help a newbie out!!!!!
12-04-2012, 08:46 PM
#1
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help a newbie out!!!!! Yea I know its a dumb question but what does your compresion really do and affect you motor if any one can help me with my dumb question
12-04-2012, 09:55 PM
#3
Your question is almost too general. Compression is everything on a motor. In fact, motors with bad rings will make below average power and if bad enough they may not even run. A motor is simply a sophisticated heat pump so without a sealed combustion chamber, it won't pump or transfer power to the crank.
12-05-2012, 04:33 PM
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Here is a visual you can kinda use....and don't try it because I really don't know what would happen. It's just a hypothetical example. If you take a small firecracker and light it in the palm of your hand with your hand wide open...you probably will only get a small burn, maybe a small cut because there is little upward resistance and thus most of the gases and forces will just go upwards. Think path of least resistance. But if you light the firecracker and then compress it by closing your hand around the firecracker in a fist you are going to get a serious flesh wound and probably a couple broken bones in your hand. The reason is because now the path of least resistance is breaking your skin and bones since there was no opening for the gases to escape. Plus when your hand was wide open there was almost unlimited surface area above for the gases to expand...but when your hand was closed there was only a couple square inches that the gases slammed against. An engine is kinda like that....the tighter you compress the fuel/air mixture the less surface area there is to absorb the energy of the exploding gases and thus more energy per square inch is directed at the top of the piston, which in turn drives the piston down very hard...and thus you get more power. There are drawback...especially in a gasoline engine such as higher combustion temperatures that can lead to head failures, pre-ignition of the fuel and or the flame speed expanding before top dead center, and a bunch of other things that can really hurt the engine if not done right. When it comes to making an engine faster....there is a whole lot to know before you just randomly pick a compression ratio and say I want that. Everything you do will affect the parts up stream and down stream and it's all gotta be matched up by somebody who knows what they are doing. Me not being one of them. Again, that's the best I could do to try to explain it. I'm no expert and I'm sure some others on here can chime in and explain it better...but that's the best I could do. Good luck.
^^^ Great explanation without getting to far into it.
12-05-2012, 07:58 PM
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12-05-2012, 08:07 PM
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Nope I started a club savage habits then found out there was one in the bay area so my goal is to be better the them or at least try geting a pewter ss kinda like there's I thing but I'm trying to learn what I don't know so when I build the motor ill know what I'm doing (oh there in cali I'm in texas)
Thanks for the help
Thanks for the help
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12-05-2012, 09:09 PM
#8
Here is a visual you can kinda use....and don't try it because I really don't know what would happen. It's just a hypothetical example. If you take a small firecracker and light it in the palm of your hand with your hand wide open...you probably will only get a small burn, maybe a small cut because there is little upward resistance and thus most of the gases and forces will just go upwards. Think path of least resistance. But if you light the firecracker and then compress it by closing your hand around the firecracker in a fist you are going to get a serious flesh wound and probably a couple broken bones in your hand. The reason is because now the path of least resistance is breaking your skin and bones since there was no opening for the gases to escape. Plus when your hand was wide open there was almost unlimited surface area above for the gases to expand...but when your hand was closed there was only a couple square inches that the gases slammed against. An engine is kinda like that....the tighter you compress the fuel/air mixture the less surface area there is to absorb the energy of the exploding gases and thus more energy per square inch is directed at the top of the piston, which in turn drives the piston down very hard...and thus you get more power. There are drawback...especially in a gasoline engine such as higher combustion temperatures that can lead to head failures, pre-ignition of the fuel and or the flame speed expanding before top dead center, and a bunch of other things that can really hurt the engine if not done right. When it comes to making an engine faster....there is a whole lot to know before you just randomly pick a compression ratio and say I want that. Everything you do will affect the parts up stream and down stream and it's all gotta be matched up by somebody who knows what they are doing. Me not being one of them. Again, that's the best I could do to try to explain it. I'm no expert and I'm sure some others on here can chime in and explain it better...but that's the best I could do. Good luck.
Good demonstration!
12-06-2012, 02:38 PM
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Thanks Pewter2000Ta, and Blackpanther99. I wasn't sure if that came out ok...and yes, I think I will drink a beer tonight...sounds good 
Savage Habits...anytime, I hope it helped. As for compression ratio's..Google the formula and then start playing with the numbers useing different volumes and it will make sense in how you can add a dome and yet the ratio's change. Take care.
Savage Habits...anytime, I hope it helped. As for compression ratio's..Google the formula and then start playing with the numbers useing different volumes and it will make sense in how you can add a dome and yet the ratio's change. Take care.
12-07-2012, 01:14 PM
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Here is a visual you can kinda use....and don't try it because I really don't know what would happen. It's just a hypothetical example. If you take a small firecracker and light it in the palm of your hand with your hand wide open...you probably will only get a small burn, maybe a small cut because there is little upward resistance and thus most of the gases and forces will just go upwards. Think path of least resistance. But if you light the firecracker and then compress it by closing your hand around the firecracker in a fist you are going to get a serious flesh wound and probably a couple broken bones in your hand. The reason is because now the path of least resistance is breaking your skin and bones since there was no opening for the gases to escape. Plus when your hand was wide open there was almost unlimited surface area above for the gases to expand...but when your hand was closed there was only a couple square inches that the gases slammed against. An engine is kinda like that....the tighter you compress the fuel/air mixture the less surface area there is to absorb the energy of the exploding gases and thus more energy per square inch is directed at the top of the piston, which in turn drives the piston down very hard...and thus you get more power. There are drawback...especially in a gasoline engine such as higher combustion temperatures that can lead to head failures, pre-ignition of the fuel and or the flame speed expanding before top dead center, and a bunch of other things that can really hurt the engine if not done right. When it comes to making an engine faster....there is a whole lot to know before you just randomly pick a compression ratio and say I want that. Everything you do will affect the parts up stream and down stream and it's all gotta be matched up by somebody who knows what they are doing. Me not being one of them. Again, that's the best I could do to try to explain it. I'm no expert and I'm sure some others on here can chime in and explain it better...but that's the best I could do. Good luck.
