2.3 stroker EVOs, what's your redline?
Ted,
What is the 25 m/sec piston speed? I am not clear on the measurements being used. Something per second? Does this imply that are higer rod to stroke 1.5 vs 1.66 equates to slower piston speeds and what are you gaining with this? Higher RPM's right?
Just trying to follow along. Thanks.
What is the 25 m/sec piston speed? I am not clear on the measurements being used. Something per second? Does this imply that are higer rod to stroke 1.5 vs 1.66 equates to slower piston speeds and what are you gaining with this? Higher RPM's right?
Just trying to follow along. Thanks.
m/sec = meters per second
To get piston speed at any rpm:
(1) Take the piston stroke in mm and multiply by 0.001 to get the stroke length in meters.
(2) Mutiply this by 2 to get the distance traveled per revolution, because the piston travels twice the stroke length in each revolution.
(3) Take the rpm and divide by 60 to get revolutions per second. Multiply this number by the distance traveled per revolution (2), and you get piston speed in m/sec.
Example: 100mm stroke and 7500rpm.
((100mm)*(0.001))*2) = 0.2 meters / revolution
(7500rpm / 60) * 0.2 meters = 25 meters / second
Changing the rod/stroke ratio doesn't change the length of the stroke, and therefore doesn't change the piston speed. The rod/stroke ratio gives you an indication as to the rpm ranges where the engine will be most mechanically efficient, as well as what types of sidewall loading the pistons will see. Generally speaking, the smaller the rod/stroke ratio, the more efficient the engine will be at low rpm and the greater the load applied to the sidewalls of the pistons. Larger rod stroke ratios are better suited to high rpm, high hp engines.
Here are rod/stroke ratios of some engines from lowest to highest so one can get an idea of where they fall in the scheme of things:
Ford 2.5L truck - 1.49
2.3L (stroker) 4G63 - 1.5
Chevy 454 V8 - 1.53
2.4L 4G64 - 1.56
Chevy 427 V8 - 1.63
Chevy 350 V8 - 1.64
2.5L WRX STI - 1.65
2.2L (late) Honda S2000 - 1.65
Ford 2.3L turbo - 1.66
2.0L 4G63 - 1.7
2.0L JDM WRX STI - 1.74
2.1L 4G64 - 1.77
2.0L (early) Honda S2000 - 1.82
Ford Taurus SHO V6 - 1.83
Chevy 302 (early Z28) - 1.9
Asiatech V10 3.0L F1 engine - 2.3
(A funny mp3 of an Asiatech V10 exhaust - www.atspeedimages.com/asiatech_v10.mp3)
To get piston speed at any rpm:
(1) Take the piston stroke in mm and multiply by 0.001 to get the stroke length in meters.
(2) Mutiply this by 2 to get the distance traveled per revolution, because the piston travels twice the stroke length in each revolution.
(3) Take the rpm and divide by 60 to get revolutions per second. Multiply this number by the distance traveled per revolution (2), and you get piston speed in m/sec.
Example: 100mm stroke and 7500rpm.
((100mm)*(0.001))*2) = 0.2 meters / revolution
(7500rpm / 60) * 0.2 meters = 25 meters / second
Changing the rod/stroke ratio doesn't change the length of the stroke, and therefore doesn't change the piston speed. The rod/stroke ratio gives you an indication as to the rpm ranges where the engine will be most mechanically efficient, as well as what types of sidewall loading the pistons will see. Generally speaking, the smaller the rod/stroke ratio, the more efficient the engine will be at low rpm and the greater the load applied to the sidewalls of the pistons. Larger rod stroke ratios are better suited to high rpm, high hp engines.
Here are rod/stroke ratios of some engines from lowest to highest so one can get an idea of where they fall in the scheme of things:
Ford 2.5L truck - 1.49
2.3L (stroker) 4G63 - 1.5
Chevy 454 V8 - 1.53
2.4L 4G64 - 1.56
Chevy 427 V8 - 1.63
Chevy 350 V8 - 1.64
2.5L WRX STI - 1.65
2.2L (late) Honda S2000 - 1.65
Ford 2.3L turbo - 1.66
2.0L 4G63 - 1.7
2.0L JDM WRX STI - 1.74
2.1L 4G64 - 1.77
2.0L (early) Honda S2000 - 1.82
Ford Taurus SHO V6 - 1.83
Chevy 302 (early Z28) - 1.9
Asiatech V10 3.0L F1 engine - 2.3
(A funny mp3 of an Asiatech V10 exhaust - www.atspeedimages.com/asiatech_v10.mp3)
Last edited by Ted B; Jun 21, 2006 at 11:11 AM.
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