Sports Compact Car
03-26-2003, 07:43 PM
#2
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Join Date: Nov 2001
Location: NJ
Posts: 4,981
ok that mag. is total crap first of all, second most people don't understand how engine displacement is measured, so they come up with their own ****. It's just like when rotaries drag race they have to race in the 6 cyl class becouse we have baiscally 6 combution areas. I think thats funny, show me a 1.3l 6 cyl. the pistons would be the size of quaters LOL
03-26-2003, 08:03 PM
#6
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Location: NJ
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well displacement is the volume inside the cumbustion chamber. Honestly I grew up old school, so I can't explain it in liters. for example lets say you have a V8 chevy 350 engine. The volume of one combustion chamber with the piston bottomed out is roughly 43.75 cubic inches, multiply that by 8 and you get 350 cubic inches.
03-26-2003, 08:05 PM
#7
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Join Date: Nov 2001
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Originally Posted by Apex13B' date='Mar 26 2003, 08:59 PM
how about a Matras 1.5L v12?
mazda's own 1.8 liter v6 in the mx3
mazda's own 1.8 liter v6 in the mx3
03-26-2003, 08:28 PM
#8
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Join Date: Jan 2003
Location: London, Ontario
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Originally Posted by turbovr6' date='Mar 26 2003, 09:03 PM
well displacement is the volume inside the cumbustion chamber. Honestly I grew up old school, so I can't explain it in liters. for example lets say you have a V8 chevy 350 engine. The volume of one combustion chamber with the piston bottomed out is roughly 43.75 cubic inches, multiply that by 8 and you get 350 cubic inches.
Displacement in a piston engine is the fluid volume DISPLACED as the piston moves from BDC to TDC. With the way you mentioned, you would have to add the volume of the combustion chamber in the head, the thickness of the head gasket, and any additional volume from the deck of the block down to the piston if it doesn't come flush to the deck or protrude. Assuming a flat top piston of course. If it is a domed piston you would be closer, if it had a dish it would be less accurate. You would get a higher value than true. Measure the volume when the piston is bottomed out and subtract the volume when it is at the top.
I'm not sure, but I think the big debate is based on the fact that a piston moves through it's displacement TWICE during each cycle, while a rotary combustion face does just once. Therefore, for us, we get a power stroke each time a combustion face goes past the spark plugs, while the piston approaches the spark plug twice for each time that plug fires. Hence we move twice as much fresh air/fuel mixture into the combustion chamber as a piston engine of the same displacement.
I guess in power output method that puts us closer to a two-stroke. If you follow Grand Prix motorcycles or dirt bikes you can see this. A 500 cc two-stroke competes against a 1000 cc four-stroke.
03-26-2003, 08:36 PM
#9
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Originally Posted by TYSON' date='Mar 26 2003, 09:28 PM
Displacement in a piston engine is the fluid volume DISPLACED as the piston moves from BDC to TDC. With the way you mentioned, you would have to add the volume of the combustion chamber in the head, the thickness of the head gasket, and any additional volume from the deck of the block down to the piston if it doesn't come flush to the deck or protrude. Assuming a flat top piston of course. If it is a domed piston you would be closer, if it had a dish it would be less accurate. You would get a higher value than true. Measure the volume when the piston is bottomed out and subtract the volume when it is at the top.