Maintenance & Technical > KX500 Original
crank stuffer
doordie:
--- Quote from: doordie on January 01, 2008, 05:54:01 AM ---
--- Quote from: BDI on December 30, 2007, 05:14:13 AM ---
--- Quote from: doordie on December 29, 2007, 11:44:15 PM ---This is a easy mod to raise ccr... :-D
--- End quote ---
Hey doordie those are ceramic main bearings aren't they? very nice 8-)
--- End quote ---
Yes,but isn?t a KX500 engine.... :wink:
BUT soon will my engines runs with this hybrid ceramic bearings.....and a composit
rod from a Swedish company www.mxcomposites.com
Ceramicbearings from a another Swedish company www.vasatech.se
--- End quote ---
BDI:
With the big square exhaust port as the piston travels down and the port opens exhaust gas velocity slows down. With the upside down triangle the exhaust gas velocity stays high as the piston goes down, do to the port narrowing. From what I have read if the port is designed right with the proper taper the upside down triangle port will flow as much as a larger square port and lend to better filling of the cylinder do to the fact that gas velocity stays high longer. This is stuff I have learned from playing with nitro rc cars. The nitro rc car engines that use this technoligy flat kill the ones with the old style square port. If you were to take both engines apart and try to decide which one was going to perform the best based on looking at the ports your knee jerk reaction would be to pick the one with the great big square port. When you take your car out and run it the one with the big square port gets sadly out performed by by the engine with the upside down triangle port.Your rc car goes from fast with the old style exhaust to retarded fast and pulling power wheelies with insane top end with the triangle port.
Desert Panther:
for me its burn then ride and blow stuff up. yea i like to burn before i ride
[/quote]
me too ! 8-) :wink:
maddoggy:
bdi, lets see if i understand your upside down triangle thoughts correctly. the narrow section of the taper will increase the exhaust pipe pressure much like an orfice increases pressure in a hydraulic system. is my understanding correct? i'm not doubting you but if this is how it works i'm still unsure of the benefits. with hydraulic orfices the pressure is increased past the orfice but the volume of oil passing through is reduced. the same would happen with the exhaust flow if i'm thinking right. just doing some out of the box thinking here. MADDOGGY
BDI:
I guess a upside down triangle is a bad description It is a trapezoid. The idea is to have the left and right port walls get slightly closer together towards the bottom. when the piston first starts to uncover the port the gasses are under high pressure so it comes out fast but as more and more of the port is uncoverd the pressure drops and the gasses slow down. the idea is if the port narrows towards the bottom the gasses keep moving fast even though the pressure is droping.It's like when the river is wide the water flows slow but when the river narrows the water moves faster. Yes I'm sure the port has to flow less but this should make great bottom end torque and mid range. I want to make up for this with larger secondary exhaust ports but I do not think this would have that great of an impact on top end because we are not talking about making the port a lot smaller and by the time the port opens all the way It has allready done the vast majority of its flowing.
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