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WooHoo! Ordered my cam today!
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[QUOTE]Originally posted by 93PONY: [QB] Yes, igonorant if you think 15psi from a turbo = 15psi from a centrifugal. Apmospheric pressure is ~14.7psi. Theoretically ~15psi forced into a given motor (say 300rwhp) will double the power. BUT, you must take compressor efficiency into account. A compressor in it's 75% efficiency range at 15psi will make 525RWHP on this motor....BUT, you must then subtract the power needed to run the blower. Anywere from 30-50hp to spin the gear box. This is fairly accurate to the real-world. True, a turbo doesn't use that kind of HP spinning any gears, but it is NOT free. Turbos take power to make power, just like the centrifugals, but they don't require nearly as much. Hard to say just how much they use, but it's definately NOT 50hp! A turbo motor produces ~1.5-2 times the pressure in the exhaust manifold as in the intake. This robs power, yet at the same time adds power.....odd you say? Not really. N/A & SC motor's power stroke is from 0-90 crank degrees. The turbo motor's powerstroke is extended due to the pressure in the exhaust. It fights to push out the exhaust gasses. Simple physics. How much does it increase the powerstroke is hard to say. Most believe it's extended ~45 degrees. So, that's an extra 45 degrees of stroke/power. There's another advantage to the ol' turbo. Full boost is achived BEFORE peak torque. On a matched setup full boost is achived before 3K rpm. On a SC....what 6K? If the motors are both making peak HP at 6000rpm, then both will make roughly the same peak HP. BUT, the power under the curve will be drastically higher w/the turbo motor. 100FTlbs of torque over the SC motor is NOT un-comon. Now lets just say these motors peak @ 5500rpm....well, the SC isn't even making full boost yet & is at a disadvantage.... You rode in my car..... Have you EVER felt a stock heads, cam, intake car w/9psi running through cats pull like that? 119MPH w/a slipping clutch @ 3550lbs going down the track.....It takes TW heads, E cam & off-road exhaust to match that on a Vortech car. We will see what the motor does w/just a cam change..... & it should peak before 6K rpm... [/QB][/QUOTE]
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