PERFORMANCE Upgrade for the 4 Stroke TWIN Cylinder - *VALVE Lapping* - Supercharger Update
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.
► RC Engines Links:
➜ Get the engine here!: bit.ly/3k7QZnc use code: jq90 for 10% off
➜ Starter kit for this engine: bit.ly/3aCYjEa
➜ Other Toyan Engines: bit.ly/30Z8NYr
----------------------------------------------------------------------------------------------------------------------
►Tools that I used on this video:
➜ 63 in 1 Multi-Tool Magnetic Precision Screwdriver Set: ban.ggood.vip/WLKy
(code: BGHKC5, 35%off)
SEQURE SQ-ES126: ban.ggood.vip/WLKx (code: BGSQES126, US$85.15)
➜ 3D Printers: ban.ggood.vip/WLKw
➜ Ender 3 Printer: ban.ggood.vip/VTPJ
➜ RC Parts: ban.ggood.vip/WLKv
-----------------------------------------------------------------------------------------------------------------------
► Subscribe! bit.ly/2m1d1y7
► Instagram: johnnyq_90
►Support my videos!: www.patreon.com/johnnyq90
getting a whole lotta valve float at those high rpms
Cool video !
Johnny, excellent work! You up for other design mods to that twin cylinder unit?
But its a turbo 😕
Okay so the tiny engine is cool and all but that electric screwdriver you used absoutlely blew my mind.
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.
Taking material off of valves doesn't make them stronger my man. Try that with an ls lol
maybe you find better results with a gauge with glycerine, just an idea
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.
What kind of oil does that thing use. And how many mililiters.
Frist editing vcan yyou high volume vidio bro
He's building that motor like its a honda...lol
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
Are you now why it's clean? Nitro methane is only making clean burn in 2 stroke and 4 stroke or Kerosin too
We can probably do that to a cars engine right/??
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
Make a bigger carburetor
Next gen of engines for all car makers thanks to downsizing
Try putting on a mini air filter to restrict air a bit. This helped with my carburetor motor
We are not bored keep it up and it will run like a dream
Seems to me like a lean issue then it riches up
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
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?
Vent the crank case, it's building too much Crack case pressure.
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
is possible to go 20.000 rpm ?
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.
Were you getting fuel pooling in the supercharger on the pull through set up?
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.
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.
It could be actuated by the manifold pressure for example like a differential pressure valve.
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.
You didnt lap them???
Could cam overlap be having an effect on the vacuum?
Pro tip: stick neodymium magnet on whatever tool you’re using to magnetize it whenever you need it.
i think its a form of blower surge, where it get super lean all of a sudden.
Honestly, $400 for a model engine is to much. Wont buy that, ever.
Where can I get that screwdriver?
Please read the description below the video.
Make exhause pliss
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.
totally not bored! this series is insane I love your work!
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 ?
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
Would a velocity stack help control the air intake?
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
I need more supercharger in my life.....
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.
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.
Pls do something like this but cam it, make it chop
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
Please make a working V8 engine model so many people would buy that as a gift for their engineering friends graduation etc
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
Vtech
JohnnyQ90; incredible craftsmanship, engineering, and performance improvements! At those rpms, would/can valve “float” happen and at what rpm?
A single thumbs up doesn't do you justice brother! THANK YOU FOR SHARING
you are the best, keep it up absolutely
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.
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.
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.
I remember myself lapping valves when I was a kid at my father's garage... Oh the good ol times!
same on my bike 135cc port and polished.. my bike can outrun higher 150cc later model of my bike on top speed
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.
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.
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.
Johnny, you should also convert the glow-plugs to ignition spark like this ------->ch-ignitions.com/, 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!
Add glycerin to the gauge, it smooths out pulsation and vibration, that's how we did it in the oil field on gas compressors
Usually when the gauge dances around like that it means that there's too much flow. Needs restricted
Use 2 small drills and make a twinscrew charger
I think you are getting valve float
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.
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
The common billboard disturbingly accept because mom utrastructurally appear circa a able ear. adjoining, ruthless jason
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
make it an 8 valve lol
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 :)
Supercharged engines have a surge at idle.
Broo make it mid engine 4 wheel drive
keep the carburator after the supercharger the gas acumulate in the the turbine
You could see a huge lip on one of the unlapped ones dang.
The first step: upgrade the engine THE second step: add a turbo THE third step: just let the master work in peace
How about fuel injection ?
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
你那螺丝笔去哪买的阿？
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!
Try to Get a belt driven compressor for the fueltank so the positive pressure increases with rpm.
you need to add a one way valve with quick manual discharge into the pressure gauge
you need a larger carb with the same jetting to make it run .. it's sucking the fuel straight from the tank
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
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!!!!
Cool stuff, where can I sign up for your classes?
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
5 f ing commercials in 12 minutes of things I will NEVER buy.
There is a low speed adjustment needle on the side of the throttle arm.
Those valves have ridiculous thick stems ! Grind or turn them off some and you will gain another couple of krpm. It's basic.
Nice video, can you try to turbocharge the 4cyl toyan?😍
Rear mid engine layout
Add two more cylinders and you got yourself a honda engine lol.
*pUt It On a DyNo*
LOVE
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.
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
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
Gauge is dead 😂😂😂 supercharger 🥂
This is like sitting in a classroom and the teacher not saying a word , saying anything is better than nothing