Torque, Horse Power and Acceleration (2014)
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[/quote]
I still don't get the 'work done' bit... but that is more than likely just my ignorance!
But at least we now seem to agree that it (torque) is not ONLY down the cylinder filling... it can be modified / effected by other aspects. Agree?[/quote]
Torque is mainly how much mixture is burned in the cylinder. Rod angularity and timing of the pressure peak also comes into play in a small way.
Power is how much work can be done in a set amount of time. The work could be lifting a weigh with a crane or overcoming wind and road resistance on a bike.
I still don't get the 'work done' bit... but that is more than likely just my ignorance!
But at least we now seem to agree that it (torque) is not ONLY down the cylinder filling... it can be modified / effected by other aspects. Agree?[/quote]
Torque is mainly how much mixture is burned in the cylinder. Rod angularity and timing of the pressure peak also comes into play in a small way.
Power is how much work can be done in a set amount of time. The work could be lifting a weigh with a crane or overcoming wind and road resistance on a bike.
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comnoz said:
Isn't it really about the power curve of a given engine design or how it is modified. Longer stroke larger displacement will result in more torque down low at the expense of RPM while a short stroke smaller displacement engine will rev much higher but it's power curve is at the top end of the RPM range resulting in poor low end torque. The CBR engines rev high and produce lots of HP even in smaller displacements, but they don't generate much power to do work until they are way up in RPM's. The amount of mixture burned is tied to displacement as much as any of the other factors of cam timing, and combustion chamber design (unless we start talking about superchargers and methods to increase the charge). To some degree it ties into the type of work you want to do.
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The whole torque/HP thing is a marketing thing not a "real" thing.
A higher HP engine makes more power, that's all there is to it. IT will outrun a lower HP engine. As Jim noted earlier, two engines of the same HP will do the same work regardless of where their power peak is located. If the gearing is appropriately adjusted, they will be neck and neck for the entire run.
The torque/HP curves that we are used to seeing over the last 50+ years were specifically developed by MARKETERS to sell engines that make their power at the low end of the rev range. But it's actually completely meaningless as far as power output is concerned.
I have always disliked the HP/Torque thing because its pointless. There should just be a "power" rating; call it whatever sort of "power" you want to call it. There are NOT two types of power in the world that cross over at 5250. But marketing folks figured out that it was a good marketing technique.
A higher HP engine makes more power, that's all there is to it. IT will outrun a lower HP engine. As Jim noted earlier, two engines of the same HP will do the same work regardless of where their power peak is located. If the gearing is appropriately adjusted, they will be neck and neck for the entire run.
The torque/HP curves that we are used to seeing over the last 50+ years were specifically developed by MARKETERS to sell engines that make their power at the low end of the rev range. But it's actually completely meaningless as far as power output is concerned.
I have always disliked the HP/Torque thing because its pointless. There should just be a "power" rating; call it whatever sort of "power" you want to call it. There are NOT two types of power in the world that cross over at 5250. But marketing folks figured out that it was a good marketing technique.
texasSlick
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comnoz said:
Agreed, but with a bit of clarification...Max cylinder filling at proper mixture results in maximum crankshaft torque....max crankshaft torque multiplied by the overall gear ratio equals max rear wheel torque (neglecting friction losses in the gearbox). To put it another way...maximum rear wheel torque occurs when max crankshaft torque occurs, but the numerical value of the rear wheel torque is crank torque times gear ratio.
Max acceleration occurs at max torque. Newtons law F=ma governs....instantaneous force is max at max torque, then instantaneous a (acelleration) is max.
Electric motors develop max torque at zero RPM. In theory, an electric motor powered vehicle would easily outdrag a gas engine allowing for similar weight and a suitable transmission for the electric vehicle. The electric motor powered vehicle takes the example of Harley vs Honda given in the video above to the extreme.
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The bore-stroke ratio has a fairly minor effect on torque production,ie: how much mix can be packed in to make combustion pressure. B/S ratio does have influence on how a engine breathes, such as how fast the piston drops to suck in mix and also adjusted for the size of the block to fit in a craft and some extra tolerance to hi rpm. Bigger bore and piston gives more torque but can get too big to spin fast. Smaller piston can turn faster but each puff gives lower torque too so takes lots more to make the lesser torque give some useful hp.
Drouins were fault prone in drives and impeller support but that has been solved. Drouin advertised the road going version as 10 PSI, which implies about 58% more torque, but that is nebulous statement as the boost pressure can be spiked above that if ya can snap throttle open fast enough and tire can hold it, otherwise w/o the engine resistance to increasing throttle it only makes as much boost as to hold speed steady, which ain't much and often shows same vacuum reading of unboosted engine. The Lake gravity injector I hope to work around has 40 mm inlet so will flow dang good even w/o the belt on.
Flywheels can store torque energy to release for a short surge or grunt but within part of a second its back to pure fuel burn pressure to accelerate so Peel has lighter flywheel to least hinder the rapid rpm rise.
I'm not that impressed with Harley torque drag racing as my 1st factory Combat could out torque/mass a 1200 cc over cammed wheelie bared Sportster - up to 80 in 2nd then got out horse powered. I got a plan to solve that to who know how fast, but enough to launch in 2nd then skip to 4th so less tire spin to control throttle eased up to match increasing rear hook up speed, even after its expanded 1/2" to lessen torque advantage. Yoose guys and have your low down torque monsters good for parking lot stunts in low gear but I want it most after 100 mph in top gear with the over size ports come into play thank you.
Jim's recently tested a big block to close to 90 lb ft at peak but I expect over 100 before reaching isolation rpm. This is literally frame twisting power and lnked isolastics is my tool of choice to take it.
Drouins were fault prone in drives and impeller support but that has been solved. Drouin advertised the road going version as 10 PSI, which implies about 58% more torque, but that is nebulous statement as the boost pressure can be spiked above that if ya can snap throttle open fast enough and tire can hold it, otherwise w/o the engine resistance to increasing throttle it only makes as much boost as to hold speed steady, which ain't much and often shows same vacuum reading of unboosted engine. The Lake gravity injector I hope to work around has 40 mm inlet so will flow dang good even w/o the belt on.
Flywheels can store torque energy to release for a short surge or grunt but within part of a second its back to pure fuel burn pressure to accelerate so Peel has lighter flywheel to least hinder the rapid rpm rise.
I'm not that impressed with Harley torque drag racing as my 1st factory Combat could out torque/mass a 1200 cc over cammed wheelie bared Sportster - up to 80 in 2nd then got out horse powered. I got a plan to solve that to who know how fast, but enough to launch in 2nd then skip to 4th so less tire spin to control throttle eased up to match increasing rear hook up speed, even after its expanded 1/2" to lessen torque advantage. Yoose guys and have your low down torque monsters good for parking lot stunts in low gear but I want it most after 100 mph in top gear with the over size ports come into play thank you.
Jim's recently tested a big block to close to 90 lb ft at peak but I expect over 100 before reaching isolation rpm. This is literally frame twisting power and lnked isolastics is my tool of choice to take it.
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'Many racers prefer a heavier crank because it makes the power delivery smoother and easier to control in a traction compromised corner. It also make the bike easier to launch. '
If you try to race using the standard commando box, and the heavy flywheel, it is simply revolting - you cannot do anything smoothly. I was brought up racing on rock hard tyres, if they chirped you crashed. With the standard box I found I was doing a big heap of revs on every down change to stop that from happening - not that it necessarily would with modern tyres. With the 4 speed CR box, the bike was perfect everywhere except off the clutch start where you had to cook the clutch to get mobile quickly enough. The compatible combination of flywheel effect and gearbox is important - if you cannot match the revs quickly, you have a problem. All corners are 'traction compromised' - in Australia we even race in the rain. I really love that because many guys back off and it all becomes so much easier. Sticky tyres don't really make you a better rider, they just shift the game up a notch until it rains.
If you have little flywheel effect and a really nasty top end motor you must always be a 110% rider, everything happens extremely quickly and is usually deadly. I don't do that stuff these days.
If you try to race using the standard commando box, and the heavy flywheel, it is simply revolting - you cannot do anything smoothly. I was brought up racing on rock hard tyres, if they chirped you crashed. With the standard box I found I was doing a big heap of revs on every down change to stop that from happening - not that it necessarily would with modern tyres. With the 4 speed CR box, the bike was perfect everywhere except off the clutch start where you had to cook the clutch to get mobile quickly enough. The compatible combination of flywheel effect and gearbox is important - if you cannot match the revs quickly, you have a problem. All corners are 'traction compromised' - in Australia we even race in the rain. I really love that because many guys back off and it all becomes so much easier. Sticky tyres don't really make you a better rider, they just shift the game up a notch until it rains.
If you have little flywheel effect and a really nasty top end motor you must always be a 110% rider, everything happens extremely quickly and is usually deadly. I don't do that stuff these days.
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mike996 said:
Assuming one engine develops it's peak power at say 3000 rpm and another one at 10000 rpm, how could gearing make enough of a difference unless you allow them enough distance to match each other...as in the Harley/Honda example...in 1/8 of a mile the Honda doesn't have enough time to develop the power needed to run with the Harley. There is no way they could be neck and neck for the entire run. They may match each other at some point if the HP were the same, but not neck and neck.
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dennisgb said:
1/8th mile drags with a 10,000 rpm motor with very little low speed torque is tough because modulating the clutch well enough to keep the motor in it's torque band is nearly impossible.
But, if the Honda were set up as a dragster with proper gearing and a slipper clutch that would allow the engine to rise instantly to it's torque peak, then the Harley wouldn't stand a chance -even in the 1/8th mile. Jim
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Yeah but then the Honda would be a hand full in normal traffic but the Harley
wouldn't. Both would flail on THE Snot. Ok Here ya go - guidelines of various color power bands installed.
http://motherboard.vice.com/blog/police ... dley-balko
wouldn't. Both would flail on THE Snot. Ok Here ya go - guidelines of various color power bands installed.
http://motherboard.vice.com/blog/police ... dley-balko
motorson
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Time to weigh back in. I didn’t mean to give Jim so much work but I know he enjoys it.
Triumph builds two versions of their 800 engine and puts one in the tiger and scrambler (I think) and the other in the Bonneville. The Tiger is a 180 degree crank (maybe a 270, huh Jim??) and the Bonneville is a 360 degree crank. The Tiger will beat the Bonneville in the ¼ mile and the Bonneville will do about 15 mph faster on top end due to horsepower. The Tiger has the low down torque and acceleration and the Bonneville has the horse power to overcome wind resistance at high speed.
Personally I think the Tiger and Scrambler would be way funner to ride. But, as Jim pointed out, if the horsepower was harnessed in a way that allowed the engine to come up to peak power and stay there. (Like a torque converter or special clutch.) Then the Bonneville would outperform the Tiger even in acceleration.
One little known fact about 4 valve heads is that they flatten the torque curve and “broaden the power band” of an engine. In a two valve engine you have to use a cam that gives torque at low rpms or horse power at high rpms but if you look at the cams of a 4 valve engine they appear to be a rather “mild” grind because they don’t need a radical race grind to get the flow at high rpms. If you do put a wild race cam in a 4 valve then “Katie bar the door!” because you are going to get some major high rpm breathing.
I talked to a guy in California back in 1976 who was putting super chargers on Norton drag bikes. He said that the main problem they were having was “peaky” power that made traction a problem. (Peaky=high rpm and narrow power band.)
It is no fun if you can’t feel the THUMP, Dan.
Triumph builds two versions of their 800 engine and puts one in the tiger and scrambler (I think) and the other in the Bonneville. The Tiger is a 180 degree crank (maybe a 270, huh Jim??) and the Bonneville is a 360 degree crank. The Tiger will beat the Bonneville in the ¼ mile and the Bonneville will do about 15 mph faster on top end due to horsepower. The Tiger has the low down torque and acceleration and the Bonneville has the horse power to overcome wind resistance at high speed.
Personally I think the Tiger and Scrambler would be way funner to ride. But, as Jim pointed out, if the horsepower was harnessed in a way that allowed the engine to come up to peak power and stay there. (Like a torque converter or special clutch.) Then the Bonneville would outperform the Tiger even in acceleration.
One little known fact about 4 valve heads is that they flatten the torque curve and “broaden the power band” of an engine. In a two valve engine you have to use a cam that gives torque at low rpms or horse power at high rpms but if you look at the cams of a 4 valve engine they appear to be a rather “mild” grind because they don’t need a radical race grind to get the flow at high rpms. If you do put a wild race cam in a 4 valve then “Katie bar the door!” because you are going to get some major high rpm breathing.
I talked to a guy in California back in 1976 who was putting super chargers on Norton drag bikes. He said that the main problem they were having was “peaky” power that made traction a problem. (Peaky=high rpm and narrow power band.)
It is no fun if you can’t feel the THUMP, Dan.
Think of torque as driving a nail. You can drive a nail in a given amount amount of time by hitting it every 5 seconds. If you could hit it every second then you are going to basically get that nail to move much faster. Think of your motorcycle as the nail. The force with which you swing the hammer is torque, the difference in the speed the nail moves is horsepower. You can get more 'work' done with a bigger hammer, (torque), or by swinging faster, (RPM).Fast Eddie said:
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comnoz said:
Jim,
I don't have much drag racing experience with motorcycles. I was trying to think of how you could rev the Honda to get the power and with a stock bike you would struggle to control it and would have to beat the crap out of it (not that people don't do that), and even then the Harley would have an advantage off the line. As a drag bike as you say it makes sense. It also points out how different engines are for different applications...so HP isn't always exactly the same...the Honda V-Tech engines in compact cars come to mind and engineering to get the best fuel economy. Having different cam profiles take over at different engine loads.
Dennis
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If sticking to reality the bigger torquer would still have acceleration advantage d/t power pulse frequency on tire hysteria grip, if road tires used instead of wide flat race slick. Kind of funny trying to rationalize a quick looking iconic sports bike loosing sprints to ancient tractor technology, so the better torquer has real world advantage. I had a 4600 lb '78 Chevy cargo van with 373 ratio posti tract rear end, 406 cid 450 lb ft V8 with jet boat cam and 2 barrel Holley throttle body fuel injector that would lift the front tires off suspension and could out drag famous turbo'd European sports cars and a lot of American iron too up the ton and more surprise out handled them in freeway turns till 120 with aero dynamics got too scary. With 4 spd over drive tranny in converter lock up mode it got 20+ mpg at 80 mph. mid 3000 rpms. My goal of course is to embarrass the angry looking plastic carbon sports bikes with digital brains, so think if can break under 10 sec 1/4 mile - that should do it. Check out online calculators that imply Peel will have torque to mass and hp ratio to do this but don't know if traction enough on 130 tire but with front tucked down 3"+ lower should help a good bit like the chopper Harley's that are hard to wheelie.
I'm concerned with the reports of boosted engines comnoz and motorson mentioned as having narrow peaky power band issues but I don't think those two have studied up nor quizzed Drouin users, ie: belt drive centrifugal snail-turbo type blowers, like i have, so hope Peel set up goes against the grain.
There's an online example of comparing a huge water wheel with 12,000 lb ft torque at 20 rpm that could accelerate a motorcyle about instantly to 12.5 mph then top out on rpm. Can only use torque up to 10% tire spin traction resistance then controlling hp-rpm rises to the top. Real dragsters only use one or two gears. I've had over powered craft and constant awareness of digital traction recovery and tire angle is required or just smoke in place or Splat right down. I figure parking lot stunt practice is best for Peels expected behavior for road racing. Power steering takes the load off pilot athletics.
I'm concerned with the reports of boosted engines comnoz and motorson mentioned as having narrow peaky power band issues but I don't think those two have studied up nor quizzed Drouin users, ie: belt drive centrifugal snail-turbo type blowers, like i have, so hope Peel set up goes against the grain.
There's an online example of comparing a huge water wheel with 12,000 lb ft torque at 20 rpm that could accelerate a motorcyle about instantly to 12.5 mph then top out on rpm. Can only use torque up to 10% tire spin traction resistance then controlling hp-rpm rises to the top. Real dragsters only use one or two gears. I've had over powered craft and constant awareness of digital traction recovery and tire angle is required or just smoke in place or Splat right down. I figure parking lot stunt practice is best for Peels expected behavior for road racing. Power steering takes the load off pilot athletics.
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When I had my 500cc short stroke triton, it made most of it's power at the top end between 8,000 to 10,000, and had very limited bottom end. If I dramatically lowered the gearing I would always get beaten at the ends of the straights, however cane the opposition around the tight parts of the circuit. With high gearing, it was hopeless on the tight bits and off the start, however very fast on big circuits at the ends of long straights and sweeping bends.. In effect on most circuits you could choose where you wanted to lose a race against bigger bikes and two strokes. My Seeley 850 has loads of bottom end, however this presents it's own gearing problem. I've never run it on a really big circuit like Phillip Island, however even on the 3Km circuit it is very high geared. My worry is that on big sweeping high speed bends it might not have enough top end to keep it's positive feel. The steering is set up for tight circuits, and that is something that is not easy to change safely. The optimum setup for the two types of bike are entirely different, and a compromise is difficult. I still have not tried the 6 speed CR box in a race, hope to do that next May. However I stay well away from Phillip Island with the Seeley 850. Broadford circuit would be better, however I'm not confident that I can restrain myself long enough to learn the circuit properly - I think I would crash there too. I love Winton Raceway - it is 11 Km from home and whenever I'm on it, I know exactly where I am all of the time - safest race circuit in Australia. Mount Gambier is good too if you enjoy a thrill.
I am really starting to believe in the commando engine, there are a lot of very good things about it which I had dismissed at first glance. I particularly like the way the barrels are offset towards the back. I wish I had thought about that when I had my triumph, getting more torque was always my major problem. After it got to the stage where I believed I had to make new barrels and find shorter rods, I gave up and sold the bike. It had all become too difficult. Pity the Daytona 500 Triumphs did not have 6 speed CR boxes, they would have been world beaters.
I am really starting to believe in the commando engine, there are a lot of very good things about it which I had dismissed at first glance. I particularly like the way the barrels are offset towards the back. I wish I had thought about that when I had my triumph, getting more torque was always my major problem. After it got to the stage where I believed I had to make new barrels and find shorter rods, I gave up and sold the bike. It had all become too difficult. Pity the Daytona 500 Triumphs did not have 6 speed CR boxes, they would have been world beaters.
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Tourque or Horsepower . Both Actually . 279 MPH Nitro Burning Norton Streamliner . http://www.youtube.com/watch?v=2BDedZ-sbrs
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In the end I actually fitted a single carburetor to the 500cc Triton with the intention of using nitro to increase the torque. However I couldn't really be buggered continuing to play with it. If you have to do that - give up. I'm an industrial chemist and using nitro compounds is not a problem for me, however it is a crass way to go. It has been done in Australian road racing, however I think you would have to want to win badly, and it would not really be satisfying getting there that way, especially if your reputation was built on the results.
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I ain't kidding myself on what will take to reach and sustain power for the fastest/straightest events I want try against the elite balloon boys, so
Alan I think Peel may eventually need like160 hp/125 torq. so need to pow wow with you and online and vendors about methanol fueling. May have to get with a 3D printer to produce a fuel needle profile or hand file like I've done on propane 'carb'. While this thread is on how to get power and which version is best for what, I'm into what happens with more than enough torque and hp so my focus on is heat handling and special tire construction. The hot rods I've had were not top end machines but hard accelerators so preventing whiplash is another concern no many think about unless they experienced it. Once craft performance reaches some threshold pilot tolerance can be the limiting factor and engine isolation sure helps. I think my illness stems form my 1st swing set trying to do a full loop on it and my fear of flying from jumping off top of swing set with cereal box Superman T-shirt to also understand truth in TV advertising. I know I'm racing toward death so want a good thrill ride.
Alan I think Peel may eventually need like160 hp/125 torq. so need to pow wow with you and online and vendors about methanol fueling. May have to get with a 3D printer to produce a fuel needle profile or hand file like I've done on propane 'carb'. While this thread is on how to get power and which version is best for what, I'm into what happens with more than enough torque and hp so my focus on is heat handling and special tire construction. The hot rods I've had were not top end machines but hard accelerators so preventing whiplash is another concern no many think about unless they experienced it. Once craft performance reaches some threshold pilot tolerance can be the limiting factor and engine isolation sure helps. I think my illness stems form my 1st swing set trying to do a full loop on it and my fear of flying from jumping off top of swing set with cereal box Superman T-shirt to also understand truth in TV advertising. I know I'm racing toward death so want a good thrill ride.
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As most can't imagine drag racing into turns, here's bee line sense of scale of behavior to put up with. Kenny Dreer is into this now so may have to re-open that connection. Power to mass is the real equation then traction.
http://www.youtube.com/watch?v=A6zedQs4ykM
http://www.youtube.com/watch?v=waoDr6pxhY4
http://www.youtube.com/watch?v=NteZ0PX1Xtw
http://www.youtube.com/watch?v=kZNgxUfWvEM
http://www.youtube.com/watch?v=fI_GvCl8ei8
http://www.youtube.com/watch?v=A6zedQs4ykM
http://www.youtube.com/watch?v=waoDr6pxhY4
http://www.youtube.com/watch?v=NteZ0PX1Xtw
http://www.youtube.com/watch?v=kZNgxUfWvEM
http://www.youtube.com/watch?v=fI_GvCl8ei8
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