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Something else to think about, in general terms, is that a piston will be farther down the bore with a short stroke at any given crank angle than it will be with a longer stroke. Which makes it more efficient in pulling in air. Don't forget to look past the mechanical aspects.
Something else to think about, in general terms, is that a piston will be farther down the bore with a short stroke at any given crank angle than it will be with a longer stroke. Which makes it more efficient in pulling in air. Don't forget to look past the mechanical aspects.
...in general terms...
Isn't that only true for the top 1/2 of the stroke.?
longer stroke means that the piston travels further down the cylinder in the same amout of time as the shorter stroke. that why the engine tends to outrun the flame in extreme cases.
but i might be wrong
You are correct, ultimately the short stroke motor will hold together at a bit higher RPMs. But we are talking 10,569 RPMs vs 10,256 RPMs (not any exact figures here, simply for demonstrational purposes). Ultimately, for a street motor, the longer stroke motor makes more power and torque at a lower RPM with zero sacrifice of top end power.
Take a B16A vs a B18C1 for example. Same bore, similar compression, 10 more HP and 20 more ft lb of torque for a very small increase in stroke and exact same revability.
seem like every body has alot to say.The GSR actually has longer rods than the B16, but only by a few mm. The 89m stroke block has rods that are only .9mm shorter than the GSR and ITR. If your argument is between the 87.2mm stroke and the 89mm stroke, you're really just splitting hairs. The difference in rod/stroke ratio is less than .04- just under 1.58:1 for the GSR/ITR and just over 1.54 for the non-VTEC B18.
Shorter stroke engines will generally have flatter torque curves, but the flow of the B18 engines are such that you can still have a really awesome pancake like torque curve and still rev/breathe to the limits of a worked head.
Now comparing the B18C to the B18A/B in terms of stroke... just pick the B18A/B crank if you have the option.
Something else to think about, in general terms, is that a piston will be farther down the bore with a short stroke at any given crank angle than it will be with a longer stroke. Which makes it more efficient in pulling in air. Don't forget to look past the mechanical aspects.
Most professional race teams are running in events that limit displacement, which in turn limits power output that might result from displacement alone. SO they go the opposite extreme route and shorten the stroke such that they can rev to 15k all day long.Makes me wonder why almost every professional race team in the world runs a short stroke and large bore for high reving application, then. Or why the top builders in the WD-40 Shoot Out all chose the GSR crank for their builds except for Rocket who gave up on trying to build a high reving 95mm stroke.