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Old 07-02-2010, 07:25 AM   #1
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Default Difference between short and long-stroke nitro engines

I was just wondering what would be the big difference.
Is one better than the other or is it related to what your gonna run it in??
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Old 07-02-2010, 07:36 AM   #2
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Quote:
Originally Posted by nitrotrippertje View Post
I was just wondering what would be the big difference.
Is one better than the other or is it related to what your gonna run it in??
The long stroke will have more low end punch than the short stroke and wont turn quite the rpms. The short stroke will tend to wind up quicker but have less bottom, also the short stroke seem to really scream on the top end. I would feel a long stroke motor would be more beneficial in a 1/8 scale truck, more torque to get things moving. Either motor would be fine in buggy.
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Old 07-02-2010, 08:59 AM   #3
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and dont forget that the bore is different too. Short stroke has a bigger bore, and long stroke has a smaller bore, a square engine is when the stoke and the bore are the same size
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Old 07-02-2010, 09:02 AM   #4
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Funny thing is that the most populair RB WS7 series were square stroke (16.4 x 16.4) and did win a lot of races. In theory all other engines with long stroke should be better......

The advance of long stroke is you can set an higher exhaust port without affecting the combustion stroke (from TDC to opening exhaust) and yes, with the same exhaust height the combustion stroke is longer with a long stroke building up more torque.

In real it does not matter much, it is all about the internal timings and materials to get a good power and how you drive/use it.
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Old 07-02-2010, 09:08 AM   #5
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Correct me if im wrong but is the werks a long stroke and picco short??
Maybe thats why i got verry different timingnumbers when measuring???
That would be alot of sence to me.
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Old 07-02-2010, 09:18 AM   #6
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It's my understanding that long stroke engines can be made to rev higher. The idea being that long stroke engines are more torquey comes from 4-stroke engines but 2 strokes with crank and sleeve port induction function differently. The long stroke allows for longer open port duration which is what drives the ablility to rev as there are no real concerns for valve and piston speed on a tiny 2-stroke engine. I'm sure there's a lot more to it than that but I think all the top on-road engines are long stroke designs.
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Old 07-02-2010, 01:49 PM   #7
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Quote:
Originally Posted by nitrotrippertje View Post
I was just wondering what would be the big difference.
That's easy. The bore and the stroke are different.

Sorry to be a smart ass but everyone else gave the thorough answer so I went the easy route.
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Old 07-02-2010, 07:33 PM   #8
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Sorry but short stroke big bore engines make more torque. Bigger piston bigger explosion.
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Old 07-02-2010, 07:38 PM   #9
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Bore doesn't effect the "size" of the explosion if displacement is equal.
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Old 07-02-2010, 07:40 PM   #10
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long stroke=torque
short stroke=hp
assuming the same displacement
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Old 07-02-2010, 09:20 PM   #11
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Long stroke torque and short rpm is not "lineary" true in a miniature 2 stroke engine.

And the bigger bore does not make a bigger combustion, displacement, timming, compression, overall engine setup does. Actually its not all good with a bigger bore, the flame front has to travel a larger distance with a bigger bore and the combustion chamber becomes a thinner and larger disc, horrible things, notice that to a certain point the longer the stroke, the higher the rpm in our engines, novarossi, picco, sirio, use 16.8 and 16.9 for their highest rpm/performance on road engines that says a lot even OS, a di hard short stroker went to the classic 16.8 stroke when they got serious about racing onroad engines.

The bigger piston allows a larger port area with less timming great things for good overall power band.

x
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