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Old 06-03-2009, 02:34 PM   #71
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Originally Posted by Papa_Complex View Post
Go right ahead, as long as you don't discount the usefulness of torque on corner exits.
It isn't the torque, it's the powerband, After taking rpm and torque at the rear wheel into account there shouldn't be any difference, 100 hp is 100 hp. Now maybe a street tuned twin will have a wider powerband that a peaky 600.
Hp is torque over a period of time, gearing will change torque, but not hp. So by the time you change the gearing of a 10,000 rpm twin to match a 15,000 I4, you lose 33% of your torque.

As to why a twin won't make the same hp is valve area and rpm. The bigger valves of a twin take up more space across the chamber, and the valve area doesn't increase as fast as displacement does, so you end up with less valve comparably, and the mass of the valve is a key limit to rpm and cam profile and spring life. Smaller valves have less mass and can rev higher. Hp is all about torque over time, higher rpm if you can maintain torque makes more hp.

F1 engines and now MotoGP engine show a similar development paths. More smaller cylinders that rev higher, with exotic methods to close the valves.
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Old 06-03-2009, 02:41 PM   #72
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Originally Posted by Rsv1000R View Post
It isn't the torque, it's the powerband, After taking rpm and torque at the rear wheel into account there shouldn't be any difference, 100 hp is 100 hp. Now maybe a street tuned twin will have a wider powerband that a peaky 600.
Hp is torque over a period of time, gearing will change torque, but not hp. So by the time you change the gearing of a 10,000 rpm twin to match a 15,000 I4, you lose 33% of your torque.

As to why a twin won't make the same hp is valve area and rpm. The bigger valves of a twin take up more space across the chamber, and the valve area doesn't increase as fast as displacement does, so you end up with less valve comparably, and the mass of the valve is a key limit to rpm and cam profile and spring life. Smaller valves have less mass and can rev higher. Hp is all about torque over time, higher rpm if you can maintain torque makes more hp.

F1 engines and now MotoGP engine show a similar development paths. More smaller cylinders that rev higher, with exotic methods to close the valves.
power pulses as well. More cylinders can do more work more often.
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Old 06-03-2009, 02:52 PM   #73
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Originally Posted by Rsv1000R View Post
It isn't the torque, it's the powerband, After taking rpm and torque at the rear wheel into account there shouldn't be any difference, 100 hp is 100 hp. Now maybe a street tuned twin will have a wider powerband that a peaky 600.
Hp is torque over a period of time, gearing will change torque, but not hp. So by the time you change the gearing of a 10,000 rpm twin to match a 15,000 I4, you lose 33% of your torque.

As to why a twin won't make the same hp is valve area and rpm. The bigger valves of a twin take up more space across the chamber, and the valve area doesn't increase as fast as displacement does, so you end up with less valve comparably, and the mass of the valve is a key limit to rpm and cam profile and spring life. Smaller valves have less mass and can rev higher. Hp is all about torque over time, higher rpm if you can maintain torque makes more hp.

F1 engines and now MotoGP engine show a similar development paths. More smaller cylinders that rev higher, with exotic methods to close the valves.
Hmmm... so more cylinders a "better" way to go then? So why reward those companies that refuse to see this "truth" with lopsided rules? Dude, I refuse to believe that you honestly think that it's okay for to go this far just to include Buell. The bike has an almost 50% hp advantage and a 30-40% torque advantage stock. Shit maybe Victory should develop an American single, with the right contacts DMG would let them run a 2000cc thumper in this class.
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Old 06-03-2009, 02:54 PM   #74
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power pulses as well. More cylinders can do more work more often.
The pulses affect traction, but the amount of displacement per revolution doesn't change.
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Old 06-03-2009, 02:56 PM   #75
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Hmmm... so more cylinders a "better" way to go then? So why reward those companies that refuse to see this "truth" with lopsided rules? Dude, I refuse to believe that you honestly think that it's okay for to go this far just to include Buell. The bike has an almost 50% hp advantage and a 30-40% torque advantage stock. Shit maybe Victory should develop an American single, with the right contacts DMG would let them run a 2000cc thumper in this class.
50% HP advantage? Are you high?
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Old 06-03-2009, 02:59 PM   #76
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50% HP advantage? Are you high?
Stock 600 around 100hp

Stock Buell 146hp according to Buell
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Old 06-03-2009, 03:04 PM   #77
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Stock 600 around 100hp

Stock Buell 146hp according to Buell
Strange how one estimate is conservative and at the wheel. And the other is peak claimed at the crank....

My 2000 r6 supposedly made 120 at the crank. My buddies 07 puts 116 to the wheel with a full system and a custom dyno tune..

The 1125 with tuning and race system might put 130-135 to the wheel.

Stock they see mid 120s at the wheel.
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Old 06-03-2009, 03:10 PM   #78
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Originally Posted by Rsv1000R View Post
It isn't the torque, it's the powerband, After taking rpm and torque at the rear wheel into account there shouldn't be any difference, 100 hp is 100 hp. Now maybe a street tuned twin will have a wider powerband that a peaky 600.
Hp is torque over a period of time, gearing will change torque, but not hp. So by the time you change the gearing of a 10,000 rpm twin to match a 15,000 I4, you lose 33% of your torque.

As to why a twin won't make the same hp is valve area and rpm. The bigger valves of a twin take up more space across the chamber, and the valve area doesn't increase as fast as displacement does, so you end up with less valve comparably, and the mass of the valve is a key limit to rpm and cam profile and spring life. Smaller valves have less mass and can rev higher. Hp is all about torque over time, higher rpm if you can maintain torque makes more hp.

F1 engines and now MotoGP engine show a similar development paths. More smaller cylinders that rev higher, with exotic methods to close the valves.
Curve on the Buells is as flat as a table top (which may be part of their problem).
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Old 06-03-2009, 03:21 PM   #79
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Curve on the Buells is as flat as a table top (which may be part of their problem).
Which is great tuning for a street engine.
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Old 06-03-2009, 03:21 PM   #80
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1100-1200 Vtwins should easily be capable of competing with 1-4 liter bikes.
.
If it's a Ducati.......but not a Buell. Lol. When is the last time a Buell had the top-end of a Duc or even an Aprilia.

Last edited by Homeslice; 06-03-2009 at 03:25 PM..
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