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Thread: supercharger

  1. #1
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    supercharger

    What do u people think about the rb supercharger for 3.3 tmaxx/revo

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    Well all it really does is let more air in and lean out the fuel mixture possibly hurting your engine, I had one and input it on the truck and it wouldn't even start due to the messed up mixture. So if you got the mixture right it would be ok but I don't think you'll tell that much of a difference. But you could try.

  3. #3
    Marshal ksb51rl's Avatar
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    26 Revo threads with "supercharger" in the title since November 2004 (probably lots more in the Maxx subforum.) Almost unanimous agreement that they are a waste of money.
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    It is as simple as this; There are times, like every time the piston is at bottom dead center, that the intake port and the exhaust port of the engine are open at the same time.

    At this moment in time, all of the air/fuel mixture is flowing right through the engine and into the exhaust pipe. This disrupts the backwave (the exhaust acts as an echo chamber) of unburned air/fuel mixture that is supposed to be flooding the cylinder, along with the fresh air/fuel mixture from the carb. The engine needs both the fresh air/fuel mixture, and the rebounding wave of unburned air/fuel mixture, in order to have the correct air/fuel mixture in the cylinder at the moment of combustion. You will never have the correct mixture with a supercharger. All you can expect to do is richen your carb to the point that the engine leans out less frequently. At this point you are wasting fuel because most of it is flowing through the engine, and out the pipe.

    This topic has been brought up many, many, many times. The end result is always the same, failure. However there are those that are steadfast to thinking that superchargers work. But in their defense (kinda), this is only due to the ignorance of how an RC 2 stroke engine works.
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  5. #5
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    Quote Originally Posted by Oomp View Post
    It is as simple as this; There are times, like every time the piston is at bottom dead center, that the intake port and the exhaust port of the engine are open at the same time.

    At this moment in time, all of the air/fuel mixture is flowing right through the engine and into the exhaust pipe. This disrupts the backwave (the exhaust acts as an echo chamber) of unburned air/fuel mixture that is supposed to be flooding the cylinder, along with the fresh air/fuel mixture from the carb. The engine needs both the fresh air/fuel mixture, and the rebounding wave of unburned air/fuel mixture, in order to have the correct air/fuel mixture in the cylinder at the moment of combustion. You will never have the correct mixture with a supercharger. All you can expect to do is richen your carb to the point that the engine leans out less frequently. At this point you are wasting fuel because most of it is flowing through the engine, and out the pipe.

    This topic has been brought up many, many, many times. The end result is always the same, failure. However there are those that are steadfast to thinking that superchargers work. But in their defense (kinda), this is only due to the ignorance of how an RC 2 stroke engine works.
    Great way of explaining it!! You would be better off sending the 3.3 to porting or polishing the engine for more performance!!

  6. #6
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    You would be better off sending the 3.3 to porting or polishing the engine for more performance!!
    Yes, this is the most effective way to get more power out of your engine.
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  7. #7
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    i know a guy who does masterful work on the 3.3...
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  8. #8
    Marshal Double G's Avatar
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    Quote Originally Posted by Oomp View Post
    It is as simple as this; There are times, like every time the piston is at bottom dead center, that the intake port and the exhaust port of the engine are open at the same time.

    At this moment in time, all of the air/fuel mixture is flowing right through the engine and into the exhaust pipe. This disrupts the backwave (the exhaust acts as an echo chamber) of unburned air/fuel mixture that is supposed to be flooding the cylinder, along with the fresh air/fuel mixture from the carb. The engine needs both the fresh air/fuel mixture, and the rebounding wave of unburned air/fuel mixture, in order to have the correct air/fuel mixture in the cylinder at the moment of combustion. You will never have the correct mixture with a supercharger. All you can expect to do is richen your carb to the point that the engine leans out less frequently. At this point you are wasting fuel because most of it is flowing through the engine, and out the pipe.

    This topic has been brought up many, many, many times. The end result is always the same, failure. However there are those that are steadfast to thinking that superchargers work. But in their defense (kinda), this is only due to the ignorance of how an RC 2 stroke engine works.
    Very well said. There recently was an argument over this very subject in the Jato forum and my impression was that there was a few people that would not believe this.

    Here's an animation of tuned pipes: http://www.bukupower.com/AnimateCorrect.html
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  9. #9
    RC Turnbuckle Jr. fallonguy's Avatar
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    Another thing a lot of people don't think or know about is the intake opening on the crank shaft is only open for a short period of time (see the animation on the link that Double G posted) and that's when the piston is a TDC. And it's the piston coming down that causes the pressure in the crankcase. So the supercharger will be doing nothing the rest of the time but cause a drag on the engine.
    Last edited by fallonguy; 04-25-2013 at 02:01 PM.
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  10. #10
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by rioyellow View Post
    What do u people think about the rb supercharger for 3.3 tmaxx/revo
    Waste of money unless you are building a shelf queen and what a lot of shiny neat looking stuff on your RC..

    Intake and Exhaust ports are open at the same time during the upstroke or downstroke of the piston... All that forced air and fuel is just pouring out the exhaust....
    Increased weight is no help.

    TRX 3.3 you can buy new for $140.00
    Supercharger to shorten the life of the engine with HIG RPM lean issues $150.00

    That's $290.00.... You can drop a nice big block in your rig for that price and have more power, performance than ANY Supercharged 3.3 could hope of delivering.

    I've forgotten how many posts I've seen with this question...

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  11. #11
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    The animation explains it even more clearly.
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  12. #12
    RC Turnbuckle Jr. fallonguy's Avatar
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    Another thing I just though about is when the intake on the crankshaft is closed where it all the air from the supercharger going? It would have to blow back through the supercharger and that would cause even more drag on the engine. The supercharger is nothing more then a fan try and take a hair dryer turn it on blow so you don't burn yourself and then hold your hand over the end see what happens.
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  13. #13
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by fallonguy View Post
    Another thing I just though about is when the intake on the crankshaft is closed where it all the air from the supercharger going? It would have to blow back through the supercharger and that would cause even more drag on the engine. The supercharger is nothing more then a fan try and take a hair dryer turn it on blow so you don't burn yourself and then hold your hand over the end see what happens.
    Most superchargers work with multi-cylindered engines, when one combustion chamber is open another is closed which prevents what you are thinking of...
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  14. #14
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    while that may be true we are talking about a single cylinder 2 stroke.... so that point is well moot
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  15. #15
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    I didn't quite explain it correctly. (No alcohol references allowed on this site, I've had to edit this) NN
    Last edited by Nitronaught; 04-26-2013 at 10:34 AM. Reason: alcohol reference
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  16. #16
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    superchargers as others have said just leans out the motor and for the cost you may as well buy a new motor Ie picco or a big block.. I dont see any way in which you could improve these motors with a bolt on part such as superchargers, boost bottles or any other device, I do however feel some type of cold air & fuel induction would work but how to make such a product Im unsure of...it again would probably be cost inaficient..
    with a colder induction you would get a bigger bang sorta like an intercooler but again for cost the simple answer is get a bigger engine or lean out your motor to improve performance and then replace when its worn..

    this is only my opinion...

  17. #17
    RC Turnbuckle Jr. fallonguy's Avatar
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    The point I was trying to make (maybe not explaining it right) The notch on the crankshaft act like a intake valve and is only open for a short period of time.

    It open just before TDC and closes just after TDC. The rest of the time the supercharger is doing nothing but causing a drag on the engine.
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  18. #18
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    fallonguy, I think you are bringing up what may be the most relevant issue as to why not a stupercharger. The supercharger is belt driven(rubberband driven?) off the flywheel, and while it is trying to push air thru the carb, but can't, it is 100% a drag on the crank.
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  19. #19
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    Superchargers and blowers are for building intake pressure for higher velocity. Without A proper intake they will just create back pressure and disrupt airflow.

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