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long, short or square stroke engines?

View Poll Results: long short or square in buggy and truggy. choose 1 for each vehicle
long stroke buggy
39.39%
short stroke buggy
24.24%
square stroke buggy
39.39%
long stroke truggy
51.52%
short stroke truggy
6.06%
square stoke truggy
6.06%
Multiple Choice Poll. Voters: 33. You may not vote on this poll

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long, short or square stroke engines?

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Old 12-04-2018, 03:27 PM
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Default long, short or square stroke engines?

as title states what is the preferred engine stroke in buggy and truggy..

long stroke has the most bottom and would be for truggy?

short stroke would have some bottom end but yet some good rpms?

square stroke would have least bottom end but best power band?

yes I get 3 port or 4 port or 7 make a difference also. less ports more bottom end. more ports smoother power band. plus I get pipes and headers make a difference also but in general what do you prefer in your buggy and truggy..


lets have a little fun in the winter silly season as lots of guys change companies and brands over the next few months.. vote in the poll . you get 2 choices.. 1 for buggy and 1 for truggy.. jeremy
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Old 12-04-2018, 05:40 PM
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I'm pretty sure I've read that the number of ports does not necessarily have an impact on performance. It's just the way that manufacturers market their engines such as NovaRossi.
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Old 12-04-2018, 07:53 PM
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theres also EXTRA long stroke super small bore
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Old 12-04-2018, 11:55 PM
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It is all marketing.
We are the customers who love the commercial bullsh*t talk of the engine brands and let us fooled to buy their latest and supposed fastest engines. For sure people who only judge an engine by its visual aspects are victims for such a marketing while the visual aspects are the least performing parts.

Take a dive into the technology of a 2-stroke engine and see there is more than different strokes and amount of ports. Then you will see that:
- a crap configured (read timed) 7-port engine will never run that good than a good configured 3-port
- a crap configured long stroke will not have the huge bottom power than a good configured short stroke
- a crap configured short stroke will not run the supposed higher revs than a good configured long stroke.
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Old 12-05-2018, 03:24 AM
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There is no real correlation between bore/stroke ratio and power band.
Take a long stroke engine, you would think a added moment arm on the crank would increase the torque, but the reduction in piston area decreases the force pushing on the crank. In the end they even out almost 100%.
A lot of this comes from 4 stroke engines where the size of the bore determines the size of the valves, and that will have an impact on how the engine can breath up top to make hp (rpm).
You will get slightly different thermal efficiency, different piston weight etc etc, but most things in the end favor an under square engine when it comes to a two stroke engine.

Pretty much the same thing with the number of ports, there is slight difference in piston support when you run more ports, and if done right you can control the gas flow slightly better with more ports if done right, but that's it.

The power on marketing though is massive for all of the above, nothing will boost the top end dollar like those, or the pure torque you use to pull the money out of your wallet.
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Old 12-06-2018, 12:17 PM
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Engine manufacturers have to release and market new products to generate sales. I’m convinced that most of the changes are inconsequential and sometimes a step backwards. For instance, it’s my opinion that the OS Speed spec ii with the J carb is the best performing OS motor manufacturered despite the design being several years old.
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Old 12-09-2018, 10:05 AM
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A bit of shame this topic has less interest. I would love to read how and why people would choose an amount of ports with which stroke
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Old 12-09-2018, 11:25 AM
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I agree with you.. seems like if its not drama a thread goes silent it seems.. i would of assume the motor guys would be all over this.. its actually a legit question that makes a difference in racing i think.. its finding the right combination for a drover to het peak performance they want
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Old 12-09-2018, 12:02 PM
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Originally Posted by Roelof View Post
A bit of shame this topic has less interest. I would love to read how and why people would choose an amount of ports with which stroke
In a way I can agree, but it would be like people saying which color is the best...
Originally Posted by J.Whiting View Post
I agree with you.. seems like if its not drama a thread goes silent it seems.. i would of assume the motor guys would be all over this.. its actually a legit question that makes a difference in racing i think.. its finding the right combination for a drover to het peak performance they want
If you come up with a complete and accurate way to do a A-B-A test, then maybe some motor guy and racer could run the tests. Sorry to say, but anything else is guessing at best.
But I'm not complaining about the subject in any way.
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Old 12-11-2018, 12:43 AM
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Well, i am not an engine guru. I have played a bit with port timings. I can make a longstroke smooth and a short stroke hit harder than the smooth longstroke. I can do that with crank timings also. I have no explanation of what the stroke does alone and agree that port configuration and timings probebly does more than the stroke/bore ratio alone. Also, rod length plays a part.
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Old 12-11-2018, 03:21 AM
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Originally Posted by am View Post
Well, i am not an engine guru. I have played a bit with port timings. I can make a longstroke smooth and a short stroke hit harder than the smooth longstroke. I can do that with crank timings also. I have no explanation of what the stroke does alone and agree that port configuration and timings probebly does more than the stroke/bore ratio alone. Also, rod length plays a part.
Actually, the rod ratio is usually at the very bottom of the list of things that matters. It has gotten a lot of attention due to different car magazines etc as the theory is easy to explain, in very controlled environment like say drag racing you might end up gaining something like 0,001% in some cases, but again it's disproved in the most developed classes.
A lot of these things are debated for full scale 4-stroke engines and might not translate 100% directly to our small 2-stroke engines.
And it's very easy to get caught up in a single parameter so that you miss a dozen of other things that changes as well.
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Old 12-11-2018, 05:01 AM
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The only way to feel the differences between strokes and ports is make all type of engines with the same configuration. So all same timings, crank bore, materials etc. and then test them in the same car with one driver. Ithink the best noticed power will come from the wide 3-port exhaust design and thats all.
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Old 12-11-2018, 06:20 AM
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Vote: Long Stroke
But drive engine Square Stroke 7 Ports and 1 Exhaust.
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Old 12-11-2018, 08:46 AM
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Originally Posted by Roelof View Post
The only way to feel the differences between strokes and ports is make all type of engines with the same configuration. So all same timings, crank bore, materials etc. and then test them in the same car with one driver. Ithink the best noticed power will come from the wide 3-port exhaust design and thats all.
There is still several things that needs to be corrected that changes things between them, things that have a greater effect then Just stroke ratio in itself.
Head design is one of those things, just matching compression isn't sufficient, and matching all the other parameters number by number would keep anyone busy for a long while. Then it's the matter of crank case design, getting volume and all the areas etc the same...
In a very broad and general term, under square is usually the way to go with 2-strokes, but the effect is still the greatest when it comes to marketing.
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Old 03-03-2019, 07:27 AM
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The shortest stroke possible, that allows all of the ports to function properly. Which may be a long stroke engine.
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