C.A.P.
Senior Heliman
Location: custer park IL.
| A little infor for the NEWBEE, on 2 cycle motors with tune pipes. As everyone know that has this motor. The oil,fuel mix is what lub's the motor bearings. A tune pipe is made in a way that the intake of the pipe is larger then the exhaust. That causes a restriction. This is done to build up presure in the pipe itself. That presure is then pushed back into the motor, Why is that done??, Is what a lot of people do not understand. So I',ll start with the carb. It works like any carb. It work on the fuel being suck into the motor and at the same time mixing the the air, That's when the needle come into play by allowing more or less fuel to mix with the air. The amount of air is let in by the intake buterfly valve (throttle) The fuel is pumped into the carb by a built in pump that uses a pulse developed by the engine it self. Then fuel is sucked into the engine. It goes under the bottom of the piston, as it is moving up building presure (compression) to fire when the spark plup is fired. This upward motion causes a vacuum, by the time it hits the intake manifold port that causes the fuel to be drawn into the engine. (Into the lower crank case). After the engine fires the piston starts to come down closing off the the intake manifold. at this point the downward motion of the piston starts to build presure in the lower crank case. (this is when the pulse for the carb is made. on the way down it pushes air into the carb through the little hole under the intake manifold port. and on the way up it sucks it back out making a pulse). This builds until the piston reachs the intake ports in the cylinder walls. When that happens the presure pushs the fuel and air mix into the upper combustion chamber to fire. Then the piston starts up again. To start the compression cycle again. When it fires the piston comes down . Until it hits the exhaust port and for at least half the port, the spent fuel and air leaves the cyinder. The second half is when the intaken ports( the are four ports in the cyinder on these engine) are reached. By that time the spent fuel and air have gone. And the new fuel and air mix is push into the upper cylinder again, When the piston starts up air is push back down the intake ports and out exhaust port. When air is pushed down the intake port, it creats more presure in lower crank case. a tuned pipe creates even more presure here causing the new mix to be pushed in the cylinder even harder. And the cycle just keeps going over and over. What the tune pipe does is restrict the exhaust a little to a lot depending on the pipe. and causes more presure in the upper cylinder and the lower crank case. To push in more fuel air mix. You can say this is like a turbo affect. When you have your engine ported. It's like put in a bigger cam in it, like a car. Because there is no external machanics, (like a turbo to create compression on lower rpms). IT only happen at the last quarter of the rpm range of the engine, or even higher depending on how much restriction there is. This also creats more heat, RPMS & hp. To do it right with a turbo on a car. You must lower your compression in your cylinder to be able to reach it's mac rpm. because the turbo is increasing the creating more compression then the piston. And on most racing turbo's there what is called a exhaust gate this opens when there is to much presure in the cylinder. Not lowering it on a car will blow a head gasket OR bend a crank or rod because of to much compression. Or the lease make the engine run rough on top rpms. Because the ENGINE is starting to fight it self. I know both Al's raise the compression on their 3d mac's and I'v heard that running with a pipe you should not go over 12,500 rpm. because of the vibration. I could be wrong there, but that is what I have heard. Your engine will only have a short but stronger hp range on top end. That's why a pipe is not for everyone. Other then the looks. Take the pipe off and you again have more RPM range to fly with. and all of this happens a thousand time faster then a bink of an eye. I wrote this to further daze and confuse the newbee. I think I may even exceeded my goal!!! |
maybe I will leave is as it is for now. anyway I am enjoying it. maybe later I will try the 231 modified to see any difference.
