short stroke big bore/ Big stroke small bore March 26, 2015 03:45PM
If I have a engine that is the same cubic inch. What would have more torque a long stroke small bore or a big bore and a short stroke?
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Re: short stroke big bore/ Big stroke small bore March 26, 2015 10:44PM
Within reason, more stroke makes more torque.
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Re: short stroke big bore/ Big stroke small bore March 27, 2015 12:42AM
Torque is cylinder pressure,nothing more,nothing less. Whichever of those two bore/stroke ratio engines
has the greatest cylinder pressure in the operating range will make the most torque.
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Re: short stroke big bore/ Big stroke small bore March 28, 2015 01:59PM
Stroke = torque. There are formulas to figure out what exactly you are looking to. HP formula is based on the amount of force and time it takes to move weight.
Hp is a relationship to torque based on speed and power. Think of using a breaker bar vs a short handle ratchet. The object is to turn a bolt 180deg. With a long breaker bar it will require less force to turn the bolt, with a shorter ratchet it is harder to turn it but you can make the sweep quicker. Same goes for inside an engine.
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Re: short stroke big bore/ Big stroke small bore March 28, 2015 05:35PM
Think of a hyd. Cyl , 6" bore will move a bigger load than a 5"" with same pressure.
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Re: short stroke big bore/ Big stroke small bore March 28, 2015 11:49PM
Not even the same as a hydraulic cylinder, because you have to factor in leverage on the crankshaft.
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Re: short stroke big bore/ Big stroke small bore March 29, 2015 12:35AM
True. Hydraulic cylinder strength is not affected by stroke. Only bore and pressure.
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Re: short stroke big bore/ Big stroke small bore March 29, 2015 12:39AM
Does the length of the rod make any difference if the bore and the stroke is the same?
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Re: short stroke big bore/ Big stroke small bore March 29, 2015 03:20AM
Short Rod is slower at BDC range and faster at TDC range. Long Rod is faster at BDC range and slower at TDC range.
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Re: short stroke big bore/ Big stroke small bore March 30, 2015 02:23PM
longer rod makes more torque,the dwell is longer and piston side pull pressure is more acceptable. If you could not add stroke a longer rod is better.
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Re: short stroke big bore/ Big stroke small bore March 30, 2015 03:56PM
So the longer rod makes the angle less from the piston?
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Re: short stroke big bore/ Big stroke small bore March 31, 2015 08:00AM
There was a study many years ago done by HotRod magazine, two gasoline engines, same displacement but different bore stroke ratios, the HP curves were nearly identical.
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Re: short stroke big bore/ Big stroke small bore April 02, 2015 02:48AM
Quote
RCP
There was a study many years ago done by HotRod magazine, two gasoline engines, same displacement but different bore stroke ratios, the HP curves were nearly identical.


Where were the torque lines??
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Re: short stroke big bore/ Big stroke small bore April 02, 2015 07:34AM
It depends on your cubic inch. If it's a 505 cu in motor, then a cubed motor is better (4 3/4X4 3/4). You can turn it harder than a motor with a longer stroke. If you are 640 cu in then you are limited in a small block. There is only stroke left to do. There is more weight in a longer stroke so the inertia is higher. (more parts breakage) There are too many variables, what turbo, pump size, weight class. I've seen where a 466 with an 4.1 charger an open rpm p-pump will make more hp than a 640 cu in super farm.
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Re: short stroke big bore/ Big stroke small bore April 02, 2015 12:22PM
Yeah a 496 with a 3 by 3.21 will take care of a big money 640 to!
It really doesn't matter 640 is 640! HEAD, CAM, TURBO, PUMP, WATER INJ SYSTEM, water! fuel!! OH INJECTORS, INJECTORS LINES, PISTONS, TIMING, DYNO YOUR ENGINE! Who dyno 's your engine! Their's guys out their that think if I cube my engine 40 cubes thats the difference yeah if it was only that easy! If all the basics are out dated sell them and up grade their first!
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Re: short stroke big bore/ Big stroke small bore April 02, 2015 01:02PM
ardree I pulled with a bbjd 619 making 980hp! I finally punched it out! Stock crank balanced with balanced light small rist pin billet rods, and rei pistons and sleeves! Went and dynode didn't leave happy 1040! Last year I bought a Hart 13 mm pump Columbus injectors Joe Busch reworked my turbo and put out board water injection on dynode last year 1240 hp I was happy a!
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