Supercharged 2-stroke engine

Discussion in 'Performance Mods' started by supercharedcustoms, Feb 3, 2010.

  1. supercharedcustoms

    supercharedcustoms New Member

    New member here on this forum. Not new to building custom bikes cars trucks or anything else fast enough to get hurt in. My latest project is taking one of these cheap chinese motors and supercharging it. I will put up a thread of how i did this with pictures when it is done. Right now it is still in the works and I want to complete it and have pics and specs for everyone before I release how it is done. If your interested in having some killer hp out of one of these lil' motors stay tuned.

  2. Bozanceroz

    Bozanceroz New Member

    thatd be sweet if u pull it off
  3. Very sweet endeavor Super.. I for one would be very interested in your results, no matter the outcome.

    Now, don't take this the wrong way but, other than saying that you did it (which could be enough of a reason for doing it) I'd be asking why use a HT engine when you could just use another like the Morini and get the same, if not more performance out of it and definitely, more long-term reliability? You will definitey have to go into the engine to make it survive, which will easily overcome the cost of an equally powered Morini.

    Like I said, it sounds cool and I'd be really interested in seeing how you do it. I've got a supercharger on my 85 Corvette and many folks said it couldn't be done. I get your enthusiasm. But there are some laws of physics that need to be overcome (as I'm sure you know quite well). I wish you well with it and please, keep us informed! Should be fun!
  4. JemmaUK

    JemmaUK Guest

    While I can see this working in principle I'm not sure this is a great idea with something with such variable build quality - have you seen what happens when a supercharged engine throws a rod?

    I saw a tractor-pull once where some bright spark had put 4 supercharged tractor engines inline on one chassis - the black smoke was impressive enough - the white smoke, and flying rod complete with coconut sized flying piston that imbedded itself into the earth by a good foot - was even more impressive (especially to the 5 year old girl it missed by inches)

    Having that between my legs at 30+mph is not something I wish to experience.

    I can see how this would work - Ettore Bugatti came up with something similar although in his case it was a chain driven double lobe rootes type on a 18cc engine - but I would trust his engineering and quality control much more than I would a CGE

    I personally see little point in this since with a little work a frame mount setup could easily be made to take the current crop of 4-5hp 2 stroke tuned engines from people such as DDM - twice the power on half the displacement - not to mention you'd get more power yet with a tuned pipe and my low percent nitro/petroil mix... True they are more expensive, but you get what you pay for and personally even the NA CGE's have always been a false economy.

    By all means see if it can be done - but I would be very suspicious if this could be done safely with the current stock of CG engines - and if an engine of this configuration fails under load I for one would not want to be the person liable for supplying it... because if it throws a rod or a piston through the side or head the only bits between it and the outside world in general will be important parts of the riders anatomy... not to mention the resulting accident and the injuries that could cause...

    Jemma xx
  5. 210061741

    210061741 Guest

    Currently i am working on a design for A high performance motor.
    Thus far i have produced some pretty good power outta the HT.
    But i rebuild them from the ground up.

    The cases are very thin and i have seen a messed up rod from a out of the box motor.
    I've been thinking about the engine exploding myself.

    I've got a plan but before i build the stage 3 motor the safty of the engine will be thourally considered.

    Supercharging a 2 cycle sounds impressive.
    What are you going to accomplish???

    All you do is increase the pressure in the case.
    If you increase the pressure too much you only blow the fuel outta the exhaust.
    Transfer port and exhaust port are open at the same time.
    Not much gain there more of a loss.

    There is an optimal pressure for the motor.
    Supercharging is more harm than good.

    Supercharge a 4 stroke not a 2 stroke.

    That's the best advice i can give you.
  6. Dilly Bar Rob

    Dilly Bar Rob Member


    But I am curious, what are you planing on using as a blower? Someone on here wanted to use an old "smog pump" from a car for this purpose... I doubt that one of those would work, for various reasons...
  7. supercharedcustoms

    supercharedcustoms New Member

    By porting intake port can be kept open slightly longer than the exhaust port leaving room for a couple psi of boost. Note the rod and piston have been beefed up through tig welding and remachining them to handle the increased power.
  8. supercharedcustoms

    supercharedcustoms New Member

    I am using a centifugal style supercharger that isn't run off the crank rather a high amp hour 12v battery that would require recarging
  9. 210061741

    210061741 Guest

    I used to design US Navy Ship Shafts.

    I hope you are shot peening that rod.
    Welding actually makes things weaker.
    Are you heat treating it properly to relieve the stress induced by welding?

    There allready is a supercharger for the 2 stroke.

    2 words.

    Expansion Chamber !!
    = up to 7psi boost.



    Cool work though mann.
    Sometimes you have to think outside the box.

    Just be careful thats all.
    It cost a whole lot of money for an Engineering Degree.
    I still owe over $30,000.

    Sometimes it's the little things that are overlooked that become disastorus.
  10. JemmaUK

    JemmaUK Guest

    Ok... a few things...

    1.) Its perfectly possible to supercharge a 2-stroke. The deltics were scavenged blown engines and that was effectively supercharging - as was the unreleased chrysler neon 2 stroke engine (yes really). The problem as I see it in this application is that you would indeed blow half the charge straight through the engine and out the other end - sorta like politicians with intelligent ideas... thats assuming the thing just doesnt detonate in the first 100 yards.

    The solution?

    Reed valve the exhaust port - problem solved.

    2.) A Tuned Pipe is in no way a supercharger or a turbocharger. If its anything its a resonance inverse-induction device to momentarily increase compression. It works in exactly the opposite way to mopars sonoramic system in that it provides a powerful boost at certain RPM's and a noticable effect at all others but from the exhaust side not the intake side.

    Using both reed valve exhaust and tuned pipe together with some sort of supercharging could give very impressive power but it would have to be tuned just right.

    Also if you are going to supercharge a 2-stroke - why not run the pressurised air through a tuned induction pipe - give you two bites of the cherry?...

    3. - here is my problem with all this... its all well and good turning the equivalent of a lawnmower engine into its F1 equivalent - but while it will be fun while it lasts it wont last very long... you are putting alot of money into something but you are starting from a poor initial position...


    1. **** castings
    2. **** manufacture
    3. Out of the box longevity about equal to a Heinkel 177 on a dry day
    4. designed deliberately to be placed between sensitive parts of your anatomy

    I have been on this site a long time now and I would say 80% of anything relating to 2-strokes is "my CGE has blown up/wont start/wont pull/sounds like a cat being swung round by its nuts"... and you want to design a supercharged engine based on that?!

    The thing is - you can get an engine off the shelf that provides a similar amount of power in a smaller and more reliable naturally aspirated package (because its based on commercial kit from known suppliers) - has scope to be tuned and piped - and would provide up to twice the power needed to shred every spoke on your back wheel... sure its a rackmount or nothing at the moment but I think peoples expertise would be better used by making a frame mounting to take something like the GP460s and their ilk..

    Look at it this way - you can build a race engine in two ways - you could take a stock 440 - replace its guts, port and polish it and slap on 2 by 4bbl Carters - change the timing, change the cams, try and convince it not to wheeze like a 70 year old once it gets over 7000rpm - and you would end up with a half decent motor...

    Or you could go out and get the crate motor version for maybe $500 more overall - and you could have something that both can win races and doesnt immolate itself on its own big-end every 2nd week...

    There is a point where you run into the law of diminishing returns - and I think to be honest for the amount of work you are going to have to put in to make this reliable you are beyond that.

    4. Another point is that generally blown or turbocharged engines run a lower compression than stock motors - eg Chrysler 2.5 NA - 9.5:1 or 10:1 - 2.5 Turbo III - 8.0:1 so when the battery you are using dies mid ride (which trust me it invariably will, most likely halfway up a hill) you will not only lose boost but you will end up with something that wont have the power to pull the skin off a rice pudding... How about driving the compressor off the drive chain - saves fuel consumption at idle and ramps up with engine acceleration. It would pull a little power off the motor but not anything particularly noticable.

    Jemma xx
  11. supercharedcustoms

    supercharedcustoms New Member

    Here's the deal, Yes the rod and piston are getting treated, also I am testing the rods for compressive and tensile strength before installing. Also I am already running an expansion chamber between the carb and port along with the supercharger. For fuel I am running 100 octane (r+m/2 method) sunoco race fuel with a 12% nitro mix and using amsoil synthetic two-stroke oil, and an ngk plug that has been gaped down. I understand this subject is highly controversial and many have their doubts, I have been running trials on the engine and tweaking as I go along. I am waiting for paint to come in so I can paint the bike, I am also playing around with gearing and rim size to get it where I want.
  12. supercharedcustoms

    supercharedcustoms New Member

    Heres the deal I am running nitro, I am running a tuned port exhaust or I would not be able to get proper resonance to get this engine to run,Ettore Bugatti builds 4stroke not 2stroke totally different ball game, I am running gasoline and nitro and syn. oil mix not diesel which is injected in at tdc. I have seen a thrown rod blow out of an engine. We were in a GEO metro doing 91mph down a hill and had a rod blow a hole in the hood when it came out the side of the 1000cc 3cylinder engine yeah it is a little scary but that is why i am testing everything before I release all the details of this build. I dont want others getting injured off of my design if they attempt to copy it.
  13. supercharedcustoms

    supercharedcustoms New Member

    By having the intake port open slightly longer boost can be obtained. compression on these china engines is low... like 6:1. while heat is increased as the compression is increased by ceramic coating the inside of the exhaust heat is taken away from the motor much quicker. supercharging a 4-stroke is easy and everyone is doing it. not everyone is working on the 2-stroke not because it cant be done but simply because it is harder.
  14. arceeguy

    arceeguy Active Member

    While I don't hate the HT engine like jemma does, a supercharger on a HT engine is about as useful as titz on a turtle IMHO.
  15. Hey, maybe the men turtles are into that sort of stuff!

    I say, it's your bike, your engine, your nubules. Be careful and creep up on it from the side of caution. Most of all, let us know how it goes.

    You're either simply addressing whatever roadblocks are thrown up in front of you on this forum or, you're addressing the issues. When we see a youtube of it running, we'll all know.

    Good luck with it.
  16. Lemsteraak

    Lemsteraak New Member

    The Bugatti supercharged 2 stroke engine is very cool. There are pictures and specifications somewhere on the web. I would study his design because it would be a huge engineering challenge, not a simple bolt on.

    The difficulties are profound. Not as simple as pressurizing the intake, for example, you have to balance the pressure inside the carburetor. Then you have to balance the pressure for the fuel intake otherwise the higher intake pressure will simply blow the fuel back into the fuel tank.

    Personally, I don't see the point, other than a design exercise. Two-stroke engines are pretty much a dead end here in the States. I think you would be wise to look into some of the new engine designs like the Ecomotor
    They, like you are after the holy grail - power density
  17. Lemsteraak

    Lemsteraak New Member

    The above post is incorrect, I said the Bugatti engine was two stroke, it is actually a dual overhead cam four stroke supercharged engine.

    Here is a link to the Bugatti Type 72

    The only supercharged two stroke engine that I know about is a GMC diesel they made during WWII, the venerable '72 series. If I remember right, they had exhaust valves, otherwise the incoming charge would blow right through.
  18. supercharedcustoms

    supercharedcustoms New Member

    Latest scoop- so i got the porting down to build pressure and she screams like no other got 3psi of boost at 61 mph with a 32 tooth sprocket on a 30" tire which is nothing like I have every rode before... little scary especially with only coaster brakes. got two healthy 10 min runs on her, all seemed well it was hot but it was not running lean or to the point where parts would fail. On the third run after about 17 mins in the piston basically melted to the wall of the cylinder locking up the rear tire at 25 mph in town scared the s*** outa me at first and then I had to laugh because I realized what really happened... while that was prolly the longest black mark on pavement left by bicycle i had ever seen, but in the end it was all worth it! Heres how I look at it, yeah I blew a bunch of spare time about $70 in parts and materials, but I had fun, learned some things along the way and have an excuse to rebuild my cruiser into a more chopped out bike with a new top end on the engine. Next time I supercharge a bike it will be with something much bigger maybe a snowmobile motor...... :)
  19. Drunkskunk

    Drunkskunk Member

    Can't wait to see it

    It may be as pointless as T1Ts on a turtle, but that would make one s3xy turtle!
  20. Pics! We need PICS!!!!

    Even if it is of the carnage. Let's see your setup before you dissect it. Then, let's see the gooey guts. It's like a slasher movie for motor geeks. :grin5: