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What do these acronyms stand for and what do they mean? (hell, what they stand for will probably answer the latter question)<P>I got my first car; a black '94 4 cyclinder. I need to fix some aesthetic s--- like the BB shaped indentments on the side of the car. I wouldn't mind painting in a different color either. Living in AZ with a black car is the devil. Also, my bumper is all scraped up which looks pretty bad.<P>I won't even pretend I know anything about cars and performance, heheh, for now, I need to make it not look like a turdbox.

DOHC = Dual OverHead Cams<BR>SOHC = Single OverHead Cam<P>If you have DOHC, you can squeeze more horsepower out of your engine, the 94's came with DOHC.

Hey, great! - here's one even I can answer:<P>First, the "OHC" part stands for<BR>Over Head Cam - meaning that the Camshafts, which operate the Engine's valves, are located on top of the head(s). <P>The DOHC means Double Over Head Cams<BR>(there are two camshafts for each bank of cylinders - one probably runs the intake valves, while the other runs the exhaust valves)<P>while SOHC means Single Over Head Cam<BR>(A single camshaft is located on top of each bank of cylinders)<P>My understanding of the advantage of OHC over other designs is this:<P>FEWER MOVING PARTS - in most older, traditional engines (American V-8s, etc.) a single cam is directly driven from the crankshaft, via gears. Because this camshaft is mounted low within the engine block, Pushrods are needed to transmit the motion of the cam lobes to the valves, via rocker arms. (Lobe pushes Pushrod, Pushrod goes up, valve goes down). <P>In OHC Engines, the cam lobes push down on the valves by nearly direct contact (Lobe pushes Valve Down). The elimination of some of the parts increases durability. <P>One drawback - the rotational energy of the crankshaft needs to be transmitted to the cams over a greater distance - usually requiring a chain or belt. (My GS uses belts)<P>BETTER RESPONSE AT HIGHER REVS - You remember this "Newton" guy from Science Class?? Well, those extra pushrods, and the heavier rockers in a Non-OHC engine have more mass. The parts can only go up & down so fast, before they stop "making the complete trip" (they sort of "float" in mid-air - because of their inertia, while they're still on their way down, the high point of the cam lobe smacks them again....)<P>Becuase the OHC "Valve Train" (the parts associated with each valve) are lighter, they have less inertia, and are able to stay properly in contact with the cam lobes, even at higher speeds.<P>This is sort of the "Idiot's Ph.D. version" - how did I do?

Hey, great! - here's one even I can answer:<P>First, the "OHC" part stands for<BR>Over Head Cam - meaning that the Camshafts, which operate the Engine's valves, are located on top of the head(s). <P>The DOHC means Double Over Head Cams<BR>(there are two camshafts for each bank of cylinders - one probably runs the intake valves, while the other runs the exhaust valves)<P>while SOHC means Single Over Head Cam<BR>(A single camshaft is located on top of each bank of cylinders)<P>My understanding of the advantage of OHC over other designs is this:<P>FEWER MOVING PARTS - in most older, traditional engines (American V-8s, etc.) a single cam is directly driven from the crankshaft, via gears. Because this camshaft is mounted low within the engine block, Pushrods are needed to transmit the motion of the cam lobes to the valves, via rocker arms. (Lobe pushes Pushrod, Pushrod goes up, valve goes down). <P>In OHC Engines, the cam lobes push down on the valves by nearly direct contact (Lobe pushes Valve Down). The elimination of some of the parts increases durability. <P>One drawback - the rotational energy of the crankshaft needs to be transmitted to the cams over a greater distance - usually requiring a chain or belt. (My GS uses belts)<P>BETTER RESPONSE AT HIGHER REVS - You remember this "Newton" guy from Science Class?? Well, those extra pushrods, and the heavier rockers in a Non-OHC engine have more mass. The parts can only go up & down so fast, before they stop "making the complete trip" (they sort of "float" in mid-air - because of their inertia, while they're still on their way down, the high point of the cam lobe smacks them again....)<P>Becuase the OHC "Valve Train" (the parts associated with each valve) are lighter, they have less inertia, and are able to stay properly in contact with the cam lobes, even at higher speeds.<P>This is sort of the "Idiot's Ph.D. version" - how did I do?

Wheee!! Now I know! Good thing to know I have what sounds like it could be considered the better of the two. I'll definately need to squeeze some more HP out of the engine as the acceleration sucks.