for instance a ratio of 10:8:4 i'm just making dat up but what is a good ratio and what is a bad one
2006-08-29 17:59:38 · 6 answers · asked by Slick Vic 3 in Cars & Transportation ➔ Other - Cars & Transportation
Compression ratio is a way to measure how tightly the piston squeezes the air inside the engine.
Picture two tin cans, one slightly larger around than the other.
Cut out one end of both, empty them and turn them both upside down so the open end is toward the floor.
Slip the smaller one inside the larger. The smaller one represents the piston and the larger one is the cylinder. The smaller one goes up and down inside the larger and if it was sealed around the edges it could create pressure inside the larger one.
The compression ratio would be the difference in the volume of air when the small one is all the way out and at the bottom compared to the volume of air when it is all the way in and at the top. If the volume of air at the bottom was 8 cubic inches and the volume of air when the piston is at the top is 1 cubic inch then the compression ratio means the 8 cubic inches is compressed to only 1 cubic inch and the ration is 8.0 to 1
If at the bottom the volume was 18 cubic inches and at the top it was 2cubic inches the compression ratio would be 18.0 to 2 which is the same as 9.0 to 1
Years ago, in the 1960's gas engines with 8.5 to 1 used the standard gas called "regular" and engines with 10.2 to 1 needed the premium gas. Today most cars have compression of about 8.5 to 1 or 9.2 to 1. Which is a good ratio by todays standards. Higher compression would mean the need for premium high octane gas.
A diesel engine compression will be at least 14.0 to 1 and can go as high as 17.0 to 1. but it can' t run on gasoline.
2006-08-29 18:55:01 · answer #1 · answered by Anonymous · 2⤊ 0⤋
The compression ratio is the ratio of the quantity air compressed from the suction degree to the firing degree of the engine. The sucks the air from the ambience throughout suction degree, mixes it with gasoline, this mixture would be compressed in distinctive ratios at compression degree & this fairly compressed mix of air with gasoline would be ignited by making use of spark plugs at firing degree to get carry of capability from the indoors combussion variety engines. i'm not an mechanical engineer, yet this what I understood, surprising me if i'm incorrect
2016-12-14 14:34:18 · answer #2 · answered by midkiff 4 · 0⤊ 0⤋
The higher the ratio produces more horsepower. You also have to know what your crank pressure is going to run at. The optimal PSI your crank pressure should be in the 145-165.
Compression ratios arent like ratios in math. They are based on a 0.00 number. The 0's being any number you want. It will always be compared to :1 thats why a 0.00 number is used.
2006-08-29 18:05:36 · answer #3 · answered by HuyaHuya 2 · 0⤊ 1⤋
Its the swept volume of the cylinder to the space in the combustion chamber.Like if you had a 100cc cylinder and 10cc of combustion space you would have a compression ratio of 10 to 1
2006-08-29 19:05:27 · answer #4 · answered by frank m 5 · 0⤊ 0⤋
In terms of engine compression, lets say your piston at top dead center (TDC) and you have an inch of space between the top of the piston and the bottom of your head, inside the combustion chamber, now when your piston is at bottom dead center (BDC) and you have 9 inches from the top of your piston to the bottom of the head, then your compression ratio is 9:1
2006-08-29 18:14:00 · answer #5 · answered by 510Driver 3 · 0⤊ 0⤋
tell you in a way how strong your motor is
2006-08-29 18:04:58 · answer #6 · answered by grey_wolf54486 3 · 0⤊ 3⤋