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Post by humanshield on Nov 12, 2016 15:33:10 GMT -5
Amazing stuff... That calculates out to .37hp PER CC SO at that rate...a 49cc scooter would have 18hp And a 250cc scooter 92.5 hp
That said... I have seen videos of 350cc Banshees making 100hp I've also read that as 2 stroke displacement increases, efficiency decreases. Anyone? I do know Cummins has some montrous 2 strokes as diesels.
So maybe that's why Top fuel dragsters and the fastest vehicles in sports are 4T ?
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Post by Deleted on Nov 12, 2016 16:17:15 GMT -5
Amazing stuff... That calculates out to .37hp PER CC SO at that rate...a 49cc scooter would have 18hp And a 250cc scooter 92.5 hp That said... I have seen videos of 350cc Banshees making 100hp I've also read that as 2 stroke displacement increases, efficiency decreases. Anyone? I do know Cummins has some montrous 2 strokes as diesels. So maybe that's why Top fuel dragsters and the fastest vehicles in sports are 4T ? Good point. I have follwed drag racing since I was a kid and Garlits had not yet broken the 200 mph barrier. Why does Top Fuel not run 2Ts? Are they not strong enough to handle the power or, is there some other reason that becomes evident once you cross a HP threshold? (Top Fuel Cars today put out over 10,000 HP From 500 cubic inches....only for like 3 seconds but that is all that is required.) Bill
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Post by spaz12 on Nov 12, 2016 16:30:07 GMT -5
Amazing stuff... That calculates out to .37hp PER CC SO at that rate...a 49cc scooter would have 18hp And a 250cc scooter 92.5 hp That said... I have seen videos of 350cc Banshees making 100hp I've also read that as 2 stroke displacement increases, efficiency decreases. Anyone? I do know Cummins has some montrous 2 strokes as diesels. So maybe that's why Top fuel dragsters and the fastest vehicles in sports are 4T ? Could you imagine if they made a 250 cubic INCH 2T? Those poor 4 stroke dragsters
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Post by birdman on Nov 12, 2016 16:34:34 GMT -5
That thing sounds really nice but 6k is a little to steep for me.
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Post by spaz12 on Nov 12, 2016 17:04:05 GMT -5
That thing sounds really nice but 6k is a little to steep for me. For just the motor, I think it's a little steep for most anyone.
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Post by Lucass2T on Nov 13, 2016 5:48:00 GMT -5
Amazing stuff... That calculates out to .37hp PER CC SO at that rate...a 49cc scooter would have 18hp And a 250cc scooter 92.5 hp That said... I have seen videos of 350cc Banshees making 100hp I've also read that as 2 stroke displacement increases, efficiency decreases. Anyone? I do know Cummins has some montrous 2 strokes as diesels. So maybe that's why Top fuel dragsters and the fastest vehicles in sports are 4T ? Could you imagine if they made a 250 cubic INCH 2T? Those poor 4 stroke dragsters Those numbers aren't that strange. A 2t can sqeeze out 400hp per liter. In 50cc racing power levels exceed 20hp. A 250gp racer like the honda Rs250 and tz250 are at about 100hp. Its all about revs. The higher the displacement the more cylinders you need to get to those high rpms. My cr500 only puts out about 70hp while a 500cc 4cyl easily doubles those numbers.
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Post by joeorange on Nov 13, 2016 7:51:58 GMT -5
the cristofolini TCR engine has a max displacement of 125cc, but can be brought up to 250cc if the twin cylinder kit is used. cristofolini racing has done some awesomely insane builds, like their 360cc V4 2 stroke engine.
i remember reading that this engine puts out over 100+hp
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Post by humanshield on Nov 13, 2016 10:59:02 GMT -5
Could you imagine if they made a 250 cubic INCH 2T? Those poor 4 stroke dragsters Those numbers aren't that strange. A 2t can sqeeze out 400hp per liter. In 50cc racing power levels exceed 20hp. A 250gp racer like the honda Rs250 and tz250 are at about 100hp. Its all about revs. The higher the displacement the more cylinders you need to get to those high rpms. My cr500 only puts out about 70hp while a 500cc 4cyl easily doubles those numbers. So is it true that 2T efficiency drops off as displacement increases? That's what I've read and why you don't see 2 stokes in the big leagues for racing. Also, I have seen 1 liter bikes making OVER 400hp...forced induction
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Post by Lucass2T on Nov 13, 2016 11:29:20 GMT -5
Those numbers aren't that strange. A 2t can sqeeze out 400hp per liter. In 50cc racing power levels exceed 20hp. A 250gp racer like the honda Rs250 and tz250 are at about 100hp. Its all about revs. The higher the displacement the more cylinders you need to get to those high rpms. My cr500 only puts out about 70hp while a 500cc 4cyl easily doubles those numbers. So is it true that 2T efficiency drops off as displacement increases? That's what I've read and why you don't see 2 stokes in the big leagues for racing. Also, I have seen 1 liter bikes making OVER 400hp...forced induction Not necessarily decreases or drops off. But when you only increase engine volume and keep with the same ammount of pistons, your max rpms drop due to weight and size of rotating engine components. And less rpm is less hp...but not necessarily less power (torque). And reason why you don't see two strokes in big leagues (anymore) is because of enviromental reasons. Remember that up until 2000 moto racing was dominated by two strokes. And forced induction engines make up to 1000hp per liter (bmw megatron f1 engine). N/a 4t's are really slow compared to n/a 2t's and forced induction 4t's.
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Post by humanshield on Nov 13, 2016 12:33:09 GMT -5
What "some" MotoGP racers have to say about 2 stoke Moto.... linkPol Espargaro: “Why should we go back to the 500cc machines if we can ride faster with what we have now? For sure, I would love to test this kind of bike. It would be a great experience. Can you imagine jumping on the bike that great champions like Wayne Rainey, Eddie Lawson, Kevin Schwantz, or Mick Doohan rode? I would love to discover their feelings while riding. In the same way, I’m sure that they also would love to test a MotoGP. A rider simply loves to ride all kind of bikes.” Bradley Smith: “The 500 two-stroke machines are over. The era is done and the new MotoGP bikes are more technically advanced. There is always an evolution in racing. Of course we enjoyed the period of the 500cc, but as everything in life we evolve. It is the same for the electric cars. I think we will arrive to a point where we will only have sport electric cars. I don’t feel too disappointed I missed that era, although I would still like to ride a 500cc machine just to say, ‘I have a picture and I rode one!’” Jorge Lorenzo: “No. I like the four-stroke bikes and the technological development of the last decade has gone in this direction. The bikes have improved a lot, not only in terms of performance but also as far as safety is concerned, so I prefer to stick with what we have. The old 500cc were dangerous and difficult to manage. I have never had the chance to ride a 500cc machine, but I remember how it was to ride the 250cc. You needed to be so delicate with the gas to avoid a crash.”
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Post by Lucass2T on Nov 13, 2016 15:05:51 GMT -5
What are you trying to say?
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Post by humanshield on Nov 13, 2016 15:17:14 GMT -5
You mentioned moto racing.
I'm saying that some modern Moto racers feel the modern 4 strokes are better performing across the board.
4 stroke technology has come a long way. So it could be that in addition to environmental issues.
In 1979, a 2 stroke 750 could nearly equal an 1100cc bike in the quarter mile.
Today not so. Today my 600cc Yamaha with 4 valves per cyl would beat or equal the 2 stroke 750 (factory for factory) in the quarter and the 600 would walk from the 750 after the quarter.
There is not as much development you can do with the 2 stokes.
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Post by Lucass2T on Nov 13, 2016 15:25:17 GMT -5
Yeah...they do...but there are 2 big but's! Did you ever noticed that the 2 strokes used carbs and the 4 strokes are all fuel injected? Carbs are such a hopelessly acient piece of technology I almost feel embarassed I still use them... They need twice the displacement to get to 2t hp levels...because of the bigger displacement they have more torque below and above the powerband and you can just lean back and with all lazyness do you laps while on a 2t you really have to work you ass off. In terms of speaking
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Post by humanshield on Nov 13, 2016 15:52:17 GMT -5
I do know someone is making a new 500cc 2 stoke racing Sportbike. So maybe 2 stokes will make a comeback with newer technology. That'd be great. Now I'm about to go for a ride on one of MY 2 stroke bikes. Later.
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Post by aeroxbud on Nov 13, 2016 16:16:58 GMT -5
When motogp went four stroke they had to have 990cc to get just a bit more performance than a 500cc two stroke. If they were able to ride 1000cc two strokes, they would win. You will never see two strokes in motogp now as they have a fuel limit. Four strokes beat them hands down at mpg, even at 240hp, and one litre classes
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