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Acceleration of a Spada

Discussion in 'Technical and Troubleshooting Torque' started by En, Oct 28, 2005.

  1. had a test ride of a spada today and couldn't really put my finger on weather it has a better acceleration that a 4cyl. anyone out there that an help me on this one?

    and whats the 'stroke' from a 4 stroke mean?

  2. A 4 stroke engine does this:
    1. Intake stroke - Piston moves down and the fuel is sucked in/injected.
    2. Compression stroke - Piston moves up and compresses the air and fuel.
    3. Power stroke - The mixture is ignited, pushing the piston down and providing power.
    4. Exhaust stroke - The piston rises back up, pushing the exhaust gas out.

    A 2 stroke engine accomplishes this in one rise and one fall of the piston rather than 4.

    Edit: So, a stroke is a movement of a piston, either up or down.

  3. Otherwise known as 1-Induction, 2-Compression, 3-Ignition, 4-Exaust. Otherwise known as 1-Suck, 2-Squeese, 3-Bang, 4-Blow.

    Fuel mixture goes in, gets squased, spark plags blow it up and then it gets pushed ut your exaust pipe.

    Two stokes have no valves, thus no cam (makes it more efficient) and replaces them with pots in the cylinder. The position of the piston means that only the induction or exaust port is unexposed at any given time. As exaust is expelled, new fuel is taken though the bottom and lubricates the engine as it goes (thus 2-stroke oil rather than a sump). This is a really simple explanation but without being able to draw picures it's near impossible to describe how engines work.

    To answer the real question, a V-twin has the same engine capacity as a Four cyl, but halve the number of cylinders. Therefore the cylinders must be twice the size (engine capacity refers to the quantity of air fuel mixture that the cylinders can hold and burn per revolution). because of the larger cylinder size on a v-twin, you get more torque (pulling power) than a four but less kilowatts (actual power) than a four. At the lower end of the rev range a twin will kill a four and the reverse is true after 8000-10,000 rpm.
  4. I noticed something similar on the Twin.
    I called it "an explosion of the mind".
    :D :D :D :D :D
  5. Hey Dan, you didn't include a link to show how Netrider works.....:D
  6. :LOL: Up to your usual standard, seany!
  7. Typically a 4-cylinder should produce more power/torque than a twin and should therefore be faster however there are other things that affect acceleration. Gearing, particularly the drive sprockets used will have a significant effect (you can trade top-speed for acceleration and vice-versa), the weight of the bike (and rider) will also have a major affect on acceleration. Wouldn't worry about it too much, you shouldn't have any problems keeping up with traffic on a Spada.

    Of course when I saw the title of this thread I had hoped it was a link to a video of someone pushing a Spada off a cliff. :( :p
  8. Wouldn't a TWIN of equal capacity and equivalent tune Produce more Torque then a FOUR. I'm am almost positive of that but i could be wrong. Yes a FOUR is going to have more Ponies but a Twin would surely have more Torque with all things even.

    Too put it in it's most basic form:

    Torque = Acceleration (Turning Force)
    HP/KW/PS = Top End Speed (yes i know gearing, aerodynamics all play a part, blah blah blah)

  9. Most people don't understand the relationship between torque and power.

    To put it really simply:
    Power = Torque x RPM x multiplier.

    It's that simple. So as far as I understand it, it's not that torque is acceleration and power is top speed, torque is basically the brute strength of the engine, where power is the work it can do over time.

    Edit: To put this in the real world, cars are a good example. A Bentley Continental has a 6.7l V8 that produces 300kw and over 800nm of torque. Now compare this to a Porsche GT3 RS which has a 3.6l 6 producing 313kw but only 390nm of torque. If these engines were put in the same car, do you thing the Bentley would accelerate twice as fast because it has twice the torque? Nup, but it'd sure tow really well.

  10. 4cl is deffinatly alot faster than the spadas twin, they really do run out of puff pretty quick...With a twin of equal capacity the torque normailly comes on sooner, which gives them there torquey feeling but the peak torque is normally lower.
  11. Super photo, ZXR!!!
  12. CBR250RR
    Max Torque:
    2.4kg-m @ 11,500

    Max Torque:
    2.6kg-m @ 9,000

    Max Torque:
    2.4 kg-m @ 8500
  13. Well, think it through. Can you think of a reason why an engine with fewer cylinders will generate more torque than an engine with more cylinders?
  14. i personally believe - more power = more speed. full stop :)

    since power is the amount of energy you can transfer to the vehicle, more power transfer means more speed. the only requirement for this is that you have to be in the power band i.e. you need to output as close to peak power as possible

    and the difference between torque and power is all to do with gearing.. same reason why if you change sprockets you're trading off between torque and power at the wheels.

    of course, there's other issues such as weight and redline that come into it too :)
  15. with twins the power comes on sooner and runs out quicker up the rev range hance that initial rush that seems to propel you through the rev range before it runs out of revs.
    In 4's the power comes on higher up in the rev range and comes in a bit of a rush.
    Twins have more linear power through the revs 4's tend to have the power higher up the rev range.
    You can therefore sit in a higher gear on a twin and accelerate quicker out of a corner then say in a 4 of equal capacity the 4 will then speed off due to the higher power output higher up.
    Of course as others have said gearing and sprockets etc all have some effect.
  16. smee, you must explain that chopper-thingy on the last page of your photo collection one day! A keg in front of the engine???
  17. Suzuki Bandit (4-cylinder)
    Max Torque:
    2.7kgm @ 10,000rpm

    So as others have pointed out v-twins often appear to have more torque since it comes on at lower revs but the fact remains that the greater the number of cylinders the greater the combustion efficiency so more power and/or torque can be produced. Obviously at some point increased frictional losses (from the greater number of moving parts) will counter this gain but you're going to need a lot more than 4 for this to happen.