Camshaft for restricted RPM range
11-28-2009, 08:25 AM
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Camshaft for restricted RPM range Hey guys,
Im by no means an expert in anything automotive but i was thinking about this one specifically for my next camaro.
How does one design a camshaft for a specific range of RPM where they want most of the power to be?
For example, if someone wants ALL the power between 5800 - 6800 RPM, they would have to find the correct duration so that the car doesnt peak too high or start making power too high, lower the centerline so that the power range is in a narrow RPM band, and apply the lift according to the cylinder heads. I have never understood why there are .649 lift cams when the heads dont flow anything over .550 or whatever.
So, with the example above, @ .50, wouldnt something around the range of 228-230 on both the intake and exhaust given there is a free flow on both sides (good intake and a open exhaust) with a seperation and centerline of >110 so that the powerband is in specific narrow range of RPM, with lift that accomedates the heads on the car, make peak torque in the high 5000 RPM with a boatload of power to the redline before the harsh dropoff? (104-110 LSA)
I could be out of my mind and have no idea what im talking about, im just really curious about this. My old 230/236 114 LSA cam with a 112 centerline had a broad torque range with a peak of 6400 RPM (i had an LS1 intake) and made peak torque at 5000 RPM (300 ftlbs from 3500 to 5500).
This cam was good for the street but not for the drag strip, i feel that something with a 1000-1500 RPM band of power, with the PROPER supporting mods (4.10 gears, 4000+ converter) is the way to go with drag racing.
PS (i know valve events mean everything, but i still dont understand them fully)
Please try not to flame me, just trying to learn.
Im by no means an expert in anything automotive but i was thinking about this one specifically for my next camaro.
How does one design a camshaft for a specific range of RPM where they want most of the power to be?
For example, if someone wants ALL the power between 5800 - 6800 RPM, they would have to find the correct duration so that the car doesnt peak too high or start making power too high, lower the centerline so that the power range is in a narrow RPM band, and apply the lift according to the cylinder heads. I have never understood why there are .649 lift cams when the heads dont flow anything over .550 or whatever.
So, with the example above, @ .50, wouldnt something around the range of 228-230 on both the intake and exhaust given there is a free flow on both sides (good intake and a open exhaust) with a seperation and centerline of >110 so that the powerband is in specific narrow range of RPM, with lift that accomedates the heads on the car, make peak torque in the high 5000 RPM with a boatload of power to the redline before the harsh dropoff? (104-110 LSA)
I could be out of my mind and have no idea what im talking about, im just really curious about this. My old 230/236 114 LSA cam with a 112 centerline had a broad torque range with a peak of 6400 RPM (i had an LS1 intake) and made peak torque at 5000 RPM (300 ftlbs from 3500 to 5500).
This cam was good for the street but not for the drag strip, i feel that something with a 1000-1500 RPM band of power, with the PROPER supporting mods (4.10 gears, 4000+ converter) is the way to go with drag racing.
PS (i know valve events mean everything, but i still dont understand them fully)
Please try not to flame me, just trying to learn.
01-02-2010, 04:18 PM
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I'm not sure why you would want to limit the power band to 1000-1500 rpm. Why not have the broadest power band possible so there is more usable power all around? The cam is the heart of the equation, but only part of it. The proper selection of components will result in a combo that works best for whatever the application is. I woud think that you would want as much power available throughout the rpm band as possible. Otherwise, you limit the drivability of the car, as well as the usability of the power band. Even at the drag strip, you would be heavily challenged to keep the car in a 1500rpm window of power.
01-02-2010, 05:49 PM
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The major effect on what rpm you get power or torque is intake tract length (valve to plenum) and to a lesser extent, the exhaust primary and collector lengths. The camshaft is important, but if you have an engine with the wrong intake length for the narrow rpm band you are running, a cam won't fix the problem.
The whole engine should be designed to run in the rpm range you want to use. 1000 rpm band is pretty narrow for an automatic even with a 4400 converter.
Yes, you are a little confused about valve events, lift requirements and how things work, but at least you realize that. I suggest you let a pro do your engine design, and especially the cam.
Jon
The whole engine should be designed to run in the rpm range you want to use. 1000 rpm band is pretty narrow for an automatic even with a 4400 converter.
Yes, you are a little confused about valve events, lift requirements and how things work, but at least you realize that. I suggest you let a pro do your engine design, and especially the cam.
Jon
