Horsepower versus torque

Discussion in 'General Discussion' started by Frank, Jul 20, 2006.

  1. ShootMyMonkey

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    Under the assumption that all else is equal. But if you're given the option of various types of powertrains, that isn't the case.
     
  2. Frank

    Frank Certified not a majority
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    From another forum, a comparison of the same cars based on the closest kilogram per Kilowatt ratio available. All in metric units.

    Code:
    Weight kW   0-100 Top  Fuel      Car
    
    1030   66   10.7  175  diesel    Toyota Yaris 1.4 D4-D Linea Terra
    1000   64   13.1  170  gasoline  Toyota Yaris 1.3 16v VVT-i Linea Sol
    
    1215   78   11.2  186  diesel    Renault Mégane Sedan 1.5 dCi 105 Privilège
    1120   72   12.5  183  gasoline  Renault Mégane 1.4 16V Accès
     
    1245   80   10.8  186  diesel    Mercedes-Benz A 180 CDI Avantgarde
    1095   70   12.6  175  gasoline  Mercedes-Benz A 150 Classic
     
    1718   110  11.3  180  diesel    Hyundai Santa Fe 2.2 CRDi VGT 2WD AV
    1547   99   12.2  174  gasoline  Hyundai Santa Fe 2.0i 16V 2WD AV
    
    1263   81   11.5  183  diesel    Ford Focus 1.6 TDCi 109pk Trend Automatic
    1154   74   10.9  185  gasoline  Ford Focus 1.6 16V Futura
    
    1244   80   12.4  192  diesel    Citroen C4 Coupé 1.6 HDi 16V 110pk VTR
    1249   80   14.6  188  gasoline  Citroen C4 1.6 16V Ligne Prestige
    The Ford diesel is the only one with an automatic transmission.


    Edit: the kg/kW header should read simply kW. Corrected.
     
    #102 Frank, Jul 22, 2006
    Last edited by a moderator: Jul 22, 2006
  3. Frank

    Frank Certified not a majority
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    Nah, there are actually plenty cars who go 60 mph in first gear. There are much less who can come close to 3 seconds while having to shift. But I don't know what I would count as the best performance. Having to shift and still be that fast is VERY good.
     
  4. RobertR1

    RobertR1 Pro
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    A good driver can powershift a car within a 1/10-2/10 of a second. It's not that big of a deal really. Controlling wheelspin during launch are much more critical. Also, a street 0-60time is a lot slower than mag tests due to less traction available.
     
  5. Frank

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    Yes, I agree. The better heel-and-toe work combined with revving the engine as high as it needs to go will make you accelerate up to a quarter faster than the factory figures. But not many people know how to do that.


    Then again, with those diesel engines you have less reason to do so, and they only burn about half the fuel.
     
  6. MPI

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    What the hell is heel-and-toe good for on the quarter mile?

    Bollocks. Diesels by their nature have a narrower powerband overall compared to petrol engines, all else equal.

    Why do you think manual diesels often comes in 6-speed? Or that diesel lorries/buses have 1152 gears? Now, I think TDI's have come a long way in the past decade, but all this praise is getting a little out of hand...
     
  7. Frank

    Frank Certified not a majority
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    For enduring less stall while shifting. It increases your score.

    Well, for starters, non-turbocharged diesels have almost gone the way of the dodo by now in consumer cars. And second, those turbo-diesels are that good.

    Then again, you might state that turbocharged gasoline engines are even better. But they are limited to the high-end segment here in Europe, because they consume three or four times the amount of fuel of a comparable turbo-diesel engine. And they're not that much better.
     
  8. MPI

    MPI
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    Do you even know what heel'n'toe is?

    And yet they have 6 gears, like the 170bhp Golf TDI... Why is that? Inquiring minds want to know...

    Now you're just pulling crap out of your ass... three or four times? Now, diesels ARE more efficient, but COME ON...
     
  9. RobertR1

    RobertR1 Pro
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    Heel and toe is a downshifting technique not upshifting. Power shifting = staying on the gas in between shifts instead of letting up. You can't really do on high HP cars though as the surge of power from powershifting will create too much wheel spin. The point is to lunge/launch the car forward to make up the time lost in shifting. The over rev from powershifting gives it another launch from the speed the vehicle is already traveling at. Necessary disclaimers about oversteer apply :)
     
  10. Frank

    Frank Certified not a majority
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    Well, yes, I think so. Keep pressing the gas pedal while braking and clutching. Which you do to reduce the time it takes your car to get back up to speed after shifting gear. Right?

    Most recent cars have six gears. It increases the fuel efficiency when cruising on the highway, and it allows the shifts to be a bit shorter, thereby increasing maximum acceleration.

    Do you have different figures?
     
  11. Frank

    Frank Certified not a majority
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    Ah, yes. Stupid of me. Yes, heel-and-toe only works when downshifting. Sorry about that.
     
  12. RobertR1

    RobertR1 Pro
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    Yes but why would you be braking when you're tyring to 0-60, 1/4mile? Heel toe is only for downshifting to match the revs (bring your rpms up to where the downshift would bring them at) when you're coming into a corner to not upset the balance of the car.

    Edit: nm, I see you just posted right above :) no worries.
     
  13. thorny

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    Actually it's interesting how similar the fuel consumption figures can be between modern petrol and diesel engines. They can be very similar unless you need a big car (from a European perspective):

    Toyota Argo 1.0 61 mpg, 1.4 diesel 68 mpg. 11% less efficient
    Golf 1.4TSI 39 mpg, 2.0 tdi diesel 49 mpg. 20% less efficient
    Honda Civic 1.8vtec 44 mpg, diesel 55.4. 20% less efficient
    BMW 3 Series 330i 32.5 mpg, 330d diesel 43.5. 25% less efficient

    In all case except the Civic the petrol has a faster 0-60 time.
     
  14. scooby_dooby

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    lol, Heel-Toe is when you're braking!

    But, on the topic of powershifting...it's bad..mmkay?? It works damn well, but if you have any love for your drivetrain you won't do it.
     
    #114 scooby_dooby, Jul 23, 2006
    Last edited by a moderator: Jul 23, 2006
  15. RobertR1

    RobertR1 Pro
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    My ex-flywheels agree with you :)
     
  16. KimB

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    Well hell, man, if you're driving for max performance, you can't care much about keeping your car in good shape for long without maintenance.
     
  17. Frank

    Frank Certified not a majority
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    What does it mean? I don't understand. Can you explain that a bit better?


    Anyway, while turbocharged gasoline engines have factory mileage figures which aren't that bad, to have a comparable mileage figure yourself, you should drive it really gentle. In which case, I would wonder why you bought such an engine in the first place. Otherwise, you could expect 6-10 miles per gallon.
     
    #117 Frank, Jul 23, 2006
    Last edited by a moderator: Jul 23, 2006
  18. RussSchultz

    RussSchultz Professional Malcontent
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    DiGuru,

    Where do you pull this stuff from?

    I have a turbo-charged gasoline engine (250 hp), and I get well within the EPA estimates.

    18 city, 26 highway is what the sticker says. On my normal day/day driving, I get about 23 if I'm gentle, and about 22 when I jackrabbit around. And I live in a very hilly city. On a full tank on the freeway, I get better than 26.
     
  19. Frank

    Frank Certified not a majority
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    Ok, that sounds pretty good. In that case I'm sorely mistaken.

    It might be the difference between using them to commute every day, and test-driving them. Because I (and many journalists) are close to or below 8 MPG when they get to drive such a car for a few hours or days.
     
  20. RussSchultz

    RussSchultz Professional Malcontent
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    Yes, if you put the computer on instantaneous mileage, and you accelerate from 0-60 in 6 seconds, you see your mileage drop into the single digits.

    Its kinda hard to do a full tank of gas that way, though.
     
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