next gen of engines for all car makers thanks to downsizing

    Ivo NevisticIvo Nevistic17 dager siden
  • Try putting on a mini air filter to restrict air a bit. This helped with my carburetor motor

    Jeandre deLangeJeandre deLange18 dager siden
  • We are not bored keep it up and it will run like a dream

    Forgiven_Light OFFICIALForgiven_Light OFFICIAL18 dager siden
  • Seems to me like a lean issue then it riches up

    Forgiven_Light OFFICIALForgiven_Light OFFICIAL18 dager siden
    • Seems to run better on the system u started with. Also fuel could be getting stuck on supercharger inlet and hoses and such causing you to have an excess of fuel built up . This would cause the improper tuning and lean and rich issues, no constant fuel mix

      Forgiven_Light OFFICIALForgiven_Light OFFICIAL18 dager siden
    • Try a air filter to get a constant restriction in a closed environment. Could mix fuel more evenly. Otherwise fuel could be getting caught on an edge. Throw oring to seal backside of slide better?

      Forgiven_Light OFFICIALForgiven_Light OFFICIAL18 dager siden
  • Vent the crank case, it's building too much Crack case pressure.

    dizily555dizily55518 dager siden
  • Growing up I was always obsessed with small engine and you sur fill my void in High school one of our teachers had a model aeroplane with a little nitro engine he let me take it home to try and get it to work I did

    Thomas HealeyThomas Healey19 dager siden
  • is possible to go 20.000 rpm ?

    Berke TosunBerke Tosun19 dager siden
  • You need to modify the Turbo. Try to build a larger Turbine, and the RPM from a Standard Turbo is 100.000-150.000 RPM.

    Haho BlablaHaho Blabla19 dager siden
  • Were you getting fuel pooling in the supercharger on the pull through set up?

    Allen LAllen L19 dager siden
  • Don't give up on this, it's definitely an issue with the Carburetor what you need is a bypass or larger Carburetor, the Supercharger is drawing too much vacuum on your pull-through setup at idle causing the Carb to remain between 20-50% throttle as it was designed for a NA engine with a lower Volume of airflow. You could try a larger Carburetor designed for an engine with a higher displacement, assuming your setup is making 0.8psi of booster above ambient that means you are forcing about 5-6% more air into the engine so maybe try a slightly larger Carb for your engine. (Standard Day Barometric pressure is 760 mmHg or 14.7psi) You should make a comparison based on your current Barometric pressure in the test environment.

    Early BirdEarly Bird20 dager siden
    • Also if you are feeling froggy you could even try porting and polishing the cylinder head, not sure if it would really make a huge difference on such a small displacement but 90⁰ angles and rough flow surfaces do cause air resistance. Any restriction in airflow is a power loss so intake and exhaust ports that are oversized and smoothed may offer some performance increase.

      Early BirdEarly Bird20 dager siden
    • It could be actuated by the manifold pressure for example like a differential pressure valve.

      Early BirdEarly Bird20 dager siden
    • A bypass could work with an intake valve which allows the engine to aspirate through the Carb directly upto the point the Supercharger creates boost.

      Early BirdEarly Bird20 dager siden
  • You didnt lap them???

    Peepee PoopooPeepee Poopoo20 dager siden
  • Could cam overlap be having an effect on the vacuum?

    xrsi89xrsi8920 dager siden
  • Pro tip: stick neodymium magnet on whatever tool you’re using to magnetize it whenever you need it.

    K BK B20 dager siden
  • i think its a form of blower surge, where it get super lean all of a sudden.

    Liam SmithLiam Smith20 dager siden
  • Honestly, $400 for a model engine is to much. Wont buy that, ever.

    Pepe The FrogPepe The Frog20 dager siden
  • Where can I get that screwdriver?

    I will bnned after I speak WhyI will bnned after I speak Why21 dag siden
    • Please read the description below the video.

      JohnnyQ90JohnnyQ9020 dager siden
  • Make exhause pliss

    Ryan nih BossRyan nih Boss21 dag siden
  • Awesome work as normal. You can't set forced induction up on these things, it's the oldest problem ever, we tried doing this literally years ago with RB superchargers etc. The simplistic carbs on these things don't have any metering so you'll get perfection at one rpm/load point but the rest of the range will be off.

    Marcus KeelerMarcus Keeler22 dager siden
  • totally not bored! this series is insane I love your work!

    Darcy KeddellDarcy Keddell23 dager siden
  • Hi i think you might need a mechanical fuel pump as well as the supercharger , so the fuel is pressurized as well as the air so it can keep up with the supercharger , the pressure nipple off the exhaust is not enough , as i have played around with pressurizing the fuel o my old car and it made a big difference ? just a idea ( try a electric Windscreen washer pump ) as a fuel pump to try it out ?

    matthew bennettmatthew bennett25 dager siden
  • Need to have a blow off valve in order to let the excess pressure blow off when you close the throttle gate that's why you're having a hard time tuning it if you made a blow off for it to be easier for it to tune

    Daniel HoffmanDaniel Hoffman25 dager siden
  • Would a velocity stack help control the air intake?

    Craig SchroederCraig Schroeder29 dager siden
  • Careful if the pistons are ringed! Most four stroke model aircraft engines are limited to about 10,000 rpm due to the piston rings failing at higher rpms.

  • The response is a bit dilated, but maybe put un air demper bitween the gauge . Like the once you put in line whit pneumatic pistons

    Denny De waalDenny De waalMåned siden
  • I need more supercharger in my life.....

    Josh NaboursJosh NaboursMåned siden
  • Think it could have been the carburetor that improved the throttle response or increased RPM? Should have kept them the same to make a better comparison. They call that lapping valves when you used the polish. Great video you are quite talented.

    Jay JohnsonJay JohnsonMåned siden
    • Yes, that would've been a better test for the viewers to see, but before lapping the valves with the new intake and carburetor, the engine went from 11k to 13k max rpm if I remember correctly. After the lapping procedure, it went to 16k. There was serious leak of pressure in the combustion before the lapping.

      JohnnyQ90JohnnyQ90Måned siden
  • Pls do something like this but cam it, make it chop

    Dominic D'angeloDominic D'angeloMåned siden
  • I think it’d be pretty cool if you could figure out how to make bigger cams to make more power and change the sound up I know you’ve got the brains to do it

    JamesJamesMåned siden
  • Please make a working V8 engine model so many people would buy that as a gift for their engineering friends graduation etc

    Imran HasanImran HasanMåned siden
  • I don't feel board by this. But I understand why you might be. It's so much easier to watch you struggle, then to struggle ourselves

    Space KissingherSpace KissingherMåned siden
  • Vtech

    Nathan GullenNathan GullenMåned siden
  • JohnnyQ90; incredible craftsmanship, engineering, and performance improvements! At those rpms, would/can valve “float” happen and at what rpm?

    CruxtCruxtMåned siden
  • A single thumbs up doesn't do you justice brother! THANK YOU FOR SHARING

    Mountainman-SU- TwisterMountainman-SU- TwisterMåned siden
  • you are the best, keep it up absolutely

    Giovanni Simone RiccardiGiovanni Simone RiccardiMåned siden
  • Im surprised at how many ppl in these comments are so hung up on the pressure gauge. Its NOT supposed to be mechanical for boost applications on a combustion engine lol! thats for steady air pressure on an air compressor lol. Because there will ALWAYS be vacuum in between combustion cycles on a boosted gas engine, is the reason why ALLLLLL boost gauges for automotive applications are DIGITAL lol.

    Auto Body EverythingAuto Body EverythingMåned siden
  • ABOUT THE TUNE.... even a full scale engine cannot be tuned for force induction unless its monitored by a MAF sensor right after the air intake or about 12'' away from the throttle body and an o2 sensor for stoichiometric values which is called max air flow tuning. option #2 is called speed density tuning which used a MAP instead (manifold absolute pressure) which monitors stoichiometric value by using a vaccum sensor right after the throttle body, an air temperature sensor at the throttle body or manifold and throttle position. MAP is best for high rpm stoic and MAF is overall more accurate BUT because the (hot wire) inside the MAF monitors air values by how much thw hot wire gets cooled down, it can be an obstruction at high rpm or intense air flow. THE ONLY WAY to have the RIGHT formula for proper air fuel ratios on a carburetor/turbo setup from idle to max rpm Is to know how much air the motor takes in naturally aspirated and also know how much air the turbo puts out per every 500 rpm or 1000 rpm and find your slope or (COMPRESSOR MAP) then you would be able to find out what your fuel delivery slope should be via throttle position. and rpm. NOTE: one pound of boost will double the amount of air flow the engine produces naturally aspired. to make things simpler, you would want to choose a desired amount of boost and know that the chosen value would remain consistent throughout the entire rpm curve just to make calculations easier than trying to find the variable every 500-1000 rpm but you dont have a way to control boost right now.

    Auto Body EverythingAuto Body EverythingMåned siden
  • At this point you have reached (and gone beyond) the maximun air pressure (supercharger) for the maximun amount of fuel (carb needle open) that is able to enter the engine. From this point forward you will need to increase the fuel preassure to keep the combustion ratio. In other words, you need a fuel pump. By the time you make this supercharger to work at the desired per square inch preassure, you will be burning a lot of fuel and it will become impractical to have such smal fuel tank.

    Pablo HernandezPablo HernandezMåned siden
  • I remember myself lapping valves when I was a kid at my father's garage... Oh the good ol times!

    Pablo HernandezPablo HernandezMåned siden
  • same on my bike 135cc port and polished.. my bike can outrun higher 150cc later model of my bike on top speed

    Flandra FranchescaFlandra FranchescaMåned siden
  • I build/set up/modify/tune drift, time attack cars, and pre runners for a living. Ive put a turbo on pretty much everything from a 2003 yz450f to a 2006 jeep commander with a grossly underpowered 4.7 liter v8 and for me, carbureted boost rule of thumb is always butterfly style carburetor. Slide configuration carbs NEVER function properly with boost. You might try making a boost chamber pre fueling. Its a must on single cylinder stuff. I know thats a twin but, stable air is better than turbulent air,. Anyway, instead of a traditional plenum, have a hollow canister with a capacity close to that of carburetor cfm squared. Theres some math involved if you want it precise but honestly its not necessary. For that little engine id say something with a 2-3 fluid oz capacity should be kosher. The canister should be cylindrical in design with the inlet and outlet on opposite ends of the part. Obviously order of placement should be turbo-canister-carb. Placement is decided by fitment, as long as it makes sense and air has a smooth and direct path to the carb atomization wont be affected in any way, as a matter of fact itll be largely improved. The last single cylinder turbo kit i built was for a little mini chopper with a xr100 engine and i designed the canister in a conical configuration decreasing diameter the closer to the carb it got attempting to increase air velocity. It worked exceptionally well. With a modified butterfly style carburetor out of a lawn mower with the jetting drilled out little by little until it was right. The tiny little ebay turbo, blow off valve and intercooler from a old snow machine turbo kit (thats a very simplified description) made 7 psi and that bone stock air cooled xr100 engine transformed into a friggin rocketship. Im serious too when boost comes on it feels similar to the powerband hit of a kx100 2 stroke. It makes turbo noises and the little chopper used to max out at like 44 mph. Now it does 56 mph. Just a thought. Turbos are so much easier with small engines because amount of boost is decided by how much air the engine moves. Ive always been leery of anything belt driven i just dont like it at all. With turbos, as long as theres no leaks, if exhaust is coming out of the valves, ur making boost. Then you have a bunch of other shit you can fiddle with to make boost sooner, later, less, or more. I really hope im half as good of a machinist as you are someday man. Youre a badass.

    Aj LauzonAj LauzonMåned siden
  • Would have thought that for that much money the little engine would have been built a little better, i.e., matched and lapped the valves at factory.

    Rob JRob JMåned siden
  • You aren't holding the RPM laser in the same spot on engine balancer. First clip you are on edge of it which would read slower than the - inside reading you were taking to hit 16,000.

    Under GodUnder GodMåned siden
  • Johnny, you should also convert the glow-plugs to ignition spark like this ------->, think you will see nice improvements too! Also try a carb from like a saito 4 stroke engine, they have dual needle valves and can be adjusted very nicely, Just some thoughts!

    zulg adamszulg adamsMåned siden
  • Add glycerin to the gauge, it smooths out pulsation and vibration, that's how we did it in the oil field on gas compressors

    dylan rinkdylan rinkMåned siden
  • Usually when the gauge dances around like that it means that there's too much flow. Needs restricted

    Samuel ChartierSamuel ChartierMåned siden
  • Use 2 small drills and make a twinscrew charger

    V-Tec Kicked In Yooo ///V-Tec Kicked In Yooo ///Måned siden
  • I think you are getting valve float

    BikeNCatsBikeNCats2 måneder siden
  • has anyone tried to use fuel injection on a model engine? this style supercharger and turbochargers dont work with carbs as well as they do with FI. now a roots or PD might work, but these style superchargers take power to make power.

    PoohsSmartBrotherPoohsSmartBrother2 måneder siden
  • It is so cool to see a craftsman create such beautiful pieces of art, and it's also cool to see all the machines, and how much performance was gained from those valves

    Bob RossBob Ross2 måneder siden
  • The common billboard disturbingly accept because mom utrastructurally appear circa a able ear. adjoining, ruthless jason

    Vi TrongVi Trong2 måneder siden
  • if the idle goes up on a blown engine its lean if its going down its rich if it goes up and down its going lean rich lean rich

    JP VJP V2 måneder siden
  • make it an 8 valve lol

    Slick MikeSlick Mike2 måneder siden
  • if you want gauge to stop jumping that much, put a restrictor to a hose attached to gauge. can be even 0,2mm, doesnt matter, presure is presure :)

    Marcin DębskiMarcin Dębski2 måneder siden
  • Supercharged engines have a surge at idle.

    Jeff AllenJeff Allen2 måneder siden
  • Broo make it mid engine 4 wheel drive

    Sooraj T RSooraj T R2 måneder siden
  • keep the carburator after the supercharger the gas acumulate in the the turbine

    Olivier LepineOlivier Lepine2 måneder siden
  • You could see a huge lip on one of the unlapped ones dang.

    Whiskey GordonWhiskey Gordon2 måneder siden
  • The first step: upgrade the engine THE second step: add a turbo THE third step: just let the master work in peace

    John GenoJohn Geno2 måneder siden
  • How about fuel injection ?

    Hazril AzHazril Az2 måneder siden
  • Is it just not holding a time since it may be on the final leg of the break in?

  • Not bored at all make more like this

    Jake CJake C2 måneder siden
  • 你那螺丝笔去哪买的阿?

    蔡東甫蔡東甫2 måneder siden
  • JonnyQ90, addressing your issue with the vacuum/pressure gage fluctuation quandary, you might employ a ''Fluid Damped'' gage. Basically, the workings of the gage are immersed in a nearly, colourless viscous fluid that slows down the majority of the erratic fluctuations in the gage. I actually made a fluid damped gage myself, in a far off land, during a critical aeroplane emergency. I prising off the bezel with the lens and filled the gage cavity completely full with a nearly colourless viscous liquid. We had a local denizen boil up some sugar cane juice until it was about the viscosity between ''light [clear] corn syrup'' and ''type 3 brake fluid''. Then when the gage was filled, sealed the lens to the bezel with ''rubber tree sap'' then wrapped ''black electrical tape'' around the gage housing to seal against the viscous fluid leaking It worked, but we were still captured anyway...please don't ask where. HaHa!

    Li, Fu Ran, Ph.D.Li, Fu Ran, Ph.D.2 måneder siden
  • Try to Get a belt driven compressor for the fueltank so the positive pressure increases with rpm.

    Sebbe vivaSebbe viva2 måneder siden
  • you need to add a one way valve with quick manual discharge into the pressure gauge

    Bruno PinguinhaBruno Pinguinha2 måneder siden
  • you need a larger carb with the same jetting to make it run .. it's sucking the fuel straight from the tank

    tom tritttom tritt2 måneder siden
  • Also, a super simple gauge could be as easy as a balloon? You could “calibrate” the balloon first with fixed pressure/size, just for a simple visual without wasting lots of money breaking gauges. Or stick a 1 way valve in between

    MrBeastbikeMrBeastbike2 måneder siden
  • Could be worth pressurising the fuel tank as you would with a 2 stroke, looking at that OS carb, that would be how that carb was running. I would say pressurise from the inlet manifold, but of course then you have the vacuum to contend with. Either way, you never bore us!!!!

    MrBeastbikeMrBeastbike2 måneder siden
  • Cool stuff, where can I sign up for your classes?

    kota jacksonkota jackson2 måneder siden
  • I think what youre getting is called Runaway, when the RPMs keep climbing and as a result building more boost and creating a stronger differential pressure. And i believe its that differential pressure thats sucking fuel out of the throttle even though you arent operating it yourself. Basically somewhere near your carb is allowing too much fuel in

    Kai YuenKai Yuen2 måneder siden
  • 5 f ing commercials in 12 minutes of things I will NEVER buy.

    Angelum BandAngelum Band2 måneder siden
  • There is a low speed adjustment needle on the side of the throttle arm.

    Fredrik AdolfsenFredrik Adolfsen2 måneder siden
  • Those valves have ridiculous thick stems ! Grind or turn them off some and you will gain another couple of krpm. It's basic.

    Guy Van BrusselGuy Van Brussel2 måneder siden
  • Nice video, can you try to turbocharge the 4cyl toyan?😍

    LdpLdp2 måneder siden
  • Rear mid engine layout

  • Add two more cylinders and you got yourself a honda engine lol.

    Juan UriarteJuan Uriarte2 måneder siden
  • *pUt It On a DyNo*

    Red S0vietArtileryRed S0vietArtilery2 måneder siden
  • LOVE

    nasos nasosnasos nasos2 måneder siden
  • seems like you need a boost chamber like the boostedboiz did for their turbo shopping kart. they couldnt get it to run for squat until they added a small chamber on the charged side of the charger.

    TaeleusTaeleus2 måneder siden
  • for the gauge you can take the end of a bic pen, cut like 1/3" off, the end with the cap, make the tiniest pin hole thru the end cap you can. might take multiple tries. i heat a needle with a lighter, then melt it straight thru. Stick the whole piece inside the line between the housing and the gauge basically whats happening and why its bouncing and breaking, is because the volume of air thats moving in the line and gauge is way too much to see any where near smooth operation. by reducing the hole size that it goes thru, its slows down and you can get a far more accurate and stable reading also works on real cars, and id suggest using an actual vac/boost guage i like your videos, they make me think

    Elite R&RElite R&R2 måneder siden
  • I think as the boost increeses, the vacuum just sucks in more fuel and it just so and with the more fuel it will spool up the rpm and suck even more but then at some point there isn't enough air because of the throttle and the engine dies back down, giving the rocking in RPM

    Peter NielsenPeter Nielsen2 måneder siden
  • Gauge is dead 😂😂😂 supercharger 🥂

    fathoni eliasfathoni elias2 måneder siden
  • This is like sitting in a classroom and the teacher not saying a word , saying anything is better than nothing

    Pyro OneExSevenPyro OneExSeven2 måneder siden