|
|
|
|
On the left is the navigational bars with hyperlinks to get you to the section that is most important to you. Below is where we will talk about different parts and offer our opinion as to why we would choose a part for one application and a similar part for another application.
Engine Blocks:Engine blocks are the largest assembly to an engine. Outside the fact that Cubic Inches creates horse power, engine blocks are huge power loss assemblies. To eliminate power loss is the same as to create power. For instance if you have a Ford 2 liter engine with 1500 gram pistons and 2000 gram rods you will have a miserable time at 5000 rpm's. It will be slow in rpm's and will be tough to achieve. Your losses will be very high. On the other hand if you have 300 gram pistons with 500 gram rods you will be able to achieve 5000 rpm's with little problems. With a piston and rod assembly of 800 grams it would be much easier rotating the assembly, therefore creating more horse power. Imagine going Mach 1,000, stopping, and reversing your direction. It would tear you to pieces, however engines do it every day. To minimize the weight of the rotating assembly you minimize the amount of weight (tons) that your trying to stop and reverse in direction. So a rule of thumb is anything that goes round and round or up an down minimize the total weight. Keep in mind structural integrity! OR BOOM !For daily driver some passing gear driving: O.E.M. pistons and rods are good.For daily driver and some drag racing: TRW forged pistons and Eagle rods are best.For drag racing with no street driving: JE pistons and BME rods are better yet.Cylinder Heads:Cylinder heads is the largest area for improvement. If you have a cylinder head with a poor chamber design you will be robbed of horse power with little you can do without spending a lot of time and money to fix the design. Sometimes it's easier to go out and purchase a new set of heads from an aftermarket company. Heads and their design are very specific in their use. If you drive a car to school or work everyday and for grocery shopping generally stock heads with small ports work best. Because the engine does not go over 3500 rpm's as a norm. If you were to use Top Fuel cylinder heads on this car the chance's are you will not be able to drive this car out of the driveway. Because of the mammoth size intake and exhaust ports in the heads. On the other hand if you have a Pro car like in Pro Stock and you are running stock O.E.M. cast iron heads with small ports on the intake and exhaust you will run out of breath before you even get started. With a stock motor and huge heads the air speed will be to slow. With a big race motor and small heads you will have a very high speed of air flow to the point that you will stall the air and the air supply will stop flowing. Horse power in these two extremes will in most terms be killed. So what do you do? Do the math. Figure out what you want the car to do. No racing, some racing, all racing. What engine size. What rpm range. How about your transmission or rear end will it stay together with the new found power? How fast do you feel the vehicle should go? How much money can you spend? Can your car go that fast on that budget? Will your vehicle be side lined or parked from to lofty of goals? Then, you will have a better idea as to what type of a head you will need. For most of us we will fall somewhere in between. If you want to turn left ( circle track), you have a lot of other considerations to make. For straight line people (drag racing) the left turn G force on the motor and fuel system is not really a factor. For us drag racers we slam the fuel into the metering block with a portion of it going up the vent and down into the barrels, therefore flooding the engine and bogging off the line. That to can be corrected.For daily driver some passing gear driving: O.E.M. heads or O.E.M. replacement heads such as S/R World heads are good.For daily driver and some heavy drag racing: Optional O.E.M. heads or aftermarket heads like Sportsman II World heads are best.For drag racing with no street driving: Aftermarket heads (Aluminum) there are many company's depending on the manufacturer of the block.Camshafts:Camshafts also known as a bump stick is the second most important horsepower maker. If you have a poorly designed head. It will not matter how big your cam is. Your head(s) will not flow worth a hoot. Flow is everything on an engine to make horsepower and with good heads you can take advantage of better camshaft designs. There are power cams for torque engines (low R.P.M.'s). There are fuel mileage cams for better gas mileage. There are horsepower cams for fast twisting engines (high R.P.M.'s). Of course street cams are for better driveability. Cams must match your head, intake, and exhaust design. If they don't you will not realize the cams potential. A huge camshaft in a stock motor will break valves and pistons. It will kill bottom end (low R.P.M.) driving. Try taking off with (low R.P.M.'s) you will not be able to get out of your own wake until you reach high R.P.M.'s. By then you will run out of valve spring and the valves will float. Tearing the top's off your valve stems and breaking keepers, rockers, and push rods. I can not recommend a camshaft here because there are thousands of possibilities out there. As a rule of thumb, I prefer a cam for a daily driver that has a duration of not more than 219 degree's of duration @ .050" lift. A lift of .500" is also a good reference, because most engines can handle a lift up to that with little to no modifications required. Most heads can't give you a satisfactory return on your camshaft if you go higher than .500" of lift on your heads. It's like this, if you go from .400" to .500" in lift and at .400" you have 200 C.F.M.'s of air flow and at .500" lift you have 240 C.F.M.'s you have gained 40 C.F.M.'s there is noticeable difference in performance and horsepower. However at .600" lift you receive 242 C.F.M.'s. Is it a gain? Yes. Is it worth the gain? Not to me. The stress you have just created on your valve train has just jumped sky high, the wear factor is higher, the spring rate is higher. These would be real losses and would equal lost horsepower and money. The answer would be go to a higher C.F.M. producing cylinder head that supports high lift cams, 295 C.F.M.'s is possible on some designs or 410 C.F.M.'s on big block engines. But remember your air speed will suffer at low R.P.M.'s with heads like these. So buy them only if you have a specific use for them. I like split duration cams and I would use them more times than not. Also, if you purchase a huge cam like .650" lift and a 300 degree duration @ .050" lift make sure that the engine can handle it and most likely it will not see any street driving either.
|
|
|
